[PATCH 17/26] block: Introduce new bio_split()

From: Kent Overstreet
Date: Sat Jun 08 2013 - 22:22:51 EST

The new bio_split() can split arbitrary bios - it's not restricted to
single page bios, like the old bio_split() (previously renamed to
bio_pair_split()). It also has different semantics - it doesn't allocate
a struct bio_pair, leaving it up to the caller to handle completions.

Then convert the existing bio_pair_split() users to the new bio_split()
- and also nvme, which was open coding bio splitting.

(We have to take that BUG_ON() out of bio_integrity_trim() because this
bio_split() needs to use it, and there's no reason it has to be used on
bios marked as cloned; BIO_CLONED doesn't seem to have clearly
documented semantics anyways.)

Signed-off-by: Kent Overstreet <koverstreet@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Cc: Matthew Wilcox <matthew.r.wilcox@xxxxxxxxx>
Cc: Keith Busch <keith.busch@xxxxxxxxx>
Cc: Vishal Verma <vishal.l.verma@xxxxxxxxx>
Cc: Jiri Kosina <jkosina@xxxxxxx>
Cc: Neil Brown <neilb@xxxxxxx>
---
drivers/block/nvme-core.c | 108 +++--------------------------------
drivers/block/pktcdvd.c | 135 ++++++++++++++++++++++++--------------------
drivers/md/bcache/bcache.h | 1 -
drivers/md/bcache/btree.c | 2 +-
drivers/md/bcache/io.c | 80 +-------------------------
drivers/md/bcache/request.c | 4 +-
drivers/md/linear.c | 96 +++++++++++++++----------------
drivers/md/raid0.c | 77 +++++++++----------------
drivers/md/raid10.c | 113 +++++++++++++++---------------------
fs/bio.c | 71 +++++++++++++++++++++++
include/linux/bio.h | 22 ++++++++
11 files changed, 304 insertions(+), 405 deletions(-)

diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index e4f2c37..d88badc 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -406,106 +406,19 @@ int nvme_setup_prps(struct nvme_dev *dev, struct nvme_common_command *cmd,
return total_len;
}

-struct nvme_bio_pair {
- struct bio b1, b2, *parent;
- struct bio_vec *bv1, *bv2;
- int err;
- atomic_t cnt;
-};
-
-static void nvme_bio_pair_endio(struct bio *bio, int err)
-{
- struct nvme_bio_pair *bp = bio->bi_private;
-
- if (err)
- bp->err = err;
-
- if (atomic_dec_and_test(&bp->cnt)) {
- bio_endio(bp->parent, bp->err);
- if (bp->bv1)
- kfree(bp->bv1);
- if (bp->bv2)
- kfree(bp->bv2);
- kfree(bp);
- }
-}
-
-static struct nvme_bio_pair *nvme_bio_split(struct bio *bio, int idx,
- int len, int offset)
-{
- struct nvme_bio_pair *bp;
-
- BUG_ON(len > bio->bi_iter.bi_size);
- BUG_ON(idx > bio->bi_vcnt);
-
- bp = kmalloc(sizeof(*bp), GFP_ATOMIC);
- if (!bp)
- return NULL;
- bp->err = 0;
-
- bp->b1 = *bio;
- bp->b2 = *bio;
-
- bp->b1.bi_iter.bi_size = len;
- bp->b2.bi_iter.bi_size -= len;
- bp->b1.bi_vcnt = idx;
- bp->b2.bi_iter.bi_idx = idx;
- bp->b2.bi_iter.bi_sector += len >> 9;
-
- if (offset) {
- bp->bv1 = kmalloc(bio->bi_max_vecs * sizeof(struct bio_vec),
- GFP_ATOMIC);
- if (!bp->bv1)
- goto split_fail_1;
-
- bp->bv2 = kmalloc(bio->bi_max_vecs * sizeof(struct bio_vec),
- GFP_ATOMIC);
- if (!bp->bv2)
- goto split_fail_2;
-
- memcpy(bp->bv1, bio->bi_io_vec,
- bio->bi_max_vecs * sizeof(struct bio_vec));
- memcpy(bp->bv2, bio->bi_io_vec,
- bio->bi_max_vecs * sizeof(struct bio_vec));
-
- bp->b1.bi_io_vec = bp->bv1;
- bp->b2.bi_io_vec = bp->bv2;
- bp->b2.bi_io_vec[idx].bv_offset += offset;
- bp->b2.bi_io_vec[idx].bv_len -= offset;
- bp->b1.bi_io_vec[idx].bv_len = offset;
- bp->b1.bi_vcnt++;
- } else
- bp->bv1 = bp->bv2 = NULL;
-
- bp->b1.bi_private = bp;
- bp->b2.bi_private = bp;
-
- bp->b1.bi_end_io = nvme_bio_pair_endio;
- bp->b2.bi_end_io = nvme_bio_pair_endio;
-
- bp->parent = bio;
- atomic_set(&bp->cnt, 2);
-
- return bp;
-
- split_fail_2:
- kfree(bp->bv1);
- split_fail_1:
- kfree(bp);
- return NULL;
-}
-
static int nvme_split_and_submit(struct bio *bio, struct nvme_queue *nvmeq,
- int idx, int len, int offset)
+ int len)
{
- struct nvme_bio_pair *bp = nvme_bio_split(bio, idx, len, offset);
- if (!bp)
+ struct bio *split = bio_split(bio, len >> 9, GFP_ATOMIC, NULL);
+ if (!split)
return -ENOMEM;

