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authorJens Axboe <axboe@kernel.dk>2023-01-27 09:50:31 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-03-10 09:34:03 +0100
commitd9399e543062251cc6102e7e5d80f3bd79115316 (patch)
tree6cda2d75d247054ff41faa3e51f80a61a815193e /io_uring
parent42fe280e267a120724e139732bc7db9e13fd1914 (diff)
downloadlinux-d9399e543062251cc6102e7e5d80f3bd79115316.tar.gz
io_uring: add reschedule point to handle_tw_list()
commit f58680085478dd292435727210122960d38e8014 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'io_uring')
-rw-r--r--io_uring/io_uring.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 5dc21591bf68..78c677869308 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -1030,10 +1030,16 @@ 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;