From patchwork Wed Nov 21 03:23:18 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lei X-Patchwork-Id: 10691711 X-Patchwork-Delegate: snitzer@redhat.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2789316B1 for ; Wed, 21 Nov 2018 03:27:21 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1136A2B409 for ; Wed, 21 Nov 2018 03:27:21 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 049922B412; Wed, 21 Nov 2018 03:27:21 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 34E062B409 for ; Wed, 21 Nov 2018 03:27:19 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 56314308FBA0; Wed, 21 Nov 2018 03:27:18 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 23457BABB; Wed, 21 Nov 2018 03:27:18 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id DFF543F600; Wed, 21 Nov 2018 03:27:17 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id wAL3RGaF018881 for ; Tue, 20 Nov 2018 22:27:16 -0500 Received: by smtp.corp.redhat.com (Postfix) id 995FA7E105; Wed, 21 Nov 2018 03:27:16 +0000 (UTC) Delivered-To: dm-devel@redhat.com Received: from localhost (ovpn-8-21.pek2.redhat.com [10.72.8.21]) by smtp.corp.redhat.com (Postfix) with ESMTP id 991F47D2F2; Wed, 21 Nov 2018 03:27:01 +0000 (UTC) From: Ming Lei To: Jens Axboe Date: Wed, 21 Nov 2018 11:23:18 +0800 Message-Id: <20181121032327.8434-11-ming.lei@redhat.com> In-Reply-To: <20181121032327.8434-1-ming.lei@redhat.com> References: <20181121032327.8434-1-ming.lei@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-loop: dm-devel@redhat.com Cc: Mike Snitzer , linux-mm@kvack.org, dm-devel@redhat.com, Christoph Hellwig , Sagi Grimberg , "Darrick J . Wong" , Omar Sandoval , cluster-devel@redhat.com, linux-ext4@vger.kernel.org, Shaohua Li , Kent Overstreet , Boaz Harrosh , Gao Xiang , Coly Li , linux-raid@vger.kernel.org, Bob Peterson , linux-bcache@vger.kernel.org, Alexander Viro , Dave Chinner , David Sterba , Ming Lei , linux-block@vger.kernel.org, Theodore Ts'o , linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org Subject: [dm-devel] [PATCH V11 10/19] block: loop: pass multi-page bvec to iov_iter X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Wed, 21 Nov 2018 03:27:18 +0000 (UTC) X-Virus-Scanned: ClamAV using ClamSMTP iov_iter is implemented on bvec itererator helpers, so it is safe to pass multi-page bvec to it, and this way is much more efficient than passing one page in each bvec. Signed-off-by: Ming Lei Reviewed-by: Christoph Hellwig --- drivers/block/loop.c | 20 ++++++++++---------- include/linux/blkdev.h | 4 ++++ 2 files changed, 14 insertions(+), 10 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 176ab1f28eca..e3683211f12d 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -510,21 +510,22 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, loff_t pos, bool rw) { struct iov_iter iter; + struct req_iterator rq_iter; struct bio_vec *bvec; struct request *rq = blk_mq_rq_from_pdu(cmd); struct bio *bio = rq->bio; struct file *file = lo->lo_backing_file; + struct bio_vec tmp; unsigned int offset; - int segments = 0; + int nr_bvec = 0; int ret; + rq_for_each_bvec(tmp, rq, rq_iter) + nr_bvec++; + if (rq->bio != rq->biotail) { - struct req_iterator iter; - struct bio_vec tmp; - __rq_for_each_bio(bio, rq) - segments += bio_segments(bio); - bvec = kmalloc_array(segments, sizeof(struct bio_vec), + bvec = kmalloc_array(nr_bvec, sizeof(struct bio_vec), GFP_NOIO); if (!bvec) return -EIO; @@ -533,10 +534,10 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, /* * The bios of the request may be started from the middle of * the 'bvec' because of bio splitting, so we can't directly - * copy bio->bi_iov_vec to new bvec. The rq_for_each_segment + * copy bio->bi_iov_vec to new bvec. The rq_for_each_bvec * API will take care of all details for us. */ - rq_for_each_segment(tmp, rq, iter) { + rq_for_each_bvec(tmp, rq, rq_iter) { *bvec = tmp; bvec++; } @@ -550,11 +551,10 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, */ offset = bio->bi_iter.bi_bvec_done; bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter); - segments = bio_segments(bio); } atomic_set(&cmd->ref, 2); - iov_iter_bvec(&iter, rw, bvec, segments, blk_rq_bytes(rq)); + iov_iter_bvec(&iter, rw, bvec, nr_bvec, blk_rq_bytes(rq)); iter.iov_offset = offset; cmd->iocb.ki_pos = pos; diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 1ad6eafc43f2..a281b6737b61 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -805,6 +805,10 @@ struct req_iterator { __rq_for_each_bio(_iter.bio, _rq) \ bio_for_each_segment(bvl, _iter.bio, _iter.iter) +#define rq_for_each_bvec(bvl, _rq, _iter) \ + __rq_for_each_bio(_iter.bio, _rq) \ + bio_for_each_bvec(bvl, _iter.bio, _iter.iter) + #define rq_iter_last(bvec, _iter) \ (_iter.bio->bi_next == NULL && \ bio_iter_last(bvec, _iter.iter))