dm zoned: fix metadata block ref counting

Since the ref field of struct dmz_mblock is always used with the
spinlock of struct dmz_metadata locked, there is no need to use an
atomic_t type. Change the type of the ref field to an unsigne
integer.

Fixes: 3b1a94c88b79 ("dm zoned: drive-managed zoned block device target")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

1 files changed, 11 insertions, 9 deletions

diff --git a/drivers/md/dm-zoned-metadata.c b/drivers/md/dm-zoned-metadata.c
index 969954915566..67b71f6e3bda 100644
--- a/drivers/md/dm-zoned-metadata.c
+++ b/drivers/md/dm-zoned-metadata.c
@@ -99,7 +99,7 @@ struct dmz_mblock {
         struct rb_node          node;
         struct list_head        link;
         sector_t                no;
-        atomic_t                ref;
+        unsigned int            ref;
         unsigned long           state;
         struct page             *page;
         void                    *data;
@@ -296,7 +296,7 @@ static struct dmz_mblock *dmz_alloc_mblock(struct dmz_metadata *zmd,
 
         RB_CLEAR_NODE(&mblk->node);
         INIT_LIST_HEAD(&mblk->link);
-        atomic_set(&mblk->ref, 0);
+        mblk->ref = 0;
         mblk->state = 0;
         mblk->no = mblk_no;
         mblk->data = page_address(mblk->page);
@@ -397,7 +397,7 @@ static struct dmz_mblock *dmz_fetch_mblock(struct dmz_metadata *zmd,
                 return NULL;
 
         spin_lock(&zmd->mblk_lock);
-        atomic_inc(&mblk->ref);
+        mblk->ref++;
         set_bit(DMZ_META_READING, &mblk->state);
         dmz_insert_mblock(zmd, mblk);
         spin_unlock(&zmd->mblk_lock);
@@ -484,7 +484,8 @@ static void dmz_release_mblock(struct dmz_metadata *zmd,
 
         spin_lock(&zmd->mblk_lock);
 
-        if (atomic_dec_and_test(&mblk->ref)) {
+        mblk->ref--;
+        if (mblk->ref == 0) {
                 if (test_bit(DMZ_META_ERROR, &mblk->state)) {
                         rb_erase(&mblk->node, &zmd->mblk_rbtree);
                         dmz_free_mblock(zmd, mblk);
@@ -511,7 +512,8 @@ static struct dmz_mblock *dmz_get_mblock(struct dmz_metadata *zmd,
         mblk = dmz_lookup_mblock(zmd, mblk_no);
         if (mblk) {
                 /* Cache hit: remove block from LRU list */
-                if (atomic_inc_return(&mblk->ref) == 1 &&
+                mblk->ref++;
+                if (mblk->ref == 1 &&
                     !test_bit(DMZ_META_DIRTY, &mblk->state))
                         list_del_init(&mblk->link);
         }
@@ -753,7 +755,7 @@ int dmz_flush_metadata(struct dmz_metadata *zmd)
 
                 spin_lock(&zmd->mblk_lock);
                 clear_bit(DMZ_META_DIRTY, &mblk->state);
-                if (atomic_read(&mblk->ref) == 0)
+                if (mblk->ref == 0)
                         list_add_tail(&mblk->link, &zmd->mblk_lru_list);
                 spin_unlock(&zmd->mblk_lock);
         }
@@ -2308,7 +2310,7 @@ static void dmz_cleanup_metadata(struct dmz_metadata *zmd)
                 mblk = list_first_entry(&zmd->mblk_dirty_list,
                                         struct dmz_mblock, link);
                 dmz_dev_warn(zmd->dev, "mblock %llu still in dirty list (ref %u)",
-                             (u64)mblk->no, atomic_read(&mblk->ref));
+                             (u64)mblk->no, mblk->ref);
                 list_del_init(&mblk->link);
                 rb_erase(&mblk->node, &zmd->mblk_rbtree);
                 dmz_free_mblock(zmd, mblk);
@@ -2326,8 +2328,8 @@ static void dmz_cleanup_metadata(struct dmz_metadata *zmd)
         root = &zmd->mblk_rbtree;
         rbtree_postorder_for_each_entry_safe(mblk, next, root, node) {
                 dmz_dev_warn(zmd->dev, "mblock %llu ref %u still in rbtree",
-                             (u64)mblk->no, atomic_read(&mblk->ref));
-                atomic_set(&mblk->ref, 0);
+                             (u64)mblk->no, mblk->ref);
+                mblk->ref = 0;
                 dmz_free_mblock(zmd, mblk);
         }