+ bio_chain(split, bio);
+
if (bio_list_empty(&nvmeq->sq_cong))
add_wait_queue(&nvmeq->sq_full, &nvmeq->sq_cong_wait);
- bio_list_add(&nvmeq->sq_cong, &bp->b1);
- bio_list_add(&nvmeq->sq_cong, &bp->b2);
+ bio_list_add(&nvmeq->sq_cong, split);
+ bio_list_add(&nvmeq->sq_cong, bio);

return 0;
}
@@ -535,8 +448,7 @@ static int nvme_map_bio(struct nvme_queue *nvmeq, struct nvme_iod *iod,
} else {
if (!first && BIOVEC_NOT_VIRT_MERGEABLE(&bvprv, &bvec))
return nvme_split_and_submit(bio, nvmeq,
- iter.bi_idx,
- length, 0);
+ length);

sg = sg ? sg + 1 : iod->sg;
sg_set_page(sg, bvec.bv_page,
@@ -545,9 +457,7 @@ static int nvme_map_bio(struct nvme_queue *nvmeq, struct nvme_iod *iod,
}

if (split_len - length < bvec.bv_len)
- return nvme_split_and_submit(bio, nvmeq, iter.bi_idx,
- split_len,
- split_len - length);
+ return nvme_split_and_submit(bio, nvmeq, split_len);
length += bvec.bv_len;
bvprv = bvec;
first = 0;
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 6c1029c..a929817 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -2352,74 +2352,29 @@ static void pkt_end_io_read_cloned(struct bio *bio, int err)
pkt_bio_finished(pd);
}

-static void pkt_make_request(struct request_queue *q, struct bio *bio)
+static void pkt_make_request_read(struct pktcdvd_device *pd, struct bio *bio)
{
- struct pktcdvd_device *pd;
- char b[BDEVNAME_SIZE];
+ struct bio *cloned_bio = bio_clone(bio, GFP_NOIO);
+ struct packet_stacked_data *psd = mempool_alloc(psd_pool, GFP_NOIO);
+
+ psd->pd = pd;
+ psd->bio = bio;
+ cloned_bio->bi_bdev = pd->bdev;
+ cloned_bio->bi_private = psd;
+ cloned_bio->bi_end_io = pkt_end_io_read_cloned;
+ pd->stats.secs_r += bio_sectors(bio);
+ pkt_queue_bio(pd, cloned_bio);
+}
+
+static void pkt_make_request_write(struct request_queue *q, struct bio *bio)
+{
+ struct pktcdvd_device *pd = q->queuedata;
sector_t zone;
struct packet_data *pkt;
int was_empty, blocked_bio;
struct pkt_rb_node *node;

