From patchwork Sun Apr 7 08:53:25 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lei X-Patchwork-Id: 10888383 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 3B9E717E0 for ; Sun, 7 Apr 2019 08:53:39 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 17543285BA for ; Sun, 7 Apr 2019 08:53:39 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0A89D28716; Sun, 7 Apr 2019 08:53:39 +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 vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9604A285BA for ; Sun, 7 Apr 2019 08:53:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726086AbfDGIxe (ORCPT ); Sun, 7 Apr 2019 04:53:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58032 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725996AbfDGIxd (ORCPT ); Sun, 7 Apr 2019 04:53:33 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id EBD95F74A7; Sun, 7 Apr 2019 08:53:32 +0000 (UTC) Received: from localhost (ovpn-8-16.pek2.redhat.com [10.72.8.16]) by smtp.corp.redhat.com (Postfix) with ESMTP id B43C719C56; Sun, 7 Apr 2019 08:53:29 +0000 (UTC) From: Ming Lei To: Jens Axboe Cc: linux-block@vger.kernel.org, Ming Lei , Qu Wenruo , linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, Omar Sandoval , Christoph Hellwig Subject: [PATCH V2] block: don't use for-inside-for in bio_for_each_segment_all Date: Sun, 7 Apr 2019 16:53:25 +0800 Message-Id: <20190407085325.9380-1-ming.lei@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Sun, 07 Apr 2019 08:53:33 +0000 (UTC) Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Commit 6dc4f100c175 ("block: allow bio_for_each_segment_all() to iterate over multi-page bvec") changes bio_for_each_segment_all() to use for-inside-for. This way breaks all bio_for_each_segment_all() call with error out branch via 'break', since now 'break' can only break from the inner loop. Fixes this issue by implementing bio_for_each_segment_all() via single 'for' loop, and now the logic is very similar with normal bvec iterator. Cc: Qu Wenruo Cc: linux-btrfs@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: Omar Sandoval Cc: Christoph Hellwig Reported-and-Tested-by: Qu Wenruo Fixes: 6dc4f100c175 ("block: allow bio_for_each_segment_all() to iterate over multi-page bvec") Signed-off-by: Ming Lei Reviewed-by: Christoph Hellwig --- include/linux/bio.h | 20 ++++++++++++-------- include/linux/bvec.h | 23 +++++++++++++++-------- 2 files changed, 27 insertions(+), 16 deletions(-) diff --git a/include/linux/bio.h b/include/linux/bio.h index bb6090aa165d..9c583bf98ff9 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -120,19 +120,23 @@ static inline bool bio_full(struct bio *bio) return bio->bi_vcnt >= bio->bi_max_vecs; } -#define mp_bvec_for_each_segment(bv, bvl, i, iter_all) \ - for (bv = bvec_init_iter_all(&iter_all); \ - (iter_all.done < (bvl)->bv_len) && \ - (mp_bvec_next_segment((bvl), &iter_all), 1); \ - iter_all.done += bv->bv_len, i += 1) +static inline bool bio_next_segment(const struct bio *bio, + struct bvec_iter_all *iter) +{ + if (iter->idx >= bio->bi_vcnt) + return false; + + bvec_advance(&bio->bi_io_vec[iter->idx], iter); + return true; +} /* * drivers should _never_ use the all version - the bio may have been split * before it got to the driver and the driver won't own all of it */ -#define bio_for_each_segment_all(bvl, bio, i, iter_all) \ - for (i = 0, iter_all.idx = 0; iter_all.idx < (bio)->bi_vcnt; iter_all.idx++) \ - mp_bvec_for_each_segment(bvl, &((bio)->bi_io_vec[iter_all.idx]), i, iter_all) +#define bio_for_each_segment_all(bvl, bio, i, iter) \ + for (i = 0, bvl = bvec_init_iter_all(&iter); \ + bio_next_segment((bio), &iter); i++) static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter, unsigned bytes) diff --git a/include/linux/bvec.h b/include/linux/bvec.h index f6275c4da13a..67eda310b643 100644 --- a/include/linux/bvec.h +++ b/include/linux/bvec.h @@ -47,8 +47,9 @@ struct bvec_iter { struct bvec_iter_all { struct bio_vec bv; - int idx; - unsigned done; + int idx; /* current index into bvec table */ + unsigned bvec_done; /* number of bytes completed in + currnet bvec */ }; static inline struct page *bvec_nth_page(struct page *page, int idx) @@ -145,18 +146,18 @@ static inline bool bvec_iter_advance(const struct bio_vec *bv, static inline struct bio_vec *bvec_init_iter_all(struct bvec_iter_all *iter_all) { - iter_all->bv.bv_page = NULL; - iter_all->done = 0; + iter_all->bvec_done = 0; + iter_all->idx = 0; return &iter_all->bv; } -static inline void mp_bvec_next_segment(const struct bio_vec *bvec, - struct bvec_iter_all *iter_all) +static inline void bvec_advance(const struct bio_vec *bvec, + struct bvec_iter_all *iter_all) { struct bio_vec *bv = &iter_all->bv; - if (bv->bv_page) { + if (iter_all->bvec_done) { bv->bv_page = nth_page(bv->bv_page, 1); bv->bv_offset = 0; } else { @@ -164,7 +165,13 @@ static inline void mp_bvec_next_segment(const struct bio_vec *bvec, bv->bv_offset = bvec->bv_offset; } bv->bv_len = min_t(unsigned int, PAGE_SIZE - bv->bv_offset, - bvec->bv_len - iter_all->done); + bvec->bv_len - iter_all->bvec_done); + iter_all->bvec_done += bv->bv_len; + + if (iter_all->bvec_done == bvec->bv_len) { + iter_all->idx++; + iter_all->bvec_done = 0; + } } /*