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authorOleg Nesterov <oleg@tv-sign.ru>2008-07-29 22:33:49 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-30 09:41:47 -0700
commit6af8bf3d86d55c98af6e453cb920ddc30867e5c7 (patch)
treea82494403b76591082a2dc391da3136c6674b356
parentdbacefc9c4f6bd365243db379473ab7041656d90 (diff)
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 <oleg@tv-sign.ru> Cc: Dmitry Adamushko <dmitry.adamushko@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/workqueue.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index ec7e4f62aaff..4a26a1382df0 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))