From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Grundler Subject: Re: SCSI QLA not working on latest *-mm SN2 Date: Tue, 21 Sep 2004 19:44:28 -0600 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <20040922014428.GD20053@colo.lackof.org> References: <20040917183029.GW642@parcelfarce.linux.theplanet.co.uk> <200409211346.58267.jbarnes@engr.sgi.com> <1095789421.2467.414.camel@mulgrave> <200409211409.11095.jbarnes@engr.sgi.com> <20040921190625.GB11708@colo.lackof.org> <20040921210341.GC146363@sgi.com> <20040921211108.GA16153@parcelfarce.linux.theplanet.co.uk> <20040921214302.GG146363@sgi.com> <20040922000211.GE16153@parcelfarce.linux.theplanet.co.uk> <20040922011652.GD147856@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from colo.lackof.org ([198.49.126.79]:26250 "EHLO colo.lackof.org") by vger.kernel.org with ESMTP id S267595AbUIVBoa (ORCPT ); Tue, 21 Sep 2004 21:44:30 -0400 Content-Disposition: inline In-Reply-To: <20040922011652.GD147856@sgi.com> List-Id: linux-scsi@vger.kernel.org To: Jeremy Higdon Cc: Matthew Wilcox , Grant Grundler , Jesse Barnes , James Bottomley , Matthew Wilcox , Andrew Vasquez , pj@sgi.com, SCSI Mailing List , mdr@cthulhu.engr.sgi.com, jeremy@cthulhu.engr.sgi.com, djh@cthulhu.engr.sgi.com, Andrew Morton On Tue, Sep 21, 2004 at 06:16:52PM -0700, Jeremy Higdon wrote: > First let's make sure that we like it best. > > The other alternative is an explicit I/O barrier. > > writel(high-water, request-in) > mmiob() /* memory-mapped I/O barrier */ > spin_unlock(hostlock) I strongly prefer a seperate function call. I'm wondering if one for write posting and a different for write ordering would be called for. These are really distinct uses but I'm not sure it's a distinction that's clear to most folks and they will get misused. If not, then io_mwb() would be my preference. > versus > > writel(high-water, request-in) > spin_unlock_iob(hostlock) More variants of spinlocks? When to use and how to implement it become even less clear. thanks, grant