[PATCH 7/9] block: Don't use bi_idx in bio_split() or require it to be 0

From: Kent Overstreet
Date: Fri Sep 07 2012 - 19:00:39 EST


Prep work for immutable bio_vecs/efficient bio splitting: they require
auditing and removing most uses of bi_idx.

So here we convert bio_split() to respect the current value of bi_idx
and use the bio_iovec() macro, instead of assuming bi_idx will be 0.

Signed-off-by: Kent Overstreet <koverstreet@xxxxxxxxxx>
CC: Jens Axboe <axboe@xxxxxxxxx>
---
drivers/block/drbd/drbd_req.c | 6 +++---
drivers/md/raid0.c | 3 +--
drivers/md/raid10.c | 3 +--
fs/bio-integrity.c | 4 ++--
fs/bio.c | 7 +++----
5 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index af69a96..57eb253 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -1155,11 +1155,11 @@ void drbd_make_request(struct request_queue *q, struct bio *bio)

/* can this bio be split generically?
* Maybe add our own split-arbitrary-bios function. */
- if (bio->bi_vcnt != 1 || bio->bi_idx != 0 || bio->bi_size > DRBD_MAX_BIO_SIZE) {
+ if (bio_segments(bio) != 1 || bio->bi_size > DRBD_MAX_BIO_SIZE) {
/* rather error out here than BUG in bio_split */
dev_err(DEV, "bio would need to, but cannot, be split: "
- "(vcnt=%u,idx=%u,size=%u,sector=%llu)\n",
- bio->bi_vcnt, bio->bi_idx, bio->bi_size,
+ "(segments=%u,size=%u,sector=%llu)\n",
+ bio_segments(bio), bio->bi_size,
(unsigned long long)bio->bi_sector);
bio_endio(bio, -EINVAL);
} else {
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 387cb89..0587450 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -509,8 +509,7 @@ static void raid0_make_request(struct mddev *mddev, struct bio *bio)
sector_t sector = bio->bi_sector;
struct bio_pair *bp;
/* Sanity check -- queue functions should prevent this happening */
- if (bio->bi_vcnt != 1 ||
- bio->bi_idx != 0)
+ 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.
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 9715aaf..bbd08f5 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1081,8 +1081,7 @@ static void make_request(struct mddev *mddev, struct bio * bio)
|| conf->prev.near_copies < conf->prev.raid_disks))) {
struct bio_pair *bp;
/* Sanity check -- queue functions should prevent this happening */
- if (bio->bi_vcnt != 1 ||
- bio->bi_idx != 0)
+ 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.
diff --git a/fs/bio-integrity.c b/fs/bio-integrity.c
index 1d64f7f..e8555a5 100644
--- a/fs/bio-integrity.c
+++ b/fs/bio-integrity.c
@@ -657,8 +657,8 @@ void bio_integrity_split(struct bio *bio, struct bio_pair *bp, int sectors)
bp->bio1.bi_integrity = &bp->bip1;
bp->bio2.bi_integrity = &bp->bip2;

- bp->iv1 = bip->bip_vec[0];
- bp->iv2 = bip->bip_vec[0];
+ bp->iv1 = bip->bip_vec[bip->bip_idx];
+ bp->iv2 = bip->bip_vec[bip->bip_idx];

bp->bip1.bip_vec = &bp->iv1;
bp->bip2.bip_vec = &bp->iv2;
diff --git a/fs/bio.c b/fs/bio.c
index a539664..126b264 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -1585,8 +1585,7 @@ struct bio_pair *bio_split(struct bio *bi, int first_sectors)
trace_block_split(bdev_get_queue(bi->bi_bdev), bi,
bi->bi_sector + first_sectors);

- BUG_ON(bi->bi_vcnt != 1);
- BUG_ON(bi->bi_idx != 0);
+ BUG_ON(bio_segments(bi) != 1);
atomic_set(&bp->cnt, 3);
bp->error = 0;
bp->bio1 = *bi;
@@ -1595,8 +1594,8 @@ struct bio_pair *bio_split(struct bio *bi, int first_sectors)
bp->bio2.bi_size -= first_sectors << 9;
bp->bio1.bi_size = first_sectors << 9;

- bp->bv1 = bi->bi_io_vec[0];
- bp->bv2 = bi->bi_io_vec[0];
+ bp->bv1 = *bio_iovec(bi);
+ bp->bv2 = *bio_iovec(bi);
bp->bv2.bv_offset += first_sectors << 9;
bp->bv2.bv_len -= first_sectors << 9;
bp->bv1.bv_len = first_sectors << 9;
--
1.7.12

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/