From: Hou Tao <houtao1@xxxxxxxxxx> [ 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@xxxxxxxxxxxxxxxxx> Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx> Signed-off-by: David Howells <dhowells@xxxxxxxxxx> Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx> Link: https://lore.kernel.org/r/20230113115211.2895845-3-houtao@xxxxxxxxxxxxxxx/ # v3 Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- 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); } -- 2.39.0 -- Linux-cachefs mailing list Linux-cachefs@xxxxxxxxxx https://listman.redhat.com/mailman/listinfo/linux-cachefs
