From d38fab605c66778a8ddfbe2ac66c3a3eb7b2295a Mon Sep 17 00:00:00 2001
From: Richard Chang <richardycc@google.com>
Date: Mon, 1 Dec 2025 18:47:48 +0900
Subject: zram: introduce compressed data writeback

Patch series "zram: introduce compressed data writeback", v2.

As writeback becomes more common there is another shortcoming that needs
to be addressed - compressed data writeback.  Currently zram does
uncompressed data writeback which is not optimal due to potential CPU and
battery wastage.  This series changes suboptimal uncompressed writeback to
a more optimal compressed data writeback.


This patch (of 7):

zram stores all written back slots raw, which implies that during
writeback zram first has to decompress slots (except for ZRAM_HUGE slots,
which are raw already).  The problem with this approach is that not every
written back page gets read back (either via read() or via page-fault),
which means that zram basically wastes CPU cycles and battery
decompressing such slots.  This changes with introduction of decompression
on demand, in other words decompression on read()/page-fault.

One caveat of decompression on demand is that async read is completed in
IRQ context, while zram decompression is sleepable.  To workaround this,
read-back decompression is offloaded to a preemptible context - system
high-prio work-queue.

At this point compressed writeback is still disabled, a follow up patch
will introduce a new device attribute which will make it possible to
toggle compressed writeback per-device.

[senozhatsky@chromium.org: rewrote original implementation]
Link: https://lkml.kernel.org/r/20251201094754.4149975-1-senozhatsky@chromium.org
Link: https://lkml.kernel.org/r/20251201094754.4149975-2-senozhatsky@chromium.org
Signed-off-by: Richard Chang <richardycc@google.com>
Co-developed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Suggested-by: Minchan Kim <minchan@google.com>
Suggested-by: Brian Geffon <bgeffon@google.com>
Cc: David Stevens <stevensd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/block/zram/zram_drv.c | 279 ++++++++++++++++++++++++++++++++++--------
 drivers/block/zram/zram_drv.h |   1 +
 2 files changed, 227 insertions(+), 53 deletions(-)

(limited to 'drivers')

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 5759823d6314..6263d300312e 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -57,9 +57,6 @@ static size_t huge_class_size;
 static const struct block_device_operations zram_devops;
 
 static void zram_free_page(struct zram *zram, size_t index);
-static int zram_read_from_zspool(struct zram *zram, struct page *page,
-				 u32 index);
-
 #define slot_dep_map(zram, index) (&(zram)->table[(index)].dep_map)
 
 static void zram_slot_lock_init(struct zram *zram, u32 index)
@@ -502,6 +499,10 @@ out:
 #ifdef CONFIG_ZRAM_WRITEBACK
 #define INVALID_BDEV_BLOCK		(~0UL)
 
+static int read_from_zspool_raw(struct zram *zram, struct page *page,
+				u32 index);
+static int read_from_zspool(struct zram *zram, struct page *page, u32 index);
+
 struct zram_wb_ctl {
 	/* idle list is accessed only by the writeback task, no concurency */
 	struct list_head idle_reqs;
@@ -522,6 +523,22 @@ struct zram_wb_req {
 	struct list_head entry;
 };
 
+struct zram_rb_req {
+	struct work_struct work;
+	struct zram *zram;
+	struct page *page;
+	/* The read bio for backing device */
+	struct bio *bio;
+	unsigned long blk_idx;
+	union {
+		/* The original bio to complete (async read) */
+		struct bio *parent;
+		/* error status (sync read) */
+		int error;
+	};
+	u32 index;
+};
+
 static ssize_t writeback_limit_enable_store(struct device *dev,
 					    struct device_attribute *attr,
 					    const char *buf, size_t len)
@@ -780,18 +797,6 @@ static void zram_release_bdev_block(struct zram *zram, unsigned long blk_idx)
 	atomic64_dec(&zram->stats.bd_count);
 }
 
-static void read_from_bdev_async(struct zram *zram, struct page *page,
-			unsigned long entry, struct bio *parent)
-{
-	struct bio *bio;
-
-	bio = bio_alloc(zram->bdev, 1, parent->bi_opf, GFP_NOIO);
-	bio->bi_iter.bi_sector = entry * (PAGE_SIZE >> 9);
-	__bio_add_page(bio, page, PAGE_SIZE, 0);
-	bio_chain(bio, parent);
-	submit_bio(bio);
-}
-
 static void release_wb_req(struct zram_wb_req *req)
 {
 	__free_page(req->page);
@@ -886,8 +891,9 @@ static void zram_account_writeback_submit(struct zram *zram)
 
 static int zram_writeback_complete(struct zram *zram, struct zram_wb_req *req)
 {
-	u32 index = req->pps->index;
-	int err;
+	u32 size, index = req->pps->index;
+	int err, prio;
+	bool huge;
 
 	err = blk_status_to_errno(req->bio.bi_status);
 	if (err) {
@@ -914,9 +920,27 @@ static int zram_writeback_complete(struct zram *zram, struct zram_wb_req *req)
 		goto out;
 	}
 
+	if (zram->wb_compressed) {
+		/*
+		 * ZRAM_WB slots get freed, we need to preserve data required
+		 * for read decompression.
+		 */
+		size = zram_get_obj_size(zram, index);
+		prio = zram_get_priority(zram, index);
+		huge = zram_test_flag(zram, index, ZRAM_HUGE);
+	}
+
 	zram_free_page(zram, index);
 	zram_set_flag(zram, index, ZRAM_WB);
 	zram_set_handle(zram, index, req->blk_idx);
+
+	if (zram->wb_compressed) {
+		if (huge)
+			zram_set_flag(zram, index, ZRAM_HUGE);
+		zram_set_obj_size(zram, index, size);
+		zram_set_priority(zram, index, prio);
+	}
+
 	atomic64_inc(&zram->stats.pages_stored);
 
 out:
@@ -1050,7 +1074,11 @@ static int zram_writeback_slots(struct zram *zram,
 		 */
 		if (!zram_test_flag(zram, index, ZRAM_PP_SLOT))
 			goto next;
-		if (zram_read_from_zspool(zram, req->page, index))
+		if (zram->wb_compressed)
+			err = read_from_zspool_raw(zram, req->page, index);
+		else
+			err = read_from_zspool(zram, req->page, index);
+		if (err)
 			goto next;
 		zram_slot_unlock(zram, index);
 
@@ -1313,24 +1341,140 @@ release_init_lock:
 	return ret;
 }
 
-struct zram_work {
-	struct work_struct work;
-	struct zram *zram;
-	unsigned long entry;
-	struct page *page;
-	int error;
-};
+static int decompress_bdev_page(struct zram *zram, struct page *page, u32 index)
+{
+	struct zcomp_strm *zstrm;
+	unsigned int size;
+	int ret, prio;
+	void *src;
+
+	zram_slot_lock(zram, index);
+	/* Since slot was unlocked we need to make sure it's still ZRAM_WB */
+	if (!zram_test_flag(zram, index, ZRAM_WB)) {
+		zram_slot_unlock(zram, index);
+		/* We read some stale data, zero it out */
+		memset_page(page, 0, 0, PAGE_SIZE);
+		return -EIO;
+	}
+
+	if (zram_test_flag(zram, index, ZRAM_HUGE)) {
+		zram_slot_unlock(zram, index);
+		return 0;
+	}
+
+	size = zram_get_obj_size(zram, index);
+	prio = zram_get_priority(zram, index);
 
-static void zram_sync_read(struct work_struct *work)
+	zstrm = zcomp_stream_get(zram->comps[prio]);
+	src = kmap_local_page(page);
+	ret = zcomp_decompress(zram->comps[prio], zstrm, src, size,
+			       zstrm->local_copy);
+	if (!ret)
+		copy_page(src, zstrm->local_copy);
+	kunmap_local(src);
+	zcomp_stream_put(zstrm);
+	zram_slot_unlock(zram, index);
+
+	return ret;
+}
+
+static void zram_deferred_decompress(struct work_struct *w)
 {
-	struct zram_work *zw = container_of(work, struct zram_work, work);
+	struct zram_rb_req *req = container_of(w, struct zram_rb_req, work);
+	struct page *page = bio_first_page_all(req->bio);
+	struct zram *zram = req->zram;
+	u32 index = req->index;
+	int ret;
+
+	ret = decompress_bdev_page(zram, page, index);
+	if (ret)
+		req->parent->bi_status = BLK_STS_IOERR;
+
+	/* Decrement parent's ->remaining */
+	bio_endio(req->parent);
+	bio_put(req->bio);
+	kfree(req);
+}
+
+static void zram_async_read_endio(struct bio *bio)
+{
+	struct zram_rb_req *req = bio->bi_private;
+	struct zram *zram = req->zram;
+
+	if (bio->bi_status) {
+		req->parent->bi_status = bio->bi_status;
+		bio_endio(req->parent);
+		bio_put(bio);
+		kfree(req);
+		return;
+	}
+
+	/*
+	 * NOTE: zram_async_read_endio() is not exactly right place for this.
+	 * Ideally, we need to do it after ZRAM_WB check, but this requires
+	 * us to use wq path even on systems that don't enable compressed
+	 * writeback, because we cannot take slot-lock in the current context.
+	 *
+	 * Keep the existing behavior for now.
+	 */
+	if (zram->wb_compressed == false) {
+		/* No decompression needed, complete the parent IO */
+		bio_endio(req->parent);
+		bio_put(bio);
+		kfree(req);
+		return;
+	}
+
+	/*
+	 * zram decompression is sleepable, so we need to deffer it to
+	 * a preemptible context.
+	 */
+	INIT_WORK(&req->work, zram_deferred_decompress);
+	queue_work(system_highpri_wq, &req->work);
+}
+
+static void read_from_bdev_async(struct zram *zram, struct page *page,
+				 u32 index, unsigned long blk_idx,
+				 struct bio *parent)
+{
+	struct zram_rb_req *req;
+	struct bio *bio;
+
+	req = kmalloc(sizeof(*req), GFP_NOIO);
+	if (!req)
+		return;
+
+	bio = bio_alloc(zram->bdev, 1, parent->bi_opf, GFP_NOIO);
+	if (!bio) {
+		kfree(req);
+		return;
+	}
+
+	req->zram = zram;
+	req->index = index;
+	req->blk_idx = blk_idx;
+	req->bio = bio;
+	req->parent = parent;
+
+	bio->bi_iter.bi_sector = blk_idx * (PAGE_SIZE >> 9);
+	bio->bi_private = req;
+	bio->bi_end_io = zram_async_read_endio;
+
+	__bio_add_page(bio, page, PAGE_SIZE, 0);
+	bio_inc_remaining(parent);
+	submit_bio(bio);
+}
+
+static void zram_sync_read(struct work_struct *w)
+{
+	struct zram_rb_req *req = container_of(w, struct zram_rb_req, work);
 	struct bio_vec bv;
 	struct bio bio;
 
-	bio_init(&bio, zw->zram->bdev, &bv, 1, REQ_OP_READ);
-	bio.bi_iter.bi_sector = zw->entry * (PAGE_SIZE >> 9);
-	__bio_add_page(&bio, zw->page, PAGE_SIZE, 0);
-	zw->error = submit_bio_wait(&bio);
+	bio_init(&bio, req->zram->bdev, &bv, 1, REQ_OP_READ);
+	bio.bi_iter.bi_sector = req->blk_idx * (PAGE_SIZE >> 9);
+	__bio_add_page(&bio, req->page, PAGE_SIZE, 0);
+	req->error = submit_bio_wait(&bio);
 }
 
 /*
@@ -1338,39 +1482,42 @@ static void zram_sync_read(struct work_struct *work)
  * chained IO with parent IO in same context, it's a deadlock. To avoid that,
  * use a worker thread context.
  */
-static int read_from_bdev_sync(struct zram *zram, struct page *page,
-				unsigned long entry)
+static int read_from_bdev_sync(struct zram *zram, struct page *page, u32 index,
+			       unsigned long blk_idx)
 {
-	struct zram_work work;
+	struct zram_rb_req req;
 
-	work.page = page;
-	work.zram = zram;
-	work.entry = entry;
+	req.page = page;
+	req.zram = zram;
+	req.blk_idx = blk_idx;
 
-	INIT_WORK_ONSTACK(&work.work, zram_sync_read);
-	queue_work(system_dfl_wq, &work.work);
-	flush_work(&work.work);
-	destroy_work_on_stack(&work.work);
+	INIT_WORK_ONSTACK(&req.work, zram_sync_read);
+	queue_work(system_dfl_wq, &req.work);
+	flush_work(&req.work);
+	destroy_work_on_stack(&req.work);
 
-	return work.error;
+	if (req.error || zram->wb_compressed == false)
+		return req.error;
+
+	return decompress_bdev_page(zram, page, index);
 }
 
-static int read_from_bdev(struct zram *zram, struct page *page,
-			unsigned long entry, struct bio *parent)
+static int read_from_bdev(struct zram *zram, struct page *page, u32 index,
+			  unsigned long blk_idx, struct bio *parent)
 {
 	atomic64_inc(&zram->stats.bd_reads);
 	if (!parent) {
 		if (WARN_ON_ONCE(!IS_ENABLED(ZRAM_PARTIAL_IO)))
 			return -EIO;
-		return read_from_bdev_sync(zram, page, entry);
+		return read_from_bdev_sync(zram, page, index, blk_idx);
 	}
-	read_from_bdev_async(zram, page, entry, parent);
+	read_from_bdev_async(zram, page, index, blk_idx, parent);
 	return 0;
 }
 #else
 static inline void reset_bdev(struct zram *zram) {};
-static int read_from_bdev(struct zram *zram, struct page *page,
-			unsigned long entry, struct bio *parent)
+static int read_from_bdev(struct zram *zram, struct page *page, u32 index,
+			  unsigned long blk_idx, struct bio *parent)
 {
 	return -EIO;
 }
@@ -1977,12 +2124,37 @@ static int read_compressed_page(struct zram *zram, struct page *page, u32 index)
 	return ret;
 }
 
+#if defined CONFIG_ZRAM_WRITEBACK
+static int read_from_zspool_raw(struct zram *zram, struct page *page, u32 index)
+{
+	struct zcomp_strm *zstrm;
+	unsigned long handle;
+	unsigned int size;
+	void *src;
+
+	handle = zram_get_handle(zram, index);
+	size = zram_get_obj_size(zram, index);
+
+	/*
+	 * We need to get stream just for ->local_copy buffer, in
+	 * case if object spans two physical pages. No decompression
+	 * takes place here, as we read raw compressed data.
+	 */
+	zstrm = zcomp_stream_get(zram->comps[ZRAM_PRIMARY_COMP]);
+	src = zs_obj_read_begin(zram->mem_pool, handle, zstrm->local_copy);
+	memcpy_to_page(page, 0, src, size);
+	zs_obj_read_end(zram->mem_pool, handle, src);
+	zcomp_stream_put(zstrm);
+
+	return 0;
+}
+#endif
+
 /*
  * Reads (decompresses if needed) a page from zspool (zsmalloc).
  * Corresponding ZRAM slot should be locked.
  */
-static int zram_read_from_zspool(struct zram *zram, struct page *page,
-				 u32 index)
+static int read_from_zspool(struct zram *zram, struct page *page, u32 index)
 {
 	if (zram_test_flag(zram, index, ZRAM_SAME) ||
 	    !zram_get_handle(zram, index))
@@ -2002,7 +2174,7 @@ static int zram_read_page(struct zram *zram, struct page *page, u32 index,
 	zram_slot_lock(zram, index);
 	if (!zram_test_flag(zram, index, ZRAM_WB)) {
 		/* Slot should be locked through out the function call */
-		ret = zram_read_from_zspool(zram, page, index);
+		ret = read_from_zspool(zram, page, index);
 		zram_slot_unlock(zram, index);
 	} else {
 		unsigned long blk_idx = zram_get_handle(zram, index);
@@ -2012,7 +2184,7 @@ static int zram_read_page(struct zram *zram, struct page *page, u32 index,
 		 * device.
 		 */
 		zram_slot_unlock(zram, index);
-		ret = read_from_bdev(zram, page, blk_idx, parent);
+		ret = read_from_bdev(zram, page, index, blk_idx, parent);
 	}
 
 	/* Should NEVER happen. Return bio error if it does. */
@@ -2273,7 +2445,7 @@ static int recompress_slot(struct zram *zram, u32 index, struct page *page,
 	if (comp_len_old < threshold)
 		return 0;
 
-	ret = zram_read_from_zspool(zram, page, index);
+	ret = read_from_zspool(zram, page, index);
 	if (ret)
 		return ret;
 
@@ -2960,6 +3132,7 @@ static int zram_add(void)
 	init_rwsem(&zram->init_lock);
 #ifdef CONFIG_ZRAM_WRITEBACK
 	zram->wb_batch_size = 32;
+	zram->wb_compressed = false;
 #endif
 
 	/* gendisk structure */
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index c6d94501376c..72fdf66c78ab 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -128,6 +128,7 @@ struct zram {
 #ifdef CONFIG_ZRAM_WRITEBACK
 	struct file *backing_dev;
 	bool wb_limit_enable;
+	bool wb_compressed;
 	u32 wb_batch_size;
 	u64 bd_wb_limit;
 	struct block_device *bdev;
-- 
cgit v1.2.3


From 4c1d61389e8e4307449eb2ebad997241cbf08fef Mon Sep 17 00:00:00 2001
From: Richard Chang <richardycc@google.com>
Date: Mon, 1 Dec 2025 18:47:49 +0900
Subject: zram: introduce writeback_compressed device attribute

Introduce witeback_compressed device attribute to toggle compressed
writeback (decompression on demand) feature.

[senozhatsky@chromium.org: rewrote original patch, added documentation]
Link: https://lkml.kernel.org/r/20251201094754.4149975-3-senozhatsky@chromium.org
Signed-off-by: Richard Chang <richardycc@google.com>
Co-developed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Brian Geffon <bgeffon@google.com>
Cc: David Stevens <stevensd@google.com>
Cc: Minchan Kim <minchan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/block/zram/zram_drv.c | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

(limited to 'drivers')

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 6263d300312e..3cc03c3f7389 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -539,6 +539,42 @@ struct zram_rb_req {
 	u32 index;
 };
 
+static ssize_t writeback_compressed_store(struct device *dev,
+					  struct device_attribute *attr,
+					  const char *buf, size_t len)
+{
+	struct zram *zram = dev_to_zram(dev);
+	bool val;
+
+	if (kstrtobool(buf, &val))
+		return -EINVAL;
+
+	down_write(&zram->init_lock);
+	if (init_done(zram)) {
+		up_write(&zram->init_lock);
+		return -EBUSY;
+	}
+
+	zram->wb_compressed = val;
+	up_write(&zram->init_lock);
+
+	return len;
+}
+
+static ssize_t writeback_compressed_show(struct device *dev,
+					 struct device_attribute *attr,
+					 char *buf)
+{
+	bool val;
+	struct zram *zram = dev_to_zram(dev);
+
+	down_read(&zram->init_lock);
+	val = zram->wb_compressed;
+	up_read(&zram->init_lock);
+
+	return sysfs_emit(buf, "%d\n", val);
+}
+
 static ssize_t writeback_limit_enable_store(struct device *dev,
 					    struct device_attribute *attr,
 					    const char *buf, size_t len)
@@ -3048,6 +3084,7 @@ static DEVICE_ATTR_WO(writeback);
 static DEVICE_ATTR_RW(writeback_limit);
 static DEVICE_ATTR_RW(writeback_limit_enable);
 static DEVICE_ATTR_RW(writeback_batch_size);
+static DEVICE_ATTR_RW(writeback_compressed);
 #endif
 #ifdef CONFIG_ZRAM_MULTI_COMP
 static DEVICE_ATTR_RW(recomp_algorithm);
@@ -3070,6 +3107,7 @@ static struct attribute *zram_disk_attrs[] = {
 	&dev_attr_writeback_limit.attr,
 	&dev_attr_writeback_limit_enable.attr,
 	&dev_attr_writeback_batch_size.attr,
+	&dev_attr_writeback_compressed.attr,
 #endif
 	&dev_attr_io_stat.attr,
 	&dev_attr_mm_stat.attr,
-- 
cgit v1.2.3


From 910bbb441c004050e188dd8da5071054099e592c Mon Sep 17 00:00:00 2001
From: Sergey Senozhatsky <senozhatsky@chromium.org>
Date: Mon, 1 Dec 2025 18:47:51 +0900
Subject: zram: move bd_stat to writeback section

Move bd_stat function and attribute declaration to
existing CONFIG_WRITEBACK ifdef-sections.

