diff mbox series

[2/2] io_uring: add reschedule point to handle_tw_list()

Message ID 20230127165332.71970-3-axboe@kernel.dk (mailing list archive)
State New
Headers show
Series Fixes for CONFIG_PREEMPT_NONE | expand

Commit Message

Jens Axboe Jan. 27, 2023, 4:53 p.m. UTC 
If CONFIG_PREEMPT_NONE is set and the task_work chains are long, we
could be running into issues blocking others for too long. Add a
reschedule check in handle_tw_list(), and flush the ctx if we need to
reschedule.

Cc: stable@vger.kernel.org # 5.10+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 io_uring/io_uring.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index bb8a532b051e..bc8845de2829 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -1179,10 +1179,16 @@  static unsigned int handle_tw_list(struct llist_node *node,
 			/* if not contended, grab and improve batching */
 			*locked = mutex_trylock(&(*ctx)->uring_lock);
 			percpu_ref_get(&(*ctx)->refs);
-		}
+		} else if (!*locked)
+			*locked = mutex_trylock(&(*ctx)->uring_lock);
 		req->io_task_work.func(req, locked);
 		node = next;
 		count++;
+		if (unlikely(need_resched())) {
+			ctx_flush_and_put(*ctx, locked);
+			*ctx = NULL;
+			cond_resched();
+		}
 	}
 
 	return count;