- pd = q->queuedata;
- if (!pd) {
- printk(DRIVER_NAME": %s incorrect request queue\n", bdevname(bio->bi_bdev, b));
- goto end_io;
- }
-
- /*
- * Clone READ bios so we can have our own bi_end_io callback.
- */
- if (bio_data_dir(bio) == READ) {
- struct bio *cloned_bio = bio_clone(bio, GFP_NOIO);
- struct packet_stacked_data *psd = mempool_alloc(psd_pool, GFP_NOIO);
-
- psd->pd = pd;
- psd->bio = bio;
- cloned_bio->bi_bdev = pd->bdev;
- cloned_bio->bi_private = psd;
- cloned_bio->bi_end_io = pkt_end_io_read_cloned;
- pd->stats.secs_r += bio_sectors(bio);
- pkt_queue_bio(pd, cloned_bio);
- return;
- }
-
- if (!test_bit(PACKET_WRITABLE, &pd->flags)) {
- printk(DRIVER_NAME": WRITE for ro device %s (%llu)\n",
- pd->name, (unsigned long long)bio->bi_iter.bi_sector);
- goto end_io;
- }
-
- if (!bio->bi_iter.bi_size || (bio->bi_iter.bi_size % CD_FRAMESIZE)) {
- printk(DRIVER_NAME": wrong bio size\n");
- goto end_io;
- }
-
- blk_queue_bounce(q, &bio);
-
zone = ZONE(bio->bi_iter.bi_sector, pd);
- VPRINTK("pkt_make_request: start = %6llx stop = %6llx\n",
- (unsigned long long)bio->bi_sector,
- (unsigned long long)bio_end_sector(bio));
-
- /* Check if we have to split the bio */
- {
- struct bio_pair *bp;
- sector_t last_zone;
- int first_sectors;
-
- last_zone = ZONE(bio_end_sector(bio) - 1, pd);
- if (last_zone != zone) {
- BUG_ON(last_zone != zone + pd->settings.size);
- first_sectors = last_zone - bio->bi_iter.bi_sector;
- bp = bio_pair_split(bio, first_sectors);
- BUG_ON(!bp);
- pkt_make_request(q, &bp->bio1);
- pkt_make_request(q, &bp->bio2);
- bio_pair_release(bp);
- return;
- }
- }

/*
* If we find a matching packet in state WAITING or READ_WAIT, we can
@@ -2493,6 +2448,64 @@ static void pkt_make_request(struct request_queue *q, struct bio *bio)
*/
wake_up(&pd->wqueue);
}
+}
+
+static void pkt_make_request(struct request_queue *q, struct bio *bio)
+{
+ struct pktcdvd_device *pd;
+ char b[BDEVNAME_SIZE];
+ struct bio *split;
+
+ pd = q->queuedata;
+ if (!pd) {
+ printk(DRIVER_NAME": %s incorrect request queue\n",
+ bdevname(bio->bi_bdev, b));
+ goto end_io;
+ }
+
+ VPRINTK("pkt_make_request: start = %6llx stop = %6llx\n",
+ (unsigned long long)bio->bi_sector,
+ (unsigned long long)(bio->bi_sector + bio_sectors(bio)));
+
+ /*
+ * Clone READ bios so we can have our own bi_end_io callback.
+ */
+ if (bio_data_dir(bio) == READ) {
+ pkt_make_request_read(pd, bio);
+ return;
+ }
+
+ if (!test_bit(PACKET_WRITABLE, &pd->flags)) {
+ printk(DRIVER_NAME": WRITE for ro device %s (%llu)\n",
+ pd->name, (unsigned long long)bio->bi_iter.bi_sector);
+ goto end_io;
+ }
+
+ if (!bio->bi_iter.bi_size || (bio->bi_iter.bi_size % CD_FRAMESIZE)) {
+ printk(DRIVER_NAME": wrong bio size\n");
+ goto end_io;
+ }
+
+ blk_queue_bounce(q, &bio);
+
+ do {
+ sector_t zone = ZONE(bio->bi_iter.bi_sector, pd);
+ sector_t last_zone = ZONE(bio_end_sector(bio) - 1, pd);
+
+ if (last_zone != zone) {
+ BUG_ON(last_zone != zone + pd->settings.size);
+
+ split = bio_split(bio, last_zone -
+ bio->bi_iter.bi_sector,
+ GFP_NOIO, fs_bio_set);
+ bio_chain(split, bio);
+ } else {
+ split = bio;
+ }
+
+ pkt_make_request_write(q, split);
+ } while (split != bio);
+
return;
end_io:
bio_io_error(bio);
diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index 850de67..14aaff5 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -1184,7 +1184,6 @@ void bch_bbio_endio(struct cache_set *, struct bio *, int, const char *);
void bch_bbio_free(struct bio *, struct cache_set *);
struct bio *bch_bbio_alloc(struct cache_set *);

