On 10/21/24 2:52 AM, Muchun Song wrote: > The memory barriers in list_del_init_careful() and list_empty_careful() > in pairs already handle the proper ordering between data.got_token > and data.wq.entry. So remove the redundant explicit barriers. And also > change a "break" statement to "return" to avoid redundant calling of > finish_wait(). Not sure why you didn't CC Omar on this one, as he literally just last week fixed an issue related to this. > > Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx> > --- > block/blk-rq-qos.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/block/blk-rq-qos.c b/block/blk-rq-qos.c > index dc510f493ba57..9b0aa7dd6779f 100644 > --- a/block/blk-rq-qos.c > +++ b/block/blk-rq-qos.c > @@ -218,7 +218,6 @@ static int rq_qos_wake_function(struct wait_queue_entry *curr, > return -1; > > data->got_token = true; > - smp_wmb(); > wake_up_process(data->task); > list_del_init_careful(&curr->entry); > return 1; > @@ -274,10 +273,9 @@ void rq_qos_wait(struct rq_wait *rqw, void *private_data, > * which means we now have two. Put our local token > * and wake anyone else potentially waiting for one. > */ > - smp_rmb(); > if (data.got_token) > cleanup_cb(rqw, private_data); > - break; > + return; > } > io_schedule(); > has_sleeper = true; -- Jens Axboe
