From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [patch for 2.6.33? 1/1] ata: call flush_dcache_page() around PIO data transfers in libata-aff.c Date: Wed, 03 Feb 2010 12:00:58 -0500 Message-ID: <4B69ABCA.1030507@pobox.com> References: <1265151518.2800.715.camel@mulgrave.site> <20100202150537.0f6a01c0.akpm@linux-foundation.org> <4B68B1E0.4090004@pobox.com> <20100202.152140.216335166.davem@davemloft.net> <1265153568.2800.815.camel@mulgrave.site> <1265192325.1970.28.camel@pc1117.cambridge.arm.com> <1265215254.2873.201.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-yw0-f198.google.com ([209.85.211.198]:63396 "EHLO mail-yw0-f198.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932569Ab0BCRBD (ORCPT ); Wed, 3 Feb 2010 12:01:03 -0500 Received: by ywh36 with SMTP id 36so1450885ywh.15 for ; Wed, 03 Feb 2010 09:01:03 -0800 (PST) In-Reply-To: <1265215254.2873.201.camel@mulgrave.site> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: James Bottomley Cc: Catalin Marinas , David Miller , akpm@linux-foundation.org, jeff@garzik.org, linux-ide@vger.kernel.org, stable@kernel.org, tj@kernel.org On 02/03/2010 11:40 AM, James Bottomley wrote: > The fix to libata looks to be just that it should kmap all the time > rather than trying to fiddle with the page to see if its higmem. For > kmap on a normal page, we should just return the offset map address and > do all the flushing. libata tests PageHighMem() because it was measurably faster to do things the current way (which includes local_irq_save/restore, only for highmem) on boxes where it actually matters. It seems more efficient to add a flush where necessary, than unconditionally punish everyone... Jeff