[PATCH v5 3/3] btrfs: scrub: convert scrub_workers_refcnt to refcount_t

[Anand Jain]

Use the refcount_t for fs_info::scrub_workers_refcnt instead of int.

Signed-off-by: Anand Jain <anand.j...@oracle.com>
---
v5: Fix refcount validation warning.
    Use refcount_set() instead of refcount_inc() when count is 0.
v4: born
 fs/btrfs/ctree.h   |  2 +-
 fs/btrfs/disk-io.c |  2 +-
 fs/btrfs/scrub.c   | 10 +++++++---
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 2399f56d8a54..d53fb37aaed0 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1074,7 +1074,7 @@ struct btrfs_fs_info {
        atomic_t scrubs_paused;
        atomic_t scrub_cancel_req;
        wait_queue_head_t scrub_pause_wait;
-       int scrub_workers_refcnt;
+       refcount_t scrub_workers_refcnt;
        struct btrfs_workqueue *scrub_workers;
        struct btrfs_workqueue *scrub_wr_completion_workers;
        struct btrfs_workqueue *scrub_nocow_workers;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 4047867473e1..76701b21ab77 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2111,7 +2111,7 @@ static void btrfs_init_scrub(struct btrfs_fs_info 
*fs_info)
        atomic_set(&fs_info->scrubs_paused, 0);
        atomic_set(&fs_info->scrub_cancel_req, 0);
        init_waitqueue_head(&fs_info->scrub_pause_wait);
-       fs_info->scrub_workers_refcnt = 0;
+       refcount_set(&fs_info->scrub_workers_refcnt, 0);
 }
 
 static void btrfs_init_balance(struct btrfs_fs_info *fs_info)
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 17925af759ae..bf2294798b6c 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -3743,7 +3743,7 @@ static noinline_for_stack int scrub_workers_get(struct 
btrfs_fs_info *fs_info,
 
        lockdep_assert_held(&fs_info->scrub_lock);
 
-       if (fs_info->scrub_workers_refcnt == 0) {
+       if (refcount_read(&fs_info->scrub_workers_refcnt) == 0) {
                fs_info->scrub_workers = btrfs_alloc_workqueue(fs_info, "scrub",
                                flags, is_dev_replace ? 1 : max_active, 4);
                if (!fs_info->scrub_workers)
@@ -3760,8 +3760,12 @@ static noinline_for_stack int scrub_workers_get(struct 
btrfs_fs_info *fs_info,
                                              max_active, 2);
                if (!fs_info->scrub_parity_workers)
                        goto fail_scrub_parity_workers;
+
+               refcount_set(&fs_info->scrub_workers_refcnt, 1);
+       } else {
+               refcount_inc(&fs_info->scrub_workers_refcnt);
        }
-       ++fs_info->scrub_workers_refcnt;
+
        return 0;
 
 fail_scrub_parity_workers:
@@ -3927,7 +3931,7 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 
devid, u64 start,
 
        mutex_lock(&fs_info->scrub_lock);
        dev->scrub_ctx = NULL;
-       if (--fs_info->scrub_workers_refcnt == 0) {
+       if (refcount_dec_and_test(&fs_info->scrub_workers_refcnt)) {
                scrub_workers = fs_info->scrub_workers;
                scrub_wr_comp = fs_info->scrub_wr_completion_workers;
                scrub_parity = fs_info->scrub_parity_workers;
-- 
1.8.3.1