author: Ming Lei <ming.lei@redhat.com> 2021-06-09 09:58:21 +0800
committer: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 2021-07-14 17:06:34 +0200
commit: 6c22172ca78142b0dff366cc70ac83b37c920981
parent: 02f04a3c5d74bd8842ce1ad44a2304e5b62a238f
Commit Summary:
Diffstat:
1 file changed, 20 insertions, 0 deletions
diff --git a/block/blk-rq-qos.h b/block/blk-rq-qos.h
index 2bc43e94f4c4..2bcb3495e376 100644
--- a/block/blk-rq-qos.h
+++ b/block/blk-rq-qos.h
@@ -7,6 +7,7 @@
#include <linux/blk_types.h>
#include <linux/atomic.h>
#include <linux/wait.h>
+#include <linux/blk-mq.h>
#include "blk-mq-debugfs.h"
@@ -99,8 +100,21 @@ static inline void rq_wait_init(struct rq_wait *rq_wait)
static inline void rq_qos_add(struct request_queue *q, struct rq_qos *rqos)
{
+ /*
+ * No IO can be in-flight when adding rqos, so freeze queue, which
+ * is fine since we only support rq_qos for blk-mq queue.
+ *
+ * Reuse ->queue_lock for protecting against other concurrent
+ * rq_qos adding/deleting
+ */
+ blk_mq_freeze_queue(q);
+
+ spin_lock_irq(&q->queue_lock);
rqos->next = q->rq_qos;
q->rq_qos = rqos;
+ spin_unlock_irq(&q->queue_lock);
+
+ blk_mq_unfreeze_queue(q);
if (rqos->ops->debugfs_attrs)
blk_mq_debugfs_register_rqos(rqos);
@@ -110,12 +124,22 @@ static inline void rq_qos_del(struct request_queue *q, struct rq_qos *rqos)
{
struct rq_qos **cur;
+ /*
+ * See comment in rq_qos_add() about freezing queue & using
+ * ->queue_lock.
+ */
+ blk_mq_freeze_queue(q);
+
+ spin_lock_irq(&q->queue_lock);
for (cur = &q->rq_qos; *cur; cur = &(*cur)->next) {
if (*cur == rqos) {
*cur = rqos->next;
break;
}
}
+ spin_unlock_irq(&q->queue_lock);
+
+ blk_mq_unfreeze_queue(q);
blk_mq_debugfs_unregister_rqos(rqos);
}