From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: Patch added to scsi-rc-fixes-2.6: [SCSI] host lock push-down Date: Wed, 10 Nov 2010 18:52:08 -0500 Message-ID: <4CDB3028.6080605@garzik.org> References: <201011102240.oAAMe86a001486@hera.kernel.org> <4CDB2A81.5030100@garzik.org> <1289432759.3016.63.camel@mulgrave.site> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-vw0-f46.google.com ([209.85.212.46]:59311 "EHLO mail-vw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757322Ab0KJXwM (ORCPT ); Wed, 10 Nov 2010 18:52:12 -0500 In-Reply-To: <1289432759.3016.63.camel@mulgrave.site> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: James Bottomley Cc: linux-scsi , LKML On 11/10/2010 06:45 PM, James Bottomley wrote: > On Wed, 2010-11-10 at 18:28 -0500, Jeff Garzik wrote: >> On 11/10/2010 05:40 PM, James Bottomley wrote: >>> Your commit: >>> >>> [SCSI] host lock push-down >>> >>> Move the mid-layer's ->queuecommand() invocation from being locked >>> with the host lock to being unlocked to facilitate speeding up the >>> critical path for drivers who don't need this lock taken anyway. >>> >>> The patch below presents a simple SCSI host lock push-down as an >>> equivalent transformation. No locking or other behavior should change >>> with this patch. All existing bugs and locking orders are preserved. >>> >>> Minimal code disturbance was attempted with this change. Most drivers >>> needed only two one-line modifications for their host lock push-down. >>> >>> Signed-off-by: Jeff Garzik >>> Signed-off-by: James Bottomley >>> >>> has been added to the upstream SCSI tree >>> You can find it here: >> >> No comments on renaming ->queuecommand to something else? > > What we wondered about doing differently isn't really relevant for a > change log ... that should just really be about what was done (to avoid > confusion). Wasn't referring to the changelog (perhaps shouldn't have quoted that); just asking the question generally. >> The consequences are rather dire if this goes unnoticed, yes? > > You mean if there's a missed in-tree driver? Yes, but I took care to > make sure all SCSI drivers were accounted for. For out of tree drivers, > as with the eh lock push down, it's caveat emptor. Thinking about out-of-tree drivers, yes. Jeff