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>

diff --git a/drivers/md/dm-zoned-metadata.c b/drivers/md/dm-zoned-metadata.c
index 969954915566f2cf1a15b684eb5b3d33dca58160..67b71f6e3bdaf457fb3e3871be8036629f623a04 100644 (file)
--- 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);
        }