lightnvm: manage lun partitions internally in mm

LUNs are exclusively owned by targets implementing a block device FTL.
Doing this reservation requires at the moment a 2-way callback gennvm
<-> target. The reason behind this is that LUNs were not assumed to
always be exclusively owned by targets. However, this design decision
goes against I/O determinism QoS (two targets would mix I/O on the same
parallel unit in the device).

This patch makes LUN reservation as part of the target creation on the
media manager. This makes that LUNs are always exclusively owned by the
target instantiated on top of them. LUN stripping and/or sharing should
be implemented on the target itself or the layers on top.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 49 insertions, 13 deletions

diff --git a/drivers/lightnvm/gennvm.c b/drivers/lightnvm/gennvm.c
index 3572ebbb50ce..9671e11356be 100644
--- a/drivers/lightnvm/gennvm.c
+++ b/drivers/lightnvm/gennvm.c
@@ -35,6 +35,45 @@ static const struct block_device_operations gen_fops = {
 	.owner		= THIS_MODULE,
 };
 
+static int gen_reserve_luns(struct nvm_dev *dev, struct nvm_target *t,
+			    int lun_begin, int lun_end)
+{
+	struct gen_dev *gn = dev->mp;
+	struct nvm_lun *lun;
+	int i;
+
+	for (i = lun_begin; i <= lun_end; i++) {
+		if (test_and_set_bit(i, dev->lun_map)) {
+			pr_err("nvm: lun %d already allocated\n", i);
+			goto err;
+		}
+
+		lun = &gn->luns[i];
+		list_add_tail(&lun->list, &t->lun_list);
+	}
+
+	return 0;
+
+err:
+	while (--i > lun_begin) {
+		lun = &gn->luns[i];
+		clear_bit(i, dev->lun_map);
+		list_del(&lun->list);
+	}
+
+	return -EBUSY;
+}
+
+static void gen_release_luns(struct nvm_dev *dev, struct nvm_target *t)
+{
+	struct nvm_lun *lun, *tmp;
+
+	list_for_each_entry_safe(lun, tmp, &t->lun_list, list) {
+		WARN_ON(!test_and_clear_bit(lun->id, dev->lun_map));
+		list_del(&lun->list);
+	}
+}
+
 static int gen_create_tgt(struct nvm_dev *dev, struct nvm_ioctl_create *create)
 {
 	struct gen_dev *gn = dev->mp;
@@ -64,9 +103,14 @@ static int gen_create_tgt(struct nvm_dev *dev, struct nvm_ioctl_create *create)
 	if (!t)
 		return -ENOMEM;
 
+	INIT_LIST_HEAD(&t->lun_list);
+
+	if (gen_reserve_luns(dev, t, s->lun_begin, s->lun_end))
+		goto err_t;
+
 	tqueue = blk_alloc_queue_node(GFP_KERNEL, dev->q->node);
 	if (!tqueue)
-		goto err_t;
+		goto err_reserve;
 	blk_queue_make_request(tqueue, tt->make_rq);
 
 	tdisk = alloc_disk(0);
@@ -105,6 +149,8 @@ err_init:
 	put_disk(tdisk);
 err_queue:
 	blk_cleanup_queue(tqueue);
+err_reserve:
+	gen_release_luns(dev, t);
 err_t:
 	kfree(t);
 	return -ENOMEM;
@@ -122,6 +168,7 @@ static void __gen_remove_target(struct nvm_target *t)
 	if (tt->exit)
 		tt->exit(tdisk->private_data);
 
+	gen_release_luns(t->dev, t);
 	put_disk(tdisk);
 
 	list_del(&t->list);
@@ -253,6 +300,7 @@ static int gen_luns_init(struct nvm_dev *dev, struct gen_dev *gn)
 		INIT_LIST_HEAD(&lun->free_list);
 		INIT_LIST_HEAD(&lun->used_list);
 		INIT_LIST_HEAD(&lun->bb_list);
+		INIT_LIST_HEAD(&lun->list);
 
 		spin_lock_init(&lun->lock);
 
@@ -569,16 +617,6 @@ static int gen_erase_blk(struct nvm_dev *dev, struct nvm_block *blk, int flags)
 	return nvm_erase_ppa(dev, &addr, 1, flags);
 }
 
-static int gen_reserve_lun(struct nvm_dev *dev, int lunid)
-{
-	return test_and_set_bit(lunid, dev->lun_map);
-}
-
-static void gen_release_lun(struct nvm_dev *dev, int lunid)
-{
-	WARN_ON(!test_and_clear_bit(lunid, dev->lun_map));
-}
-
 static struct nvm_lun *gen_get_lun(struct nvm_dev *dev, int lunid)
 {
 	struct gen_dev *gn = dev->mp;
@@ -625,8 +663,6 @@ static struct nvmm_type gen = {
 	.mark_blk		= gen_mark_blk,
 
 	.get_lun		= gen_get_lun,
-	.reserve_lun		= gen_reserve_lun,
-	.release_lun		= gen_release_lun,
 	.lun_info_print		= gen_lun_info_print,
 
 	.get_area		= gen_get_area,