-struct bio *bch_bio_split(struct bio *, int, gfp_t, struct bio_set *);
void bch_generic_make_request(struct bio *, struct bio_split_pool *);
void __bch_submit_bbio(struct bio *, struct cache_set *);
void bch_submit_bbio(struct bio *, struct cache_set *, struct bkey *, unsigned);
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index b6c3a05..e724b21 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -2214,7 +2214,7 @@ static int submit_partial_cache_hit(struct btree *b, struct btree_op *op,
unsigned sectors = min_t(uint64_t, INT_MAX,
KEY_OFFSET(k) - bio->bi_iter.bi_sector);

- n = bch_bio_split(bio, sectors, GFP_NOIO, s->d->bio_split);
+ n = bio_next_split(bio, sectors, GFP_NOIO, s->d->bio_split);
if (n == bio)
op->lookup_done = true;

diff --git a/drivers/md/bcache/io.c b/drivers/md/bcache/io.c
index 246b420..4224cfd 100644
--- a/drivers/md/bcache/io.c
+++ b/drivers/md/bcache/io.c
@@ -9,82 +9,6 @@
#include "bset.h"
#include "debug.h"

-/**
- * bch_bio_split - split a bio
- * @bio: bio to split
- * @sectors: number of sectors to split from the front of @bio
- * @gfp: gfp mask
- * @bs: bio set to allocate from
- *
- * Allocates and returns a new bio which represents @sectors from the start of
- * @bio, and updates @bio to represent the remaining sectors.
- *
- * If bio_sectors(@bio) was less than or equal to @sectors, returns @bio
- * unchanged.
- *
- * The newly allocated bio will point to @bio's bi_io_vec, if the split was on a
- * bvec boundry; it is the caller's responsibility to ensure that @bio is not
- * freed before the split.
- */
-struct bio *bch_bio_split(struct bio *bio, int sectors,
- gfp_t gfp, struct bio_set *bs)
-{
- unsigned vcnt = 0, nbytes = sectors << 9;
- struct bio_vec bv;
- struct bvec_iter iter;
- struct bio *ret = NULL;
-
- BUG_ON(sectors <= 0);
-
- if (sectors >= bio_sectors(bio))
- return bio;
-
- if (bio->bi_rw & REQ_DISCARD) {
- ret = bio_alloc_bioset(gfp, 1, bs);
- goto out;
- }
-
- bio_for_each_segment(bv, bio, iter) {
- vcnt++;
-
- if (nbytes <= bv.bv_len)
- break;
-
- nbytes -= bv.bv_len;
- }
-
- ret = bio_alloc_bioset(gfp, vcnt, bs);
- if (!ret)
- return NULL;
-
- bio_for_each_segment(bv, bio, iter) {
- ret->bi_io_vec[ret->bi_vcnt++] = bv;
-
- if (ret->bi_vcnt == vcnt)
- break;
- }
-
- ret->bi_io_vec[ret->bi_vcnt - 1].bv_len = nbytes;
-out:
- ret->bi_bdev = bio->bi_bdev;
- ret->bi_iter.bi_sector = bio->bi_iter.bi_sector;
- ret->bi_iter.bi_size = sectors << 9;
- ret->bi_rw = bio->bi_rw;
-
- if (bio_integrity(bio)) {
- if (bio_integrity_clone(ret, bio, gfp)) {
- bio_put(ret);
- return NULL;
- }
-
- bio_integrity_trim(ret, 0, bio_sectors(ret));
- }
-
- bio_advance(bio, ret->bi_iter.bi_size);
-
- return ret;
-}
-
static unsigned bch_bio_max_sectors(struct bio *bio)
{
unsigned ret = bio_sectors(bio);
@@ -176,8 +100,8 @@ void bch_generic_make_request(struct bio *bio, struct bio_split_pool *p)
bio_get(bio);

do {
- n = bch_bio_split(bio, bch_bio_max_sectors(bio),
- GFP_NOIO, s->p->bio_split);
+ n = bio_next_split(bio, bch_bio_max_sectors(bio),
+ GFP_NOIO, s->p->bio_split);

n->bi_end_io = bch_bio_submit_split_endio;
n->bi_private = &s->cl;
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index b0de7a43..ca513d4 100644
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -509,7 +509,7 @@ static void bch_insert_data_loop(struct closure *cl)
if (!bch_alloc_sectors(k, bio_sectors(bio), s))
goto err;