Link: https://lkml.kernel.org/r/20251201094754.4149975-5-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Brian Geffon <bgeffon@google.com>
Cc: David Stevens <stevensd@google.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Richard Chang <richardycc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/block/zram/zram_drv.c | 48 +++++++++++++++++++------------------------
 1 file changed, 21 insertions(+), 27 deletions(-)

(limited to 'drivers')

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 3cc03c3f7389..1a0f550219b1 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -539,6 +539,24 @@ struct zram_rb_req {
 	u32 index;
 };
 
+#define FOUR_K(x) ((x) * (1 << (PAGE_SHIFT - 12)))
+static ssize_t bd_stat_show(struct device *dev, struct device_attribute *attr,
+			    char *buf)
+{
+	struct zram *zram = dev_to_zram(dev);
+	ssize_t ret;
+
+	down_read(&zram->init_lock);
+	ret = sysfs_emit(buf,
+			 "%8llu %8llu %8llu\n",
+			 FOUR_K((u64)atomic64_read(&zram->stats.bd_count)),
+			 FOUR_K((u64)atomic64_read(&zram->stats.bd_reads)),
+			 FOUR_K((u64)atomic64_read(&zram->stats.bd_writes)));
+	up_read(&zram->init_lock);
+
+	return ret;
+}
+
 static ssize_t writeback_compressed_store(struct device *dev,
 					  struct device_attribute *attr,
 					  const char *buf, size_t len)
@@ -1976,28 +1994,8 @@ static ssize_t mm_stat_show(struct device *dev,
 	return ret;
 }
 
-#ifdef CONFIG_ZRAM_WRITEBACK
-#define FOUR_K(x) ((x) * (1 << (PAGE_SHIFT - 12)))
-static ssize_t bd_stat_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
-{
-	struct zram *zram = dev_to_zram(dev);
-	ssize_t ret;
-
-	down_read(&zram->init_lock);
-	ret = sysfs_emit(buf,
-			"%8llu %8llu %8llu\n",
-			FOUR_K((u64)atomic64_read(&zram->stats.bd_count)),
-			FOUR_K((u64)atomic64_read(&zram->stats.bd_reads)),
-			FOUR_K((u64)atomic64_read(&zram->stats.bd_writes)));
-	up_read(&zram->init_lock);
-
-	return ret;
-}
-#endif
-
 static ssize_t debug_stat_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
+			       struct device_attribute *attr, char *buf)
 {
 	int version = 1;
 	struct zram *zram = dev_to_zram(dev);
@@ -2015,9 +2013,6 @@ static ssize_t debug_stat_show(struct device *dev,
 
 static DEVICE_ATTR_RO(io_stat);
 static DEVICE_ATTR_RO(mm_stat);
-#ifdef CONFIG_ZRAM_WRITEBACK
-static DEVICE_ATTR_RO(bd_stat);
-#endif
 static DEVICE_ATTR_RO(debug_stat);
 
 static void zram_meta_free(struct zram *zram, u64 disksize)
@@ -3079,6 +3074,7 @@ static DEVICE_ATTR_WO(mem_used_max);
 static DEVICE_ATTR_WO(idle);
 static DEVICE_ATTR_RW(comp_algorithm);
 #ifdef CONFIG_ZRAM_WRITEBACK
+static DEVICE_ATTR_RO(bd_stat);
 static DEVICE_ATTR_RW(backing_dev);
 static DEVICE_ATTR_WO(writeback);
 static DEVICE_ATTR_RW(writeback_limit);
@@ -3102,6 +3098,7 @@ static struct attribute *zram_disk_attrs[] = {
 	&dev_attr_idle.attr,
 	&dev_attr_comp_algorithm.attr,
 #ifdef CONFIG_ZRAM_WRITEBACK
+	&dev_attr_bd_stat.attr,
 	&dev_attr_backing_dev.attr,
 	&dev_attr_writeback.attr,
 	&dev_attr_writeback_limit.attr,
@@ -3111,9 +3108,6 @@ static struct attribute *zram_disk_attrs[] = {
 #endif
 	&dev_attr_io_stat.attr,
 	&dev_attr_mm_stat.attr,
-#ifdef CONFIG_ZRAM_WRITEBACK
-	&dev_attr_bd_stat.attr,
-#endif
 	&dev_attr_debug_stat.attr,
 #ifdef CONFIG_ZRAM_MULTI_COMP
 	&dev_attr_recomp_algorithm.attr,
-- 
cgit v1.2.3


From 7ad688c0cdc46d01fc46f6d226813715542c531e Mon Sep 17 00:00:00 2001
From: Sergey Senozhatsky <senozhatsky@chromium.org>
Date: Mon, 1 Dec 2025 18:47:52 +0900
Subject: zram: rename zram_free_page()

We don't free page in zram_free_page(), not all slots even have any memory
associated with them (e.g.  ZRAM_SAME).  We free the slot (or reset it),
rename the function accordingly.

Link: https://lkml.kernel.org/r/20251201094754.4149975-6-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Brian Geffon <bgeffon@google.com>
Cc: David Stevens <stevensd@google.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Richard Chang <richardycc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/block/zram/zram_drv.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

(limited to 'drivers')

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 1a0f550219b1..615756d5d05d 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -56,7 +56,7 @@ static size_t huge_class_size;
 
 static const struct block_device_operations zram_devops;
 
-static void zram_free_page(struct zram *zram, size_t index);
+static void zram_slot_free(struct zram *zram, u32 index);
 #define slot_dep_map(zram, index) (&(zram)->table[(index)].dep_map)
 
 static void zram_slot_lock_init(struct zram *zram, u32 index)
@@ -984,7 +984,7 @@ static int zram_writeback_complete(struct zram *zram, struct zram_wb_req *req)
 		huge = zram_test_flag(zram, index, ZRAM_HUGE);
 	}
 
-	zram_free_page(zram, index);
+	zram_slot_free(zram, index);
 	zram_set_flag(zram, index, ZRAM_WB);
 	zram_set_handle(zram, index, req->blk_idx);
 
@@ -2025,7 +2025,7 @@ static void zram_meta_free(struct zram *zram, u64 disksize)
 
 	/* Free all pages that are still in this zram device */
 	for (index = 0; index < num_pages; index++)
-		zram_free_page(zram, index);
+		zram_slot_free(zram, index);
 
 	zs_destroy_pool(zram->mem_pool);
 	vfree(zram->table);
@@ -2057,7 +2057,7 @@ static bool zram_meta_alloc(struct zram *zram, u64 disksize)
 	return true;
 }
 
-static void zram_free_page(struct zram *zram, size_t index)
+static void zram_slot_free(struct zram *zram, u32 index)
 {
 	unsigned long handle;
 
@@ -2256,7 +2256,7 @@ static int write_same_filled_page(struct zram *zram, unsigned long fill,
 				  u32 index)
 {
 	zram_slot_lock(zram, index);
-	zram_free_page(zram, index);
+	zram_slot_free(zram, index);
 	zram_set_flag(zram, index, ZRAM_SAME);
 	zram_set_handle(zram, index, fill);
 	zram_slot_unlock(zram, index);
@@ -2294,7 +2294,7 @@ static int write_incompressible_page(struct zram *zram, struct page *page,
 	kunmap_local(src);
 
 	zram_slot_lock(zram, index);
-	zram_free_page(zram, index);
+	zram_slot_free(zram, index);
 	zram_set_flag(zram, index, ZRAM_HUGE);
 	zram_set_handle(zram, index, handle);
 	zram_set_obj_size(zram, index, PAGE_SIZE);
@@ -2359,7 +2359,7 @@ static int zram_write_page(struct zram *zram, struct page *page, u32 index)
 	zcomp_stream_put(zstrm);
 
 	zram_slot_lock(zram, index);
-	zram_free_page(zram, index);
+	zram_slot_free(zram, index);
 	zram_set_handle(zram, index, handle);
 	zram_set_obj_size(zram, index, comp_len);
 	zram_slot_unlock(zram, index);
@@ -2581,7 +2581,7 @@ static int recompress_slot(struct zram *zram, u32 index, struct page *page,
 	zs_obj_write(zram->mem_pool, handle_new, zstrm->buffer, comp_len_new);
 	zcomp_stream_put(zstrm);
 
-	zram_free_page(zram, index);
+	zram_slot_free(zram, index);
 	zram_set_handle(zram, index, handle_new);
 	zram_set_obj_size(zram, index, comp_len_new);
 	zram_set_priority(zram, index, prio);
@@ -2784,7 +2784,7 @@ static void zram_bio_discard(struct zram *zram, struct bio *bio)
 
 	while (n >= PAGE_SIZE) {
 		zram_slot_lock(zram, index);
-		zram_free_page(zram, index);
+		zram_slot_free(zram, index);
 		zram_slot_unlock(zram, index);
 		atomic64_inc(&zram->stats.notify_free);
 		index++;
@@ -2892,7 +2892,7 @@ static void zram_slot_free_notify(struct block_device *bdev,
 		return;
 	}
 
-	zram_free_page(zram, index);
+	zram_slot_free(zram, index);
 	zram_slot_unlock(zram, index);
 }
 
-- 
cgit v1.2.3


From 0d38260c2a11de147f0c4701b344fdfa6bcdd04c Mon Sep 17 00:00:00 2001
From: Sergey Senozhatsky <senozhatsky@chromium.org>
Date: Mon, 1 Dec 2025 18:47:53 +0900
Subject: zram: switch to guard() for init_lock

Use init_lock guard() in sysfs store/show handlers, in order to simplify
and, more importantly, to modernize the code.

While at it, fix up more coding styles.

Link: https://lkml.kernel.org/r/20251201094754.4149975-7-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Brian Geffon <bgeffon@google.com>
Cc: David Stevens <stevensd@google.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Richard Chang <richardycc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/block/zram/zram_drv.c | 211 +++++++++++++++---------------------------
 1 file changed, 77 insertions(+), 134 deletions(-)

(limited to 'drivers')

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 615756d5d05d..4b8a26c60539 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -360,15 +360,14 @@ static bool page_same_filled(void *ptr, unsigned long *element)
 	return true;
 }
 
-static ssize_t initstate_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
+static ssize_t initstate_show(struct device *dev, struct device_attribute *attr,
+			      char *buf)
 {
 	u32 val;
 	struct zram *zram = dev_to_zram(dev);
 
-	down_read(&zram->init_lock);
+	guard(rwsem_read)(&zram->init_lock);
 	val = init_done(zram);
-	up_read(&zram->init_lock);
 
 	return sysfs_emit(buf, "%u\n", val);
 }
@@ -382,7 +381,8 @@ static ssize_t disksize_show(struct device *dev,
 }
 
 static ssize_t mem_limit_store(struct device *dev,
-		struct device_attribute *attr, const char *buf, size_t len)
+			       struct device_attribute *attr, const char *buf,
+			       size_t len)
 {
 	u64 limit;
 	char *tmp;
@@ -392,15 +392,15 @@ static ssize_t mem_limit_store(struct device *dev,
 	if (buf == tmp) /* no chars parsed, invalid input */
 		return -EINVAL;
 
-	down_write(&zram->init_lock);
+	guard(rwsem_write)(&zram->init_lock);
 	zram->limit_pages = PAGE_ALIGN(limit) >> PAGE_SHIFT;
-	up_write(&zram->init_lock);
 
 	return len;
 }
 
 static ssize_t mem_used_max_store(struct device *dev,
-		struct device_attribute *attr, const char *buf, size_t len)
+				  struct device_attribute *attr,
+				  const char *buf, size_t len)
 {
 	int err;
 	unsigned long val;
@@ -410,12 +410,11 @@ static ssize_t mem_used_max_store(struct device *dev,
 	if (err || val != 0)
 		return -EINVAL;
 
-	down_read(&zram->init_lock);
+	guard(rwsem_read)(&zram->init_lock);
 	if (init_done(zram)) {
 		atomic_long_set(&zram->stats.max_used_pages,
 				zs_get_total_pages(zram->mem_pool));
 	}
-	up_read(&zram->init_lock);
 
 	return len;
 }
@@ -458,12 +457,11 @@ static void mark_idle(struct zram *zram, ktime_t cutoff)
 	}
 }
 
-static ssize_t idle_store(struct device *dev,
-		struct device_attribute *attr, const char *buf, size_t len)
+static ssize_t idle_store(struct device *dev, struct device_attribute *attr,
+			  const char *buf, size_t len)
 {
 	struct zram *zram = dev_to_zram(dev);
 	ktime_t cutoff_time = 0;
-	ssize_t rv = -EINVAL;
 
 	if (!sysfs_streq(buf, "all")) {
 		/*
@@ -476,24 +474,19 @@ static ssize_t idle_store(struct device *dev,
 			cutoff_time = ktime_sub(ktime_get_boottime(),
 					ns_to_ktime(age_sec * NSEC_PER_SEC));
 		else
-			goto out;
+			return -EINVAL;
 	}
 
-	down_read(&zram->init_lock);
+	guard(rwsem_read)(&zram->init_lock);
 	if (!init_done(zram))
-		goto out_unlock;
+		return -EINVAL;
 
 	/*
 	 * A cutoff_time of 0 marks everything as idle, this is the
 	 * "all" behavior.
 	 */
 	mark_idle(zram, cutoff_time);
-	rv = len;
-
-out_unlock:
-	up_read(&zram->init_lock);
-out:
-	return rv;
+	return len;
 }
 
 #ifdef CONFIG_ZRAM_WRITEBACK
@@ -546,13 +539,12 @@ static ssize_t bd_stat_show(struct device *dev, struct device_attribute *attr,
 	struct zram *zram = dev_to_zram(dev);
 	ssize_t ret;
 
-	down_read(&zram->init_lock);
+	guard(rwsem_read)(&zram->init_lock);
 	ret = sysfs_emit(buf,
 			 "%8llu %8llu %8llu\n",
 			 FOUR_K((u64)atomic64_read(&zram->stats.bd_count)),
 			 FOUR_K((u64)atomic64_read(&zram->stats.bd_reads)),
 			 FOUR_K((u64)atomic64_read(&zram->stats.bd_writes)));
-	up_read(&zram->init_lock);
 
 	return ret;
 }
@@ -567,14 +559,12 @@ static ssize_t writeback_compressed_store(struct device *dev,
 	if (kstrtobool(buf, &val))
 		return -EINVAL;
 
-	down_write(&zram->init_lock);
+	guard(rwsem_write)(&zram->init_lock);
 	if (init_done(zram)) {
-		up_write(&zram->init_lock);
 		return -EBUSY;
 	}
 
 	zram->wb_compressed = val;
-	up_write(&zram->init_lock);
 
 	return len;
 }
@@ -586,9 +576,8 @@ static ssize_t writeback_compressed_show(struct device *dev,
 	bool val;
 	struct zram *zram = dev_to_zram(dev);
 
-	down_read(&zram->init_lock);
+	guard(rwsem_read)(&zram->init_lock);
 	val = zram->wb_compressed;
-	up_read(&zram->init_lock);
 
 	return sysfs_emit(buf, "%d\n", val);
 }
@@ -599,17 +588,14 @@ static ssize_t writeback_limit_enable_store(struct device *dev,
 {
 	struct zram *zram = dev_to_zram(dev);
 	u64 val;
-	ssize_t ret = -EINVAL;
 
 	if (kstrtoull(buf, 10, &val))
-		return ret;
+		return -EINVAL;
 
-	down_write(&zram->init_lock);
+	guard(rwsem_write)(&zram->init_lock);
 	zram->wb_limit_enable = val;
-	up_write(&zram->init_lock);
-	ret = len;
 
-	return ret;
+	return len;
 }
 
 static ssize_t writeback_limit_enable_show(struct device *dev,
@@ -619,9 +605,8 @@ static ssize_t writeback_limit_enable_show(struct device *dev,
 	bool val;
 	struct zram *zram = dev_to_zram(dev);
 
-	down_read(&zram->init_lock);
+	guard(rwsem_read)(&zram->init_lock);
 	val = zram->wb_limit_enable;
-	up_read(&zram->init_lock);
 
 	return sysfs_emit(buf, "%d\n", val);
 }
@@ -632,10 +617,9 @@ static ssize_t writeback_limit_store(struct device *dev,
 {
 	struct zram *zram = dev_to_zram(dev);
 	u64 val;
-	ssize_t ret = -EINVAL;
 
 	if (kstrtoull(buf, 10, &val))
-		return ret;
+		return -EINVAL;
 
 	/*
 	 * When the page size is greater than 4KB, if bd_wb_limit is set to
@@ -647,12 +631,10 @@ static ssize_t writeback_limit_store(struct device *dev,
 	 */
 	val = rounddown(val, PAGE_SIZE / 4096);
 
-	down_write(&zram->init_lock);
+	guard(rwsem_write)(&zram->init_lock);
 	zram->bd_wb_limit = val;
-	up_write(&zram->init_lock);
-	ret = len;
 
-	return ret;
+	return len;
 }
 
 static ssize_t writeback_limit_show(struct device *dev,
@@ -661,9 +643,8 @@ static ssize_t writeback_limit_show(struct device *dev,
 	u64 val;
 	struct zram *zram = dev_to_zram(dev);
 
-	down_read(&zram->init_lock);
+	guard(rwsem_read)(&zram->init_lock);
 	val = zram->bd_wb_limit;
-	up_read(&zram->init_lock);
 
 	return sysfs_emit(buf, "%llu\n", val);
 }
@@ -681,9 +662,8 @@ static ssize_t writeback_batch_size_store(struct device *dev,
 	if (!val)
 		return -EINVAL;
 
-	down_write(&zram->init_lock);
+	guard(rwsem_write)(&zram->init_lock);
 	zram->wb_batch_size = val;
-	up_write(&zram->init_lock);
 
 	return len;
 }
@@ -695,9 +675,8 @@ static ssize_t writeback_batch_size_show(struct device *dev,
 	u32 val;
 	struct zram *zram = dev_to_zram(dev);
 
-	down_read(&zram->init_lock);
+	guard(rwsem_read)(&zram->init_lock);
 	val = zram->wb_batch_size;
-	up_read(&zram->init_lock);
 
 	return sysfs_emit(buf, "%u\n", val);
 }
@@ -717,37 +696,33 @@ static void reset_bdev(struct zram *zram)
 }
 
 static ssize_t backing_dev_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
+				struct device_attribute *attr, char *buf)
 {
 	struct file *file;
 	struct zram *zram = dev_to_zram(dev);
 	char *p;
 	ssize_t ret;
 
