diff options
| -rw-r--r-- | drivers/block/zram/zram_drv.c | 76 | ||||
| -rw-r--r-- | drivers/block/zram/zram_drv.h | 20 |
2 files changed, 64 insertions, 32 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 0abcf4a31c78..db94572b35c4 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -53,9 +53,9 @@ static ssize_t name##_show(struct device *d, \ } \ static DEVICE_ATTR_RO(name); -static inline int init_done(struct zram *zram) +static inline bool init_done(struct zram *zram) { - return zram->meta != NULL; + return zram->disksize; } static inline struct zram *dev_to_zram(struct device *dev) @@ -356,6 +356,18 @@ out_error: return NULL; } +static inline bool zram_meta_get(struct zram *zram) +{ + if (atomic_inc_not_zero(&zram->refcount)) + return true; + return false; +} + +static inline void zram_meta_put(struct zram *zram) +{ + atomic_dec(&zram->refcount); +} + static void update_position(u32 *index, int *offset, struct bio_vec *bvec) { if (*offset + bvec->bv_len >= PAGE_SIZE) @@ -717,6 +729,10 @@ static void zram_bio_discard(struct zram *zram, u32 index, static void zram_reset_device(struct zram *zram) { + struct zram_meta *meta; + struct zcomp *comp; + u64 disksize; + down_write(&zram->init_lock); zram->limit_pages = 0; @@ -726,16 +742,31 @@ static void zram_reset_device(struct zram *zram) return; } - zcomp_destroy(zram->comp); - zram->max_comp_streams = 1; - zram_meta_free(zram->meta, zram->disksize); - zram->meta = NULL; + meta = zram->meta; + comp = zram->comp; + disksize = zram->disksize; + /* + * Refcount will go down to 0 eventually and r/w handler + * cannot handle further I/O so it will bail out by + * check zram_meta_get. + */ + zram_meta_put(zram); + /* + * We want to free zram_meta in process context to avoid + * deadlock between reclaim path and any other locks. + */ + wait_event(zram->io_done, atomic_read(&zram->refcount) == 0); + /* Reset stats */ memset(&zram->stats, 0, sizeof(zram->stats)); zram->disksize = 0; + zram->max_comp_streams = 1; set_capacity(zram->disk, 0); up_write(&zram->init_lock); + /* I/O operation under all of CPU are done so let's free */ + zram_meta_free(meta, disksize); + zcomp_destroy(comp); } static ssize_t disksize_store(struct device *dev, @@ -771,6 +802,8 @@ static ssize_t disksize_store(struct device *dev, goto out_destroy_comp; } + init_waitqueue_head(&zram->io_done); + atomic_set(&zram->refcount, 1); zram->meta = meta; zram->comp = comp; zram->disksize = disksize; @@ -901,23 +934,21 @@ static void zram_make_request(struct request_queue *queue, struct bio *bio) { struct zram *zram = queue->queuedata; - down_read(&zram->init_lock); - if (unlikely(!init_done(zram))) + if (unlikely(!zram_meta_get(zram))) goto error; if (!valid_io_request(zram, bio->bi_iter.bi_sector, bio->bi_iter.bi_size)) { atomic64_inc(&zram->stats.invalid_io); - goto error; + goto put_zram; } __zram_make_request(zram, bio); - up_read(&zram->init_lock); - + zram_meta_put(zram); return; - +put_zram: + zram_meta_put(zram); error: - up_read(&zram->init_lock); bio_io_error(bio); } @@ -939,21 +970,19 @@ static void zram_slot_free_notify(struct block_device *bdev, static int zram_rw_page(struct block_device *bdev, sector_t sector, struct page *page, int rw) { - int offset, err; + int offset, err = -EIO; u32 index; struct zram *zram; struct bio_vec bv; zram = bdev->bd_disk->private_data; + if (unlikely(!zram_meta_get(zram))) + goto out; + if (!valid_io_request(zram, sector, PAGE_SIZE)) { atomic64_inc(&zram->stats.invalid_io); - return -EINVAL; - } - - down_read(&zram->init_lock); - if (unlikely(!init_done(zram))) { - err = -EIO; - goto out_unlock; + err = -EINVAL; + goto put_zram; } index = sector >> SECTORS_PER_PAGE_SHIFT; @@ -964,8 +993,9 @@ static int zram_rw_page(struct block_device *bdev, sector_t sector, bv.bv_offset = 0; err = zram_bvec_rw(zram, &bv, index, offset, rw); -out_unlock: - up_read(&zram->init_lock); +put_zram: + zram_meta_put(zram); +out: /* * If I/O fails, just return error(ie, non-zero) without * calling page_endio. diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h index b05a816b09ac..5249f51ccdb3 100644 --- a/drivers/block/zram/zram_drv.h +++ b/drivers/block/zram/zram_drv.h @@ -100,24 +100,26 @@ struct zram_meta { struct zram { struct zram_meta *meta; + struct zcomp *comp; struct request_queue *queue; struct gendisk *disk; - struct zcomp *comp; - - /* Prevent concurrent execution of device init, reset and R/W request */ + /* Prevent concurrent execution of device init */ struct rw_semaphore init_lock; /* - * This is the limit on amount of *uncompressed* worth of data - * we can store in a disk. + * the number of pages zram can consume for storing compressed data */ - u64 disksize; /* bytes */ + unsigned long limit_pages; int max_comp_streams; + struct zram_stats stats; + atomic_t refcount; /* refcount for zram_meta */ + /* wait all IO under all of cpu are done */ + wait_queue_head_t io_done; /* - * the number of pages zram can consume for storing compressed data + * This is the limit on amount of *uncompressed* worth of data + * we can store in a disk. */ - unsigned long limit_pages; - + u64 disksize; /* bytes */ char compressor[10]; }; #endif |