From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f194.google.com ([209.85.192.194]:35364 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934345AbcJ2IP3 (ORCPT ); Sat, 29 Oct 2016 04:15:29 -0400 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 , Mike Christie , Hannes Reinecke , Keith Busch , Mike Snitzer , Johannes Thumshirn , Bart Van Assche Subject: [PATCH 45/60] block: bio: introduce bio_for_each_segment_all_rd() and its write pair Date: Sat, 29 Oct 2016 16:08:44 +0800 Message-Id: <1477728600-12938-46-git-send-email-tom.leiming@gmail.com> 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-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org This patches introduce bio_for_each_segment_all_rd() and bio_for_each_segment_all_wt(). bio_for_each_segment_all_rd() is for replacing bio_for_each_segment_all() in case the bvec from bio->bi_io_vec is accessed as readonly. bio_for_each_segment_all_wt() is for replacing bio_for_each_segment_all() in case the bvec from bio->bi_io_vec need to be updated. Signed-off-by: Ming Lei --- include/linux/bio.h | 15 +++++++++++++++ include/linux/blk_types.h | 6 ++++++ 2 files changed, 21 insertions(+) diff --git a/include/linux/bio.h b/include/linux/bio.h index ec1c0f2aaa19..f8a025ffaa9c 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -215,6 +215,21 @@ static inline void bio_advance_iter_mp(struct bio *bio, struct bvec_iter *iter, #define bio_for_each_segment_mp(bvl, bio, iter) \ __bio_for_each_segment_mp(bvl, bio, iter, (bio)->bi_iter) +/* the bio has to be singlepage bvecs based */ +#define bio_for_each_segment_all_wt(bvl, bio, i) \ + bio_for_each_segment_all((bvl), (bio), (i)) + +/* + * This helper returns singlepage bvec to caller for readonly + * purpose, and the caller can _not_ change the bvec stored in + * bio->bi_io_vec[] via this helper. + */ +#define bio_for_each_segment_all_rd(bvl, bio, i, bi) \ + for ((bi).iter = BVEC_ITER_ALL_INIT, i = 0, bvl = &(bi).bv; \ + (bi).iter.bi_idx < (bio)->bi_vcnt && \ + (((bi).bv = bio_iter_iovec((bio), (bi).iter)), 1); \ + bio_advance_iter((bio), &(bi).iter, (bi).bv.bv_len), i++) + #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len) static inline unsigned __bio_segments(struct bio *bio, bool mp) diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index cd395ecec99d..b4a202e98016 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -108,6 +108,12 @@ struct bio { #define BIO_RESET_BYTES offsetof(struct bio, bi_max_vecs) +/* this iter is only for implementing bio_for_each_segment_rd() */ +struct bvec_iter_all { + struct bvec_iter iter; + struct bio_vec bv; /* in-flight singlepage bvec */ +}; + /* * bio flags */ -- 2.7.4