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Subject: Re: [PATCH V9 2/4] blk-mq: refactor the code of issue request
 directly
To:     Jens Axboe <axboe@kernel.dk>
Cc:     ming.lei@redhat.com, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <1543995842-20704-1-git-send-email-jianchao.w.wang@oracle.com>
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 <d46af0a7-62f3-4988-2b1c-857378282356@kernel.dk>
From:   "jianchao.wang" <jianchao.w.wang@oracle.com>
Message-ID: <f1f368b7-fb2f-5ef4-4179-6086a0d91c35@oracle.com>
Date:   Thu, 6 Dec 2018 09:12:33 +0800
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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@oracle.com>
>> ---
>>  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