Re: [PATCH V9 2/4] blk-mq: refactor the code of issue request directly

From: jianchao.wang
Date: Wed Dec 05 2018 - 20:12:00 EST




On 12/6/18 12:27 AM, Jens Axboe wrote:
> On 12/5/18 12:44 AM, Jianchao Wang wrote:
>> Merge blk_mq_try_issue_directly and __blk_mq_try_issue_directly
>> into one interface to unify the interfaces to issue requests
>> directly. The merged interface takes over the requests totally,
>> it could insert, end or do nothing based on the return value of
>> .queue_rq and 'bypass' parameter. Then caller needn't any other
>> handling any more and then code could be cleaned up.
>>
>> Signed-off-by: Jianchao Wang <jianchao.w.wang@xxxxxxxxxx>
>> ---
>> block/blk-mq.c | 116 +++++++++++++++++++++++++++------------------------------
>> 1 file changed, 54 insertions(+), 62 deletions(-)
>>
>> diff --git a/block/blk-mq.c b/block/blk-mq.c
>> index 153af90..fe92e52 100644
>> --- a/block/blk-mq.c
>> +++ b/block/blk-mq.c
>> @@ -1815,93 +1815,85 @@ static bool blk_rq_can_direct_dispatch(struct request *rq)
>> return req_op(rq) == REQ_OP_READ || req_op(rq) == REQ_OP_WRITE;
>> }
>>
>> -static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
>> +static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
>> struct request *rq,
>> blk_qc_t *cookie,
>> - bool bypass_insert, bool last)
>> + bool bypass, bool last)
>> {
>> struct request_queue *q = rq->q;
>> bool run_queue = true;
>> + blk_status_t ret = BLK_STS_RESOURCE;
>> + int srcu_idx;
>> bool force = false;
>>
>> + if (!blk_rq_can_direct_dispatch(rq)) {
>> + /*
>> + * Insert request to hctx dispatch list for 'bypass == true'
>> + * case, otherwise, the caller will fail forever.
>> + */
>> + if (bypass)
>> + force = true;
>> + goto out;
>> + }
>
> Same here, of course.

Yes, I will change it next version.

>
> Otherwise looks fine.
>

Thanks
Jianchao