From 11ba820bf163e224bf5dd44e545a66a44a5b1d7a Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Wed, 15 Jan 2020 21:51:17 -0700 Subject: [PATCH] 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: 8a4955ff1cca ("io_uring: sqthread should grab ctx->uring_lock for submissions") Reported-by: Bijan Mottahedeh Signed-off-by: Jens Axboe --- fs/io_uring.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index 3130ed16456e..52e5764540e4 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -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; -- 2.30.2