- n = bch_bio_split(bio, KEY_SIZE(k), GFP_NOIO, split);
+ n = bio_next_split(bio, KEY_SIZE(k), GFP_NOIO, split);

n->bi_end_io = bch_insert_data_endio;
n->bi_private = cl;
@@ -853,7 +853,7 @@ static int cached_dev_cache_miss(struct btree *b, struct search *s,
struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
struct bio *miss;

- miss = bch_bio_split(bio, sectors, GFP_NOIO, s->d->bio_split);
+ miss = bio_next_split(bio, sectors, GFP_NOIO, s->d->bio_split);
if (miss == bio)
s->op.lookup_done = true;

diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index e9b53e9..56f534b 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -288,65 +288,65 @@ static int linear_stop (struct mddev *mddev)

static void linear_make_request(struct mddev *mddev, struct bio *bio)
{
+ char b[BDEVNAME_SIZE];
struct dev_info *tmp_dev;
- sector_t start_sector;
+ struct bio *split;
+ sector_t start_sector, end_sector, data_offset;

if (unlikely(bio->bi_rw & REQ_FLUSH)) {
md_flush_request(mddev, bio);
return;
}

- rcu_read_lock();
- tmp_dev = which_dev(mddev, bio->bi_iter.bi_sector);
- start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors;
-
-
- if (unlikely(bio->bi_iter.bi_sector >= (tmp_dev->end_sector)
- || (bio->bi_iter.bi_sector < start_sector))) {
- char b[BDEVNAME_SIZE];
-
- printk(KERN_ERR
- "md/linear:%s: make_request: Sector %llu out of bounds on "
- "dev %s: %llu sectors, offset %llu\n",
- mdname(mddev),
- (unsigned long long)bio->bi_iter.bi_sector,
- bdevname(tmp_dev->rdev->bdev, b),
- (unsigned long long)tmp_dev->rdev->sectors,
- (unsigned long long)start_sector);
- rcu_read_unlock();
- bio_io_error(bio);
- return;
- }
- if (unlikely(bio_end_sector(bio) > tmp_dev->end_sector)) {
- /* This bio crosses a device boundary, so we have to
- * split it.
- */
- struct bio_pair *bp;
- sector_t end_sector = tmp_dev->end_sector;
+ do {
+ rcu_read_lock();

- rcu_read_unlock();
-
- bp = bio_pair_split(bio, end_sector - bio->bi_iter.bi_sector);
+ tmp_dev = which_dev(mddev, bio->bi_iter.bi_sector);
+ start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors;
+ end_sector = tmp_dev->end_sector;
+ data_offset = tmp_dev->rdev->data_offset;
+ bio->bi_bdev = tmp_dev->rdev->bdev;

- linear_make_request(mddev, &bp->bio1);
- linear_make_request(mddev, &bp->bio2);
- bio_pair_release(bp);
- return;
- }
-
- bio->bi_bdev = tmp_dev->rdev->bdev;
- bio->bi_iter.bi_sector = bio->bi_iter.bi_sector - start_sector
- + tmp_dev->rdev->data_offset;
- rcu_read_unlock();
+ rcu_read_unlock();

- if (unlikely((bio->bi_rw & REQ_DISCARD) &&
- !blk_queue_discard(bdev_get_queue(bio->bi_bdev)))) {
- /* Just ignore it */
- bio_endio(bio, 0);
- return;
- }
+ if (unlikely(bio->bi_iter.bi_sector >= end_sector ||
+ bio->bi_iter.bi_sector < start_sector))
+ goto out_of_bounds;
+
+ if (unlikely(bio_end_sector(bio) > end_sector)) {
+ /* This bio crosses a device boundary, so we have to
+ * split it.
+ */
+ split = bio_split(bio, end_sector -
+ bio->bi_iter.bi_sector,
+ GFP_NOIO, fs_bio_set);
+ bio_chain(split, bio);
+ } else {
+ split = bio;
+ }

