Commit 11ba820b authored Jan 15, 2020 by Jens Axboe

io_uring: ensure workqueue offload grabs ring mutex for poll list

A previous commit moved the locking for the async sqthread, but didn't
take into account that the io-wq workers still need it. We can't use
req->in_async for this anymore as both the sqthread and io-wq workers
set it, gate the need for locking on io_wq_current_is_worker() instead.

Fixes: 8a4955ff ("io_uring: sqthread should grab ctx->uring_lock for submissions")
Reported-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent 797f3f53

fs/io_uring.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -3286,10 +3286,19 @@ static int io_issue_sqe(struct io_kiocb req, const struct io_uring_sqe sqe,
		return ret;

		if (ctx->flags & IORING_SETUP_IOPOLL) {
		const bool in_async = io_wq_current_is_worker();

		if (req->result == -EAGAIN)
		return -EAGAIN;

		/* workqueue context doesn't hold uring_lock, grab it now */
		if (in_async)
		mutex_lock(&ctx->uring_lock);

		io_iopoll_req_issued(req);

		if (in_async)
		mutex_unlock(&ctx->uring_lock);
		}

		return 0;

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