From mboxrd@z Thu Jan 1 00:00:00 1970 From: "David S. Miller" Subject: Re: [patch][9/9] block: remove bio walking Date: Thu, 9 Sep 2004 09:01:16 -0700 Sender: linux-ide-owner@vger.kernel.org Message-ID: <20040909090116.11e7a031.davem@davemloft.net> References: <200409082127.04331.bzolnier@elka.pw.edu.pl> <200409091553.13918.bzolnier@elka.pw.edu.pl> <20040909150444.C6434@flint.arm.linux.org.uk> <200409091628.25304.bzolnier@elka.pw.edu.pl> <20040909155420.D6434@flint.arm.linux.org.uk> <20040909154453.GG1737@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from adsl-63-197-226-105.dsl.snfc21.pacbell.net ([63.197.226.105]:5765 "EHLO cheetah.davemloft.net") by vger.kernel.org with ESMTP id S266143AbUIIQBm (ORCPT ); Thu, 9 Sep 2004 12:01:42 -0400 In-Reply-To: <20040909154453.GG1737@suse.de> List-Id: linux-ide@vger.kernel.org To: Jens Axboe Cc: bzolnier@elka.pw.edu.pl, linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, jgarzik@pobox.com On Thu, 9 Sep 2004 17:44:53 +0200 Jens Axboe wrote: > On Thu, Sep 09 2004, Russell King wrote: > > Essentially, kernel PIO writes data into the page cache, and that action > > may leave data in the CPU's caches. Since the kernels mappings may not > > be coherent with mappings in userspace, data written to the kernel > > mappings may remain in the data cache, and stale data would be visible > > to user space. > > > > There has been talk about using flush_dcache_page() to resolve > > this issue, but I'm not sure what the outcome was. Certainly > > flush_dcache_page() is supposed to be used before the data in the > > kernels page cache is read or written. > > Have you ever tested bouncing on arm? It seems to be lacking a > flush_dcache_page() indeed, how does this look? This looks like a good fix to me too.