From: NeilBrown <neilb@suse.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 11/11] block: don't check for BIO_MAX_PAGES in blk_bio_segment_split()
Date: Thu, 20 Apr 2017 15:38:50 +1000 [thread overview]
Message-ID: <149266673048.27388.6882396367486800999.stgit@noble> (raw)
In-Reply-To: <149266645258.27388.14083229348123176454.stgit@noble>
blk_bio_segment_split() makes sure bios have no more than
BIO_MAX_PAGES entries in the bi_io_vec.
This was done because bio_clone_bioset() (when given a
mempool bioset) could not handle larger io_vecs.
No driver uses bio_clone_bioset() any more, they all
use bio_clone_fast() if anything, and bio_clone_fast()
doesn't clone the bi_io_vec.
The main user of of bio_clone_bioset() at this level
is bounce.c, and bouncing now happens before blk_bio_segment_split(),
so that is not of concern.
So remove the big helpful comment and the code.
Signed-off-by: NeilBrown <neilb@suse.com>
---
block/blk-merge.c | 16 ----------------
1 file changed, 16 deletions(-)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index e7862e9dcc39..cea544ec5d96 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -108,25 +108,9 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
bool do_split = true;
struct bio *new = NULL;
const unsigned max_sectors = get_max_io_size(q, bio);
- unsigned bvecs = 0;
bio_for_each_segment(bv, bio, iter) {
/*
- * With arbitrary bio size, the incoming bio may be very
- * big. We have to split the bio into small bios so that
- * each holds at most BIO_MAX_PAGES bvecs because
- * bio_clone_bioset() can fail to allocate big bvecs.
- *
- * Those drivers which will need to use bio_clone_bioset()
- * should tell us in some way. For now, impose the
- * BIO_MAX_PAGES limit on all queues.
- *
- * TODO: handle users of bio_clone_bioset() differently.
- */
- if (bvecs++ >= BIO_MAX_PAGES)
- goto split;
-
- /*
* If the queue doesn't support SG gaps and adding this
* offset would create a gap, disallow it.
*/
next prev parent reply other threads:[~2017-04-20 5:46 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-20 5:38 [PATCH 00/11] block: assorted cleanup for bio splitting and cloning NeilBrown
2017-04-20 5:38 ` [PATCH 01/11] blk: remove bio_set arg from blk_queue_split() NeilBrown
2017-04-21 11:21 ` Christoph Hellwig
2017-04-21 15:14 ` Ming Lei
2017-04-22 9:16 ` Javier González
2017-04-24 2:32 ` NeilBrown
2017-04-20 5:38 ` [PATCH 02/11] blk: make the bioset rescue_workqueue optional NeilBrown
2017-04-21 11:24 ` Christoph Hellwig
2017-04-24 1:51 ` NeilBrown
2017-04-24 15:10 ` Christoph Hellwig
2017-05-01 5:00 ` NeilBrown
2017-05-01 14:02 ` Jens Axboe
2017-05-02 3:33 ` NeilBrown
2017-04-20 5:38 ` [PATCH 07/11] pktcdvd: use bio_clone_fast() instead of bio_clone() NeilBrown
2017-04-21 11:29 ` Christoph Hellwig
2017-04-20 5:38 ` [PATCH 05/11] rbd: " NeilBrown
2017-04-21 11:31 ` Christoph Hellwig
2017-04-20 5:38 ` [PATCH 03/11] blk: use non-rescuing bioset for q->bio_split NeilBrown
2017-04-21 11:25 ` Christoph Hellwig
2017-04-20 5:38 ` [PATCH 04/11] block: Improvements to bounce-buffer handling NeilBrown
2017-04-21 11:28 ` Christoph Hellwig
2017-04-21 15:39 ` Ming Lei
2017-04-20 5:38 ` [PATCH 06/11] drbd: use bio_clone_fast() instead of bio_clone() NeilBrown
2017-04-21 11:30 ` Christoph Hellwig
2017-04-20 5:38 ` [PATCH 09/11] bcache: use kmalloc to allocate bio in bch_data_verify() NeilBrown
2017-04-21 11:31 ` Christoph Hellwig
2017-04-21 11:32 ` Kent Overstreet
2017-04-21 15:41 ` Ming Lei
2017-04-20 5:38 ` [PATCH 08/11] xen-blkfront: remove bio splitting NeilBrown
2017-04-20 10:00 ` Roger Pau Monné
2017-04-21 11:36 ` Christoph Hellwig
2017-04-21 11:46 ` Roger Pau Monne
2017-04-20 5:38 ` NeilBrown [this message]
2017-04-21 11:34 ` [PATCH 11/11] block: don't check for BIO_MAX_PAGES in blk_bio_segment_split() Christoph Hellwig
2017-04-21 15:48 ` Ming Lei
2017-04-24 3:16 ` NeilBrown
2017-04-24 3:14 ` NeilBrown
2017-04-20 5:38 ` [PATCH 10/11] block: remove bio_clone() and all references NeilBrown
2017-04-21 11:32 ` Christoph Hellwig
2017-04-21 15:43 ` Ming Lei
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