From 6af8bf3d86d55c98af6e453cb920ddc30867e5c7 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 29 Jul 2008 22:33:49 -0700 Subject: [PATCH] workqueues: add comments to __create_workqueue_key() Dmitry Adamushko pointed out that the error handling in __create_workqueue_key() is not clear, add the comment. Signed-off-by: Oleg Nesterov Cc: Dmitry Adamushko Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/workqueue.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index ec7e4f6..4a26a13 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -830,10 +830,21 @@ struct workqueue_struct *__create_workqueue_key(const char *name, start_workqueue_thread(cwq, -1); } else { cpu_maps_update_begin(); + /* + * We must place this wq on list even if the code below fails. + * cpu_down(cpu) can remove cpu from cpu_populated_map before + * destroy_workqueue() takes the lock, in that case we leak + * cwq[cpu]->thread. + */ spin_lock(&workqueue_lock); list_add(&wq->list, &workqueues); spin_unlock(&workqueue_lock); - + /* + * We must initialize cwqs for each possible cpu even if we + * are going to call destroy_workqueue() finally. Otherwise + * cpu_up() can hit the uninitialized cwq once we drop the + * lock. + */ for_each_possible_cpu(cpu) { cwq = init_cpu_workqueue(wq, cpu); if (err || !cpu_online(cpu)) -- 2.7.4