io_uring: cancel deferred requests in try_cancel

As io_uring_cancel_files() and others let SQO to run between io_uring_try_cancel_requests(), SQO may generate new deferred requests, so it's safer to try to cancel them in it. Signed-off-by: Pavel Begunkov <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
kawasaki · Mar 12, 2021 · e1915f7 · e1915f7
1 parent d052d1d
commit e1915f7
Showing 1 changed file with 6 additions and 4 deletions.
diff --git a/fs/io_uring.c b/fs/io_uring.c
@@ -8577,11 +8577,11 @@ static bool io_cancel_task_cb(struct io_wq_work *work, void *data)
 	return ret;
 }
 
-static void io_cancel_defer_files(struct io_ring_ctx *ctx,
+static bool io_cancel_defer_files(struct io_ring_ctx *ctx,
 				  struct task_struct *task,
 				  struct files_struct *files)
 {
-	struct io_defer_entry *de = NULL;
+	struct io_defer_entry *de;
 	LIST_HEAD(list);
 
 	spin_lock_irq(&ctx->completion_lock);
@@ -8592,6 +8592,8 @@ static void io_cancel_defer_files(struct io_ring_ctx *ctx,
 		}
 	}
 	spin_unlock_irq(&ctx->completion_lock);
+	if (list_empty(&list))
+		return false;
 
 	while (!list_empty(&list)) {
 		de = list_first_entry(&list, struct io_defer_entry, list);
@@ -8601,6 +8603,7 @@ static void io_cancel_defer_files(struct io_ring_ctx *ctx,
 		io_req_complete(de->req, -ECANCELED);
 		kfree(de);
 	}
+	return true;
 }
 
 static bool io_cancel_ctx_cb(struct io_wq_work *work, void *data)
@@ -8666,6 +8669,7 @@ static void io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
 			}
 		}
 
+		ret |= io_cancel_defer_files(ctx, task, files);
 		ret |= io_poll_remove_all(ctx, task, files);
 		ret |= io_kill_timeouts(ctx, task, files);
 		ret |= io_run_task_work();
@@ -8734,8 +8738,6 @@ static void io_uring_cancel_task_requests(struct io_ring_ctx *ctx,
 			atomic_inc(&task->io_uring->in_idle);
 	}
 
-	io_cancel_defer_files(ctx, task, files);
-
 	io_uring_cancel_files(ctx, task, files);
 	if (!files)
 		io_uring_try_cancel_requests(ctx, task, NULL);