From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vladislav Bolkhovitin 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 Message-ID: <4A56373C.4050409@vlnb.net> References: <4A563259.5000601@vlnb.net> <20090709181713.GQ23611@kernel.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from moutng.kundenserver.de ([212.227.17.9]:55457 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753148AbZGISaX (ORCPT ); Thu, 9 Jul 2009 14:30:23 -0400 In-Reply-To: <20090709181713.GQ23611@kernel.dk> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Jens Axboe Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, scst-devel@lists.sourceforge.net, Tejun Heo , Boaz Harrosh , James Bottomley , FUJITA Tomonori 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