author: Baolin Wang <baolin.wang@linux.alibaba.com> 2021-01-28 13:58:15 +0800
committer: Jens Axboe <axboe@kernel.dk> 2021-01-28 07:31:48 -0700
commit: 6c635caef410aa757befbd8857c1eadde5cc22ed
parent: 8dc932d3e8afb65e12eba7495f046c83884c49bf
Commit Summary:
Diffstat:
1 file changed, 12 insertions, 5 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 031114d454a6..4221a1539391 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1016,6 +1016,8 @@ static void blkcg_css_offline(struct cgroup_subsys_state *css)
*/
void blkcg_destroy_blkgs(struct blkcg *blkcg)
{
+ might_sleep();
+
spin_lock_irq(&blkcg->lock);
while (!hlist_empty(&blkcg->blkg_list)) {
@@ -1023,14 +1025,20 @@ void blkcg_destroy_blkgs(struct blkcg *blkcg)
struct blkcg_gq, blkcg_node);
struct request_queue *q = blkg->q;
- if (spin_trylock(&q->queue_lock)) {
- blkg_destroy(blkg);
- spin_unlock(&q->queue_lock);
- } else {
+ if (need_resched() || !spin_trylock(&q->queue_lock)) {
+ /*
+ * Given that the system can accumulate a huge number
+ * of blkgs in pathological cases, check to see if we
+ * need to rescheduling to avoid softlockup.
+ */
spin_unlock_irq(&blkcg->lock);
- cpu_relax();
+ cond_resched();
spin_lock_irq(&blkcg->lock);
+ continue;
}
+
+ blkg_destroy(blkg);
+ spin_unlock(&q->queue_lock);
}
spin_unlock_irq(&blkcg->lock);