- generic_make_request(bio);
+ split->bi_iter.bi_sector = split->bi_iter.bi_sector -
+ start_sector + data_offset;
+
+ if (unlikely((split->bi_rw & REQ_DISCARD) &&
+ !blk_queue_discard(bdev_get_queue(split->bi_bdev)))) {
+ /* Just ignore it */
+ bio_endio(split, 0);
+ } else
+ generic_make_request(split);
+ } while (split != bio);
+ return;
+
+out_of_bounds:
+ printk(KERN_ERR
+ "md/linear:%s: make_request: Sector %llu out of bounds on "
+ "dev %s: %llu sectors, offset %llu\n",
+ mdname(mddev),
+ (unsigned long long)bio->bi_iter.bi_sector,
+ bdevname(tmp_dev->rdev->bdev, b),
+ (unsigned long long)tmp_dev->rdev->sectors,
+ (unsigned long long)start_sector);
+ bio_io_error(bio);
}

static void linear_status (struct seq_file *seq, struct mddev *mddev)
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 5edc3f7..49d1188 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -513,65 +513,44 @@ static inline int is_io_in_chunk_boundary(struct mddev *mddev,

static void raid0_make_request(struct mddev *mddev, struct bio *bio)
{
- unsigned int chunk_sects;
- sector_t sector_offset;
struct strip_zone *zone;
struct md_rdev *tmp_dev;
+ struct bio *split;

if (unlikely(bio->bi_rw & REQ_FLUSH)) {
md_flush_request(mddev, bio);
return;
}

- chunk_sects = mddev->chunk_sectors;
- if (unlikely(!is_io_in_chunk_boundary(mddev, chunk_sects, bio))) {
+ do {
sector_t sector = bio->bi_iter.bi_sector;
- struct bio_pair *bp;
- /* Sanity check -- queue functions should prevent this happening */
- if (bio_segments(bio) > 1)
- goto bad_map;
- /* This is a one page bio that upper layers
- * refuse to split for us, so we need to split it.
- */
- if (likely(is_power_of_2(chunk_sects)))
- bp = bio_pair_split(bio, chunk_sects - (sector &
- (chunk_sects-1)));
- else
- bp = bio_pair_split(bio, chunk_sects -
- sector_div(sector, chunk_sects));
- raid0_make_request(mddev, &bp->bio1);
- raid0_make_request(mddev, &bp->bio2);
- bio_pair_release(bp);
- return;
- }
-
- sector_offset = bio->bi_iter.bi_sector;
- zone = find_zone(mddev->private, &sector_offset);
- tmp_dev = map_sector(mddev, zone, bio->bi_iter.bi_sector,
- &sector_offset);
- bio->bi_bdev = tmp_dev->bdev;
- bio->bi_iter.bi_sector = sector_offset + zone->dev_start +
- tmp_dev->data_offset;
-
- if (unlikely((bio->bi_rw & REQ_DISCARD) &&
- !blk_queue_discard(bdev_get_queue(bio->bi_bdev)))) {
- /* Just ignore it */
- bio_endio(bio, 0);
- return;
- }
-
- generic_make_request(bio);
- return;
-
-bad_map:
- printk("md/raid0:%s: make_request bug: can't convert block across chunks"
- " or bigger than %dk %llu %d\n",
- mdname(mddev), chunk_sects / 2,
- (unsigned long long)bio->bi_iter.bi_sector,
- bio_sectors(bio) / 2);
+ unsigned chunk_sects = mddev->chunk_sectors;
+
+ unsigned sectors = chunk_sects -
+ (likely(is_power_of_2(chunk_sects))
+ ? (sector & (chunk_sects-1))
+ : sector_div(sector, chunk_sects));
+
+ if (sectors < bio_sectors(bio)) {
+ split = bio_split(bio, sectors, GFP_NOIO, fs_bio_set);
+ bio_chain(split, bio);
+ } else {
+ split = bio;
+ }

- bio_io_error(bio);
- return;
+ zone = find_zone(mddev->private, &sector);
+ tmp_dev = map_sector(mddev, zone, sector, &sector);
+ split->bi_bdev = tmp_dev->bdev;
+ split->bi_iter.bi_sector = sector + zone->dev_start +
+ tmp_dev->data_offset;
+
+ if (unlikely((split->bi_rw & REQ_DISCARD) &&
+ !blk_queue_discard(bdev_get_queue(split->bi_bdev)))) {
+ /* Just ignore it */
+ bio_endio(split, 0);
+ } else
+ generic_make_request(split);
+ } while (split != bio);
}

static void raid0_status(struct seq_file *seq, struct mddev *mddev)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 7b68d82..867a996 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1144,14 +1144,12 @@ static void raid10_unplug(struct blk_plug_cb *cb, bool from_schedule)
kfree(plug);
}

