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-rw-r--r--block/blk-cgroup.c24
1 files changed, 9 insertions, 15 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index e9e3b038c702..27d39a810cb6 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -500,7 +500,7 @@ static struct blkio_group *blkg_alloc(struct blkio_cgroup *blkcg,
500 return NULL; 500 return NULL;
501 501
502 spin_lock_init(&blkg->stats_lock); 502 spin_lock_init(&blkg->stats_lock);
503 rcu_assign_pointer(blkg->q, q); 503 blkg->q = q;
504 INIT_LIST_HEAD(&blkg->q_node); 504 INIT_LIST_HEAD(&blkg->q_node);
505 blkg->blkcg = blkcg; 505 blkg->blkcg = blkcg;
506 blkg->refcnt = 1; 506 blkg->refcnt = 1;
@@ -611,7 +611,6 @@ struct blkio_group *blkg_lookup_create(struct blkio_cgroup *blkcg,
611 611
612 hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list); 612 hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
613 list_add(&blkg->q_node, &q->blkg_list); 613 list_add(&blkg->q_node, &q->blkg_list);
614 q->nr_blkgs++;
615 614
616 spin_unlock(&blkcg->lock); 615 spin_unlock(&blkcg->lock);
617out: 616out:
@@ -648,9 +647,6 @@ static void blkg_destroy(struct blkio_group *blkg)
648 list_del_init(&blkg->q_node); 647 list_del_init(&blkg->q_node);
649 hlist_del_init_rcu(&blkg->blkcg_node); 648 hlist_del_init_rcu(&blkg->blkcg_node);
650 649
651 WARN_ON_ONCE(q->nr_blkgs <= 0);
652 q->nr_blkgs--;
653
654 /* 650 /*
655 * Put the reference taken at the time of creation so that when all 651 * Put the reference taken at the time of creation so that when all
656 * queues are gone, group can be destroyed. 652 * queues are gone, group can be destroyed.
@@ -1232,8 +1228,9 @@ static int blkio_read_blkg_stats(struct blkio_cgroup *blkcg,
1232 struct hlist_node *n; 1228 struct hlist_node *n;
1233 uint64_t cgroup_total = 0; 1229 uint64_t cgroup_total = 0;
1234 1230
1235 rcu_read_lock(); 1231 spin_lock_irq(&blkcg->lock);
1236 hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) { 1232
1233 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
1237 const char *dname = blkg_dev_name(blkg); 1234 const char *dname = blkg_dev_name(blkg);
1238 int plid = BLKIOFILE_POLICY(cft->private); 1235 int plid = BLKIOFILE_POLICY(cft->private);
1239 1236
@@ -1243,15 +1240,16 @@ static int blkio_read_blkg_stats(struct blkio_cgroup *blkcg,
1243 cgroup_total += blkio_get_stat_cpu(blkg, plid, 1240 cgroup_total += blkio_get_stat_cpu(blkg, plid,
1244 cb, dname, type); 1241 cb, dname, type);
1245 } else { 1242 } else {
1246 spin_lock_irq(&blkg->stats_lock); 1243 spin_lock(&blkg->stats_lock);
1247 cgroup_total += blkio_get_stat(blkg, plid, 1244 cgroup_total += blkio_get_stat(blkg, plid,
1248 cb, dname, type); 1245 cb, dname, type);
1249 spin_unlock_irq(&blkg->stats_lock); 1246 spin_unlock(&blkg->stats_lock);
1250 } 1247 }
1251 } 1248 }
1252 if (show_total) 1249 if (show_total)
1253 cb->fill(cb, "Total", cgroup_total); 1250 cb->fill(cb, "Total", cgroup_total);
1254 rcu_read_unlock(); 1251
1252 spin_unlock_irq(&blkcg->lock);
1255 return 0; 1253 return 0;
1256} 1254}
1257 1255
@@ -1583,28 +1581,24 @@ static int blkiocg_pre_destroy(struct cgroup_subsys *subsys,
1583{ 1581{
1584 struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup); 1582 struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
1585 1583
1586 rcu_read_lock();
1587 spin_lock_irq(&blkcg->lock); 1584 spin_lock_irq(&blkcg->lock);
1588 1585
1589 while (!hlist_empty(&blkcg->blkg_list)) { 1586 while (!hlist_empty(&blkcg->blkg_list)) {
1590 struct blkio_group *blkg = hlist_entry(blkcg->blkg_list.first, 1587 struct blkio_group *blkg = hlist_entry(blkcg->blkg_list.first,
1591 struct blkio_group, blkcg_node); 1588 struct blkio_group, blkcg_node);
1592 struct request_queue *q = rcu_dereference(blkg->q); 1589 struct request_queue *q = blkg->q;
1593 1590
1594 if (spin_trylock(q->queue_lock)) { 1591 if (spin_trylock(q->queue_lock)) {
1595 blkg_destroy(blkg); 1592 blkg_destroy(blkg);
1596 spin_unlock(q->queue_lock); 1593 spin_unlock(q->queue_lock);
1597 } else { 1594 } else {
1598 spin_unlock_irq(&blkcg->lock); 1595 spin_unlock_irq(&blkcg->lock);
1599 rcu_read_unlock();
1600 cpu_relax(); 1596 cpu_relax();
1601 rcu_read_lock();
1602 spin_lock(&blkcg->lock); 1597 spin_lock(&blkcg->lock);
1603 } 1598 }
1604 } 1599 }
1605 1600
1606 spin_unlock_irq(&blkcg->lock); 1601 spin_unlock_irq(&blkcg->lock);
1607 rcu_read_unlock();
1608 return 0; 1602 return 0;
1609} 1603}
1610 1604