-	down_read(&zram->init_lock);
+	guard(rwsem_read)(&zram->init_lock);
 	file = zram->backing_dev;
 	if (!file) {
 		memcpy(buf, "none\n", 5);
-		up_read(&zram->init_lock);
 		return 5;
 	}
 
 	p = file_path(file, buf, PAGE_SIZE - 1);
-	if (IS_ERR(p)) {
-		ret = PTR_ERR(p);
-		goto out;
-	}
+	if (IS_ERR(p))
+		return PTR_ERR(p);
 
 	ret = strlen(p);
 	memmove(buf, p, ret);
 	buf[ret++] = '\n';
-out:
-	up_read(&zram->init_lock);
 	return ret;
 }
 
 static ssize_t backing_dev_store(struct device *dev,
-		struct device_attribute *attr, const char *buf, size_t len)
+				 struct device_attribute *attr, const char *buf,
+				 size_t len)
 {
 	char *file_name;
 	size_t sz;
@@ -762,7 +737,7 @@ static ssize_t backing_dev_store(struct device *dev,
 	if (!file_name)
 		return -ENOMEM;
 
-	down_write(&zram->init_lock);
+	guard(rwsem_write)(&zram->init_lock);
 	if (init_done(zram)) {
 		pr_info("Can't setup backing device for initialized device\n");
 		err = -EBUSY;
@@ -810,7 +785,6 @@ static ssize_t backing_dev_store(struct device *dev,
 	zram->backing_dev = backing_dev;
 	zram->bitmap = bitmap;
 	zram->nr_pages = nr_pages;
-	up_write(&zram->init_lock);
 
 	pr_info("setup backing device %s\n", file_name);
 	kfree(file_name);
@@ -822,8 +796,6 @@ out:
 	if (backing_dev)
 		filp_close(backing_dev, NULL);
 
-	up_write(&zram->init_lock);
-
 	kfree(file_name);
 
 	return err;
@@ -1291,33 +1263,29 @@ static ssize_t writeback_store(struct device *dev,
 	ssize_t ret = len;
 	int err, mode = 0;
 
-	down_read(&zram->init_lock);
-	if (!init_done(zram)) {
-		up_read(&zram->init_lock);
+	guard(rwsem_read)(&zram->init_lock);
+	if (!init_done(zram))
 		return -EINVAL;
-	}
 
 	/* Do not permit concurrent post-processing actions. */
-	if (atomic_xchg(&zram->pp_in_progress, 1)) {
-		up_read(&zram->init_lock);
+	if (atomic_xchg(&zram->pp_in_progress, 1))
 		return -EAGAIN;
-	}
 
 	if (!zram->backing_dev) {
 		ret = -ENODEV;
-		goto release_init_lock;
+		goto out;
 	}
 
 	pp_ctl = init_pp_ctl();
 	if (!pp_ctl) {
 		ret = -ENOMEM;
-		goto release_init_lock;
+		goto out;
 	}
 
 	wb_ctl = init_wb_ctl(zram);
 	if (!wb_ctl) {
 		ret = -ENOMEM;
-		goto release_init_lock;
+		goto out;
 	}
 
 	args = skip_spaces(buf);
@@ -1341,7 +1309,7 @@ static ssize_t writeback_store(struct device *dev,
 			err = parse_mode(param, &mode);
 			if (err) {
 				ret = err;
-				goto release_init_lock;
+				goto out;
 			}
 
 			scan_slots_for_writeback(zram, mode, lo, hi, pp_ctl);
@@ -1352,7 +1320,7 @@ static ssize_t writeback_store(struct device *dev,
 			err = parse_mode(val, &mode);
 			if (err) {
 				ret = err;
-				goto release_init_lock;
+				goto out;
 			}
 
 			scan_slots_for_writeback(zram, mode, lo, hi, pp_ctl);
@@ -1363,7 +1331,7 @@ static ssize_t writeback_store(struct device *dev,
 			err = parse_page_index(val, nr_pages, &lo, &hi);
 			if (err) {
 				ret = err;
-				goto release_init_lock;
+				goto out;
 			}
 
 			scan_slots_for_writeback(zram, mode, lo, hi, pp_ctl);
@@ -1374,7 +1342,7 @@ static ssize_t writeback_store(struct device *dev,
 			err = parse_page_indexes(val, nr_pages, &lo, &hi);
 			if (err) {
 				ret = err;
-				goto release_init_lock;
+				goto out;
 			}
 
 			scan_slots_for_writeback(zram, mode, lo, hi, pp_ctl);
@@ -1386,11 +1354,10 @@ static ssize_t writeback_store(struct device *dev,
 	if (err)
 		ret = err;
 
-release_init_lock:
+out:
 	release_pp_ctl(zram, pp_ctl);
 	release_wb_ctl(wb_ctl);
 	atomic_set(&zram->pp_in_progress, 0);
-	up_read(&zram->init_lock);
 
 	return ret;
 }
@@ -1608,9 +1575,8 @@ static ssize_t read_block_state(struct file *file, char __user *buf,
 	if (!kbuf)
 		return -ENOMEM;
 
-	down_read(&zram->init_lock);
+	guard(rwsem_read)(&zram->init_lock);
 	if (!init_done(zram)) {
-		up_read(&zram->init_lock);
 		kvfree(kbuf);
 		return -EINVAL;
 	}
@@ -1646,7 +1612,6 @@ next:
 		*ppos += 1;
 	}
 
-	up_read(&zram->init_lock);
 	if (copy_to_user(buf, kbuf, written))
 		written = -EFAULT;
 	kvfree(kbuf);
@@ -1713,16 +1678,14 @@ static int __comp_algorithm_store(struct zram *zram, u32 prio, const char *buf)
 		return -EINVAL;
 	}
 
-	down_write(&zram->init_lock);
+	guard(rwsem_write)(&zram->init_lock);
 	if (init_done(zram)) {
-		up_write(&zram->init_lock);
 		kfree(compressor);
 		pr_info("Can't change algorithm for initialized device\n");
 		return -EBUSY;
 	}
 
 	comp_algorithm_set(zram, prio, compressor);
-	up_write(&zram->init_lock);
 	return 0;
 }
 
@@ -1843,9 +1806,8 @@ static ssize_t comp_algorithm_show(struct device *dev,
 	struct zram *zram = dev_to_zram(dev);
 	ssize_t sz;
 
-	down_read(&zram->init_lock);
+	guard(rwsem_read)(&zram->init_lock);
 	sz = zcomp_available_show(zram->comp_algs[ZRAM_PRIMARY_COMP], buf, 0);
-	up_read(&zram->init_lock);
 	return sz;
 }
 
@@ -1870,7 +1832,7 @@ static ssize_t recomp_algorithm_show(struct device *dev,
 	ssize_t sz = 0;
 	u32 prio;
 
-	down_read(&zram->init_lock);
+	guard(rwsem_read)(&zram->init_lock);
 	for (prio = ZRAM_SECONDARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
 		if (!zram->comp_algs[prio])
 			continue;
@@ -1878,7 +1840,6 @@ static ssize_t recomp_algorithm_show(struct device *dev,
 		sz += sysfs_emit_at(buf, sz, "#%d: ", prio);
 		sz += zcomp_available_show(zram->comp_algs[prio], buf, sz);
 	}
-	up_read(&zram->init_lock);
 	return sz;
 }
 
@@ -1924,42 +1885,38 @@ static ssize_t recomp_algorithm_store(struct device *dev,
 }
 #endif
 
-static ssize_t compact_store(struct device *dev,
-		struct device_attribute *attr, const char *buf, size_t len)
+static ssize_t compact_store(struct device *dev, struct device_attribute *attr,
+			     const char *buf, size_t len)
 {
 	struct zram *zram = dev_to_zram(dev);
 
-	down_read(&zram->init_lock);
-	if (!init_done(zram)) {
-		up_read(&zram->init_lock);
+	guard(rwsem_read)(&zram->init_lock);
+	if (!init_done(zram))
 		return -EINVAL;
-	}
 
 	zs_compact(zram->mem_pool);
-	up_read(&zram->init_lock);
 
 	return len;
 }
 
-static ssize_t io_stat_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
+static ssize_t io_stat_show(struct device *dev, struct device_attribute *attr,
+			    char *buf)
 {
 	struct zram *zram = dev_to_zram(dev);
 	ssize_t ret;
 
-	down_read(&zram->init_lock);
+	guard(rwsem_read)(&zram->init_lock);
 	ret = sysfs_emit(buf,
 			"%8llu %8llu 0 %8llu\n",
 			(u64)atomic64_read(&zram->stats.failed_reads),
 			(u64)atomic64_read(&zram->stats.failed_writes),
 			(u64)atomic64_read(&zram->stats.notify_free));
-	up_read(&zram->init_lock);
 
 	return ret;
 }
 
-static ssize_t mm_stat_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
+static ssize_t mm_stat_show(struct device *dev, struct device_attribute *attr,
+			    char *buf)
 {
 	struct zram *zram = dev_to_zram(dev);
 	struct zs_pool_stats pool_stats;
@@ -1969,7 +1926,7 @@ static ssize_t mm_stat_show(struct device *dev,
 
 	memset(&pool_stats, 0x00, sizeof(struct zs_pool_stats));
 
-	down_read(&zram->init_lock);
+	guard(rwsem_read)(&zram->init_lock);
 	if (init_done(zram)) {
 		mem_used = zs_get_total_pages(zram->mem_pool);
 		zs_pool_stats(zram->mem_pool, &pool_stats);
@@ -1989,7 +1946,6 @@ static ssize_t mm_stat_show(struct device *dev,
 			atomic_long_read(&pool_stats.pages_compacted),
 			(u64)atomic64_read(&zram->stats.huge_pages),
 			(u64)atomic64_read(&zram->stats.huge_pages_since));
-	up_read(&zram->init_lock);
 
 	return ret;
 }
@@ -2001,12 +1957,11 @@ static ssize_t debug_stat_show(struct device *dev,
 	struct zram *zram = dev_to_zram(dev);
 	ssize_t ret;
 
-	down_read(&zram->init_lock);
+	guard(rwsem_read)(&zram->init_lock);
 	ret = sysfs_emit(buf,
 			"version: %d\n0 %8llu\n",
 			version,
 			(u64)atomic64_read(&zram->stats.miss_free));
-	up_read(&zram->init_lock);
 
 	return ret;
 }
@@ -2669,17 +2624,13 @@ static ssize_t recompress_store(struct device *dev,
 	if (threshold >= huge_class_size)
 		return -EINVAL;
 
-	down_read(&zram->init_lock);
-	if (!init_done(zram)) {
-		ret = -EINVAL;
-		goto release_init_lock;
-	}
+	guard(rwsem_read)(&zram->init_lock);
+	if (!init_done(zram))
+		return -EINVAL;
 
 	/* Do not permit concurrent post-processing actions. */
-	if (atomic_xchg(&zram->pp_in_progress, 1)) {
-		up_read(&zram->init_lock);
+	if (atomic_xchg(&zram->pp_in_progress, 1))
 		return -EAGAIN;
-	}
 
 	if (algo) {
 		bool found = false;
@@ -2697,26 +2648,26 @@ static ssize_t recompress_store(struct device *dev,
 
 		if (!found) {
 			ret = -EINVAL;
-			goto release_init_lock;
+			goto out;
 		}
 	}
 
 	prio_max = min(prio_max, (u32)zram->num_active_comps);
 	if (prio >= prio_max) {
 		ret = -EINVAL;
-		goto release_init_lock;
+		goto out;
 	}
 
 	page = alloc_page(GFP_KERNEL);
 	if (!page) {
 		ret = -ENOMEM;
-		goto release_init_lock;
+		goto out;
 	}
 
 	ctl = init_pp_ctl();
 	if (!ctl) {
 		ret = -ENOMEM;
-		goto release_init_lock;
+		goto out;
 	}
 
 	scan_slots_for_recompress(zram, mode, prio_max, ctl);
@@ -2747,12 +2698,11 @@ next:
 		cond_resched();
 	}
 
-release_init_lock:
+out:
 	if (page)
 		__free_page(page);
 	release_pp_ctl(zram, ctl);
 	atomic_set(&zram->pp_in_progress, 0);
-	up_read(&zram->init_lock);
 	return ret;
 }
 #endif
@@ -2931,7 +2881,7 @@ static void zram_destroy_comps(struct zram *zram)
 
 static void zram_reset_device(struct zram *zram)
 {
-	down_write(&zram->init_lock);
+	guard(rwsem_write)(&zram->init_lock);
 
 	zram->limit_pages = 0;
 
@@ -2947,11 +2897,10 @@ static void zram_reset_device(struct zram *zram)
 	reset_bdev(zram);
 
 	comp_algorithm_set(zram, ZRAM_PRIMARY_COMP, default_compressor);
-	up_write(&zram->init_lock);
 }
 
-static ssize_t disksize_store(struct device *dev,
-		struct device_attribute *attr, const char *buf, size_t len)
+static ssize_t disksize_store(struct device *dev, struct device_attribute *attr,
+			      const char *buf, size_t len)
 {
 	u64 disksize;
 	struct zcomp *comp;
@@ -2963,18 +2912,15 @@ static ssize_t disksize_store(struct device *dev,
 	if (!disksize)
 		return -EINVAL;
 
-	down_write(&zram->init_lock);
+	guard(rwsem_write)(&zram->init_lock);
 	if (init_done(zram)) {
 		pr_info("Cannot change disksize for initialized device\n");
-		err = -EBUSY;
-		goto out_unlock;
+		return -EBUSY;
 	}
 
 	disksize = PAGE_ALIGN(disksize);
-	if (!zram_meta_alloc(zram, disksize)) {
-		err = -ENOMEM;
-		goto out_unlock;
-	}
+	if (!zram_meta_alloc(zram, disksize))
+		return -ENOMEM;
 
 	for (prio = ZRAM_PRIMARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
 		if (!zram->comp_algs[prio])
@@ -2994,15 +2940,12 @@ static ssize_t disksize_store(struct device *dev,
 	}
 	zram->disksize = disksize;
 	set_capacity_and_notify(zram->disk, zram->disksize >> SECTOR_SHIFT);
-	up_write(&zram->init_lock);
 
 	return len;
 
 out_free_comps:
 	zram_destroy_comps(zram);
 	zram_meta_free(zram, disksize);
-out_unlock:
-	up_write(&zram->init_lock);
 	return err;
 }
 
-- 
cgit v1.2.3


From 0327a862135b0b0b5e67f1434468326b733562bf Mon Sep 17 00:00:00 2001
From: Sergey Senozhatsky <senozhatsky@chromium.org>
Date: Mon, 1 Dec 2025 18:47:54 +0900
Subject: zram: consolidate device-attr declarations

Do not spread device attributes declarations across the file, move
io_stat, mm_stat, debug_stat to a common device-attr section.

Link: https://lkml.kernel.org/r/20251201094754.4149975-8-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Brian Geffon <bgeffon@google.com>
Cc: David Stevens <stevensd@google.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Richard Chang <richardycc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/block/zram/zram_drv.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

(limited to 'drivers')

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 4b8a26c60539..67a9e7c005c3 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1966,10 +1966,6 @@ static ssize_t debug_stat_show(struct device *dev,
 	return ret;
 }
 
-static DEVICE_ATTR_RO(io_stat);
-static DEVICE_ATTR_RO(mm_stat);
-static DEVICE_ATTR_RO(debug_stat);
-
 static void zram_meta_free(struct zram *zram, u64 disksize)
 {
 	size_t num_pages = disksize >> PAGE_SHIFT;
@@ -3008,6 +3004,9 @@ static const struct block_device_operations zram_devops = {
 	.owner = THIS_MODULE
 };
 
+static DEVICE_ATTR_RO(io_stat);
+static DEVICE_ATTR_RO(mm_stat);
+static DEVICE_ATTR_RO(debug_stat);
 static DEVICE_ATTR_WO(compact);
 static DEVICE_ATTR_RW(disksize);
 static DEVICE_ATTR_RO(initstate);
-- 
cgit v1.2.3


From 2e8ff2f51dde73a26b94aed2df4827177bd25e6e Mon Sep 17 00:00:00 2001
From: Sergey Senozhatsky <senozhatsky@chromium.org>
Date: Mon, 15 Dec 2025 14:47:11 +0900
Subject: zram: use u32 for entry ac_time tracking

We can reduce sizeof(zram_table_entry) on 64-bit systems by converting
flags and ac_time to u32.  Entry flags fit into u32, and for ac_time u32
gives us over a century of entry lifespan (approx 136 years) which is
plenty (zram uses system boot time (seconds)).

In struct zram_table_entry we use bytes aliasing, because bit-wait API
(for slot lock) requires a whole unsigned long word.

Link: https://lkml.kernel.org/r/d7c0b48450c70eeb5fd8acd6ecd23593f30dbf1f.1765775954.git.senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Suggested-by: David Stevens <stevensd@google.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Richard Chang <richardycc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/block/zram/zram_drv.c | 60 +++++++++++++++++++++----------------------
 drivers/block/zram/zram_drv.h |  9 +++++--
 2 files changed, 37 insertions(+), 32 deletions(-)

(limited to 'drivers')

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 67a9e7c005c3..65f99ff3e2e5 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -81,7 +81,7 @@ static void zram_slot_lock_init(struct zram *zram, u32 index)
  */
 static __must_check bool zram_slot_trylock(struct zram *zram, u32 index)
 {
-	unsigned long *lock = &zram->table[index].flags;
+	unsigned long *lock = &zram->table[index].__lock;
 
 	if (!test_and_set_bit_lock(ZRAM_ENTRY_LOCK, lock)) {
 		mutex_acquire(slot_dep_map(zram, index), 0, 1, _RET_IP_);
@@ -94,7 +94,7 @@ static __must_check bool zram_slot_trylock(struct zram *zram, u32 index)
 
 static void zram_slot_lock(struct zram *zram, u32 index)
 {
-	unsigned long *lock = &zram->table[index].flags;
+	unsigned long *lock = &zram->table[index].__lock;
 
 	mutex_acquire(slot_dep_map(zram, index), 0, 0, _RET_IP_);
 	wait_on_bit_lock(lock, ZRAM_ENTRY_LOCK, TASK_UNINTERRUPTIBLE);
@@ -103,7 +103,7 @@ static void zram_slot_lock(struct zram *zram, u32 index)
 
 static void zram_slot_unlock(struct zram *zram, u32 index)
 {
-	unsigned long *lock = &zram->table[index].flags;
+	unsigned long *lock = &zram->table[index].__lock;
 
 	mutex_release(slot_dep_map(zram, index), _RET_IP_);
 	clear_and_wake_up_bit(ZRAM_ENTRY_LOCK, lock);
@@ -130,34 +130,33 @@ static void zram_set_handle(struct zram *zram, u32 index, unsigned long handle)
 }
 
 static bool zram_test_flag(struct zram *zram, u32 index,
-			enum zram_pageflags flag)
+			   enum zram_pageflags flag)
 {
-	return zram->table[index].flags & BIT(flag);
+	return zram->table[index].attr.flags & BIT(flag);
 }
 
 static void zram_set_flag(struct zram *zram, u32 index,
-			enum zram_pageflags flag)
+			  enum zram_pageflags flag)
 {
-	zram->table[index].flags |= BIT(flag);
+	zram->table[index].attr.flags |= BIT(flag);
 }
 
 static void zram_clear_flag(struct zram *zram, u32 index,
-			enum zram_pageflags flag)
+			    enum zram_pageflags flag)
 {
-	zram->table[index].flags &= ~BIT(flag);
+	zram->table[index].attr.flags &= ~BIT(flag);
 }
 
 static size_t zram_get_obj_size(struct zram *zram, u32 index)
 {
-	return zram->table[index].flags & (BIT(ZRAM_FLAG_SHIFT) - 1);
+	return zram->table[index].attr.flags & (BIT(ZRAM_FLAG_SHIFT) - 1);
 }
 
