[02/27] blk-stat: make q->stats->lock irqsafe
diff mbox series

Message ID 20200901185257.645114-3-tj@kernel.org
State In Next
Commit e11d80a849e010f78243bb6f6af7dccef3a71a90
Headers show
Series
  • [01/27] blk-iocost: ioc_pd_free() shouldn't assume irq disabled
Related show

Commit Message

Tejun Heo Sept. 1, 2020, 6:52 p.m. UTC
blk-iocost calls blk_stat_enable_accounting() while holding an irqsafe lock
which triggers a lockdep splat because q->stats->lock isn't irqsafe. Let's
make it irqsafe.

Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: cd006509b0a9 ("blk-iocost: account for IO size when testing latencies")
Cc: stable@vger.kernel.org # v5.8+
---
 block/blk-stat.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

Patch
diff mbox series

diff --git a/block/blk-stat.c b/block/blk-stat.c
index 7da302ff88d0..ae3dd1fb8e61 100644
--- a/block/blk-stat.c
+++ b/block/blk-stat.c
@@ -137,6 +137,7 @@  void blk_stat_add_callback(struct request_queue *q,
 			   struct blk_stat_callback *cb)
 {
 	unsigned int bucket;
+	unsigned long flags;
 	int cpu;
 
 	for_each_possible_cpu(cpu) {
@@ -147,20 +148,22 @@  void blk_stat_add_callback(struct request_queue *q,
 			blk_rq_stat_init(&cpu_stat[bucket]);
 	}
 
-	spin_lock(&q->stats->lock);
+	spin_lock_irqsave(&q->stats->lock, flags);
 	list_add_tail_rcu(&cb->list, &q->stats->callbacks);
 	blk_queue_flag_set(QUEUE_FLAG_STATS, q);
-	spin_unlock(&q->stats->lock);
+	spin_unlock_irqrestore(&q->stats->lock, flags);
 }
 
 void blk_stat_remove_callback(struct request_queue *q,
 			      struct blk_stat_callback *cb)
 {
-	spin_lock(&q->stats->lock);
+	unsigned long flags;
+
+	spin_lock_irqsave(&q->stats->lock, flags);
 	list_del_rcu(&cb->list);
 	if (list_empty(&q->stats->callbacks) && !q->stats->enable_accounting)
 		blk_queue_flag_clear(QUEUE_FLAG_STATS, q);
-	spin_unlock(&q->stats->lock);
+	spin_unlock_irqrestore(&q->stats->lock, flags);
 
 	del_timer_sync(&cb->timer);
 }
@@ -183,10 +186,12 @@  void blk_stat_free_callback(struct blk_stat_callback *cb)
 
 void blk_stat_enable_accounting(struct request_queue *q)
 {
-	spin_lock(&q->stats->lock);
+	unsigned long flags;
+
+	spin_lock_irqsave(&q->stats->lock, flags);
 	q->stats->enable_accounting = true;
 	blk_queue_flag_set(QUEUE_FLAG_STATS, q);
-	spin_unlock(&q->stats->lock);
+	spin_unlock_irqrestore(&q->stats->lock, flags);
 }
 EXPORT_SYMBOL_GPL(blk_stat_enable_accounting);