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 040e6c1..366fc35 100644 (file)
--- 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;
        }