Ming Lei <[email protected]> writes:
> You can add
> Reviewed-by: Ming Lei <[email protected]>
> if the following trivial issues(especially the 2nd one) are addressed.
[snip]
>> @@ -1891,7 +1890,12 @@ static void blk_mq_del_queue_tag_set(struct
>> request_queue *q)
>>
>> mutex_lock(&set->tag_list_lock);
>> list_del_init(&q->tag_set_list);
>> - blk_mq_update_tag_set_depth(set);
>> + if (set->tag_list.next == set->tag_list.prev) {
>
> list_is_singular() should be better.
Didn't even know that existed. Thanks.
>> + /* just transitioned to unshared */
>> + set->flags &= ~BLK_MQ_F_TAG_SHARED;
>> + /* update existing queue */
>> + blk_mq_update_tag_set_depth(set, false);
>> + }
>> mutex_unlock(&set->tag_list_lock);
>> }
>>
>> @@ -1901,8 +1905,17 @@ static void blk_mq_add_queue_tag_set(struct
>> blk_mq_tag_set *set,
>> q->tag_set = set;
>>
>> mutex_lock(&set->tag_list_lock);
>> +
>> + /* Check to see if we're transitioning to shared (from 1 to 2
>> queues). */
>> + if (!list_empty(&set->tag_list) && !(set->flags &
>> BLK_MQ_F_TAG_SHARED)) {
>> + set->flags |= BLK_MQ_F_TAG_SHARED;
>> + /* update existing queue */
>> + blk_mq_update_tag_set_depth(set, true);
>> + }
>> + if (set->flags & BLK_MQ_F_TAG_SHARED)
>
> The above should be 'else if', otherwise the current queue will be set
> twice.
I moved the list add below this to avoid that very issue. See:
>> + queue_set_hctx_shared(q, true);
>> list_add_tail(&q->tag_set_list, &set->tag_list);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This seemed the cleanest way to structure the code to avoid the double
walking of the hctx list for the current q.
-Jeff
>> - blk_mq_update_tag_set_depth(set);
>> +
>> mutex_unlock(&set->tag_list_lock);
>> }
>>
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