-static void zram_set_obj_size(struct zram *zram,
-					u32 index, size_t size)
+static void zram_set_obj_size(struct zram *zram, u32 index, size_t size)
 {
-	unsigned long flags = zram->table[index].flags >> ZRAM_FLAG_SHIFT;
+	unsigned long flags = zram->table[index].attr.flags >> ZRAM_FLAG_SHIFT;
 
-	zram->table[index].flags = (flags << ZRAM_FLAG_SHIFT) | size;
+	zram->table[index].attr.flags = (flags << ZRAM_FLAG_SHIFT) | size;
 }
 
 static inline bool zram_allocated(struct zram *zram, u32 index)
@@ -208,14 +207,14 @@ static inline void zram_set_priority(struct zram *zram, u32 index, u32 prio)
 	 * Clear previous priority value first, in case if we recompress
 	 * further an already recompressed page
 	 */
-	zram->table[index].flags &= ~(ZRAM_COMP_PRIORITY_MASK <<
-				      ZRAM_COMP_PRIORITY_BIT1);
-	zram->table[index].flags |= (prio << ZRAM_COMP_PRIORITY_BIT1);
+	zram->table[index].attr.flags &= ~(ZRAM_COMP_PRIORITY_MASK <<
+					   ZRAM_COMP_PRIORITY_BIT1);
+	zram->table[index].attr.flags |= (prio << ZRAM_COMP_PRIORITY_BIT1);
 }
 
 static inline u32 zram_get_priority(struct zram *zram, u32 index)
 {
-	u32 prio = zram->table[index].flags >> ZRAM_COMP_PRIORITY_BIT1;
+	u32 prio = zram->table[index].attr.flags >> ZRAM_COMP_PRIORITY_BIT1;
 
 	return prio & ZRAM_COMP_PRIORITY_MASK;
 }
@@ -225,7 +224,7 @@ static void zram_accessed(struct zram *zram, u32 index)
 	zram_clear_flag(zram, index, ZRAM_IDLE);
 	zram_clear_flag(zram, index, ZRAM_PP_SLOT);
 #ifdef CONFIG_ZRAM_TRACK_ENTRY_ACTIME
-	zram->table[index].ac_time = ktime_get_boottime();
+	zram->table[index].attr.ac_time = (u32)ktime_get_boottime_seconds();
 #endif
 }
 
@@ -447,7 +446,7 @@ static void mark_idle(struct zram *zram, ktime_t cutoff)
 
 #ifdef CONFIG_ZRAM_TRACK_ENTRY_ACTIME
 		is_idle = !cutoff ||
-			ktime_after(cutoff, zram->table[index].ac_time);
+			ktime_after(cutoff, zram->table[index].attr.ac_time);
 #endif
 		if (is_idle)
 			zram_set_flag(zram, index, ZRAM_IDLE);
@@ -461,18 +460,19 @@ static ssize_t idle_store(struct device *dev, struct device_attribute *attr,
 			  const char *buf, size_t len)
 {
 	struct zram *zram = dev_to_zram(dev);
-	ktime_t cutoff_time = 0;
+	ktime_t cutoff = 0;
 
 	if (!sysfs_streq(buf, "all")) {
 		/*
 		 * If it did not parse as 'all' try to treat it as an integer
 		 * when we have memory tracking enabled.
 		 */
-		u64 age_sec;
+		u32 age_sec;
 
-		if (IS_ENABLED(CONFIG_ZRAM_TRACK_ENTRY_ACTIME) && !kstrtoull(buf, 0, &age_sec))
-			cutoff_time = ktime_sub(ktime_get_boottime(),
-					ns_to_ktime(age_sec * NSEC_PER_SEC));
+		if (IS_ENABLED(CONFIG_ZRAM_TRACK_ENTRY_ACTIME) &&
+		    !kstrtouint(buf, 0, &age_sec))
+			cutoff = ktime_sub((u32)ktime_get_boottime_seconds(),
+					   age_sec);
 		else
 			return -EINVAL;
 	}
@@ -482,10 +482,10 @@ static ssize_t idle_store(struct device *dev, struct device_attribute *attr,
 		return -EINVAL;
 
 	/*
-	 * A cutoff_time of 0 marks everything as idle, this is the
+	 * A cutoff of 0 marks everything as idle, this is the
 	 * "all" behavior.
 	 */
-	mark_idle(zram, cutoff_time);
+	mark_idle(zram, cutoff);
 	return len;
 }
 
@@ -1588,7 +1588,7 @@ static ssize_t read_block_state(struct file *file, char __user *buf,
 		if (!zram_allocated(zram, index))
 			goto next;
 
-		ts = ktime_to_timespec64(zram->table[index].ac_time);
+		ts = ktime_to_timespec64(zram->table[index].attr.ac_time);
 		copied = snprintf(kbuf + written, count,
 			"%12zd %12lld.%06lu %c%c%c%c%c%c\n",
 			index, (s64)ts.tv_sec,
@@ -2013,7 +2013,7 @@ static void zram_slot_free(struct zram *zram, u32 index)
 	unsigned long handle;
 
 #ifdef CONFIG_ZRAM_TRACK_ENTRY_ACTIME
-	zram->table[index].ac_time = 0;
+	zram->table[index].attr.ac_time = 0;
 #endif
 
 	zram_clear_flag(zram, index, ZRAM_IDLE);
@@ -3286,7 +3286,7 @@ static int __init zram_init(void)
 	struct zram_table_entry zram_te;
 	int ret;
 
-	BUILD_BUG_ON(__NR_ZRAM_PAGEFLAGS > sizeof(zram_te.flags) * 8);
+	BUILD_BUG_ON(__NR_ZRAM_PAGEFLAGS > sizeof(zram_te.attr.flags) * 8);
 
 	ret = cpuhp_setup_state_multi(CPUHP_ZCOMP_PREPARE, "block/zram:prepare",
 				      zcomp_cpu_up_prepare, zcomp_cpu_dead);
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index 72fdf66c78ab..48d6861c6647 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -65,10 +65,15 @@ enum zram_pageflags {
  */
 struct zram_table_entry {
 	unsigned long handle;
-	unsigned long flags;
+	union {
+		unsigned long __lock;
+		struct attr {
+			u32 flags;
 #ifdef CONFIG_ZRAM_TRACK_ENTRY_ACTIME
-	ktime_t ac_time;
+			u32 ac_time;
 #endif
+		} attr;
+	};
 	struct lockdep_map dep_map;
 };
 
-- 
cgit v1.2.3


From bde60fe747216d3449a1a74f07937a5273717b69 Mon Sep 17 00:00:00 2001
From: Sergey Senozhatsky <senozhatsky@chromium.org>
Date: Mon, 15 Dec 2025 14:47:12 +0900
Subject: zram: rename internal slot API

We have a somewhat confusing internal API naming.  E.g.  the following
code:

	zram_slot_lock()
	if (zram_allocated())
		zram_set_flag()
	zram_slot_unlock()

may look like it does something on zram device level, but in fact it tests
and sets slot entry flags, not the device ones.

Rename API to explicitly distinguish functions that operate on the slot
level from functions that operate on the zram device level.

While at it, fixup some coding styles.

[senozhatsky@chromium.org: fix up mark_slot_accessed()]
  Link: https://lkml.kernel.org/r/20260115031922.3813659-1-senozhatsky@chromium.org
Link: https://lkml.kernel.org/r/775a0b1a0ace5caf1f05965d8bc637c1192820fa.1765775954.git.senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Brian Geffon <bgeffon@google.com>
Cc: David Stevens <stevensd@google.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Richard Chang <richardycc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/block/zram/zram_drv.c | 363 +++++++++++++++++++++---------------------
 1 file changed, 182 insertions(+), 181 deletions(-)

(limited to 'drivers')

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 65f99ff3e2e5..bd9a37fca675 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -56,10 +56,10 @@ static size_t huge_class_size;
 
 static const struct block_device_operations zram_devops;
 
-static void zram_slot_free(struct zram *zram, u32 index);
+static void slot_free(struct zram *zram, u32 index);
 #define slot_dep_map(zram, index) (&(zram)->table[(index)].dep_map)
 
-static void zram_slot_lock_init(struct zram *zram, u32 index)
+static void slot_lock_init(struct zram *zram, u32 index)
 {
 	static struct lock_class_key __key;
 
@@ -79,7 +79,7 @@ static void zram_slot_lock_init(struct zram *zram, u32 index)
  * 4) Use TRY lock variant when in atomic context
  *    - must check return value and handle locking failers
  */
-static __must_check bool zram_slot_trylock(struct zram *zram, u32 index)
+static __must_check bool slot_trylock(struct zram *zram, u32 index)
 {
 	unsigned long *lock = &zram->table[index].__lock;
 
@@ -92,7 +92,7 @@ static __must_check bool zram_slot_trylock(struct zram *zram, u32 index)
 	return false;
 }
 
-static void zram_slot_lock(struct zram *zram, u32 index)
+static void slot_lock(struct zram *zram, u32 index)
 {
 	unsigned long *lock = &zram->table[index].__lock;
 
@@ -101,7 +101,7 @@ static void zram_slot_lock(struct zram *zram, u32 index)
 	lock_acquired(slot_dep_map(zram, index), _RET_IP_);
 }
 
-static void zram_slot_unlock(struct zram *zram, u32 index)
+static void slot_unlock(struct zram *zram, u32 index)
 {
 	unsigned long *lock = &zram->table[index].__lock;
 
@@ -119,51 +119,80 @@ static inline struct zram *dev_to_zram(struct device *dev)
 	return (struct zram *)dev_to_disk(dev)->private_data;
 }
 
-static unsigned long zram_get_handle(struct zram *zram, u32 index)
+static unsigned long get_slot_handle(struct zram *zram, u32 index)
 {
 	return zram->table[index].handle;
 }
 
-static void zram_set_handle(struct zram *zram, u32 index, unsigned long handle)
+static void set_slot_handle(struct zram *zram, u32 index, unsigned long handle)
 {
 	zram->table[index].handle = handle;
 }
 
-static bool zram_test_flag(struct zram *zram, u32 index,
+static bool test_slot_flag(struct zram *zram, u32 index,
 			   enum zram_pageflags flag)
 {
 	return zram->table[index].attr.flags & BIT(flag);
 }
 
-static void zram_set_flag(struct zram *zram, u32 index,
+static void set_slot_flag(struct zram *zram, u32 index,
 			  enum zram_pageflags flag)
 {
 	zram->table[index].attr.flags |= BIT(flag);
 }
 
-static void zram_clear_flag(struct zram *zram, u32 index,
+static void clear_slot_flag(struct zram *zram, u32 index,
 			    enum zram_pageflags flag)
 {
 	zram->table[index].attr.flags &= ~BIT(flag);
 }
 
-static size_t zram_get_obj_size(struct zram *zram, u32 index)
+static size_t get_slot_size(struct zram *zram, u32 index)
 {
 	return zram->table[index].attr.flags & (BIT(ZRAM_FLAG_SHIFT) - 1);
 }
 
-static void zram_set_obj_size(struct zram *zram, u32 index, size_t size)
+static void set_slot_size(struct zram *zram, u32 index, size_t size)
 {
 	unsigned long flags = zram->table[index].attr.flags >> ZRAM_FLAG_SHIFT;
 
 	zram->table[index].attr.flags = (flags << ZRAM_FLAG_SHIFT) | size;
 }
 
-static inline bool zram_allocated(struct zram *zram, u32 index)
+static inline bool slot_allocated(struct zram *zram, u32 index)
 {
-	return zram_get_obj_size(zram, index) ||
-			zram_test_flag(zram, index, ZRAM_SAME) ||
-			zram_test_flag(zram, index, ZRAM_WB);
+	return get_slot_size(zram, index) ||
+		test_slot_flag(zram, index, ZRAM_SAME) ||
+		test_slot_flag(zram, index, ZRAM_WB);
+}
+
+static inline void set_slot_comp_priority(struct zram *zram, u32 index,
+					  u32 prio)
+{
+	prio &= ZRAM_COMP_PRIORITY_MASK;
+	/*
+	 * Clear previous priority value first, in case if we recompress
+	 * further an already recompressed page
+	 */
+	zram->table[index].attr.flags &= ~(ZRAM_COMP_PRIORITY_MASK <<
+					   ZRAM_COMP_PRIORITY_BIT1);
+	zram->table[index].attr.flags |= (prio << ZRAM_COMP_PRIORITY_BIT1);
+}
+
+static inline u32 get_slot_comp_priority(struct zram *zram, u32 index)
+{
+	u32 prio = zram->table[index].attr.flags >> ZRAM_COMP_PRIORITY_BIT1;
+
+	return prio & ZRAM_COMP_PRIORITY_MASK;
+}
+
+static void mark_slot_accessed(struct zram *zram, u32 index)
+{
+	clear_slot_flag(zram, index, ZRAM_IDLE);
+	clear_slot_flag(zram, index, ZRAM_PP_SLOT);
+#ifdef CONFIG_ZRAM_TRACK_ENTRY_ACTIME
+	zram->table[index].attr.ac_time = (u32)ktime_get_boottime_seconds();
+#endif
 }
 
 static inline void update_used_max(struct zram *zram, const unsigned long pages)
@@ -200,34 +229,6 @@ static inline bool is_partial_io(struct bio_vec *bvec)
 }
 #endif
 
-static inline void zram_set_priority(struct zram *zram, u32 index, u32 prio)
-{
-	prio &= ZRAM_COMP_PRIORITY_MASK;
-	/*
-	 * Clear previous priority value first, in case if we recompress
-	 * further an already recompressed page
-	 */
-	zram->table[index].attr.flags &= ~(ZRAM_COMP_PRIORITY_MASK <<
-					   ZRAM_COMP_PRIORITY_BIT1);
-	zram->table[index].attr.flags |= (prio << ZRAM_COMP_PRIORITY_BIT1);
-}
-
-static inline u32 zram_get_priority(struct zram *zram, u32 index)
-{
-	u32 prio = zram->table[index].attr.flags >> ZRAM_COMP_PRIORITY_BIT1;
-
-	return prio & ZRAM_COMP_PRIORITY_MASK;
-}
-
-static void zram_accessed(struct zram *zram, u32 index)
-{
-	zram_clear_flag(zram, index, ZRAM_IDLE);
-	zram_clear_flag(zram, index, ZRAM_PP_SLOT);
-#ifdef CONFIG_ZRAM_TRACK_ENTRY_ACTIME
-	zram->table[index].attr.ac_time = (u32)ktime_get_boottime_seconds();
-#endif
-}
-
 #if defined CONFIG_ZRAM_WRITEBACK || defined CONFIG_ZRAM_MULTI_COMP
 struct zram_pp_slot {
 	unsigned long		index;
@@ -263,9 +264,9 @@ static void release_pp_slot(struct zram *zram, struct zram_pp_slot *pps)
 {
 	list_del_init(&pps->entry);
 
-	zram_slot_lock(zram, pps->index);
-	zram_clear_flag(zram, pps->index, ZRAM_PP_SLOT);
-	zram_slot_unlock(zram, pps->index);
+	slot_lock(zram, pps->index);
+	clear_slot_flag(zram, pps->index, ZRAM_PP_SLOT);
+	slot_unlock(zram, pps->index);
 
 	kfree(pps);
 }
@@ -304,10 +305,10 @@ static bool place_pp_slot(struct zram *zram, struct zram_pp_ctl *ctl,
 	INIT_LIST_HEAD(&pps->entry);
 	pps->index = index;
 
-	bid = zram_get_obj_size(zram, pps->index) / PP_BUCKET_SIZE_RANGE;
+	bid = get_slot_size(zram, pps->index) / PP_BUCKET_SIZE_RANGE;
 	list_add(&pps->entry, &ctl->pp_buckets[bid]);
 
-	zram_set_flag(zram, pps->index, ZRAM_PP_SLOT);
+	set_slot_flag(zram, pps->index, ZRAM_PP_SLOT);
 	return true;
 }
 
@@ -436,11 +437,11 @@ static void mark_idle(struct zram *zram, ktime_t cutoff)
 		 *
 		 * And ZRAM_WB slots simply cannot be ZRAM_IDLE.
 		 */
-		zram_slot_lock(zram, index);
-		if (!zram_allocated(zram, index) ||
-		    zram_test_flag(zram, index, ZRAM_WB) ||
-		    zram_test_flag(zram, index, ZRAM_SAME)) {
-			zram_slot_unlock(zram, index);
+		slot_lock(zram, index);
+		if (!slot_allocated(zram, index) ||
+		    test_slot_flag(zram, index, ZRAM_WB) ||
+		    test_slot_flag(zram, index, ZRAM_SAME)) {
+			slot_unlock(zram, index);
 			continue;
 		}
 
@@ -449,10 +450,10 @@ static void mark_idle(struct zram *zram, ktime_t cutoff)
 			ktime_after(cutoff, zram->table[index].attr.ac_time);
 #endif
 		if (is_idle)
-			zram_set_flag(zram, index, ZRAM_IDLE);
+			set_slot_flag(zram, index, ZRAM_IDLE);
 		else
-			zram_clear_flag(zram, index, ZRAM_IDLE);
-		zram_slot_unlock(zram, index);
+			clear_slot_flag(zram, index, ZRAM_IDLE);
+		slot_unlock(zram, index);
 	}
 }
 
@@ -933,7 +934,7 @@ static int zram_writeback_complete(struct zram *zram, struct zram_wb_req *req)
 	}
 
 	atomic64_inc(&zram->stats.bd_writes);
-	zram_slot_lock(zram, index);
+	slot_lock(zram, index);
 	/*
 	 * We release slot lock during writeback so slot can change under us:
 	 * slot_free() or slot_free() and zram_write_page(). In both cases
@@ -941,7 +942,7 @@ static int zram_writeback_complete(struct zram *zram, struct zram_wb_req *req)
 	 * set ZRAM_PP_SLOT on such slots until current post-processing
 	 * finishes.
 	 */
-	if (!zram_test_flag(zram, index, ZRAM_PP_SLOT)) {
+	if (!test_slot_flag(zram, index, ZRAM_PP_SLOT)) {
 		zram_release_bdev_block(zram, req->blk_idx);
 		goto out;
 	}
@@ -951,26 +952,26 @@ static int zram_writeback_complete(struct zram *zram, struct zram_wb_req *req)
 		 * ZRAM_WB slots get freed, we need to preserve data required
 		 * for read decompression.
 		 */
-		size = zram_get_obj_size(zram, index);
-		prio = zram_get_priority(zram, index);
-		huge = zram_test_flag(zram, index, ZRAM_HUGE);
+		size = get_slot_size(zram, index);
+		prio = get_slot_comp_priority(zram, index);
+		huge = test_slot_flag(zram, index, ZRAM_HUGE);
 	}
 
