From patchwork Wed Jun 27 12:45:38 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lei X-Patchwork-Id: 10491417 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 E4CA3602B3 for ; Wed, 27 Jun 2018 12:49:01 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D3E6128D84 for ; Wed, 27 Jun 2018 12:49:01 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C67C928D8A; Wed, 27 Jun 2018 12:49:01 +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 715D528D84 for ; Wed, 27 Jun 2018 12:49:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934526AbeF0Mss (ORCPT ); Wed, 27 Jun 2018 08:48:48 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:60880 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S934000AbeF0Msq (ORCPT ); Wed, 27 Jun 2018 08:48:46 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 92AB181A4EBC; Wed, 27 Jun 2018 12:48:45 +0000 (UTC) Received: from localhost (ovpn-12-44.pek2.redhat.com [10.72.12.44]) by smtp.corp.redhat.com (Postfix) with ESMTP id 76A372026D5B; Wed, 27 Jun 2018 12:48:37 +0000 (UTC) From: Ming Lei To: Jens Axboe , Christoph Hellwig , Kent Overstreet Cc: David Sterba , Huang Ying , Mike Snitzer , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Theodore Ts'o , "Darrick J . Wong" , Coly Li , Filipe Manana , Randy Dunlap , Ming Lei Subject: [PATCH V7 14/24] block: introduce bvec_last_segment() Date: Wed, 27 Jun 2018 20:45:38 +0800 Message-Id: <20180627124548.3456-15-ming.lei@redhat.com> In-Reply-To: <20180627124548.3456-1-ming.lei@redhat.com> References: <20180627124548.3456-1-ming.lei@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Wed, 27 Jun 2018 12:48:45 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Wed, 27 Jun 2018 12:48:45 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'ming.lei@redhat.com' RCPT:'' 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 BTRFS and guard_bio_eod() need to get the last singlepage segment from one multipage bvec, so introduce this helper to make them happy. Signed-off-by: Ming Lei --- include/linux/bvec.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/include/linux/bvec.h b/include/linux/bvec.h index 417d44cf1e82..2269c7608a3e 100644 --- a/include/linux/bvec.h +++ b/include/linux/bvec.h @@ -219,4 +219,29 @@ static inline bool mp_bvec_iter_advance(const struct bio_vec *bv, .bi_bvec_done = 0, \ } +/* + * Get the last singlepage segment from the multipage bvec and store it + * in @seg + */ +static inline void bvec_last_segment(const struct bio_vec *bvec, + struct bio_vec *seg) +{ + unsigned total = bvec->bv_offset + bvec->bv_len; + unsigned last_page = total / PAGE_SIZE; + + if (last_page * PAGE_SIZE == total) + last_page--; + + seg->bv_page = nth_page(bvec->bv_page, last_page); + + /* the whole segment is inside the last page */ + if (bvec->bv_offset >= last_page * PAGE_SIZE) { + seg->bv_offset = bvec->bv_offset % PAGE_SIZE; + seg->bv_len = bvec->bv_len; + } else { + seg->bv_offset = 0; + seg->bv_len = total - last_page * PAGE_SIZE; + } +} + #endif /* __LINUX_BVEC_ITER_H */