Linux-Block Archive on lore.kernel.org
 help / color / Atom feed
From: Bart Van Assche <bvanassche@acm.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
	Bart Van Assche <bvanassche@acm.org>,
	Johannes Thumshirn <jthumshirn@suse.de>,
	Ming Lei <ming.lei@redhat.com>, Hannes Reinecke <hare@suse.com>
Subject: [PATCH v2 3/5] block: Simplify bvec_split_segs()
Date: Thu,  1 Aug 2019 15:50:42 -0700
Message-ID: <20190801225044.143478-4-bvanassche@acm.org> (raw)
In-Reply-To: <20190801225044.143478-1-bvanassche@acm.org>

Simplify this function by by removing two if-tests. Other than requiring
that the @sectors pointer is not NULL, this patch does not change the
behavior of bvec_split_segs().

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 block/blk-merge.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 51ed971709c3..7cea5050bbcf 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -167,17 +167,17 @@ static bool bvec_split_segs(const struct request_queue *q,
 {
 	unsigned len = bv->bv_len;
 	unsigned total_len = 0;
-	unsigned new_nsegs = 0, seg_size = 0;
+	unsigned seg_size = 0;
 
 	/*
 	 * Multi-page bvec may be too big to hold in one segment, so the
 	 * current bvec has to be splitted as multiple segments.
 	 */
-	while (len && new_nsegs + *nsegs < max_segs) {
+	while (len && *nsegs < max_segs) {
 		seg_size = get_max_segment_size(q, bv->bv_offset + total_len);
 		seg_size = min(seg_size, len);
 
-		new_nsegs++;
+		(*nsegs)++;
 		total_len += seg_size;
 		len -= seg_size;
 
@@ -185,11 +185,7 @@ static bool bvec_split_segs(const struct request_queue *q,
 			break;
 	}
 
-	if (new_nsegs) {
-		*nsegs += new_nsegs;
-		if (sectors)
-			*sectors += total_len >> 9;
-	}
+	*sectors += total_len >> 9;
 
 	/* split in the middle of the bvec if len != 0 */
 	return !!len;
@@ -349,6 +345,7 @@ EXPORT_SYMBOL(blk_queue_split);
 unsigned int blk_recalc_rq_segments(struct request *rq)
 {
 	unsigned int nr_phys_segs = 0;
+	unsigned int nr_sectors = 0;
 	struct req_iterator iter;
 	struct bio_vec bv;
 
@@ -365,7 +362,8 @@ unsigned int blk_recalc_rq_segments(struct request *rq)
 	}
 
 	rq_for_each_bvec(bv, rq, iter)
-		bvec_split_segs(rq->q, &bv, &nr_phys_segs, NULL, UINT_MAX);
+		bvec_split_segs(rq->q, &bv, &nr_phys_segs, &nr_sectors,
+				UINT_MAX);
 	return nr_phys_segs;
 }
 
-- 
2.22.0.770.g0f2c4a37fd-goog


  parent reply index

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-01 22:50 [PATCH v2 0/5] Optimize bio splitting Bart Van Assche
2019-08-01 22:50 ` [PATCH v2 1/5] block: Declare several function pointer arguments 'const' Bart Van Assche
2019-09-13 22:57   ` Chaitanya Kulkarni
2019-08-01 22:50 ` [PATCH v2 2/5] block: Document the bio splitting functions Bart Van Assche
2019-09-13 23:02   ` Chaitanya Kulkarni
2019-08-01 22:50 ` Bart Van Assche [this message]
2019-08-01 22:50 ` [PATCH v2 4/5] block: Simplify blk_bio_segment_split() Bart Van Assche
2019-08-01 22:50 ` [PATCH v2 5/5] block: Improve physical block alignment of split bios Bart Van Assche
2019-08-02 13:36 ` [PATCH v2 0/5] Optimize bio splitting Jens Axboe

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190801225044.143478-4-bvanassche@acm.org \
    --to=bvanassche@acm.org \
    --cc=axboe@kernel.dk \
    --cc=hare@suse.com \
    --cc=hch@lst.de \
    --cc=jthumshirn@suse.de \
    --cc=linux-block@vger.kernel.org \
    --cc=ming.lei@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Block Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-block/0 linux-block/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-block linux-block/ https://lore.kernel.org/linux-block \
		linux-block@vger.kernel.org linux-block@archiver.kernel.org
	public-inbox-index linux-block

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-block


AGPL code for this site: git clone https://public-inbox.org/ public-inbox