From mboxrd@z Thu Jan 1 00:00:00 1970 From: Saeed Bishara Subject: Re: IO buffer alignment for block devices Date: Mon, 13 Sep 2004 18:16:47 +0300 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <4145B9DF.7020408@il.marvell.com> References: <41459729.5060106@il.marvell.com> <1095084876.1762.8.camel@mulgrave> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from shosh.galileo.co.il ([199.203.130.250]:20702 "EHLO il.marvell.com") by vger.kernel.org with ESMTP id S268670AbUIMPQ5 (ORCPT ); Mon, 13 Sep 2004 11:16:57 -0400 In-Reply-To: <1095084876.1762.8.camel@mulgrave> List-Id: linux-scsi@vger.kernel.org To: James Bottomley Cc: SCSI Mailing List James Bottomley wrote: >On Mon, 2004-09-13 at 08:48, Saeed Bishara wrote: > > >> Is there any minimal alignment for the IO buffers (sg and single) >>sent to a scsi LLD? >> I found that buffers that come from buffer cache, page cache and sg >>are page aligned , and the raw driver send sector aligned buffers. >> so can I assume that the minimal alignment of the buffer is 512 bytes? >> >> > >You can assume it will be whatever you set blk_queue_dma_alignment() to >in your slave configure routines. If the LLD doesn't set this, then it >will be 8 bytes. However, beware, setting this higher can cause user > > isn't the default 512, this is what I see in blk_queue_make_request. >generated commands to be errored if they fail the alignment checks. > >James > > > any Ideas about lk 2.4? >To unsubscribe from this list: send the line "unsubscribe linux-scsi" in >the body of a message to majordomo@vger.kernel.org >More majordomo info at http://vger.kernel.org/majordomo-info.html > > > >