From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH 2/2 resend] libata-sff: avoid byte swapping in ata_sff_data_xfer() Date: Wed, 08 Apr 2009 02:33:41 -0400 Message-ID: <49DC4545.5020702@pobox.com> References: <200902152230.38271.sshtylyov@ru.mvista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:54838 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760855AbZDHGdq (ORCPT ); Wed, 8 Apr 2009 02:33:46 -0400 In-Reply-To: <200902152230.38271.sshtylyov@ru.mvista.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Sergei Shtylyov Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, alan@lxorguk.ukuu.org.uk Sergei Shtylyov wrote: > Handling of the trailing byte in ata_sff_data_xfer() is suboptimal bacause: > > - it always initializes the padding buffer to 0 which is not really needed in > both the read and write cases; > > - it has to use memcpy() to transfer a single byte from/to the padding buffer; > > - it uses io{read|write}16() accessors which swap bytes on the big endian CPUs > and so have to additionally convert the data from/to the little endian format > instead of using io{read|write}16_rep() accessors which are not supposed to > change the byte ordering. > > Signed-off-by: Sergei Shtylyov applied