From: Jens Axboe <axboe@kernel.dk>
Date: Mon, 9 Dec 2019 21:52:35 +0000 (-0700)
Subject: io_uring: sqthread should grab ctx->uring_lock for submissions
X-Git-Tag: v5.5-rc2~24^2~7
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8a4955ff1cca7d4da480774034a16e7c28bafec8;p=thirdparty%2Flinux.git

io_uring: sqthread should grab ctx->uring_lock for submissions

We use the mutex to guard against registered file updates, for instance.
Ensure we're safe in accessing that state against concurrent updates.

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

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 040e6c11ff375..366fc351869df 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2996,12 +2996,7 @@ static int io_issue_sqe(struct io_kiocb *req, struct io_kiocb **nxt,
 		if (req->result == -EAGAIN)
 			return -EAGAIN;
 
-		/* workqueue context doesn't hold uring_lock, grab it now */
-		if (req->in_async)
-			mutex_lock(&ctx->uring_lock);
 		io_iopoll_req_issued(req);
-		if (req->in_async)
-			mutex_unlock(&ctx->uring_lock);
 	}
 
 	return 0;
@@ -3655,7 +3650,9 @@ static int io_sq_thread(void *data)
 		}
 
 		to_submit = min(to_submit, ctx->sq_entries);
+		mutex_lock(&ctx->uring_lock);
 		ret = io_submit_sqes(ctx, to_submit, NULL, -1, &cur_mm, true);
+		mutex_unlock(&ctx->uring_lock);
 		if (ret > 0)
 			inflight += ret;
 	}