Re: [PATCH] blk-mq: avoid to synchronize rcu inside blk_cleanup_queue()

[Jens Axboe <axboe@xxxxxxxxx>]

On 6/22/18 3:31 PM, Ming Lei wrote:
>> diff --git a/block/blk-mq.c b/block/blk-mq.c
>> index 8e57b84e50e9..18ad2b95ff63 100644
>> --- a/block/blk-mq.c
>> +++ b/block/blk-mq.c
>> @@ -2351,8 +2351,12 @@ static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set *set,
>>  static void blk_mq_del_queue_tag_set(struct request_queue *q)
>>  {
>>  	struct blk_mq_tag_set *set = q->tag_set;
>> +	bool shared;
>>  
>>  	mutex_lock(&set->tag_list_lock);
>> +
>> +	shared = !list_is_singular(&set->tag_list);
> 
> Or:
> 	shared = set->flags & BLK_MQ_F_TAG_SHARED;

That'd work too, yeah.

-- 
Jens Axboe