-	zram_slot_free(zram, index);
-	zram_set_flag(zram, index, ZRAM_WB);
-	zram_set_handle(zram, index, req->blk_idx);
+	slot_free(zram, index);
+	set_slot_flag(zram, index, ZRAM_WB);
+	set_slot_handle(zram, index, req->blk_idx);
 
 	if (zram->wb_compressed) {
 		if (huge)
-			zram_set_flag(zram, index, ZRAM_HUGE);
-		zram_set_obj_size(zram, index, size);
-		zram_set_priority(zram, index, prio);
+			set_slot_flag(zram, index, ZRAM_HUGE);
+		set_slot_size(zram, index, size);
+		set_slot_comp_priority(zram, index, prio);
 	}
 
 	atomic64_inc(&zram->stats.pages_stored);
 
 out:
-	zram_slot_unlock(zram, index);
+	slot_unlock(zram, index);
 	return 0;
 }
 
@@ -1091,14 +1092,14 @@ static int zram_writeback_slots(struct zram *zram,
 		}
 
 		index = pps->index;
-		zram_slot_lock(zram, index);
+		slot_lock(zram, index);
 		/*
 		 * scan_slots() sets ZRAM_PP_SLOT and releases slot lock, so
 		 * slots can change in the meantime. If slots are accessed or
 		 * freed they lose ZRAM_PP_SLOT flag and hence we don't
 		 * post-process them.
 		 */
-		if (!zram_test_flag(zram, index, ZRAM_PP_SLOT))
+		if (!test_slot_flag(zram, index, ZRAM_PP_SLOT))
 			goto next;
 		if (zram->wb_compressed)
 			err = read_from_zspool_raw(zram, req->page, index);
@@ -1106,7 +1107,7 @@ static int zram_writeback_slots(struct zram *zram,
 			err = read_from_zspool(zram, req->page, index);
 		if (err)
 			goto next;
-		zram_slot_unlock(zram, index);
+		slot_unlock(zram, index);
 
 		/*
 		 * From now on pp-slot is owned by the req, remove it from
@@ -1128,7 +1129,7 @@ static int zram_writeback_slots(struct zram *zram,
 		continue;
 
 next:
-		zram_slot_unlock(zram, index);
+		slot_unlock(zram, index);
 		release_pp_slot(zram, pps);
 	}
 
@@ -1221,27 +1222,27 @@ static int scan_slots_for_writeback(struct zram *zram, u32 mode,
 	while (index < hi) {
 		bool ok = true;
 
-		zram_slot_lock(zram, index);
-		if (!zram_allocated(zram, index))
+		slot_lock(zram, index);
+		if (!slot_allocated(zram, index))
 			goto next;
 
-		if (zram_test_flag(zram, index, ZRAM_WB) ||
-		    zram_test_flag(zram, index, ZRAM_SAME))
+		if (test_slot_flag(zram, index, ZRAM_WB) ||
+		    test_slot_flag(zram, index, ZRAM_SAME))
 			goto next;
 
 		if (mode & IDLE_WRITEBACK &&
-		    !zram_test_flag(zram, index, ZRAM_IDLE))
+		    !test_slot_flag(zram, index, ZRAM_IDLE))
 			goto next;
 		if (mode & HUGE_WRITEBACK &&
-		    !zram_test_flag(zram, index, ZRAM_HUGE))
+		    !test_slot_flag(zram, index, ZRAM_HUGE))
 			goto next;
 		if (mode & INCOMPRESSIBLE_WRITEBACK &&
-		    !zram_test_flag(zram, index, ZRAM_INCOMPRESSIBLE))
+		    !test_slot_flag(zram, index, ZRAM_INCOMPRESSIBLE))
 			goto next;
 
 		ok = place_pp_slot(zram, ctl, index);
 next:
-		zram_slot_unlock(zram, index);
+		slot_unlock(zram, index);
 		if (!ok)
 			break;
 		index++;
@@ -1369,22 +1370,22 @@ static int decompress_bdev_page(struct zram *zram, struct page *page, u32 index)
 	int ret, prio;
 	void *src;
 
-	zram_slot_lock(zram, index);
+	slot_lock(zram, index);
 	/* Since slot was unlocked we need to make sure it's still ZRAM_WB */
-	if (!zram_test_flag(zram, index, ZRAM_WB)) {
-		zram_slot_unlock(zram, index);
+	if (!test_slot_flag(zram, index, ZRAM_WB)) {
+		slot_unlock(zram, index);
 		/* We read some stale data, zero it out */
 		memset_page(page, 0, 0, PAGE_SIZE);
 		return -EIO;
 	}
 
-	if (zram_test_flag(zram, index, ZRAM_HUGE)) {
-		zram_slot_unlock(zram, index);
+	if (test_slot_flag(zram, index, ZRAM_HUGE)) {
+		slot_unlock(zram, index);
 		return 0;
 	}
 
-	size = zram_get_obj_size(zram, index);
-	prio = zram_get_priority(zram, index);
+	size = get_slot_size(zram, index);
+	prio = get_slot_comp_priority(zram, index);
 
 	zstrm = zcomp_stream_get(zram->comps[prio]);
 	src = kmap_local_page(page);
@@ -1394,7 +1395,7 @@ static int decompress_bdev_page(struct zram *zram, struct page *page, u32 index)
 		copy_page(src, zstrm->local_copy);
 	kunmap_local(src);
 	zcomp_stream_put(zstrm);
-	zram_slot_unlock(zram, index);
+	slot_unlock(zram, index);
 
 	return ret;
 }
@@ -1584,8 +1585,8 @@ static ssize_t read_block_state(struct file *file, char __user *buf,
 	for (index = *ppos; index < nr_pages; index++) {
 		int copied;
 
-		zram_slot_lock(zram, index);
-		if (!zram_allocated(zram, index))
+		slot_lock(zram, index);
+		if (!slot_allocated(zram, index))
 			goto next;
 
 		ts = ktime_to_timespec64(zram->table[index].attr.ac_time);
@@ -1593,22 +1594,22 @@ static ssize_t read_block_state(struct file *file, char __user *buf,
 			"%12zd %12lld.%06lu %c%c%c%c%c%c\n",
 			index, (s64)ts.tv_sec,
 			ts.tv_nsec / NSEC_PER_USEC,
-			zram_test_flag(zram, index, ZRAM_SAME) ? 's' : '.',
-			zram_test_flag(zram, index, ZRAM_WB) ? 'w' : '.',
-			zram_test_flag(zram, index, ZRAM_HUGE) ? 'h' : '.',
-			zram_test_flag(zram, index, ZRAM_IDLE) ? 'i' : '.',
-			zram_get_priority(zram, index) ? 'r' : '.',
-			zram_test_flag(zram, index,
+			test_slot_flag(zram, index, ZRAM_SAME) ? 's' : '.',
+			test_slot_flag(zram, index, ZRAM_WB) ? 'w' : '.',
+			test_slot_flag(zram, index, ZRAM_HUGE) ? 'h' : '.',
+			test_slot_flag(zram, index, ZRAM_IDLE) ? 'i' : '.',
+			get_slot_comp_priority(zram, index) ? 'r' : '.',
+			test_slot_flag(zram, index,
 				       ZRAM_INCOMPRESSIBLE) ? 'n' : '.');
 
 		if (count <= copied) {
-			zram_slot_unlock(zram, index);
+			slot_unlock(zram, index);
 			break;
 		}
 		written += copied;
 		count -= copied;
 next:
-		zram_slot_unlock(zram, index);
+		slot_unlock(zram, index);
 		*ppos += 1;
 	}
 
@@ -1976,7 +1977,7 @@ static void zram_meta_free(struct zram *zram, u64 disksize)
 
 	/* Free all pages that are still in this zram device */
 	for (index = 0; index < num_pages; index++)
-		zram_slot_free(zram, index);
+		slot_free(zram, index);
 
 	zs_destroy_pool(zram->mem_pool);
 	vfree(zram->table);
@@ -2003,12 +2004,12 @@ static bool zram_meta_alloc(struct zram *zram, u64 disksize)
 		huge_class_size = zs_huge_class_size(zram->mem_pool);
 
 	for (index = 0; index < num_pages; index++)
-		zram_slot_lock_init(zram, index);
+		slot_lock_init(zram, index);
 
 	return true;
 }
 
-static void zram_slot_free(struct zram *zram, u32 index)
+static void slot_free(struct zram *zram, u32 index)
 {
 	unsigned long handle;
 
@@ -2016,19 +2017,19 @@ static void zram_slot_free(struct zram *zram, u32 index)
 	zram->table[index].attr.ac_time = 0;
 #endif
 
-	zram_clear_flag(zram, index, ZRAM_IDLE);
-	zram_clear_flag(zram, index, ZRAM_INCOMPRESSIBLE);
-	zram_clear_flag(zram, index, ZRAM_PP_SLOT);
-	zram_set_priority(zram, index, 0);
+	clear_slot_flag(zram, index, ZRAM_IDLE);
+	clear_slot_flag(zram, index, ZRAM_INCOMPRESSIBLE);
+	clear_slot_flag(zram, index, ZRAM_PP_SLOT);
+	set_slot_comp_priority(zram, index, 0);
 
-	if (zram_test_flag(zram, index, ZRAM_HUGE)) {
-		zram_clear_flag(zram, index, ZRAM_HUGE);
+	if (test_slot_flag(zram, index, ZRAM_HUGE)) {
+		clear_slot_flag(zram, index, ZRAM_HUGE);
 		atomic64_dec(&zram->stats.huge_pages);
 	}
 
-	if (zram_test_flag(zram, index, ZRAM_WB)) {
-		zram_clear_flag(zram, index, ZRAM_WB);
-		zram_release_bdev_block(zram, zram_get_handle(zram, index));
+	if (test_slot_flag(zram, index, ZRAM_WB)) {
+		clear_slot_flag(zram, index, ZRAM_WB);
+		zram_release_bdev_block(zram, get_slot_handle(zram, index));
 		goto out;
 	}
 
@@ -2036,24 +2037,24 @@ static void zram_slot_free(struct zram *zram, u32 index)
 	 * No memory is allocated for same element filled pages.
 	 * Simply clear same page flag.
 	 */
-	if (zram_test_flag(zram, index, ZRAM_SAME)) {
-		zram_clear_flag(zram, index, ZRAM_SAME);
+	if (test_slot_flag(zram, index, ZRAM_SAME)) {
+		clear_slot_flag(zram, index, ZRAM_SAME);
 		atomic64_dec(&zram->stats.same_pages);
 		goto out;
 	}
 
-	handle = zram_get_handle(zram, index);
+	handle = get_slot_handle(zram, index);
 	if (!handle)
 		return;
 
 	zs_free(zram->mem_pool, handle);
 
-	atomic64_sub(zram_get_obj_size(zram, index),
+	atomic64_sub(get_slot_size(zram, index),
 		     &zram->stats.compr_data_size);
 out:
 	atomic64_dec(&zram->stats.pages_stored);
-	zram_set_handle(zram, index, 0);
-	zram_set_obj_size(zram, index, 0);
+	set_slot_handle(zram, index, 0);
+	set_slot_size(zram, index, 0);
 }
 
 static int read_same_filled_page(struct zram *zram, struct page *page,
@@ -2062,7 +2063,7 @@ static int read_same_filled_page(struct zram *zram, struct page *page,
 	void *mem;
 
 	mem = kmap_local_page(page);
-	zram_fill_page(mem, PAGE_SIZE, zram_get_handle(zram, index));
+	zram_fill_page(mem, PAGE_SIZE, get_slot_handle(zram, index));
 	kunmap_local(mem);
 	return 0;
 }
@@ -2073,7 +2074,7 @@ static int read_incompressible_page(struct zram *zram, struct page *page,
 	unsigned long handle;
 	void *src, *dst;
 
-	handle = zram_get_handle(zram, index);
+	handle = get_slot_handle(zram, index);
 	src = zs_obj_read_begin(zram->mem_pool, handle, NULL);
 	dst = kmap_local_page(page);
 	copy_page(dst, src);
@@ -2091,9 +2092,9 @@ static int read_compressed_page(struct zram *zram, struct page *page, u32 index)
 	void *src, *dst;
 	int ret, prio;
 
-	handle = zram_get_handle(zram, index);
-	size = zram_get_obj_size(zram, index);
-	prio = zram_get_priority(zram, index);
+	handle = get_slot_handle(zram, index);
+	size = get_slot_size(zram, index);
+	prio = get_slot_comp_priority(zram, index);
 
 	zstrm = zcomp_stream_get(zram->comps[prio]);
 	src = zs_obj_read_begin(zram->mem_pool, handle, zstrm->local_copy);
@@ -2114,8 +2115,8 @@ static int read_from_zspool_raw(struct zram *zram, struct page *page, u32 index)
 	unsigned int size;
 	void *src;
 
-	handle = zram_get_handle(zram, index);
-	size = zram_get_obj_size(zram, index);
+	handle = get_slot_handle(zram, index);
+	size = get_slot_size(zram, index);
 
 	/*
 	 * We need to get stream just for ->local_copy buffer, in
@@ -2138,11 +2139,11 @@ static int read_from_zspool_raw(struct zram *zram, struct page *page, u32 index)
  */
 static int read_from_zspool(struct zram *zram, struct page *page, u32 index)
 {
-	if (zram_test_flag(zram, index, ZRAM_SAME) ||
-	    !zram_get_handle(zram, index))
+	if (test_slot_flag(zram, index, ZRAM_SAME) ||
+	    !get_slot_handle(zram, index))
 		return read_same_filled_page(zram, page, index);
 
-	if (!zram_test_flag(zram, index, ZRAM_HUGE))
+	if (!test_slot_flag(zram, index, ZRAM_HUGE))
 		return read_compressed_page(zram, page, index);
 	else
 		return read_incompressible_page(zram, page, index);
@@ -2153,19 +2154,19 @@ static int zram_read_page(struct zram *zram, struct page *page, u32 index,
 {
 	int ret;
 
-	zram_slot_lock(zram, index);
-	if (!zram_test_flag(zram, index, ZRAM_WB)) {
+	slot_lock(zram, index);
+	if (!test_slot_flag(zram, index, ZRAM_WB)) {
 		/* Slot should be locked through out the function call */
 		ret = read_from_zspool(zram, page, index);
-		zram_slot_unlock(zram, index);
+		slot_unlock(zram, index);
 	} else {
-		unsigned long blk_idx = zram_get_handle(zram, index);
+		unsigned long blk_idx = get_slot_handle(zram, index);
 
 		/*
 		 * The slot should be unlocked before reading from the backing
 		 * device.
 		 */
-		zram_slot_unlock(zram, index);
+		slot_unlock(zram, index);
 		ret = read_from_bdev(zram, page, index, blk_idx, parent);
 	}
 
@@ -2206,11 +2207,11 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
 static int write_same_filled_page(struct zram *zram, unsigned long fill,
 				  u32 index)
 {
-	zram_slot_lock(zram, index);
-	zram_slot_free(zram, index);
-	zram_set_flag(zram, index, ZRAM_SAME);
-	zram_set_handle(zram, index, fill);
-	zram_slot_unlock(zram, index);
+	slot_lock(zram, index);
+	slot_free(zram, index);
+	set_slot_flag(zram, index, ZRAM_SAME);
+	set_slot_handle(zram, index, fill);
+	slot_unlock(zram, index);
 
 	atomic64_inc(&zram->stats.same_pages);
 	atomic64_inc(&zram->stats.pages_stored);
@@ -2244,12 +2245,12 @@ static int write_incompressible_page(struct zram *zram, struct page *page,
 	zs_obj_write(zram->mem_pool, handle, src, PAGE_SIZE);
 	kunmap_local(src);
 
-	zram_slot_lock(zram, index);
-	zram_slot_free(zram, index);
-	zram_set_flag(zram, index, ZRAM_HUGE);
-	zram_set_handle(zram, index, handle);
-	zram_set_obj_size(zram, index, PAGE_SIZE);
-	zram_slot_unlock(zram, index);
+	slot_lock(zram, index);
+	slot_free(zram, index);
+	set_slot_flag(zram, index, ZRAM_HUGE);
+	set_slot_handle(zram, index, handle);
+	set_slot_size(zram, index, PAGE_SIZE);
+	slot_unlock(zram, index);
 
 	atomic64_add(PAGE_SIZE, &zram->stats.compr_data_size);
 	atomic64_inc(&zram->stats.huge_pages);
@@ -2309,11 +2310,11 @@ static int zram_write_page(struct zram *zram, struct page *page, u32 index)
 	zs_obj_write(zram->mem_pool, handle, zstrm->buffer, comp_len);
 	zcomp_stream_put(zstrm);
 
-	zram_slot_lock(zram, index);
-	zram_slot_free(zram, index);
-	zram_set_handle(zram, index, handle);
-	zram_set_obj_size(zram, index, comp_len);
-	zram_slot_unlock(zram, index);
+	slot_lock(zram, index);
+	slot_free(zram, index);
+	set_slot_handle(zram, index, handle);
+	set_slot_size(zram, index, comp_len);
+	slot_unlock(zram, index);
 
 	/* Update stats */
 	atomic64_inc(&zram->stats.pages_stored);
@@ -2364,30 +2365,30 @@ static int scan_slots_for_recompress(struct zram *zram, u32 mode, u32 prio_max,
 	for (index = 0; index < nr_pages; index++) {
 		bool ok = true;
 
-		zram_slot_lock(zram, index);
-		if (!zram_allocated(zram, index))
+		slot_lock(zram, index);
+		if (!slot_allocated(zram, index))
 			goto next;
 
 		if (mode & RECOMPRESS_IDLE &&
-		    !zram_test_flag(zram, index, ZRAM_IDLE))
+		    !test_slot_flag(zram, index, ZRAM_IDLE))
 			goto next;
 
 		if (mode & RECOMPRESS_HUGE &&
-		    !zram_test_flag(zram, index, ZRAM_HUGE))
+		    !test_slot_flag(zram, index, ZRAM_HUGE))
 			goto next;
 
-		if (zram_test_flag(zram, index, ZRAM_WB) ||
-		    zram_test_flag(zram, index, ZRAM_SAME) ||
-		    zram_test_flag(zram, index, ZRAM_INCOMPRESSIBLE))
+		if (test_slot_flag(zram, index, ZRAM_WB) ||
+		    test_slot_flag(zram, index, ZRAM_SAME) ||
+		    test_slot_flag(zram, index, ZRAM_INCOMPRESSIBLE))
 			goto next;
 
 		/* Already compressed with same of higher priority */
-		if (zram_get_priority(zram, index) + 1 >= prio_max)
+		if (get_slot_comp_priority(zram, index) + 1 >= prio_max)
 			goto next;
 
 		ok = place_pp_slot(zram, ctl, index);
 next:
-		zram_slot_unlock(zram, index);
+		slot_unlock(zram, index);
 		if (!ok)
 			break;
 	}
@@ -2416,11 +2417,11 @@ static int recompress_slot(struct zram *zram, u32 index, struct page *page,
 	void *src;
 	int ret = 0;
 
-	handle_old = zram_get_handle(zram, index);
+	handle_old = get_slot_handle(zram, index);
 	if (!handle_old)
 		return -EINVAL;
 
-	comp_len_old = zram_get_obj_size(zram, index);
+	comp_len_old = get_slot_size(zram, index);
 	/*
 	 * Do not recompress objects that are already "small enough".
 	 */
@@ -2436,11 +2437,11 @@ static int recompress_slot(struct zram *zram, u32 index, struct page *page,
 	 * we don't preserve IDLE flag and don't incorrectly pick this entry
 	 * for different post-processing type (e.g. writeback).
 	 */
-	zram_clear_flag(zram, index, ZRAM_IDLE);
+	clear_slot_flag(zram, index, ZRAM_IDLE);
 
 	class_index_old = zs_lookup_class_index(zram->mem_pool, comp_len_old);
 
-	prio = max(prio, zram_get_priority(zram, index) + 1);
+	prio = max(prio, get_slot_comp_priority(zram, index) + 1);
 	/*
 	 * Recompression slots scan should not select slots that are
 	 * already compressed with a higher priority algorithm, but
@@ -2507,7 +2508,7 @@ static int recompress_slot(struct zram *zram, u32 index, struct page *page,
 		 */
 		if (prio < zram->num_active_comps)
 			return 0;
-		zram_set_flag(zram, index, ZRAM_INCOMPRESSIBLE);
+		set_slot_flag(zram, index, ZRAM_INCOMPRESSIBLE);
 		return 0;
 	}
 
