From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [patch 5/6] ps3: BD/DVD/CD-ROM Storage Driver Date: Mon, 16 Jul 2007 16:38:52 +0200 Message-ID: <20070716143852.GW5195@kernel.dk> References: <20070704132212.726923000@pademelon.sonytel.be> <1184335333.3402.20.camel@localhost.localdomain> <200707131619.54898.arnd@arndb.de> <1184340528.3402.32.camel@localhost.localdomain> <20070716121649.GI5195@kernel.dk> <1184593643.3447.9.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from brick.kernel.dk ([80.160.20.94]:25351 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758052AbXGPOje (ORCPT ); Mon, 16 Jul 2007 10:39:34 -0400 Content-Disposition: inline In-Reply-To: <1184593643.3447.9.camel@localhost.localdomain> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: James Bottomley Cc: Geert Uytterhoeven , Arnd Bergmann , linux-scsi@vger.kernel.org, Linux Kernel Development , Alessandro Rubini , Linux/PPC Development , Paul Mackerras On Mon, Jul 16 2007, James Bottomley wrote: > On Mon, 2007-07-16 at 14:16 +0200, Jens Axboe wrote: > > On Mon, Jul 16 2007, Geert Uytterhoeven wrote: > > > On Fri, 13 Jul 2007, Geert Uytterhoeven wrote: > > > > Ah, that explains it. flush_dcache_page() is used in some drivers. > > > > I'll update my patches. Thanks for the comments! > > > > > > Does this look OK? > > > - Replaced KM_USER0 by KM_IRQ0 (all routines are either called from an > > > interrupt handler, from .request_fn (ps3disk), or from .queuecommand > > > (ps3rom)) > > > > That looks good. > > > > > - Add a call to flush_kernel_dcache_page() in routines that write to buffers > > > > Hmm, I would have thought a flush_dcache_page() would be more > > appropriate, the backing could be page cache pages. > > No ... that was the point of flush_kernel_dcache_page(). The page in > question is page cache backed and contains user mappings. However, the > block layer has already done a flush_dcache_page() in get_user_pages() > and the user shouldn't be touching memory under I/O (unless they want > self induced aliasing problems) so we're free to assume all the user > cachelines are purged, hence all we have to do is flush the kernel alias > to bring the page up to date and make the users see it correctly. Oh indeed, I missed the flush_dcache_page() in get_user_pages(). -- Jens Axboe