From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f197.google.com (mail-pf1-f197.google.com [209.85.210.197]) by kanga.kvack.org (Postfix) with ESMTP id 9166B6B441E for ; Mon, 26 Nov 2018 17:40:06 -0500 (EST) Received: by mail-pf1-f197.google.com with SMTP id f69so1520366pff.5 for ; Mon, 26 Nov 2018 14:40:06 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id y17sor2365228pll.68.2018.11.26.14.40.05 for (Google Transport Security); Mon, 26 Nov 2018 14:40:05 -0800 (PST) Date: Mon, 26 Nov 2018 14:40:03 -0800 From: Omar Sandoval Subject: Re: [PATCH V12 14/20] bcache: avoid to use bio_for_each_segment_all() in bch_bio_alloc_pages() Message-ID: <20181126224003.GK30411@vader> References: <20181126021720.19471-1-ming.lei@redhat.com> <20181126021720.19471-15-ming.lei@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181126021720.19471-15-ming.lei@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Ming Lei Cc: Jens Axboe , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Theodore Ts'o , Omar Sandoval , Sagi Grimberg , Dave Chinner , Kent Overstreet , Mike Snitzer , dm-devel@redhat.com, Alexander Viro , linux-fsdevel@vger.kernel.org, Shaohua Li , linux-raid@vger.kernel.org, David Sterba , linux-btrfs@vger.kernel.org, "Darrick J . Wong" , linux-xfs@vger.kernel.org, Gao Xiang , Christoph Hellwig , linux-ext4@vger.kernel.org, Coly Li , linux-bcache@vger.kernel.org, Boaz Harrosh , Bob Peterson , cluster-devel@redhat.com On Mon, Nov 26, 2018 at 10:17:14AM +0800, Ming Lei wrote: > bch_bio_alloc_pages() is always called on one new bio, so it is safe > to access the bvec table directly. Given it is the only kind of this > case, open code the bvec table access since bio_for_each_segment_all() > will be changed to support for iterating over multipage bvec. > > Acked-by: Coly Li > Reviewed-by: Christoph Hellwig Reviewed-by: Omar Sandoval > Signed-off-by: Ming Lei > --- > drivers/md/bcache/util.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/md/bcache/util.c b/drivers/md/bcache/util.c > index 20eddeac1531..62fb917f7a4f 100644 > --- a/drivers/md/bcache/util.c > +++ b/drivers/md/bcache/util.c > @@ -270,7 +270,11 @@ int bch_bio_alloc_pages(struct bio *bio, gfp_t gfp_mask) > int i; > struct bio_vec *bv; > > - bio_for_each_segment_all(bv, bio, i) { > + /* > + * This is called on freshly new bio, so it is safe to access the > + * bvec table directly. > + */ > + for (i = 0, bv = bio->bi_io_vec; i < bio->bi_vcnt; bv++, i++) { > bv->bv_page = alloc_page(gfp_mask); > if (!bv->bv_page) { > while (--bv >= bio->bi_io_vec) > -- > 2.9.5 >