@@ -2532,10 +2533,10 @@ static int recompress_slot(struct zram *zram, u32 index, struct page *page,
 	zs_obj_write(zram->mem_pool, handle_new, zstrm->buffer, comp_len_new);
 	zcomp_stream_put(zstrm);
 
-	zram_slot_free(zram, index);
-	zram_set_handle(zram, index, handle_new);
-	zram_set_obj_size(zram, index, comp_len_new);
-	zram_set_priority(zram, index, prio);
+	slot_free(zram, index);
+	set_slot_handle(zram, index, handle_new);
+	set_slot_size(zram, index, comp_len_new);
+	set_slot_comp_priority(zram, index, prio);
 
 	atomic64_add(comp_len_new, &zram->stats.compr_data_size);
 	atomic64_inc(&zram->stats.pages_stored);
@@ -2675,15 +2676,15 @@ static ssize_t recompress_store(struct device *dev,
 		if (!num_recomp_pages)
 			break;
 
-		zram_slot_lock(zram, pps->index);
-		if (!zram_test_flag(zram, pps->index, ZRAM_PP_SLOT))
+		slot_lock(zram, pps->index);
+		if (!test_slot_flag(zram, pps->index, ZRAM_PP_SLOT))
 			goto next;
 
 		err = recompress_slot(zram, pps->index, page,
 				      &num_recomp_pages, threshold,
 				      prio, prio_max);
 next:
-		zram_slot_unlock(zram, pps->index);
+		slot_unlock(zram, pps->index);
 		release_pp_slot(zram, pps);
 
 		if (err) {
@@ -2729,9 +2730,9 @@ static void zram_bio_discard(struct zram *zram, struct bio *bio)
 	}
 
 	while (n >= PAGE_SIZE) {
-		zram_slot_lock(zram, index);
-		zram_slot_free(zram, index);
-		zram_slot_unlock(zram, index);
+		slot_lock(zram, index);
+		slot_free(zram, index);
+		slot_unlock(zram, index);
 		atomic64_inc(&zram->stats.notify_free);
 		index++;
 		n -= PAGE_SIZE;
@@ -2760,9 +2761,9 @@ static void zram_bio_read(struct zram *zram, struct bio *bio)
 		}
 		flush_dcache_page(bv.bv_page);
 
-		zram_slot_lock(zram, index);
-		zram_accessed(zram, index);
-		zram_slot_unlock(zram, index);
+		slot_lock(zram, index);
+		mark_slot_accessed(zram, index);
+		slot_unlock(zram, index);
 
 		bio_advance_iter_single(bio, &iter, bv.bv_len);
 	} while (iter.bi_size);
@@ -2790,9 +2791,9 @@ static void zram_bio_write(struct zram *zram, struct bio *bio)
 			break;
 		}
 
-		zram_slot_lock(zram, index);
-		zram_accessed(zram, index);
-		zram_slot_unlock(zram, index);
+		slot_lock(zram, index);
+		mark_slot_accessed(zram, index);
+		slot_unlock(zram, index);
 
 		bio_advance_iter_single(bio, &iter, bv.bv_len);
 	} while (iter.bi_size);
@@ -2833,13 +2834,13 @@ static void zram_slot_free_notify(struct block_device *bdev,
 	zram = bdev->bd_disk->private_data;
 
 	atomic64_inc(&zram->stats.notify_free);
-	if (!zram_slot_trylock(zram, index)) {
+	if (!slot_trylock(zram, index)) {
 		atomic64_inc(&zram->stats.miss_free);
 		return;
 	}
 
-	zram_slot_free(zram, index);
-	zram_slot_unlock(zram, index);
+	slot_free(zram, index);
+	slot_unlock(zram, index);
 }
 
 static void zram_comp_params_reset(struct zram *zram)
-- 
cgit v1.2.3


From 4932844eb87076a8c51bc6bcf8bfcf7ad30edd75 Mon Sep 17 00:00:00 2001
From: Sergey Senozhatsky <senozhatsky@chromium.org>
Date: Mon, 15 Dec 2025 14:47:13 +0900
Subject: zram: trivial fix of recompress_slot() coding styles

A minor fixup of 80-cols breakage in recompress_slot() comment and
zs_malloc() call.

Link: https://lkml.kernel.org/r/ff3254847dbdc6fbd2e3fed53c572a261d60b7b6.1765775954.git.senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Brian Geffon <bgeffon@google.com>
Cc: David Stevens <stevensd@google.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Richard Chang <richardycc@google.com>
Cc: Chris Mason <clm@meta.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/block/zram/zram_drv.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

(limited to 'drivers')

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index bd9a37fca675..df30150e6ed8 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -2517,14 +2517,15 @@ static int recompress_slot(struct zram *zram, u32 index, struct page *page,
 	 * avoid direct reclaim.  Allocation error is not fatal since
 	 * we still have the old object in the mem_pool.
 	 *
-	 * XXX: technically, the node we really want here is the node that holds
-	 * the original compressed data. But that would require us to modify
-	 * zsmalloc API to return this information. For now, we will make do with
-	 * the node of the page allocated for recompression.
+	 * XXX: technically, the node we really want here is the node that
+	 * holds the original compressed data. But that would require us to
+	 * modify zsmalloc API to return this information. For now, we will
+	 * make do with the node of the page allocated for recompression.
 	 */
 	handle_new = zs_malloc(zram->mem_pool, comp_len_new,
 			       GFP_NOIO | __GFP_NOWARN |
-			       __GFP_HIGHMEM | __GFP_MOVABLE, page_to_nid(page));
+			       __GFP_HIGHMEM | __GFP_MOVABLE,
+			       page_to_nid(page));
 	if (IS_ERR_VALUE(handle_new)) {
 		zcomp_stream_put(zstrm);
 		return PTR_ERR((void *)handle_new);
-- 
cgit v1.2.3


From 8b05d2d8af817c6a1e23032df51e7ad83030d543 Mon Sep 17 00:00:00 2001
From: Sergey Senozhatsky <senozhatsky@chromium.org>
Date: Thu, 15 Jan 2026 12:30:06 +0900
Subject: zram: fixup read_block_state()

ac_time is now in seconds, do not use ktime_to_timespec64()

[akpm@linux-foundation.org: remove now-unused local `ts']
[akpm@linux-foundation.org: fix build]
Link: https://lkml.kernel.org/r/20260115033031.3818977-1-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reported-by: Chris Mason <clm@meta.com>
Closes: https://lkml.kernel.org/r/20260114124522.1326519-1-clm@meta.com
Cc: Brian Geffon <bgeffon@google.com>
Cc: David Stevens <stevensd@google.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Richard Chang <richardycc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/block/zram/zram_drv.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

(limited to 'drivers')

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index df30150e6ed8..7dcfc71d2cac 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1570,7 +1570,6 @@ static ssize_t read_block_state(struct file *file, char __user *buf,
 	ssize_t index, written = 0;
 	struct zram *zram = file->private_data;
 	unsigned long nr_pages = zram->disksize >> PAGE_SHIFT;
-	struct timespec64 ts;
 
 	kbuf = kvmalloc(count, GFP_KERNEL);
 	if (!kbuf)
@@ -1589,11 +1588,9 @@ static ssize_t read_block_state(struct file *file, char __user *buf,
 		if (!slot_allocated(zram, index))
 			goto next;
 
-		ts = ktime_to_timespec64(zram->table[index].attr.ac_time);
 		copied = snprintf(kbuf + written, count,
-			"%12zd %12lld.%06lu %c%c%c%c%c%c\n",
-			index, (s64)ts.tv_sec,
-			ts.tv_nsec / NSEC_PER_USEC,
+			"%12zd %12u.%06d %c%c%c%c%c%c\n",
+			index, zram->table[index].attr.ac_time, 0,
 			test_slot_flag(zram, index, ZRAM_SAME) ? 's' : '.',
 			test_slot_flag(zram, index, ZRAM_WB) ? 'w' : '.',
 			test_slot_flag(zram, index, ZRAM_HUGE) ? 'h' : '.',
-- 
cgit v1.2.3


From 657a81fe3b41bd58c63e15ae282f992dda5c8eee Mon Sep 17 00:00:00 2001
From: Sergey Senozhatsky <senozhatsky@chromium.org>
Date: Tue, 16 Dec 2025 16:13:42 +0900
Subject: zram: drop pp_in_progress

pp_in_progress makes sure that only one post-processing (writeback or
recomrpession) is active at any given time.  Functionality wise it,
basically, shadows zram init_lock, when init_lock is acquired in writer
mode.

Switch recompress_store() and writeback_store() to take zram init_lock in
writer mode, like all store() sysfs handlers should do, so that we can
drop pp_in_progress.  Recompression and writeback can be somewhat slow, so
holding init_lock in writer mode can block zram attrs reads, but in
reality the only zram attrs reads that take place are mm_stat reads, and
usually it's the same process that reads mm_stat and does recompression or
writeback.

Link: https://lkml.kernel.org/r/20251216071342.687993-1-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/block/zram/zram_drv.c | 32 ++++++++------------------------
 drivers/block/zram/zram_drv.h |  1 -
 2 files changed, 8 insertions(+), 25 deletions(-)

(limited to 'drivers')

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 7dcfc71d2cac..ed717b65f0a9 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -902,7 +902,7 @@ release_wb_ctl:
 
 static void zram_account_writeback_rollback(struct zram *zram)
 {
-	lockdep_assert_held_read(&zram->init_lock);
+	lockdep_assert_held_write(&zram->init_lock);
 
 	if (zram->wb_limit_enable)
 		zram->bd_wb_limit +=  1UL << (PAGE_SHIFT - 12);
@@ -910,7 +910,7 @@ static void zram_account_writeback_rollback(struct zram *zram)
 
 static void zram_account_writeback_submit(struct zram *zram)
 {
-	lockdep_assert_held_read(&zram->init_lock);
+	lockdep_assert_held_write(&zram->init_lock);
 
 	if (zram->wb_limit_enable && zram->bd_wb_limit > 0)
 		zram->bd_wb_limit -=  1UL << (PAGE_SHIFT - 12);
@@ -1264,24 +1264,16 @@ static ssize_t writeback_store(struct device *dev,
 	ssize_t ret = len;
 	int err, mode = 0;
 
-	guard(rwsem_read)(&zram->init_lock);
+	guard(rwsem_write)(&zram->init_lock);
 	if (!init_done(zram))
 		return -EINVAL;
 
-	/* Do not permit concurrent post-processing actions. */
-	if (atomic_xchg(&zram->pp_in_progress, 1))
-		return -EAGAIN;
-
-	if (!zram->backing_dev) {
-		ret = -ENODEV;
-		goto out;
-	}
+	if (!zram->backing_dev)
+		return -ENODEV;
 
 	pp_ctl = init_pp_ctl();
-	if (!pp_ctl) {
-		ret = -ENOMEM;
-		goto out;
-	}
+	if (!pp_ctl)
+		return -ENOMEM;
 
 	wb_ctl = init_wb_ctl(zram);
 	if (!wb_ctl) {
@@ -1358,7 +1350,6 @@ static ssize_t writeback_store(struct device *dev,
 out:
 	release_pp_ctl(zram, pp_ctl);
 	release_wb_ctl(wb_ctl);
-	atomic_set(&zram->pp_in_progress, 0);
 
 	return ret;
 }
@@ -2619,14 +2610,10 @@ static ssize_t recompress_store(struct device *dev,
 	if (threshold >= huge_class_size)
 		return -EINVAL;
 
-	guard(rwsem_read)(&zram->init_lock);
+	guard(rwsem_write)(&zram->init_lock);
 	if (!init_done(zram))
 		return -EINVAL;
 
-	/* Do not permit concurrent post-processing actions. */
-	if (atomic_xchg(&zram->pp_in_progress, 1))
-		return -EAGAIN;
-
 	if (algo) {
 		bool found = false;
 
@@ -2697,7 +2684,6 @@ out:
 	if (page)
 		__free_page(page);
 	release_pp_ctl(zram, ctl);
-	atomic_set(&zram->pp_in_progress, 0);
 	return ret;
 }
 #endif
@@ -2888,7 +2874,6 @@ static void zram_reset_device(struct zram *zram)
 	zram->disksize = 0;
 	zram_destroy_comps(zram);
 	memset(&zram->stats, 0, sizeof(zram->stats));
-	atomic_set(&zram->pp_in_progress, 0);
 	reset_bdev(zram);
 
 	comp_algorithm_set(zram, ZRAM_PRIMARY_COMP, default_compressor);
@@ -3124,7 +3109,6 @@ static int zram_add(void)
 	zram->disk->fops = &zram_devops;
 	zram->disk->private_data = zram;
 	snprintf(zram->disk->disk_name, 16, "zram%d", device_id);
-	atomic_set(&zram->pp_in_progress, 0);
 	zram_comp_params_reset(zram);
 	comp_algorithm_set(zram, ZRAM_PRIMARY_COMP, default_compressor);
 
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index 48d6861c6647..469a3dab44ad 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -143,6 +143,5 @@ struct zram {
 #ifdef CONFIG_ZRAM_MEMORY_TRACKING
 	struct dentry *debugfs_dir;
 #endif
-	atomic_t pp_in_progress;
 };
 #endif
-- 
cgit v1.2.3


From a9853ac1c3bcf79cef46046529a3f7912ff5ecee Mon Sep 17 00:00:00 2001
From: Heiko Carstens <hca@linux.ibm.com>
Date: Wed, 26 Nov 2025 15:36:02 +0100
Subject: zram: remove KMSG_COMPONENT macro

The KMSG_COMPONENT macro is a leftover of the s390 specific "kernel
message catalog" from 2008 [1] which never made it upstream.

The macro was added to s390 code to allow for an out-of-tree patch which
used this to generate unique message ids.  Also this out-of-tree doesn't
exist anymore.

The pattern of how the KMSG_COMPONENT is used was partially also used for
non s390 specific code, for whatever reasons.

Remove the macro in order to get rid of a pointless indirection.

Link: https://lkml.kernel.org/r/20251126143602.2207435-1-hca@linux.ibm.com
Link: https://lwn.net/Articles/292650/ [1]
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/block/zram/zram_drv.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

(limited to 'drivers')

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index ed717b65f0a9..1d6760b3b557 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -12,8 +12,7 @@
  *
  */
 
-#define KMSG_COMPONENT "zram"
-#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+#define pr_fmt(fmt) "zram: " fmt
 
 #include <linux/module.h>
 #include <linux/kernel.h>
-- 
cgit v1.2.3


From 0be909f114c4e82a4fe5964851af1ab8889dc76c Mon Sep 17 00:00:00 2001
From: Sergey Senozhatsky <senozhatsky@chromium.org>
Date: Wed, 7 Jan 2026 14:21:44 +0900
Subject: zsmalloc: use actual object size to detect spans

Using class->size to detect spanning objects is not entirely correct,
because some size classes can hold a range of object sizes of up to
class->size bytes in length, due to size-classes merge.  Such classes use
padding for cases when actually written objects are smaller than
class->size.  zs_obj_read_begin() can incorrectly hit the slow path and
perform memcpy of such objects, basically copying padding bytes.  Instead
of class->size zs_obj_read_begin() should use the actual compressed object
length (both zram and zswap know it) so that it can correctly handle
situations when a written object is small enough to fit into the first
physical page.

Link: https://lkml.kernel.org/r/20260107052145.3586917-1-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Yosry Ahmed <yosry.ahmed@linux.dev>	[zsmalloc & zswap]
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/block/zram/zram_drv.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

(limited to 'drivers')

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 1d6760b3b557..f92845ef9192 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -2062,11 +2062,11 @@ static int read_incompressible_page(struct zram *zram, struct page *page,
 	void *src, *dst;
 
 	handle = get_slot_handle(zram, index);
-	src = zs_obj_read_begin(zram->mem_pool, handle, NULL);
+	src = zs_obj_read_begin(zram->mem_pool, handle, PAGE_SIZE, NULL);
 	dst = kmap_local_page(page);
 	copy_page(dst, src);
 	kunmap_local(dst);
-	zs_obj_read_end(zram->mem_pool, handle, src);
+	zs_obj_read_end(zram->mem_pool, handle, PAGE_SIZE, src);
 
 	return 0;
 }
@@ -2084,11 +2084,12 @@ static int read_compressed_page(struct zram *zram, struct page *page, u32 index)
 	prio = get_slot_comp_priority(zram, index);
 
 	zstrm = zcomp_stream_get(zram->comps[prio]);
-	src = zs_obj_read_begin(zram->mem_pool, handle, zstrm->local_copy);
+	src = zs_obj_read_begin(zram->mem_pool, handle, size,
+				zstrm->local_copy);
 	dst = kmap_local_page(page);
 	ret = zcomp_decompress(zram->comps[prio], zstrm, src, size, dst);
 	kunmap_local(dst);
-	zs_obj_read_end(zram->mem_pool, handle, src);
+	zs_obj_read_end(zram->mem_pool, handle, size, src);
 	zcomp_stream_put(zstrm);
 
 	return ret;
@@ -2111,9 +2112,10 @@ static int read_from_zspool_raw(struct zram *zram, struct page *page, u32 index)
 	 * takes place here, as we read raw compressed data.
 	 */
 	zstrm = zcomp_stream_get(zram->comps[ZRAM_PRIMARY_COMP]);
-	src = zs_obj_read_begin(zram->mem_pool, handle, zstrm->local_copy);
+	src = zs_obj_read_begin(zram->mem_pool, handle, size,
+				zstrm->local_copy);
 	memcpy_to_page(page, 0, src, size);
-	zs_obj_read_end(zram->mem_pool, handle, src);
+	zs_obj_read_end(zram->mem_pool, handle, size, src);
 	zcomp_stream_put(zstrm);
 
 	return 0;
-- 
cgit v1.2.3


From 6e31add91a10e3804f020ec4e87cb9c3b2b6c3ec Mon Sep 17 00:00:00 2001
From: "David Hildenbrand (Red Hat)" <david@kernel.org>
Date: Tue, 20 Jan 2026 00:01:09 +0100
Subject: vmw_balloon: adjust BALLOON_DEFLATE when deflating while migrating
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Patch series "mm: balloon infrastructure cleanups", v3.

I started with wanting to remove the dependency of the balloon
infrastructure on the page lock, but ended up performing various other
cleanups, some of which I had on my todo list for years.

This series heavily cleans up and simplifies our balloon infrastructure,
including our balloon page migration functionality.

With this series, we no longer make use of the page lock for PageOffline
pages as part of the balloon infrastructure (preparing for memdescs where
PageOffline pages won't have any such lock), and simplifies migration
handling such that refcounting can more easily be adjusted later
(long-term focus is for PageOffline pages to not have a refcount either).

Plenty of related cleanups.


This patch (of 24):

When we're effectively deflating the balloon while migrating a page
because inflating the new page failed, we're not adjusting
BALLOON_DEFLATE.

Let's do that.  This is a preparation for factoring out this handling to
the core code, making it work in a similar way first.

As this (deflating while migrating because of inflation error) is a corner
case that I don't really expect to happen in practice and the stats are
not that crucial, this likely doesn't classify as a fix.

