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Date:   Wed, 27 Mar 2019 15:16:33 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>
Cc:     Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@fb.com>,
        Keith Busch <keith.busch@intel.com>,
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Subject: Re: [PATCH 01/15] block: add a req_bvec helper
Message-ID: <20190327141633.GA26200@lst.de>
References: <20190321231037.25104-1-hch@lst.de> <20190321231037.25104-2-hch@lst.de> <SN6PR04MB4527D352D115DFAB042B18D2865E0@SN6PR04MB4527.namprd04.prod.outlook.com>
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On Mon, Mar 25, 2019 at 05:07:44AM +0000, Chaitanya Kulkarni wrote:
> > +static inline struct bio_vec req_bvec(struct request *rq)
> > +{
> > +	if (rq->rq_flags & RQF_SPECIAL_PAYLOAD)
> > +		return rq->special_vec;
> Quick question here mostly for my understanding, do we also have to 
> check here for nr_phys_segments for the operations such as write-zeroes ? OR
> 
> this may never get called in write-zeroes context ? OR
> not applicable ?

We assume the caller checks that we have nr_phys_segments.  I'll
add a commen to document that.