[PATCH V11 14/19] block: handle non-cluster bio out of blk_bio_segment_split

Ming Lei
2018-11-21T03:28:25Z

We will enable multi-page bvec soon, but non-cluster queue can't
handle the multi-page bvec at all. This patch borrows bounce's
idea to clone new single-page bio for non-cluster queue, and moves
its handling out of blk_bio_segment_split().

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
block/Makefile | 3 ++-
block/blk-merge.c | 6 ++++-
block/blk.h | 2 ++
block/non-cluster.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 79 insertions(+), 2 deletions(-)
create mode 100644 block/non-cluster.c

diff --git a/block/Makefile b/block/Makefile
index eee1b4ceecf9..e07d59438c4b 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -9,7 +9,8 @@ obj-$(CONFIG_BLOCK) := bio.o elevator.o blk-core.o blk-sysfs.o \
blk-lib.o blk-mq.o blk-mq-tag.o blk-stat.o \
blk-mq-sysfs.o blk-mq-cpumap.o blk-mq-sched.o ioctl.o \
genhd.o partition-generic.o ioprio.o \
- badblocks.o partitions/ blk-rq-qos.o
+ badblocks.o partitions/ blk-rq-qos.o \
+ non-cluster.o

obj-$(CONFIG_BOUNCE) += bounce.o
obj-$(CONFIG_BLK_SCSI_REQUEST) += scsi_ioctl.o
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 8829c51b4e75..7c44216c1b58 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -247,7 +247,7 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
goto split;
}

- if (bvprvp && blk_queue_cluster(q)) {
+ if (bvprvp) {
if (seg_size + bv.bv_len > queue_max_segment_size(q))
goto new_segment;
if (!biovec_phys_mergeable(q, bvprvp, &bv))
@@ -307,6 +307,10 @@ void blk_queue_split(struct request_queue *q, struct bio **bio)
split = blk_bio_write_same_split(q, *bio, &q->bio_split, &nsegs);
break;
default:
+ if (!blk_queue_cluster(q)) {
+ blk_queue_non_cluster_bio(q, bio);
+ return;
+ }
split = blk_bio_segment_split(q, *bio, &q->bio_split, &nsegs);
break;
}
diff --git a/block/blk.h b/block/blk.h
index 31c0e45aba3a..6fc5821ced55 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -338,6 +338,8 @@ struct bio *blk_next_bio(struct bio *bio, unsigned int nr_pages, gfp_t gfp);

struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask, struct bio_set *bs);

+void blk_queue_non_cluster_bio(struct request_queue *q, struct bio **bio_orig);
+
#ifdef CONFIG_BLK_DEV_ZONED
void blk_queue_free_zone_bitmaps(struct request_queue *q);
#else
diff --git a/block/non-cluster.c b/block/non-cluster.c
new file mode 100644
index 000000000000..9c2910be9404
--- /dev/null
+++ b/block/non-cluster.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0
+/* non-cluster handling for block devices */
+
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/swap.h>
+#include <linux/gfp.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/backing-dev.h>
+#include <linux/init.h>
+#include <linux/printk.h>
+
+#include "blk.h"
+
+static struct bio_set non_cluster_bio_set, non_cluster_bio_split;
+
+static __init int init_non_cluster_bioset(void)
+{
+ WARN_ON(bioset_init(&non_cluster_bio_set, BIO_POOL_SIZE, 0,
+ BIOSET_NEED_BVECS));
+ WARN_ON(bioset_integrity_create(&non_cluster_bio_set, BIO_POOL_SIZE));
+ WARN_ON(bioset_init(&non_cluster_bio_split, BIO_POOL_SIZE, 0, 0));
+
+ return 0;
+}
+__initcall(init_non_cluster_bioset);
+
+static void non_cluster_end_io(struct bio *bio)
+{
+ struct bio *bio_orig = bio->bi_private;
+
+ bio_orig->bi_status = bio->bi_status;
+ bio_endio(bio_orig);
+ bio_put(bio);
+}
+
+void blk_queue_non_cluster_bio(struct request_queue *q, struct bio **bio_orig)
+{
+ struct bio *bio;
+ struct bvec_iter iter;
+ struct bio_vec from;
+ unsigned i = 0;
+ unsigned sectors = 0;
+ unsigned short max_segs = min_t(unsigned short, BIO_MAX_PAGES,
+ queue_max_segments(q));
+
+ bio_for_each_segment(from, *bio_orig, iter) {
+ if (i++ < max_segs)
+ sectors += from.bv_len >> 9;
+ else
+ break;
+ }
+
+ if (sectors < bio_sectors(*bio_orig)) {
+ bio = bio_split(*bio_orig, sectors, GFP_NOIO,
+ &non_cluster_bio_split);
+ bio_chain(bio, *bio_orig);
+ generic_make_request(*bio_orig);
+ *bio_orig = bio;
+ }
+ bio = bio_clone_bioset(*bio_orig, GFP_NOIO, &non_cluster_bio_set);
+
+ bio->bi_phys_segments = bio_segments(bio);
+ bio_set_flag(bio, BIO_SEG_VALID);
+ bio->bi_end_io = non_cluster_end_io;
+
+ bio->bi_private = *bio_orig;
+ *bio_orig = bio;
+}
--
2.9.5