Re: [RFC 2/2] io_uring: acquire ctx->uring_lock before calling io_issue_sqe()

[Jens Axboe <axboe@xxxxxxxxx>]

On 1/15/20 7:37 PM, Bijan Mottahedeh wrote:
> io_issue_sqe() calls io_iopoll_req_issued() which manipulates poll_list,
> so acquire ctx->uring_lock beforehand similar to other instances of
> calling io_issue_sqe().

Is the below not enough?

diff --git a/fs/io_uring.c b/fs/io_uring.c
index f9709a3a673c..900e86189ce7 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4272,10 +4272,18 @@ 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 = req->in_async;
+
 		if (req->result == -EAGAIN)
 			return -EAGAIN;
 
+		if (in_async)
+			mutex_lock(&ctx->uring_lock);
+
 		io_iopoll_req_issued(req);
+
+		if (in_async)
+			mutex_unlock(&ctx->uring_lock);
 	}
 
 	return 0;

-- 
Jens Axboe