From patchwork Thu Apr 11 21:08:25 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Jerome Glisse X-Patchwork-Id: 10896821 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 3AE671708 for ; Thu, 11 Apr 2019 21:09:04 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 24AE528DF6 for ; Thu, 11 Apr 2019 21:09:04 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 18F7228DFB; Thu, 11 Apr 2019 21:09:04 +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=ham 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 738CC28DF6 for ; Thu, 11 Apr 2019 21:09:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727169AbfDKVJB (ORCPT ); Thu, 11 Apr 2019 17:09:01 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33756 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727144AbfDKVI6 (ORCPT ); Thu, 11 Apr 2019 17:08:58 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E0FA5DC8FB; Thu, 11 Apr 2019 21:08:57 +0000 (UTC) Received: from localhost.localdomain.com (unknown [10.20.6.236]) by smtp.corp.redhat.com (Postfix) with ESMTP id 397AA5C220; Thu, 11 Apr 2019 21:08:54 +0000 (UTC) From: jglisse@redhat.com To: linux-kernel@vger.kernel.org Cc: =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-mm@kvack.org, John Hubbard , Jan Kara , Dan Williams , Alexander Viro , Johannes Thumshirn , Christoph Hellwig , Jens Axboe , Ming Lei , Dave Chinner , Jason Gunthorpe , Matthew Wilcox Subject: [PATCH v1 06/15] block: convert bio_vec.bv_page to bv_pfn to store pfn and not page Date: Thu, 11 Apr 2019 17:08:25 -0400 Message-Id: <20190411210834.4105-7-jglisse@redhat.com> In-Reply-To: <20190411210834.4105-1-jglisse@redhat.com> References: <20190411210834.4105-1-jglisse@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Thu, 11 Apr 2019 21:08:58 +0000 (UTC) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Jérôme Glisse To be able to store flags with each bio_vec store the pfn value and not the page this leave us with couple uppers bits we can latter use for flags. Signed-off-by: Jérôme Glisse Cc: linux-fsdevel@vger.kernel.org Cc: linux-block@vger.kernel.org Cc: linux-mm@kvack.org Cc: John Hubbard Cc: Jan Kara Cc: Dan Williams Cc: Alexander Viro Cc: Johannes Thumshirn Cc: Christoph Hellwig Cc: Jens Axboe Cc: Ming Lei Cc: Dave Chinner Cc: Jason Gunthorpe Cc: Matthew Wilcox --- Documentation/block/biodoc.txt | 7 +++++-- include/linux/bvec.h | 29 +++++++++++++++++++++-------- 2 files changed, 26 insertions(+), 10 deletions(-) diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt index ac18b488cb5e..c673d4285781 100644 --- a/Documentation/block/biodoc.txt +++ b/Documentation/block/biodoc.txt @@ -410,7 +410,7 @@ mapped to bio structures. 2.2 The bio struct The bio structure uses a vector representation pointing to an array of tuples -of to describe the i/o buffer, and has various other +of to describe the i/o buffer, and has various other fields describing i/o parameters and state that needs to be maintained for performing the i/o. @@ -418,11 +418,14 @@ Notice that this representation means that a bio has no virtual address mapping at all (unlike buffer heads). struct bio_vec { - struct page *bv_page; + unsigned long *bv_pfn; unsigned short bv_len; unsigned short bv_offset; }; +You should not access the bv_pfn fields directly but use helpers to get the +corresponding struct page as bv_pfn can encode more than page pfn value. + /* * main unit of I/O for the block layer and lower layers (ie drivers) */ diff --git a/include/linux/bvec.h b/include/linux/bvec.h index d701cd968f13..ac84ac66a333 100644 --- a/include/linux/bvec.h +++ b/include/linux/bvec.h @@ -29,7 +29,7 @@ * was unsigned short, but we might as well be ready for > 64kB I/O pages */ struct bio_vec { - struct page *bv_page; + unsigned long bv_pfn; unsigned int bv_len; unsigned int bv_offset; }; @@ -51,14 +51,19 @@ struct bvec_iter_all { unsigned done; }; +static inline unsigned long page_to_bvec_pfn(struct page *page) +{ + return page ? page_to_pfn(page) : -1UL; +} + static inline struct page *bvec_page(const struct bio_vec *bvec) { - return bvec->bv_page; + return bvec->bv_pfn == -1UL ? NULL : pfn_to_page(bvec->bv_pfn); } static inline void bvec_set_page(struct bio_vec *bvec, struct page *page) { - bvec->bv_page = page; + bvec->bv_pfn = page_to_bvec_pfn(page); } static inline struct page *bvec_nth_page(struct page *page, int idx) @@ -70,11 +75,15 @@ static inline struct page *bvec_nth_page(struct page *page, int idx) * various member access, note that bio_data should of course not be used * on highmem page vectors */ -#define BIO_VEC_INIT(p, l, o) {.bv_page = (p), .bv_len = (l), .bv_offset = (o)} +#define BIO_VEC_INIT(p, l, o) {.bv_pfn = page_to_bvec_pfn(p), \ + .bv_len = (l), .bv_offset = (o)} #define __bvec_iter_bvec(bvec, iter) (&(bvec)[(iter).bi_idx]) /* multi-page (mp_bvec) helpers */ +#define mp_bvec_iter_pfn(bvec, iter) \ + ((__bvec_iter_bvec((bvec), (iter)))->bv_pfn) + #define mp_bvec_iter_page(bvec, iter) \ (bvec_page(__bvec_iter_bvec((bvec), (iter)))) @@ -90,7 +99,7 @@ static inline struct page *bvec_nth_page(struct page *page, int idx) #define mp_bvec_iter_bvec(bvec, iter) \ ((struct bio_vec) { \ - .bv_page = mp_bvec_iter_page((bvec), (iter)), \ + .bv_pfn = mp_bvec_iter_pfn((bvec), (iter)), \ .bv_len = mp_bvec_iter_len((bvec), (iter)), \ .bv_offset = mp_bvec_iter_offset((bvec), (iter)), \ }) @@ -100,16 +109,20 @@ static inline struct page *bvec_nth_page(struct page *page, int idx) (mp_bvec_iter_offset((bvec), (iter)) % PAGE_SIZE) #define bvec_iter_len(bvec, iter) \ - min_t(unsigned, mp_bvec_iter_len((bvec), (iter)), \ + min_t(unsigned, mp_bvec_iter_len((bvec), (iter)), \ PAGE_SIZE - bvec_iter_offset((bvec), (iter))) #define bvec_iter_page(bvec, iter) \ - bvec_nth_page(mp_bvec_iter_page((bvec), (iter)), \ + bvec_nth_page(mp_bvec_iter_page((bvec), (iter)), \ mp_bvec_iter_page_idx((bvec), (iter))) +#define bvec_iter_pfn(bvec, iter) \ + (mp_bvec_iter_pfn((bvec), (iter)) + \ + mp_bvec_iter_page_idx((bvec), (iter))) + #define bvec_iter_bvec(bvec, iter) \ ((struct bio_vec) { \ - .bv_page = bvec_iter_page((bvec), (iter)), \ + .bv_pfn = bvec_iter_pfn((bvec), (iter)), \ .bv_len = bvec_iter_len((bvec), (iter)), \ .bv_offset = bvec_iter_offset((bvec), (iter)), \ })