On 2024/10/21 16:52, 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().
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Good catch! Just a small nit below, feel free to add:
Reviewed-by: Chengming Zhou <chengming.zhou@xxxxxxxxx>
---
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;
}
Would it be better to move this acquire_inflight_cb() above out of
the do-while(1) since we rely on the waker to get inflight counter
for us?
Thanks.
io_schedule();
has_sleeper = true;