Link: https://lkml.kernel.org/r/20260119230133.3551867-1-david@kernel.org
Link: https://lkml.kernel.org/r/20260119230133.3551867-2-david@kernel.org
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Eugenio Pérez <eperezma@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/misc/vmw_balloon.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'drivers')

diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index cc1d18b3df5c..2cc34c4968fa 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -1818,6 +1818,8 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
 	if (status == VMW_BALLOON_SUCCESS) {
 		balloon_page_insert(&b->b_dev_info, newpage);
 		__count_vm_event(BALLOON_MIGRATE);
+	} else {
+		__count_vm_event(BALLOON_DEFLATE);
 	}
 
 	/*
-- 
cgit v1.2.3


From d2346b09c51574fd6c281e3b8092116df1e42f81 Mon Sep 17 00:00:00 2001
From: "David Hildenbrand (Red Hat)" <david@kernel.org>
Date: Tue, 20 Jan 2026 00:01:10 +0100
Subject: vmw_balloon: remove vmballoon_compaction_init()
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Now that there is not a lot of logic left, let's just inline setting up
the migration function and drop all these excessive comments that are not
really required (or true) anymore.

To avoid #ifdef in the caller we can instead use IS_ENABLED() and make the
compiler happy by only providing the function declaration.

Link: https://lkml.kernel.org/r/20260119230133.3551867-3-david@kernel.org
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Eugenio Pérez <eperezma@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/misc/vmw_balloon.c | 30 +++++-------------------------
 1 file changed, 5 insertions(+), 25 deletions(-)

(limited to 'drivers')

diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index 2cc34c4968fa..07e60a4b846a 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -1833,27 +1833,10 @@ out_unlock:
 	up_read(&b->conf_sem);
 	return ret;
 }
-
-/**
- * vmballoon_compaction_init() - initialized compaction for the balloon.
- *
- * @b: pointer to the balloon.
- *
- * If during the initialization a failure occurred, this function does not
- * perform cleanup. The caller must call vmballoon_compaction_deinit() in this
- * case.
- *
- * Return: zero on success or error code on failure.
- */
-static __init void vmballoon_compaction_init(struct vmballoon *b)
-{
-	b->b_dev_info.migratepage = vmballoon_migratepage;
-}
-
 #else /* CONFIG_BALLOON_COMPACTION */
-static inline void vmballoon_compaction_init(struct vmballoon *b)
-{
-}
+int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
+			  struct page *newpage, struct page *page,
+			  enum migrate_mode mode);
 #endif /* CONFIG_BALLOON_COMPACTION */
 
 static int __init vmballoon_init(void)
@@ -1873,12 +1856,9 @@ static int __init vmballoon_init(void)
 	if (error)
 		return error;
 
-	/*
-	 * Initialization of compaction must be done after the call to
-	 * balloon_devinfo_init() .
-	 */
 	balloon_devinfo_init(&balloon.b_dev_info);
-	vmballoon_compaction_init(&balloon);
+	if (IS_ENABLED(CONFIG_BALLOON_COMPACTION))
+		balloon.b_dev_info.migratepage = vmballoon_migratepage;
 
 	INIT_LIST_HEAD(&balloon.huge_pages);
 	spin_lock_init(&balloon.comm_lock);
-- 
cgit v1.2.3


From 1258460bd31ed6e0d504adeaf9df7e6c1b348d14 Mon Sep 17 00:00:00 2001
From: "David Hildenbrand (Red Hat)" <david@kernel.org>
Date: Tue, 20 Jan 2026 00:01:13 +0100
Subject: mm/balloon_compaction: centralize basic page migration handling
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Let's update the balloon page references, the balloon page list, the
BALLOON_MIGRATE counter and the isolated-pages counter in
balloon_page_migrate(), after letting the balloon->migratepage() callback
deal with the actual inflation+deflation.

Note that we now perform the balloon list modifications outside of any
implementation-specific locks: which is fine, there is nothing special
about these page actions that the lock would be protecting.

The old page is already no longer in the list (isolated) and the new page
is not yet in the list.

Let's use -ENOENT to communicate the special "inflation of new page failed
after already deflating the old page" to balloon_page_migrate() so it can
handle it accordingly.

While at it, rename balloon->b_dev_info to make it match the other
functions.  Also, drop the comment above balloon_page_migrate(), which
seems unnecessary.

Link: https://lkml.kernel.org/r/20260119230133.3551867-6-david@kernel.org
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Eugenio Pérez <eperezma@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/misc/vmw_balloon.c      | 49 +++++++----------------------------------
 drivers/virtio/virtio_balloon.c | 12 ----------
 2 files changed, 8 insertions(+), 53 deletions(-)

(limited to 'drivers')

diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index 07e60a4b846a..52b8c0f1eead 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -1724,18 +1724,17 @@ static inline void vmballoon_debugfs_exit(struct vmballoon *b)
  * @page: a ballooned page that should be migrated.
  * @mode: migration mode, ignored.
  *
- * This function is really open-coded, but that is according to the interface
- * that balloon_compaction provides.
- *
  * Return: zero on success, -EAGAIN when migration cannot be performed
- *	   momentarily, and -EBUSY if migration failed and should be retried
- *	   with that specific page.
+ *	   momentarily, -EBUSY if migration failed and should be retried
+ *	   with that specific page, and -ENOENT when deflating @page
+ *	   succeeded but inflating @newpage failed, effectively deflating
+ *	   the balloon.
  */
 static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
 				 struct page *newpage, struct page *page,
 				 enum migrate_mode mode)
 {
-	unsigned long status, flags;
+	unsigned long status;
 	struct vmballoon *b;
 	int ret = 0;
 
@@ -1773,14 +1772,6 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
 		goto out_unlock;
 	}
 
-	/*
-	 * The page is isolated, so it is safe to delete it without holding
-	 * @pages_lock . We keep holding @comm_lock since we will need it in a
-	 * second.
-	 */
-	balloon_page_finalize(page);
-	put_page(page);
-
 	/* Inflate */
 	vmballoon_add_page(b, 0, newpage);
 	status = vmballoon_lock_op(b, 1, VMW_BALLOON_4K_PAGE,
@@ -1799,36 +1790,12 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
 		 * change.
 		 */
 		atomic64_dec(&b->size);
-	} else {
 		/*
-		 * Success. Take a reference for the page, and we will add it to
-		 * the list after acquiring the lock.
+		 * Tell the core that we're deflating the old page and don't
+		 * need the new page.
 		 */
-		get_page(newpage);
-	}
-
-	/* Update the balloon list under the @pages_lock */
-	spin_lock_irqsave(&b->b_dev_info.pages_lock, flags);
-
-	/*
-	 * On inflation success, we already took a reference for the @newpage.
-	 * If we succeed just insert it to the list and update the statistics
-	 * under the lock.
-	 */
-	if (status == VMW_BALLOON_SUCCESS) {
-		balloon_page_insert(&b->b_dev_info, newpage);
-		__count_vm_event(BALLOON_MIGRATE);
-	} else {
-		__count_vm_event(BALLOON_DEFLATE);
+		ret = -ENOENT;
 	}
-
-	/*
-	 * We deflated successfully, so regardless to the inflation success, we
-	 * need to reduce the number of isolated_pages.
-	 */
-	b->b_dev_info.isolated_pages--;
-	spin_unlock_irqrestore(&b->b_dev_info.pages_lock, flags);
-
 out_unlock:
 	up_read(&b->conf_sem);
 	return ret;
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 74fe59f5a78c..df2756c071da 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -827,7 +827,6 @@ static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info,
 {
 	struct virtio_balloon *vb = container_of(vb_dev_info,
 			struct virtio_balloon, vb_dev_info);
-	unsigned long flags;
 
 	/*
 	 * In order to avoid lock contention while migrating pages concurrently
@@ -840,8 +839,6 @@ static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info,
 	if (!mutex_trylock(&vb->balloon_lock))
 		return -EAGAIN;
 
-	get_page(newpage); /* balloon reference */
-
 	/*
 	  * When we migrate a page to a different zone and adjusted the
 	  * managed page count when inflating, we have to fixup the count of
@@ -854,11 +851,6 @@ static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info,
 	}
 
 	/* balloon's page migration 1st step  -- inflate "newpage" */
-	spin_lock_irqsave(&vb_dev_info->pages_lock, flags);
-	balloon_page_insert(vb_dev_info, newpage);
-	vb_dev_info->isolated_pages--;
-	__count_vm_event(BALLOON_MIGRATE);
-	spin_unlock_irqrestore(&vb_dev_info->pages_lock, flags);
 	vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE;
 	set_page_pfns(vb, vb->pfns, newpage);
 	tell_host(vb, vb->inflate_vq);
@@ -869,10 +861,6 @@ static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info,
 	tell_host(vb, vb->deflate_vq);
 
 	mutex_unlock(&vb->balloon_lock);
-
-	balloon_page_finalize(page);
-	put_page(page); /* balloon reference */
-
 	return 0;
 }
 #endif /* CONFIG_BALLOON_COMPACTION */
-- 
cgit v1.2.3


From a00de9ba30aa71fe68ab45a9d2df595a7c39dd74 Mon Sep 17 00:00:00 2001
From: "David Hildenbrand (Red Hat)" <david@kernel.org>
Date: Tue, 20 Jan 2026 00:01:14 +0100
Subject: mm/balloon_compaction: centralize adjust_managed_page_count()
 handling
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Let's centralize it, by allowing for the driver to enable this handling
through a new flag (bool for now) in the balloon device info.

Note that we now adjust the counter when adding/removing a page into the
balloon list: when removing a page to deflate it, it will now happen
before the driver communicated with hypervisor, not afterwards.

This shouldn't make a difference in practice.

Link: https://lkml.kernel.org/r/20260119230133.3551867-7-david@kernel.org
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
Acked-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Eugenio Pérez <eperezma@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/virtio/virtio_balloon.c | 19 ++-----------------
 1 file changed, 2 insertions(+), 17 deletions(-)

(limited to 'drivers')

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index df2756c071da..15c1cf5fd249 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -274,9 +274,6 @@ static unsigned int fill_balloon(struct virtio_balloon *vb, size_t num)
 
 		set_page_pfns(vb, vb->pfns + vb->num_pfns, page);
 		vb->num_pages += VIRTIO_BALLOON_PAGES_PER_PAGE;
-		if (!virtio_has_feature(vb->vdev,
-					VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
-			adjust_managed_page_count(page, -1);
 		vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE;
 	}
 
@@ -295,9 +292,6 @@ static void release_pages_balloon(struct virtio_balloon *vb,
 	struct page *page, *next;
 
 	list_for_each_entry_safe(page, next, pages, lru) {
-		if (!virtio_has_feature(vb->vdev,
-					VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
-			adjust_managed_page_count(page, 1);
 		list_del(&page->lru);
 		put_page(page); /* balloon reference */
 	}
@@ -839,17 +833,6 @@ static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info,
 	if (!mutex_trylock(&vb->balloon_lock))
 		return -EAGAIN;
 
-	/*
-	  * When we migrate a page to a different zone and adjusted the
-	  * managed page count when inflating, we have to fixup the count of
-	  * both involved zones.
-	  */
-	if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM) &&
-	    page_zone(page) != page_zone(newpage)) {
-		adjust_managed_page_count(page, 1);
-		adjust_managed_page_count(newpage, -1);
-	}
-
 	/* balloon's page migration 1st step  -- inflate "newpage" */
 	vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE;
 	set_page_pfns(vb, vb->pfns, newpage);
@@ -958,6 +941,8 @@ static int virtballoon_probe(struct virtio_device *vdev)
 	if (err)
 		goto out_free_vb;
 
+	if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
+		vb->vb_dev_info.adjust_managed_page_count = true;
 #ifdef CONFIG_BALLOON_COMPACTION
 	vb->vb_dev_info.migratepage = virtballoon_migratepage;
 #endif
-- 
cgit v1.2.3


From c33b47c334f933d846cadf7c2cff24433e5b3bb0 Mon Sep 17 00:00:00 2001
From: "David Hildenbrand (Red Hat)" <david@kernel.org>
Date: Tue, 20 Jan 2026 00:01:15 +0100
Subject: vmw_balloon: stop using the balloon_dev_info lock
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Let's not piggy-back on the existing lock and use a separate lock for the
huge page list.  Now that we use a separate lock, there is no need to
disable interrupts, so use the non-irqsave variants.  We only required the
irqsave variants because of the balloon device lock.

This is a preparation for changing the locking used to protect
balloon_dev_info.

While at it, talk about "page migration" instead of "page compaction".
We'll change that in core code soon as well.

Link: https://lkml.kernel.org/r/20260119230133.3551867-8-david@kernel.org
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Eugenio Pérez <eperezma@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/misc/vmw_balloon.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

(limited to 'drivers')

diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index 52b8c0f1eead..53e9335b6718 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -354,10 +354,15 @@ struct vmballoon {
 	/**
 	 * @huge_pages - list of the inflated 2MB pages.
 	 *
-	 * Protected by @b_dev_info.pages_lock .
+	 * Protected by @huge_pages_lock.
 	 */
 	struct list_head huge_pages;
 
+	/**
+	 * @huge_pages_lock: lock for the list of inflated 2MB pages.
+	 */
+	spinlock_t huge_pages_lock;
+
 	/**
 	 * @vmci_doorbell.
 	 *
@@ -987,7 +992,6 @@ static void vmballoon_enqueue_page_list(struct vmballoon *b,
 					unsigned int *n_pages,
 					enum vmballoon_page_size_type page_size)
 {
-	unsigned long flags;
 	struct page *page;
 
 	if (page_size == VMW_BALLOON_4K_PAGE) {
@@ -995,9 +999,9 @@ static void vmballoon_enqueue_page_list(struct vmballoon *b,
 	} else {
 		/*
 		 * Keep the huge pages in a local list which is not available
-		 * for the balloon compaction mechanism.
+		 * for the balloon page migration.
 		 */
-		spin_lock_irqsave(&b->b_dev_info.pages_lock, flags);
+		spin_lock(&b->huge_pages_lock);
 
 		list_for_each_entry(page, pages, lru) {
 			vmballoon_mark_page_offline(page, VMW_BALLOON_2M_PAGE);
@@ -1006,7 +1010,7 @@ static void vmballoon_enqueue_page_list(struct vmballoon *b,
 		list_splice_init(pages, &b->huge_pages);
 		__count_vm_events(BALLOON_INFLATE, *n_pages *
 				  vmballoon_page_in_frames(VMW_BALLOON_2M_PAGE));
-		spin_unlock_irqrestore(&b->b_dev_info.pages_lock, flags);
+		spin_unlock(&b->huge_pages_lock);
 	}
 
 	*n_pages = 0;
@@ -1033,7 +1037,6 @@ static void vmballoon_dequeue_page_list(struct vmballoon *b,
 {
 	struct page *page, *tmp;
 	unsigned int i = 0;
-	unsigned long flags;
 
 	/* In the case of 4k pages, use the compaction infrastructure */
 	if (page_size == VMW_BALLOON_4K_PAGE) {
@@ -1043,7 +1046,7 @@ static void vmballoon_dequeue_page_list(struct vmballoon *b,
 	}
 
 	/* 2MB pages */
-	spin_lock_irqsave(&b->b_dev_info.pages_lock, flags);
+	spin_lock(&b->huge_pages_lock);
 	list_for_each_entry_safe(page, tmp, &b->huge_pages, lru) {
 		vmballoon_mark_page_online(page, VMW_BALLOON_2M_PAGE);
 
@@ -1054,7 +1057,7 @@ static void vmballoon_dequeue_page_list(struct vmballoon *b,
 
 	__count_vm_events(BALLOON_DEFLATE,
 			  i * vmballoon_page_in_frames(VMW_BALLOON_2M_PAGE));
-	spin_unlock_irqrestore(&b->b_dev_info.pages_lock, flags);
+	spin_unlock(&b->huge_pages_lock);
 	*n_pages = i;
 }
 
@@ -1828,6 +1831,7 @@ static int __init vmballoon_init(void)
 		balloon.b_dev_info.migratepage = vmballoon_migratepage;
 
 	INIT_LIST_HEAD(&balloon.huge_pages);
+	spin_lock_init(&balloon.huge_pages_lock);
 	spin_lock_init(&balloon.comm_lock);
 	init_rwsem(&balloon.conf_sem);
 	balloon.vmci_doorbell = VMCI_INVALID_HANDLE;
-- 
cgit v1.2.3


From f7e15373143aba99a6ec51dc4db7187bff6c9a0a Mon Sep 17 00:00:00 2001
From: "David Hildenbrand (Red Hat)" <david@kernel.org>
Date: Tue, 20 Jan 2026 00:01:20 +0100
Subject: drivers/virtio/virtio_balloon: stop using balloon_page_push/pop()
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Let's stop using these functions so we can remove them.  They look like
belonging to the balloon API for managing the device balloon list when
really they are just simple helpers only used by virtio-balloon.

Let's just inline them and switch to a proper list_for_each_entry_safe().

Link: https://lkml.kernel.org/r/20260119230133.3551867-13-david@kernel.org
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Eugenio Pérez <eperezma@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/virtio/virtio_balloon.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

(limited to 'drivers')

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 15c1cf5fd249..6ae00de78b61 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -242,8 +242,8 @@ static void set_page_pfns(struct virtio_balloon *vb,
 static unsigned int fill_balloon(struct virtio_balloon *vb, size_t num)
 {
 	unsigned int num_allocated_pages;
+	struct page *page, *next;
 	unsigned int num_pfns;
-	struct page *page;
 	LIST_HEAD(pages);
 
 	/* We can only do one array worth at a time. */
@@ -262,14 +262,15 @@ static unsigned int fill_balloon(struct virtio_balloon *vb, size_t num)
 			break;
 		}
 
-		balloon_page_push(&pages, page);
+		list_add(&page->lru, &pages);
 	}
 
 	mutex_lock(&vb->balloon_lock);
 
 	vb->num_pfns = 0;
 
-	while ((page = balloon_page_pop(&pages))) {
+	list_for_each_entry_safe(page, next, &pages, lru) {
+		list_del(&page->lru);
 		balloon_page_enqueue(&vb->vb_dev_info, page);
 
 		set_page_pfns(vb, vb->pfns + vb->num_pfns, page);
@@ -474,15 +475,19 @@ static inline s64 towards_target(struct virtio_balloon *vb)
 static unsigned long return_free_pages_to_mm(struct virtio_balloon *vb,
 					     unsigned long num_to_return)
 {
-	struct page *page;
-	unsigned long num_returned;
+	unsigned long num_returned = 0;
+	struct page *page, *next;
+
+	if (unlikely(!num_to_return))
+		return 0;
 
 	spin_lock_irq(&vb->free_page_list_lock);
-	for (num_returned = 0; num_returned < num_to_return; num_returned++) {
-		page = balloon_page_pop(&vb->free_page_list);
-		if (!page)
-			break;
+
+	list_for_each_entry_safe(page, next, &vb->free_page_list, lru) {
+		list_del(&page->lru);
 		__free_pages(page, VIRTIO_BALLOON_HINT_BLOCK_ORDER);
+		if (++num_returned == num_to_return)
+			break;
 	}
 	vb->num_free_page_blocks -= num_returned;
 	spin_unlock_irq(&vb->free_page_list_lock);
@@ -717,7 +722,7 @@ static int get_free_page_and_send(struct virtio_balloon *vb)
 		}
 		virtqueue_kick(vq);
 		spin_lock_irq(&vb->free_page_list_lock);
-		balloon_page_push(&vb->free_page_list, page);
+		list_add(&page->lru, &vb->free_page_list);
 		vb->num_free_page_blocks++;
 		spin_unlock_irq(&vb->free_page_list_lock);
 	} else {
-- 
cgit v1.2.3


From 25b48b4cdf912f70998336b861a4bf767ee3d332 Mon Sep 17 00:00:00 2001
From: "David Hildenbrand (Red Hat)" <david@kernel.org>
Date: Tue, 20 Jan 2026 00:01:28 +0100
Subject: mm: rename balloon_compaction.(c|h) to balloon.(c|h)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Even without CONFIG_BALLOON_COMPACTION this infrastructure implements
basic list and page management for a memory balloon.

