From patchwork Sat Oct 29 08:08:07 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lei X-Patchwork-Id: 9403137 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 27D9D606DC for ; Sat, 29 Oct 2016 08:12:56 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 15C512A5D6 for ; Sat, 29 Oct 2016 08:12:56 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id EF78D2A5EA; Sat, 29 Oct 2016 08:12:55 +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=-6.8 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED,FREEMAIL_FROM,RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9AF6B2A5D6 for ; Sat, 29 Oct 2016 08:12:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756905AbcJ2IMj (ORCPT ); Sat, 29 Oct 2016 04:12:39 -0400 Received: from mail-pf0-f195.google.com ([209.85.192.195]:35482 "EHLO mail-pf0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756891AbcJ2IMe (ORCPT ); Sat, 29 Oct 2016 04:12:34 -0400 Received: by mail-pf0-f195.google.com with SMTP id s8so3377051pfj.2; Sat, 29 Oct 2016 01:12:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=L3ZAa35RkWTeSJIhSYW4W19+gzvPYhHKHt+lmMA7DJ4=; b=HB31Yh5TlF22LBbtX1MtHPs89H9sUtEAQZs3Jsom/jfYCNWThW/he1t1HhX4TOOGSM Kz2+xKsGjbaQ1m0LRC0eOS6DQj0wOE+wmd2yyvu2rnd/REi9d6/0D8x4E0q+nb+8/rZm Udt5gtoPj986nJCV/YUjLbZGyXD2Zzwp7nDFi2AbkAkIgWhoObnMCQGtMzHjAfGA+1tq DbRedQEX4Z3YK6Kesurg6XyNC1LVL9+JQlJpBGO0StKKD4KpY1zWhcDBSH5Y4P4PgMk0 vRyxsL1l0MY8EYmwBT33otJoPy/hCtgQly4St4Se80TSo/4PXAmYgDfFJYKAzP+qSS4M x1qw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=L3ZAa35RkWTeSJIhSYW4W19+gzvPYhHKHt+lmMA7DJ4=; b=SA23zucPyJQ3gmvWOVuhmKDpRA9rkuKPNM4SCS34f12iZ6jlG6vvl5+nRSH0sCGM6d Bl+SCC3iecvDJ4hoNtEoPjj8YDLBVddY17BRhzWnJoNaYOa5WTVmZriJWqKn4FvyW/d4 bMLxj00Z730ODIzcbo1nRYguG8/MaIBgSjR4Pi6Bi40XCn3fn9YUhGy37UPScMLwz3IO OzJyQs/RnaILtLWAmRl2OHEMj2wcqJYNsbsfgSb+P/zwZpUFioocWckE8NV9VDz4ouK5 2Y93oqTqUHIxSOAj0dUXJzquRT7BY3v1t4p4xk2kyaqc3SDiX+uj54Ww2Yqa8kJ2Wtwm ixlw== X-Gm-Message-State: ABUngvdDaW4VPST8VcEsn7CGQ3QJQxwFIhjqGOFzZw8cTaNJraDax4Cwi7m/xcYu0Ksvww== X-Received: by 10.98.95.193 with SMTP id t184mr31397364pfb.85.1477728753649; Sat, 29 Oct 2016 01:12:33 -0700 (PDT) Received: from localhost ([45.34.23.101]) by smtp.gmail.com with ESMTPSA id 3sm23565641pam.21.2016.10.29.01.12.32 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 29 Oct 2016 01:12:33 -0700 (PDT) From: Ming Lei To: Jens Axboe , linux-kernel@vger.kernel.org Cc: linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, Christoph Hellwig , "Kirill A . Shutemov" , Ming Lei , Alasdair Kergon , Mike Snitzer , dm-devel@redhat.com (maintainer:DEVICE-MAPPER (LVM)), Shaohua Li , linux-raid@vger.kernel.org (open list:SOFTWARE RAID (Multiple Disks) SUPPORT) Subject: [PATCH 08/60] dm: use bvec iterator helpers to implement .get_page and .next_page Date: Sat, 29 Oct 2016 16:08:07 +0800 Message-Id: <1477728600-12938-9-git-send-email-tom.leiming@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1477728600-12938-1-git-send-email-tom.leiming@gmail.com> References: <1477728600-12938-1-git-send-email-tom.leiming@gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Firstly we have mature bvec/bio iterator helper for iterate each page in one bio, not necessary to reinvent a wheel to do that. Secondly the coming multipage bvecs requires this patch. Also add comments about the direct access to bvec table. Signed-off-by: Ming Lei --- drivers/md/dm-io.c | 34 ++++++++++++++++++++++++---------- 1 file changed, 24 insertions(+), 10 deletions(-) diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c index 0bf1a12e35fe..2ef573c220fc 100644 --- a/drivers/md/dm-io.c +++ b/drivers/md/dm-io.c @@ -162,7 +162,10 @@ struct dpages { struct page **p, unsigned long *len, unsigned *offset); void (*next_page)(struct dpages *dp); - unsigned context_u; + union { + unsigned context_u; + struct bvec_iter context_bi; + }; void *context_ptr; void *vma_invalidate_address; @@ -204,25 +207,36 @@ static void list_dp_init(struct dpages *dp, struct page_list *pl, unsigned offse static void bio_get_page(struct dpages *dp, struct page **p, unsigned long *len, unsigned *offset) { - struct bio_vec *bvec = dp->context_ptr; - *p = bvec->bv_page; - *len = bvec->bv_len - dp->context_u; - *offset = bvec->bv_offset + dp->context_u; + struct bio_vec bv = bvec_iter_bvec((struct bio_vec *)dp->context_ptr, + dp->context_bi); + + *p = bv.bv_page; + *len = bv.bv_len; + *offset = bv.bv_offset; + + /* avoid to figure out it in bio_next_page() again */ + dp->context_bi.bi_sector = (sector_t)bv.bv_len; } static void bio_next_page(struct dpages *dp) { - struct bio_vec *bvec = dp->context_ptr; - dp->context_ptr = bvec + 1; - dp->context_u = 0; + unsigned int len = (unsigned int)dp->context_bi.bi_sector; + + bvec_iter_advance((struct bio_vec *)dp->context_ptr, + &dp->context_bi, len); } static void bio_dp_init(struct dpages *dp, struct bio *bio) { dp->get_page = bio_get_page; dp->next_page = bio_next_page; - dp->context_ptr = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter); - dp->context_u = bio->bi_iter.bi_bvec_done; + + /* + * We just use bvec iterator to retrieve pages, so it is ok to + * access the bvec table directly here + */ + dp->context_ptr = bio->bi_io_vec; + dp->context_bi = bio->bi_iter; } /*