io_uring: remove not needed PF_EXITING check

Since cancellation got moved before exit_signals(), there is no one left
who can call io_run_task_work() with PF_EXIING set, so remove the check.
Note that __io_req_task_submit() still needs a similar check.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/f7f305ececb1e6044ea649fb983ca754805bb884.1624739600.git.asml.silence@gmail.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -2235,12 +2235,6 @@ static inline unsigned int io_put_rw_kbuf(struct io_kiocb *req)
 
 static inline bool io_run_task_work(void)
 {
-	/*
-	 * Not safe to run on exiting task, and the task_work handling will
-	 * not add work to such a task.
-	 */
-	if (unlikely(current->flags & PF_EXITING))
-		return false;
 	if (current->task_works) {
 		__set_current_state(TASK_RUNNING);
 		task_work_run();
@@ -9020,7 +9014,8 @@ static void io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
 		ret |= io_cancel_defer_files(ctx, task, cancel_all);
 		ret |= io_poll_remove_all(ctx, task, cancel_all);
 		ret |= io_kill_timeouts(ctx, task, cancel_all);
-		ret |= io_run_task_work();
+		if (task)
+			ret |= io_run_task_work();
 		ret |= io_run_ctx_fallback(ctx);
 		if (!ret)
 			break;