All of lore.kernel.org
 help / color / mirror / Atom feed
From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: Mike Snitzer <snitzer@redhat.com>,
	linux-block@vger.kernel.org, dm-devel@redhat.com
Subject: [PATCH 2/5] dm: open code blk_max_size_offset in max_io_len
Date: Tue, 12 Oct 2021 18:36:10 +0200	[thread overview]
Message-ID: <20211012163613.994933-3-hch@lst.de> (raw)
In-Reply-To: <20211012163613.994933-1-hch@lst.de>

max_io_len always passed in an explicit, non-zero chunk_sectors into
blk_max_size_offset.  That means much of blk_max_size_offset is not needed
and open coding it simplifies the code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/md/dm.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index a011d09cb0fac..0b6dfe8667438 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -944,24 +944,18 @@ static inline sector_t max_io_len_target_boundary(struct dm_target *ti,
 static sector_t max_io_len(struct dm_target *ti, sector_t sector)
 {
 	sector_t target_offset = dm_target_offset(ti, sector);
-	sector_t len = max_io_len_target_boundary(ti, target_offset);
-	sector_t max_len;
+	unsigned int len = max_io_len_target_boundary(ti, target_offset);
 
 	/*
 	 * Does the target need to split IO even further?
 	 * - varied (per target) IO splitting is a tenet of DM; this
 	 *   explains why stacked chunk_sectors based splitting via
-	 *   blk_max_size_offset() isn't possible here. So pass in
-	 *   ti->max_io_len to override stacked chunk_sectors.
+	 *   blk_queue_split() isn't possible here.
 	 */
-	if (ti->max_io_len) {
-		max_len = blk_max_size_offset(ti->table->md->queue,
-					      target_offset, ti->max_io_len);
-		if (len > max_len)
-			len = max_len;
-	}
-
-	return len;
+	if (!ti->max_io_len)
+		return len;
+	return min3(len, ti->table->md->queue->limits.max_sectors,
+		    chunk_size_left(target_offset, ti->max_io_len));
 }
 
 int dm_set_target_max_io_len(struct dm_target *ti, sector_t len)
-- 
2.30.2


WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, dm-devel@redhat.com,
	Mike Snitzer <snitzer@redhat.com>
Subject: [dm-devel] [PATCH 2/5] dm: open code blk_max_size_offset in max_io_len
Date: Tue, 12 Oct 2021 18:36:10 +0200	[thread overview]
Message-ID: <20211012163613.994933-3-hch@lst.de> (raw)
In-Reply-To: <20211012163613.994933-1-hch@lst.de>

max_io_len always passed in an explicit, non-zero chunk_sectors into
blk_max_size_offset.  That means much of blk_max_size_offset is not needed
and open coding it simplifies the code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/md/dm.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index a011d09cb0fac..0b6dfe8667438 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -944,24 +944,18 @@ static inline sector_t max_io_len_target_boundary(struct dm_target *ti,
 static sector_t max_io_len(struct dm_target *ti, sector_t sector)
 {
 	sector_t target_offset = dm_target_offset(ti, sector);
-	sector_t len = max_io_len_target_boundary(ti, target_offset);
-	sector_t max_len;
+	unsigned int len = max_io_len_target_boundary(ti, target_offset);
 
 	/*
 	 * Does the target need to split IO even further?
 	 * - varied (per target) IO splitting is a tenet of DM; this
 	 *   explains why stacked chunk_sectors based splitting via
-	 *   blk_max_size_offset() isn't possible here. So pass in
-	 *   ti->max_io_len to override stacked chunk_sectors.
+	 *   blk_queue_split() isn't possible here.
 	 */
-	if (ti->max_io_len) {
-		max_len = blk_max_size_offset(ti->table->md->queue,
-					      target_offset, ti->max_io_len);
-		if (len > max_len)
-			len = max_len;
-	}
-
-	return len;
+	if (!ti->max_io_len)
+		return len;
+	return min3(len, ti->table->md->queue->limits.max_sectors,
+		    chunk_size_left(target_offset, ti->max_io_len));
 }
 
 int dm_set_target_max_io_len(struct dm_target *ti, sector_t len)
-- 
2.30.2

--
dm-devel mailing list
dm-devel@redhat.com
https://listman.redhat.com/mailman/listinfo/dm-devel


  parent reply	other threads:[~2021-10-12 16:40 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-12 16:36 simplify I/O size calculation helpers Christoph Hellwig
2021-10-12 16:36 ` [dm-devel] " Christoph Hellwig
2021-10-12 16:36 ` [PATCH 1/5] block: factor out a chunk_size_left helper Christoph Hellwig
2021-10-12 16:36   ` [dm-devel] " Christoph Hellwig
2021-10-12 16:50   ` Bart Van Assche
2021-10-12 16:50     ` Bart Van Assche
2021-10-12 16:36 ` Christoph Hellwig [this message]
2021-10-12 16:36   ` [dm-devel] [PATCH 2/5] dm: open code blk_max_size_offset in max_io_len Christoph Hellwig
2021-10-12 16:36 ` [PATCH 3/5] block: open code blk_max_size_offset in blk_rq_get_max_sectors Christoph Hellwig
2021-10-12 16:36   ` [dm-devel] " Christoph Hellwig
2021-10-12 16:36 ` [PATCH 4/5] block: fold blk_max_size_offset into get_max_io_size Christoph Hellwig
2021-10-12 16:36   ` [dm-devel] " Christoph Hellwig
2021-10-12 16:36 ` [PATCH 5/5] block: pass the start sector to get_max_io_size Christoph Hellwig
2021-10-12 16:36   ` [dm-devel] " Christoph Hellwig

Reply instructions:

You may reply publicly 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=20211012163613.994933-3-hch@lst.de \
    --to=hch@lst.de \
    --cc=axboe@kernel.dk \
    --cc=dm-devel@redhat.com \
    --cc=linux-block@vger.kernel.org \
    --cc=snitzer@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
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.