Merge tag 'nfs-for-5.1-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

[uclinux-h8/linux.git] / block / blk-sysfs.c

diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 590d1ef..5968591 100644 (file)
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -468,6 +468,9 @@ static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
        else if (val >= 0)
                val *= 1000ULL;
 
+       if (wbt_get_min_lat(q) == val)
+               return count;
+
        /*
         * Ensure that the queue is idled, in case the latency update
         * ends up either enabling or disabling wbt completely. We can't
@@ -817,21 +820,16 @@ static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 }
 
 /**
- * __blk_release_queue - release a request queue when it is no longer needed
+ * __blk_release_queue - release a request queue
  * @work: pointer to the release_work member of the request queue to be released
  *
  * Description:
- *     blk_release_queue is the counterpart of blk_init_queue(). It should be
- *     called when a request queue is being released; typically when a block
- *     device is being de-registered. Its primary task it to free the queue
- *     itself.
- *
- * Notes:
- *     The low level driver must have finished any outstanding requests first
- *     via blk_cleanup_queue().
- *
- *     Although blk_release_queue() may be called with preemption disabled,
- *     __blk_release_queue() may sleep.
+ *     This function is called when a block device is being unregistered. The
+ *     process of releasing a request queue starts with blk_cleanup_queue, which
+ *     set the appropriate flags and then calls blk_put_queue, that decrements
+ *     the reference counter of the request queue. Once the reference counter
+ *     of the request queue reaches zero, blk_release_queue is called to release
+ *     all allocated resources of the request queue.
  */
 static void __blk_release_queue(struct work_struct *work)
 {