From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761292AbXGPTEX (ORCPT ); Mon, 16 Jul 2007 15:04:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758537AbXGPTEG (ORCPT ); Mon, 16 Jul 2007 15:04:06 -0400 Received: from ug-out-1314.google.com ([66.249.92.170]:58999 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756153AbXGPTED (ORCPT ); Mon, 16 Jul 2007 15:04:03 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:from:to:subject:date:user-agent:cc:references:in-reply-to:mime-version:content-disposition:message-id:content-type:content-transfer-encoding; b=UfSPof6iXB2G3HVTC5TuHw4WhEgiNO6aTBnFrofzofaQmi+ycVPecqIPUQBaxpFEh95Wa1UEuPtFpayDgaHRRZzXFULdX/cmNkP/b/JwAtCLirpd0vhdv3mCJlYhKIKei7wzY70qZyjfdF0eJimynO0BN6+AECOI/QmQawoQjgw= From: Bartlomiej Zolnierkiewicz To: Jens Axboe Subject: Re: [PATCH 03/33] block: convert to using sg helpers Date: Mon, 16 Jul 2007 21:21:32 +0200 User-Agent: KMail/1.9.6 Cc: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org References: <11845792671245-git-send-email-jens.axboe@oracle.com> <11845792672399-git-send-email-jens.axboe@oracle.com> In-Reply-To: <11845792672399-git-send-email-jens.axboe@oracle.com> MIME-Version: 1.0 Content-Disposition: inline Message-Id: <200707162121.32936.bzolnier@gmail.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Monday 16 July 2007, Jens Axboe wrote: > Convert the main rq mapper (blk_rq_map_sg()) to the sg helper setup. > > Signed-off-by: Jens Axboe > --- > block/ll_rw_blk.c | 19 ++++++++++++------- > 1 files changed, 12 insertions(+), 7 deletions(-) > > diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c > index ef42bb2..ab71087 100644 > --- a/block/ll_rw_blk.c > +++ b/block/ll_rw_blk.c > @@ -30,6 +30,7 @@ > #include > #include > #include > +#include > > /* > * for max sense size > @@ -1307,9 +1308,11 @@ static int blk_hw_contig_segment(request_queue_t *q, struct bio *bio, > * map a request to scatterlist, return number of sg entries setup. Caller > * must make sure sg can hold rq->nr_phys_segments entries > */ > -int blk_rq_map_sg(request_queue_t *q, struct request *rq, struct scatterlist *sg) > +int blk_rq_map_sg(request_queue_t *q, struct request *rq, > + struct scatterlist *sglist) > { > struct bio_vec *bvec, *bvprv; > + struct scatterlist *next_sg, *sg; > struct bio *bio; > int nsegs, i, cluster; > > @@ -1320,6 +1323,7 @@ int blk_rq_map_sg(request_queue_t *q, struct request *rq, struct scatterlist *sg > * for each bio in rq > */ > bvprv = NULL; > + sg = next_sg = &sglist[0]; > rq_for_each_bio(bio, rq) { > /* > * for each segment in bio > @@ -1328,7 +1332,7 @@ int blk_rq_map_sg(request_queue_t *q, struct request *rq, struct scatterlist *sg > int nbytes = bvec->bv_len; > > if (bvprv && cluster) { > - if (sg[nsegs - 1].length + nbytes > q->max_segment_size) > + if (sg->length + nbytes > q->max_segment_size) > goto new_segment; > > if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec)) > @@ -1336,14 +1340,15 @@ int blk_rq_map_sg(request_queue_t *q, struct request *rq, struct scatterlist *sg > if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec)) > goto new_segment; > > - sg[nsegs - 1].length += nbytes; > + sg->length += nbytes; > } else { > new_segment: > - memset(&sg[nsegs],0,sizeof(struct scatterlist)); Is this intended? If so why this is no longer needed? > - sg[nsegs].page = bvec->bv_page; > - sg[nsegs].length = nbytes; > - sg[nsegs].offset = bvec->bv_offset; > + sg = next_sg; > + next_sg = sg_next(sg); > > + sg->page = bvec->bv_page; > + sg->length = nbytes; > + sg->offset = bvec->bv_offset; > nsegs++; > } > bvprv = bvec;