Re: [PATCH 1/2] blk-mq: add two interfaces to lock/unlock blk_mq_tags->lock

["yukuai (C)" <yukuai3@huawei.com>]

On 2021/08/09 0:44, Bart Van Assche wrote:
> On 8/7/21 8:17 PM, Yu Kuai wrote:
>> +void blk_mq_tags_lock(struct blk_mq_tags *tags, unsigned long *flags)
>> +{
>> +	spin_lock_irqsave(&tags->lock, *flags);
>> +}
>> +EXPORT_SYMBOL(blk_mq_tags_lock);
>> +
>> +void blk_mq_tags_unlock(struct blk_mq_tags *tags, unsigned long *flags)
>> +{
>> +	spin_unlock_irqrestore(&tags->lock, *flags);
>> +}
>> +EXPORT_SYMBOL(blk_mq_tags_unlock);
> 
> The tag map lock is an implementation detail and hence this lock must
> not be used directly by block drivers. I propose to introduce and export
> a new function to block drivers that does the following:
> * Lock tags->lock.
> * Call blk_mq_tag_to_rq().
> * Check whether the request is in the started state. If so, increment
> its reference count.
> * Unlock tags->lock.

Hi, Bart

Thanks for your advice, will do this in next iteration.

Best regards
Kuai