From: Hou Tao houtao1@huawei.com
[ Upstream commit 3288666c72568fe1cc7f5c5ae33dfd3ab18004c8 ]
fscache_create_volume_work() uses wake_up_bit() to wake up the processes which are waiting for the completion of volume creation. According to comments in wake_up_bit() and waitqueue_active(), an extra smp_mb() is needed to guarantee the memory order between FSCACHE_VOLUME_CREATING flag and waitqueue_active() before invoking wake_up_bit().
Fixing it by using clear_and_wake_up_bit() to add the missing memory barrier.
Reviewed-by: Jingbo Xu jefflexu@linux.alibaba.com Signed-off-by: Hou Tao houtao1@huawei.com Signed-off-by: David Howells dhowells@redhat.com Reviewed-by: Jeff Layton jlayton@kernel.org Link: https://lore.kernel.org/r/20230113115211.2895845-3-houtao@huaweicloud.com/ # v3 Signed-off-by: Sasha Levin sashal@kernel.org --- fs/fscache/volume.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/fs/fscache/volume.c b/fs/fscache/volume.c index ab8ceddf9efad..d9fdd90668b0f 100644 --- a/fs/fscache/volume.c +++ b/fs/fscache/volume.c @@ -279,8 +279,7 @@ static void fscache_create_volume_work(struct work_struct *work) fscache_end_cache_access(volume->cache, fscache_access_acquire_volume_end);
- clear_bit_unlock(FSCACHE_VOLUME_CREATING, &volume->flags); - wake_up_bit(&volume->flags, FSCACHE_VOLUME_CREATING); + clear_and_wake_up_bit(FSCACHE_VOLUME_CREATING, &volume->flags); fscache_put_volume(volume, fscache_volume_put_create_work); }