Link: https://lkml.kernel.org/r/20260119230133.3551867-21-david@kernel.org
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Eugenio Pérez <eperezma@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/misc/vmw_balloon.c      | 2 +-
 drivers/virtio/virtio_balloon.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

(limited to 'drivers')

diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index 53e9335b6718..7fd3f709108c 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -29,7 +29,7 @@
 #include <linux/rwsem.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
-#include <linux/balloon_compaction.h>
+#include <linux/balloon.h>
 #include <linux/vmw_vmci_defs.h>
 #include <linux/vmw_vmci_api.h>
 #include <asm/hypervisor.h>
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 6ae00de78b61..de8041c3285a 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -13,7 +13,7 @@
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/module.h>
-#include <linux/balloon_compaction.h>
+#include <linux/balloon.h>
 #include <linux/oom.h>
 #include <linux/wait.h>
 #include <linux/mm.h>
-- 
cgit v1.2.3


From cd8e95d80bc29b3c72288bd31e845b11755ef6a5 Mon Sep 17 00:00:00 2001
From: "David Hildenbrand (Red Hat)" <david@kernel.org>
Date: Tue, 20 Jan 2026 00:01:30 +0100
Subject: mm: rename CONFIG_BALLOON_COMPACTION to CONFIG_BALLOON_MIGRATION
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

While compaction depends on migration, the other direction is not the
case.  So let's make it clearer that this is all about migration of
balloon pages.

Adjust all comments/docs in the core to talk about "migration" instead of
"compaction".

While at it add some "/* CONFIG_BALLOON_MIGRATION */".

Link: https://lkml.kernel.org/r/20260119230133.3551867-23-david@kernel.org
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Eugenio Pérez <eperezma@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/misc/vmw_balloon.c      | 8 ++++----
 drivers/virtio/virtio_balloon.c | 6 +++---
 2 files changed, 7 insertions(+), 7 deletions(-)

(limited to 'drivers')

diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index 7fd3f709108c..216a16395968 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -1719,7 +1719,7 @@ static inline void vmballoon_debugfs_exit(struct vmballoon *b)
 #endif	/* CONFIG_DEBUG_FS */
 
 
-#ifdef CONFIG_BALLOON_COMPACTION
+#ifdef CONFIG_BALLOON_MIGRATION
 /**
  * vmballoon_migratepage() - migrates a balloon page.
  * @b_dev_info: balloon device information descriptor.
@@ -1803,11 +1803,11 @@ out_unlock:
 	up_read(&b->conf_sem);
 	return ret;
 }
-#else /* CONFIG_BALLOON_COMPACTION */
+#else /* CONFIG_BALLOON_MIGRATION */
 int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
 			  struct page *newpage, struct page *page,
 			  enum migrate_mode mode);
-#endif /* CONFIG_BALLOON_COMPACTION */
+#endif /* CONFIG_BALLOON_MIGRATION */
 
 static int __init vmballoon_init(void)
 {
@@ -1827,7 +1827,7 @@ static int __init vmballoon_init(void)
 		return error;
 
 	balloon_devinfo_init(&balloon.b_dev_info);
-	if (IS_ENABLED(CONFIG_BALLOON_COMPACTION))
+	if (IS_ENABLED(CONFIG_BALLOON_MIGRATION))
 		balloon.b_dev_info.migratepage = vmballoon_migratepage;
 
 	INIT_LIST_HEAD(&balloon.huge_pages);
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index de8041c3285a..4e549abe59ff 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -802,7 +802,7 @@ static void report_free_page_func(struct work_struct *work)
 	}
 }
 
-#ifdef CONFIG_BALLOON_COMPACTION
+#ifdef CONFIG_BALLOON_MIGRATION
 /*
  * virtballoon_migratepage - perform the balloon page migration on behalf of
  *			     a compaction thread.     (called under page lock)
@@ -851,7 +851,7 @@ static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info,
 	mutex_unlock(&vb->balloon_lock);
 	return 0;
 }
-#endif /* CONFIG_BALLOON_COMPACTION */
+#endif /* CONFIG_BALLOON_MIGRATION */
 
 static unsigned long shrink_free_pages(struct virtio_balloon *vb,
 				       unsigned long pages_to_free)
@@ -948,7 +948,7 @@ static int virtballoon_probe(struct virtio_device *vdev)
 
 	if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
 		vb->vb_dev_info.adjust_managed_page_count = true;
-#ifdef CONFIG_BALLOON_COMPACTION
+#ifdef CONFIG_BALLOON_MIGRATION
 	vb->vb_dev_info.migratepage = virtballoon_migratepage;
 #endif
 	if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) {
-- 
cgit v1.2.3


From 1421758055ca6028d3b758914863f38d434bf36b Mon Sep 17 00:00:00 2001
From: "David Hildenbrand (Red Hat)" <david@kernel.org>
Date: Tue, 20 Jan 2026 00:01:31 +0100
Subject: mm: rename CONFIG_MEMORY_BALLOON -> CONFIG_BALLOON
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Let's make it consistent with the naming of the files but also with the
naming of CONFIG_BALLOON_MIGRATION.

While at it, add a "/* CONFIG_BALLOON */".

Link: https://lkml.kernel.org/r/20260119230133.3551867-24-david@kernel.org
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Eugenio Pérez <eperezma@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/misc/Kconfig   | 2 +-
 drivers/virtio/Kconfig | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

(limited to 'drivers')

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index d7d41b054b98..5cc79d1517af 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -410,7 +410,7 @@ config DS1682
 config VMWARE_BALLOON
 	tristate "VMware Balloon Driver"
 	depends on VMWARE_VMCI && X86 && HYPERVISOR_GUEST
-	select MEMORY_BALLOON
+	select BALLOON
 	help
 	  This is VMware physical memory management driver which acts
 	  like a "balloon" that can be inflated to reclaim physical pages
diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index 6db5235a7693..ce5bc0d9ea28 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -112,7 +112,7 @@ config VIRTIO_PMEM
 config VIRTIO_BALLOON
 	tristate "Virtio balloon driver"
 	depends on VIRTIO
-	select MEMORY_BALLOON
+	select BALLOON
 	select PAGE_REPORTING
 	help
 	 This driver supports increasing and decreasing the amount
-- 
cgit v1.2.3


From 6efc548d8a08ae918020225e16d040ce3903bff7 Mon Sep 17 00:00:00 2001
From: Sergey Senozhatsky <senozhatsky@chromium.org>
Date: Thu, 15 Jan 2026 17:08:07 +0900
Subject: zram: rename init_lock to dev_lock

init_lock has completely outgrown its initial purpose and is no longer
used only to "prevent concurrent execution of device init" as the stale
comment suggests.  The scope of this lock is much bigger now.

These days this lock (rw_semaphore) controls how a task owns the
corresponding zram device: either in shared mode or in exclusive mode.

All zram device attribute writes should own the device in exclusive mode,
which synchronizes these tasks and prevents, for example, concurrent
execution of recompression and writeback.

All zram device attribute reads should own the device in shared mode.

Rename the lock to dev_lock to better reflect its current purpose.

Link: https://lkml.kernel.org/r/20260115080807.3957860-1-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/block/zram/zram_drv.c | 60 +++++++++++++++++++++----------------------
 drivers/block/zram/zram_drv.h |  4 +--
 2 files changed, 32 insertions(+), 32 deletions(-)

(limited to 'drivers')

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index f92845ef9192..61d3e2c74901 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -365,7 +365,7 @@ static ssize_t initstate_show(struct device *dev, struct device_attribute *attr,
 	u32 val;
 	struct zram *zram = dev_to_zram(dev);
 
-	guard(rwsem_read)(&zram->init_lock);
+	guard(rwsem_read)(&zram->dev_lock);
 	val = init_done(zram);
 
 	return sysfs_emit(buf, "%u\n", val);
@@ -391,7 +391,7 @@ static ssize_t mem_limit_store(struct device *dev,
 	if (buf == tmp) /* no chars parsed, invalid input */
 		return -EINVAL;
 
-	guard(rwsem_write)(&zram->init_lock);
+	guard(rwsem_write)(&zram->dev_lock);
 	zram->limit_pages = PAGE_ALIGN(limit) >> PAGE_SHIFT;
 
 	return len;
@@ -409,7 +409,7 @@ static ssize_t mem_used_max_store(struct device *dev,
 	if (err || val != 0)
 		return -EINVAL;
 
-	guard(rwsem_read)(&zram->init_lock);
+	guard(rwsem_read)(&zram->dev_lock);
 	if (init_done(zram)) {
 		atomic_long_set(&zram->stats.max_used_pages,
 				zs_get_total_pages(zram->mem_pool));
@@ -477,7 +477,7 @@ static ssize_t idle_store(struct device *dev, struct device_attribute *attr,
 			return -EINVAL;
 	}
 
-	guard(rwsem_read)(&zram->init_lock);
+	guard(rwsem_read)(&zram->dev_lock);
 	if (!init_done(zram))
 		return -EINVAL;
 
@@ -539,7 +539,7 @@ static ssize_t bd_stat_show(struct device *dev, struct device_attribute *attr,
 	struct zram *zram = dev_to_zram(dev);
 	ssize_t ret;
 
-	guard(rwsem_read)(&zram->init_lock);
+	guard(rwsem_read)(&zram->dev_lock);
 	ret = sysfs_emit(buf,
 			 "%8llu %8llu %8llu\n",
 			 FOUR_K((u64)atomic64_read(&zram->stats.bd_count)),
@@ -559,7 +559,7 @@ static ssize_t writeback_compressed_store(struct device *dev,
 	if (kstrtobool(buf, &val))
 		return -EINVAL;
 
-	guard(rwsem_write)(&zram->init_lock);
+	guard(rwsem_write)(&zram->dev_lock);
 	if (init_done(zram)) {
 		return -EBUSY;
 	}
@@ -576,7 +576,7 @@ static ssize_t writeback_compressed_show(struct device *dev,
 	bool val;
 	struct zram *zram = dev_to_zram(dev);
 
-	guard(rwsem_read)(&zram->init_lock);
+	guard(rwsem_read)(&zram->dev_lock);
 	val = zram->wb_compressed;
 
 	return sysfs_emit(buf, "%d\n", val);
@@ -592,7 +592,7 @@ static ssize_t writeback_limit_enable_store(struct device *dev,
 	if (kstrtoull(buf, 10, &val))
 		return -EINVAL;
 
-	guard(rwsem_write)(&zram->init_lock);
+	guard(rwsem_write)(&zram->dev_lock);
 	zram->wb_limit_enable = val;
 
 	return len;
@@ -605,7 +605,7 @@ static ssize_t writeback_limit_enable_show(struct device *dev,
 	bool val;
 	struct zram *zram = dev_to_zram(dev);
 
-	guard(rwsem_read)(&zram->init_lock);
+	guard(rwsem_read)(&zram->dev_lock);
 	val = zram->wb_limit_enable;
 
 	return sysfs_emit(buf, "%d\n", val);
@@ -631,7 +631,7 @@ static ssize_t writeback_limit_store(struct device *dev,
 	 */
 	val = rounddown(val, PAGE_SIZE / 4096);
 
-	guard(rwsem_write)(&zram->init_lock);
+	guard(rwsem_write)(&zram->dev_lock);
 	zram->bd_wb_limit = val;
 
 	return len;
@@ -643,7 +643,7 @@ static ssize_t writeback_limit_show(struct device *dev,
 	u64 val;
 	struct zram *zram = dev_to_zram(dev);
 
-	guard(rwsem_read)(&zram->init_lock);
+	guard(rwsem_read)(&zram->dev_lock);
 	val = zram->bd_wb_limit;
 
 	return sysfs_emit(buf, "%llu\n", val);
@@ -662,7 +662,7 @@ static ssize_t writeback_batch_size_store(struct device *dev,
 	if (!val)
 		return -EINVAL;
 
-	guard(rwsem_write)(&zram->init_lock);
+	guard(rwsem_write)(&zram->dev_lock);
 	zram->wb_batch_size = val;
 
 	return len;
@@ -675,7 +675,7 @@ static ssize_t writeback_batch_size_show(struct device *dev,
 	u32 val;
 	struct zram *zram = dev_to_zram(dev);
 
-	guard(rwsem_read)(&zram->init_lock);
+	guard(rwsem_read)(&zram->dev_lock);
 	val = zram->wb_batch_size;
 
 	return sysfs_emit(buf, "%u\n", val);
@@ -703,7 +703,7 @@ static ssize_t backing_dev_show(struct device *dev,
 	char *p;
 	ssize_t ret;
 
-	guard(rwsem_read)(&zram->init_lock);
+	guard(rwsem_read)(&zram->dev_lock);
 	file = zram->backing_dev;
 	if (!file) {
 		memcpy(buf, "none\n", 5);
@@ -737,7 +737,7 @@ static ssize_t backing_dev_store(struct device *dev,
 	if (!file_name)
 		return -ENOMEM;
 
-	guard(rwsem_write)(&zram->init_lock);
+	guard(rwsem_write)(&zram->dev_lock);
 	if (init_done(zram)) {
 		pr_info("Can't setup backing device for initialized device\n");
 		err = -EBUSY;
@@ -901,7 +901,7 @@ release_wb_ctl:
 
 static void zram_account_writeback_rollback(struct zram *zram)
 {
-	lockdep_assert_held_write(&zram->init_lock);
+	lockdep_assert_held_write(&zram->dev_lock);
 
 	if (zram->wb_limit_enable)
 		zram->bd_wb_limit +=  1UL << (PAGE_SHIFT - 12);
@@ -909,7 +909,7 @@ static void zram_account_writeback_rollback(struct zram *zram)
 
 static void zram_account_writeback_submit(struct zram *zram)
 {
-	lockdep_assert_held_write(&zram->init_lock);
+	lockdep_assert_held_write(&zram->dev_lock);
 
 	if (zram->wb_limit_enable && zram->bd_wb_limit > 0)
 		zram->bd_wb_limit -=  1UL << (PAGE_SHIFT - 12);
@@ -1263,7 +1263,7 @@ static ssize_t writeback_store(struct device *dev,
 	ssize_t ret = len;
 	int err, mode = 0;
 
-	guard(rwsem_write)(&zram->init_lock);
+	guard(rwsem_write)(&zram->dev_lock);
 	if (!init_done(zram))
 		return -EINVAL;
 
@@ -1565,7 +1565,7 @@ static ssize_t read_block_state(struct file *file, char __user *buf,
 	if (!kbuf)
 		return -ENOMEM;
 
-	guard(rwsem_read)(&zram->init_lock);
+	guard(rwsem_read)(&zram->dev_lock);
 	if (!init_done(zram)) {
 		kvfree(kbuf);
 		return -EINVAL;
@@ -1666,7 +1666,7 @@ static int __comp_algorithm_store(struct zram *zram, u32 prio, const char *buf)
 		return -EINVAL;
 	}
 
-	guard(rwsem_write)(&zram->init_lock);
+	guard(rwsem_write)(&zram->dev_lock);
 	if (init_done(zram)) {
 		kfree(compressor);
 		pr_info("Can't change algorithm for initialized device\n");
@@ -1794,7 +1794,7 @@ static ssize_t comp_algorithm_show(struct device *dev,
 	struct zram *zram = dev_to_zram(dev);
 	ssize_t sz;
 
-	guard(rwsem_read)(&zram->init_lock);
+	guard(rwsem_read)(&zram->dev_lock);
 	sz = zcomp_available_show(zram->comp_algs[ZRAM_PRIMARY_COMP], buf, 0);
 	return sz;
 }
@@ -1820,7 +1820,7 @@ static ssize_t recomp_algorithm_show(struct device *dev,
 	ssize_t sz = 0;
 	u32 prio;
 
-	guard(rwsem_read)(&zram->init_lock);
+	guard(rwsem_read)(&zram->dev_lock);
 	for (prio = ZRAM_SECONDARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
 		if (!zram->comp_algs[prio])
 			continue;
@@ -1878,7 +1878,7 @@ static ssize_t compact_store(struct device *dev, struct device_attribute *attr,
 {
 	struct zram *zram = dev_to_zram(dev);
 
-	guard(rwsem_read)(&zram->init_lock);
+	guard(rwsem_read)(&zram->dev_lock);
 	if (!init_done(zram))
 		return -EINVAL;
 
@@ -1893,7 +1893,7 @@ static ssize_t io_stat_show(struct device *dev, struct device_attribute *attr,
 	struct zram *zram = dev_to_zram(dev);
 	ssize_t ret;
 
-	guard(rwsem_read)(&zram->init_lock);
+	guard(rwsem_read)(&zram->dev_lock);
 	ret = sysfs_emit(buf,
 			"%8llu %8llu 0 %8llu\n",
 			(u64)atomic64_read(&zram->stats.failed_reads),
@@ -1914,7 +1914,7 @@ static ssize_t mm_stat_show(struct device *dev, struct device_attribute *attr,
 
 	memset(&pool_stats, 0x00, sizeof(struct zs_pool_stats));
 
-	guard(rwsem_read)(&zram->init_lock);
+	guard(rwsem_read)(&zram->dev_lock);
 	if (init_done(zram)) {
 		mem_used = zs_get_total_pages(zram->mem_pool);
 		zs_pool_stats(zram->mem_pool, &pool_stats);
@@ -1945,7 +1945,7 @@ static ssize_t debug_stat_show(struct device *dev,
 	struct zram *zram = dev_to_zram(dev);
 	ssize_t ret;
 
-	guard(rwsem_read)(&zram->init_lock);
+	guard(rwsem_read)(&zram->dev_lock);
 	ret = sysfs_emit(buf,
 			"version: %d\n0 %8llu\n",
 			version,
@@ -2611,7 +2611,7 @@ static ssize_t recompress_store(struct device *dev,
 	if (threshold >= huge_class_size)
 		return -EINVAL;
 
-	guard(rwsem_write)(&zram->init_lock);
+	guard(rwsem_write)(&zram->dev_lock);
 	if (!init_done(zram))
 		return -EINVAL;
 
@@ -2863,7 +2863,7 @@ static void zram_destroy_comps(struct zram *zram)
 
 static void zram_reset_device(struct zram *zram)
 {
-	guard(rwsem_write)(&zram->init_lock);
+	guard(rwsem_write)(&zram->dev_lock);
 
 	zram->limit_pages = 0;
 
@@ -2893,7 +2893,7 @@ static ssize_t disksize_store(struct device *dev, struct device_attribute *attr,
 	if (!disksize)
 		return -EINVAL;
 
-	guard(rwsem_write)(&zram->init_lock);
+	guard(rwsem_write)(&zram->dev_lock);
 	if (init_done(zram)) {
 		pr_info("Cannot change disksize for initialized device\n");
 		return -EBUSY;
@@ -3088,7 +3088,7 @@ static int zram_add(void)
 		goto out_free_dev;
 	device_id = ret;
 
-	init_rwsem(&zram->init_lock);
+	init_rwsem(&zram->dev_lock);
 #ifdef CONFIG_ZRAM_WRITEBACK
 	zram->wb_batch_size = 32;
 	zram->wb_compressed = false;
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index 469a3dab44ad..515a72d9c06f 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -111,8 +111,8 @@ struct zram {
 	struct zcomp *comps[ZRAM_MAX_COMPS];
 	struct zcomp_params params[ZRAM_MAX_COMPS];
 	struct gendisk *disk;
-	/* Prevent concurrent execution of device init */
-	struct rw_semaphore init_lock;
+	/* Locks the device either in exclusive or in shared mode */
+	struct rw_semaphore dev_lock;
 	/*
 	 * the number of pages zram can consume for storing compressed data
 	 */
-- 
cgit v1.2.3