-static void make_request(struct mddev *mddev, struct bio * bio)
+static void __make_request(struct mddev *mddev, struct bio *bio)
{
struct r10conf *conf = mddev->private;
struct r10bio *r10_bio;
struct bio *read_bio;
int i;
- sector_t chunk_mask = (conf->geo.chunk_mask & conf->prev.chunk_mask);
- int chunk_sects = chunk_mask + 1;
const int rw = bio_data_dir(bio);
const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
const unsigned long do_fua = (bio->bi_rw & REQ_FUA);
@@ -1166,69 +1164,6 @@ static void make_request(struct mddev *mddev, struct bio * bio)
int max_sectors;
int sectors;

- if (unlikely(bio->bi_rw & REQ_FLUSH)) {
- md_flush_request(mddev, bio);
- return;
- }
-
- /* If this request crosses a chunk boundary, we need to
- * split it. This will only happen for 1 PAGE (or less) requests.
- */
- if (unlikely((bio->bi_iter.bi_sector & chunk_mask) + bio_sectors(bio)
- > chunk_sects
- && (conf->geo.near_copies < conf->geo.raid_disks
- || conf->prev.near_copies < conf->prev.raid_disks))) {
- struct bio_pair *bp;
- /* Sanity check -- queue functions should prevent this happening */
- if (bio_segments(bio) > 1)
- goto bad_map;
- /* This is a one page bio that upper layers
- * refuse to split for us, so we need to split it.
- */
- bp = bio_pair_split(bio, chunk_sects -
- (bio->bi_iter.bi_sector & (chunk_sects - 1)));
-
- /* Each of these 'make_request' calls will call 'wait_barrier'.
- * If the first succeeds but the second blocks due to the resync
- * thread raising the barrier, we will deadlock because the
- * IO to the underlying device will be queued in generic_make_request
- * and will never complete, so will never reduce nr_pending.
- * So increment nr_waiting here so no new raise_barriers will
- * succeed, and so the second wait_barrier cannot block.
- */
- spin_lock_irq(&conf->resync_lock);
- conf->nr_waiting++;
- spin_unlock_irq(&conf->resync_lock);
-
- make_request(mddev, &bp->bio1);
- make_request(mddev, &bp->bio2);
-
- spin_lock_irq(&conf->resync_lock);
- conf->nr_waiting--;
- wake_up(&conf->wait_barrier);
- spin_unlock_irq(&conf->resync_lock);
-
- bio_pair_release(bp);
- return;
- bad_map:
- printk("md/raid10:%s: make_request bug: can't convert block across chunks"
- " or bigger than %dk %llu %d\n", mdname(mddev), chunk_sects/2,
- (unsigned long long)bio->bi_iter.bi_sector,
- bio_sectors(bio) / 2);
-
- bio_io_error(bio);
- return;
- }
-
- md_write_start(mddev, bio);
-
- /*
- * Register the new request and wait if the reconstruction
- * thread has put up a bar for new requests.
- * Continue immediately if no resync is active currently.
- */
- wait_barrier(conf);
-
sectors = bio_sectors(bio);
while (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
bio->bi_iter.bi_sector < conf->reshape_progress &&
@@ -1592,6 +1527,52 @@ retry_write:
goto retry_write;
}
one_write_done(r10_bio);
+}
+
+static void make_request(struct mddev *mddev, struct bio *bio)
+{
+ struct r10conf *conf = mddev->private;
+ sector_t chunk_mask = (conf->geo.chunk_mask & conf->prev.chunk_mask);
+ int chunk_sects = chunk_mask + 1;
+
+ struct bio *split;
+
+ if (unlikely(bio->bi_rw & REQ_FLUSH)) {
+ md_flush_request(mddev, bio);
+ return;
+ }
+
+ md_write_start(mddev, bio);
+
+ /*
+ * Register the new request and wait if the reconstruction
+ * thread has put up a bar for new requests.
+ * Continue immediately if no resync is active currently.
+ */
+ wait_barrier(conf);
+
+ do {
+
+ /*
+ * If this request crosses a chunk boundary, we need to split
+ * it.
+ */
+ if (unlikely((bio->bi_iter.bi_sector & chunk_mask) +
+ bio_sectors(bio) > chunk_sects
+ && (conf->geo.near_copies < conf->geo.raid_disks
+ || conf->prev.near_copies <
+ conf->prev.raid_disks))) {
+ split = bio_split(bio, chunk_sects -
+ (bio->bi_iter.bi_sector &
+ (chunk_sects - 1)),
+ GFP_NOIO, fs_bio_set);
+ bio_chain(split, bio);
+ } else {
+ split = bio;
+ }
+
+ __make_request(mddev, split);
+ } while (split != bio);

