Message-ID: <4A56373C.4050409@vlnb.net>
Date: Thu, 09 Jul 2009 22:30:20 +0400
From: Vladislav Bolkhovitin <vst@vlnb.net>
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To: Jens Axboe <jens.axboe@oracle.com>
CC: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
       scst-devel@lists.sourceforge.net, Tejun Heo <tj@kernel.org>,
       Boaz Harrosh <bharrosh@panasas.com>,
       James Bottomley <James.Bottomley@HansenPartnership.com>,
       FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Subject: Re: [PATCH]: Rename REQ_COPY_USER to more descriptive	REQ_HAS_TAIL_SPACE_FOR_PADDING
References: <4A563259.5000601@vlnb.net> <20090709181713.GQ23611@kernel.dk>
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Jens Axboe, on 07/09/2009 10:17 PM wrote:
> On Thu, Jul 09 2009, Vladislav Bolkhovitin wrote:
>> Currently names of REQ_COPY_USER and __REQ_COPY_USER constants are confusing,
>> because they actually mean that the buffer for the corresponding requests
>> has space in the tail for padding in case of DMA padding restrictions.
> 
> No, that's not what it means, the fact that there's padding room is a
> side effect of the map type. So I'd suggest adding a comment above that
> if {} in blk_rq_map_sg(), something that should have been there from the
> beginning.

Can you elaborate a bit more about what REQ_COPY_USER should mean, please?

As far as I can see from the sources, currently it's used to only to 
determine if there is the padding space. Maybe, the original meaning 
doesn't make sense anymore?

Thanks,
Vlad


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