diff options
Diffstat (limited to 'include/linux/blkdev.h')
| -rw-r--r-- | include/linux/blkdev.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 1c0cf6af392c..e39c45bc0a97 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -568,7 +568,22 @@ struct request_queue { struct blk_flush_queue *fq; struct list_head flush_list; + /* + * Protects against I/O scheduler switching, particularly when updating + * q->elevator. Since the elevator update code path may also modify q-> + * nr_requests and wbt latency, this lock also protects the sysfs attrs + * nr_requests and wbt_lat_usec. Additionally the nr_hw_queues update + * may modify hctx tags, reserved-tags and cpumask, so this lock also + * helps protect the hctx sysfs/debugfs attrs. To ensure proper locking + * order during an elevator or nr_hw_queue update, first freeze the + * queue, then acquire ->elevator_lock. + */ + struct mutex elevator_lock; + struct mutex sysfs_lock; + /* + * Protects queue limits and also sysfs attribute read_ahead_kb. + */ struct mutex limits_lock; /* |