io_uring: remove req cancel in ->flush()

Every close(io_uring) causes cancellation of all inflight requests
carrying ->files. That's not nice but was neccessary up until recently.
Now task->files removal is handled in the core code, so that part of
flush can be removed.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -8684,19 +8684,11 @@ static void io_uring_del_task_file(struct file *file)
 		fput(file);
 }
 
-static void __io_uring_attempt_task_drop(struct file *file)
-{
-	struct file *old = xa_load(&current->io_uring->xa, (unsigned long)file);
-
-	if (old == file)
-		io_uring_del_task_file(file);
-}
-
 /*
  * Drop task note for this file if we're the only ones that hold it after
  * pending fput()
  */
-static void io_uring_attempt_task_drop(struct file *file, bool exiting)
+static void io_uring_attempt_task_drop(struct file *file)
 {
 	if (!current->io_uring)
 		return;
@@ -8704,10 +8696,9 @@ static void io_uring_attempt_task_drop(struct file *file, bool exiting)
 	 * fput() is pending, will be 2 if the only other ref is our potential
 	 * task file note. If the task is exiting, drop regardless of count.
 	 */
-	if (!exiting && atomic_long_read(&file->f_count) != 2)
-		return;
-
-	__io_uring_attempt_task_drop(file);
+	if (fatal_signal_pending(current) || (current->flags & PF_EXITING) ||
+	    atomic_long_read(&file->f_count) == 2)
+		io_uring_del_task_file(file);
 }
 
 void __io_uring_files_cancel(struct files_struct *files)
@@ -8765,16 +8756,7 @@ void __io_uring_task_cancel(void)
 
 static int io_uring_flush(struct file *file, void *data)
 {
-	struct io_ring_ctx *ctx = file->private_data;
-
-	/*
-	 * If the task is going away, cancel work it may have pending
-	 */
-	if (fatal_signal_pending(current) || (current->flags & PF_EXITING))
-		data = NULL;
-
-	io_uring_cancel_task_requests(ctx, data);
-	io_uring_attempt_task_drop(file, !data);
+	io_uring_attempt_task_drop(file);
 	return 0;
 }