From: Hou Tao <houtao1@xxxxxxxxxx> 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(). Considering clear_bit_unlock() before wake_up_bit() is an atomic operation, use smp_mb__after_atomic() instead of smp_mb() to provide such guarantee. Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx> --- fs/fscache/volume.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/fscache/volume.c b/fs/fscache/volume.c index fc3dd3bc851d..734d17f404e7 100644 --- a/fs/fscache/volume.c +++ b/fs/fscache/volume.c @@ -281,6 +281,11 @@ static void fscache_create_volume_work(struct work_struct *work) fscache_access_acquire_volume_end); clear_bit_unlock(FSCACHE_VOLUME_CREATING, &volume->flags); + /* + * Paired with barrier in wait_on_bit(). Check wake_up_bit() and + * waitqueue_active() for details. + */ + smp_mb__after_atomic(); wake_up_bit(&volume->flags, FSCACHE_VOLUME_CREATING); fscache_put_volume(volume, fscache_volume_put_create_work); } -- 2.29.2 -- Linux-cachefs mailing list Linux-cachefs@xxxxxxxxxx https://listman.redhat.com/mailman/listinfo/linux-cachefs
