From: Vladislav Bolkhovitin <vst@vlnb.net>
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
Date: Thu, 09 Jul 2009 22:30:20 +0400 [thread overview]
Message-ID: <4A56373C.4050409@vlnb.net> (raw)
In-Reply-To: <20090709181713.GQ23611@kernel.dk>
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
next prev parent reply other threads:[~2009-07-09 18:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-09 18:09 [PATCH]: Rename REQ_COPY_USER to more descriptive REQ_HAS_TAIL_SPACE_FOR_PADDING Vladislav Bolkhovitin
2009-07-09 18:17 ` Jens Axboe
2009-07-09 18:30 ` Vladislav Bolkhovitin [this message]
2009-07-14 16:34 ` Vladislav Bolkhovitin
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