/* In case raid10d snuck in to freeze_array */
wake_up(&conf->wait_barrier);
diff --git a/fs/bio.c b/fs/bio.c
index 3968b8f..a674101 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -1712,6 +1712,77 @@ void bio_endio(struct bio *bio, int error)
}
EXPORT_SYMBOL(bio_endio);

+/**
+ * bio_split - split a bio
+ * @bio: bio to split
+ * @sectors: number of sectors to split from the front of @bio
+ * @gfp: gfp mask
+ * @bs: bio set to allocate from
+ *
+ * Allocates and returns a new bio which represents @sectors from the start of
+ * @bio, and updates @bio to represent the remaining sectors.
+ *
+ * If bio_sectors(@bio) was less than or equal to @sectors, returns @bio
+ * unchanged.
+ */
+struct bio *bio_split(struct bio *bio, int sectors,
+ gfp_t gfp, struct bio_set *bs)
+{
+ unsigned vcnt = 0, nbytes = sectors << 9;
+ struct bio_vec bv;
+ struct bvec_iter iter;
+ struct bio *split = NULL;
+
+ BUG_ON(sectors <= 0);
+ BUG_ON(sectors >= bio_sectors(bio));
+
+ if (bio->bi_rw & REQ_DISCARD) {
+ split = bio_alloc_bioset(gfp, 1, bs);
+ goto out;
+ }
+
+ bio_for_each_segment(bv, bio, iter) {
+ vcnt++;
+
+ if (nbytes <= bv.bv_len)
+ break;
+
+ nbytes -= bv.bv_len;
+ }
+
+ split = bio_alloc_bioset(gfp, vcnt, bs);
+ if (!split)
+ return NULL;
+
+ bio_for_each_segment(bv, bio, iter) {
+ split->bi_io_vec[split->bi_vcnt++] = bv;
+
+ if (split->bi_vcnt == vcnt)
+ break;
+ }
+
+ split->bi_io_vec[split->bi_vcnt - 1].bv_len = nbytes;
+out:
+ split->bi_bdev = bio->bi_bdev;
+ split->bi_iter.bi_sector = bio->bi_iter.bi_sector;
+ split->bi_iter.bi_size = sectors << 9;
+ split->bi_rw = bio->bi_rw;
+
+ if (bio_integrity(bio)) {
+ if (bio_integrity_clone(split, bio, gfp)) {
+ bio_put(split);
+ return NULL;
+ }
+
+ bio_integrity_trim(split, 0, bio_sectors(split));
+ }
+
+ bio_advance(bio, split->bi_iter.bi_size);
+
+ return split;
+}
+EXPORT_SYMBOL(bio_split);
+
void bio_pair_release(struct bio_pair *bp)
{
if (atomic_dec_and_test(&bp->cnt)) {
diff --git a/include/linux/bio.h b/include/linux/bio.h
index dd70f7e..866db8a 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -284,6 +284,28 @@ struct bio_pair {
extern struct bio_pair *bio_pair_split(struct bio *bi, int first_sectors);
extern void bio_pair_release(struct bio_pair *dbio);

+extern struct bio *bio_split(struct bio *bio, int sectors,
+ gfp_t gfp, struct bio_set *bs);
+
+/**
+ * bio_next_split - get next @sectors from a bio, splitting if necessary
+ * @bio: bio to split
+ * @sectors: number of sectors to split from the front of @bio
+ * @gfp: gfp mask
+ * @bs: bio set to allocate from
+ *
+ * Returns a bio representing the next @sectors of @bio - if the bio is smaller
+ * than @sectors, returns the original bio unchanged.
+ */
+static inline struct bio *bio_next_split(struct bio *bio, int sectors,
+ gfp_t gfp, struct bio_set *bs)
+{
+ if (sectors >= bio_sectors(bio))
+ return bio;
+
+ return bio_split(bio, sectors, gfp, bs);
+}
+
extern struct bio_set *bioset_create(unsigned int, unsigned int);
extern void bioset_free(struct bio_set *);
extern mempool_t *biovec_create_pool(struct bio_set *bs, int pool_entries);
--
1.8.3.rc1

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