From: Josef Bacik josef@toxicpanda.com
[ Upstream commit 64e7ea875ef63b2801be7954cf7257d1bfccc266 ]
If we raced with somebody else getting an inflight counter we could fail to get an inflight counter with no sleepers on the list, and thus need to go to sleep. In this case has_sleepers should be true because we are now relying on the waker to get our inflight counter for us. And in the case of spurious wakeups we'd still want this to be the case. So set has_sleepers to true if we went to sleep to make sure we're woken up the proper way.
Reviewed-by: Oleg Nesterov oleg@redhat.com Signed-off-by: Josef Bacik josef@toxicpanda.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/blk-rq-qos.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/blk-rq-qos.c b/block/blk-rq-qos.c index 659ccb8b693fa..e5d75280b431e 100644 --- a/block/blk-rq-qos.c +++ b/block/blk-rq-qos.c @@ -260,7 +260,7 @@ void rq_qos_wait(struct rq_wait *rqw, void *private_data, break; } io_schedule(); - has_sleeper = false; + has_sleeper = true; } while (1); finish_wait(&rqw->wait, &data.wq); }