tree 7f4c0cd460986806724361175382efb35d7ced6b
parent 09ca6c40c2024211657fdb2c50522a355610c3b7
author Jens Axboe <axboe@kernel.dk> 1614959079 -0700
committer Jens Axboe <axboe@kernel.dk> 1614959079 -0700

io_uring: make SQPOLL thread parking saner

We have this weird true/false return from parking, and then some of the
callers decide to look at that. It can lead to unbalanced parks and
sqd locking. Have the callers check the thread status once it's parked.
We know we have the lock at that point, so it's either valid or it's NULL.

Fix race with parking on thread exit. We need to be careful here with
ordering of the sdq->lock and the IO_SQ_THREAD_SHOULD_PARK bit.

Rename sqd->completion to sqd->parked to reflect that this is the only
thing this completion event doesn.

Signed-off-by: Jens Axboe <axboe@kernel.dk>