From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: [PATCH 1/3] SCSI: Make cmd_serial_number an atomic Date: Sun, 03 Apr 2011 07:14:54 -0500 Message-ID: <1301832894.2631.2.camel@mulgrave.site> References: <20110401202051.GL4183@linux.intel.com> <20110402133643.GB18990@infradead.org> <20110402210240.GD7286@parisc-linux.org> <20110403110057.GC3872@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from cantor2.suse.de ([195.135.220.15]:52725 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752150Ab1DCMPA (ORCPT ); Sun, 3 Apr 2011 08:15:00 -0400 In-Reply-To: <20110403110057.GC3872@infradead.org> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Christoph Hellwig Cc: Matthew Wilcox , Matthew Wilcox , linux-scsi@vger.kernel.org On Sun, 2011-04-03 at 07:00 -0400, Christoph Hellwig wrote: > On Sat, Apr 02, 2011 at 03:02:40PM -0600, Matthew Wilcox wrote: > > Fair enough, but you're making the perfect the enemy of the good. > > How about putting this patch in for now (since it harms nothing), and > > then it'll all go away when you delete cmd_serial_number? > > If you change it anyway for mpt2sas just keep the atomic counter in > it's local structures. Or even better verify with LSI if the > serial_number check can't simply be removed entirely, which I think it > could. Also I'm not really sure atomic counter conversion is the correct thing to do. Someone from intel said it would perform worse than the current spinlock based serial number the last time we discussed the conversion (converting it to atomic was my first thought at the time). James