Re: [PATCH v13 03/18] block: Preserve the order of requeued zoned writes

[Bart Van Assche <bvanassche@acm.org>]

On 10/18/23 17:15, Damien Le Moal wrote:
> On 10/19/23 02:54, Bart Van Assche wrote:
>> blk_mq_requeue_work() inserts requeued requests in front of other
>> requests. This is fine for all request types except for sequential zoned
>> writes. Hence this patch.
>>
>> Note: moving this functionality into the mq-deadline I/O scheduler is
>> not an option because we want to be able to use zoned storage without
>> I/O scheduler.
>>
>> Cc: Christoph Hellwig <hch@lst.de>
>> Cc: Damien Le Moal <dlemoal@kernel.org>
>> Cc: Ming Lei <ming.lei@redhat.com>
>> Cc: Hannes Reinecke <hare@suse.de>
>> Signed-off-by: Bart Van Assche <bvanassche@acm.org>
>> ---
>>   block/blk-mq.c | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/block/blk-mq.c b/block/blk-mq.c
>> index 502dafa76716..ce6ddb249959 100644
>> --- a/block/blk-mq.c
>> +++ b/block/blk-mq.c
>> @@ -1485,7 +1485,9 @@ static void blk_mq_requeue_work(struct work_struct *work)
>>   			blk_mq_request_bypass_insert(rq, 0);
>>   		} else {
>>   			list_del_init(&rq->queuelist);
>> -			blk_mq_insert_request(rq, BLK_MQ_INSERT_AT_HEAD);
>> +			blk_mq_insert_request(rq,
>> +					      !blk_rq_is_seq_zoned_write(rq) ?
>> +					      BLK_MQ_INSERT_AT_HEAD : 0);
> 
> Something like:
> 
> 		} else {
> 			blk_insert_t flags = BLK_MQ_INSERT_AT_HEAD;
> 
> 			if (blk_rq_is_seq_zoned_write(rq))
> 				flags = 0;
> 			blk_mq_insert_request(rq, flags);
> 		}
> 
> would be a lot easier to read in my opinion.

Hi Damien,

I will make this change.

Thanks,

Bart.