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dm: clean up clone_bio
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Remove the no-longer-used struct bio_set argument from clone_bio and split_bvec.
Use tio->ti in __map_bio() instead of passing in ti.
Factor out some code for setting up cloned bios.
Take target_request_nr as a parameter to alloc_tio().

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: Joe Thornber <ejt@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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Alasdair G Kergon committed Mar 1, 2013
1 parent 88ae4c5 commit bd2a49b
Showing 1 changed file with 57 additions and 45 deletions.
102 changes: 57 additions & 45 deletions drivers/md/dm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -985,12 +985,13 @@ int dm_set_target_max_io_len(struct dm_target *ti, sector_t len)
}
EXPORT_SYMBOL_GPL(dm_set_target_max_io_len);

static void __map_bio(struct dm_target *ti, struct dm_target_io *tio)
static void __map_bio(struct dm_target_io *tio)
{
int r;
sector_t sector;
struct mapped_device *md;
struct bio *clone = &tio->clone;
struct dm_target *ti = tio->ti;

clone->bi_end_io = clone_endio;
clone->bi_private = tio;
Expand Down Expand Up @@ -1031,62 +1032,78 @@ struct clone_info {
unsigned short idx;
};

static void bio_setup_sector(struct bio *bio, sector_t sector, sector_t len)
{
bio->bi_sector = sector;
bio->bi_size = to_bytes(len);
}

static void bio_setup_bv(struct bio *bio, unsigned short idx, unsigned short bv_count)
{
bio->bi_idx = idx;
bio->bi_vcnt = idx + bv_count;
bio->bi_flags &= ~(1 << BIO_SEG_VALID);
}

static void clone_bio_integrity(struct bio *bio, struct bio *clone,
unsigned short idx, unsigned len, unsigned offset,
unsigned trim)
{
if (!bio_integrity(bio))
return;

bio_integrity_clone(clone, bio, GFP_NOIO);

if (trim)
bio_integrity_trim(clone, bio_sector_offset(bio, idx, offset), len);
}

/*
* Creates a little bio that just does part of a bvec.
*/
static void split_bvec(struct dm_target_io *tio, struct bio *bio,
sector_t sector, unsigned short idx, unsigned int offset,
unsigned int len, struct bio_set *bs)
unsigned int len)
{
struct bio *clone = &tio->clone;
struct bio_vec *bv = bio->bi_io_vec + idx;

*clone->bi_io_vec = *bv;

clone->bi_sector = sector;
bio_setup_sector(clone, sector, len);

clone->bi_bdev = bio->bi_bdev;
clone->bi_rw = bio->bi_rw;
clone->bi_vcnt = 1;
clone->bi_size = to_bytes(len);
clone->bi_io_vec->bv_offset = offset;
clone->bi_io_vec->bv_len = clone->bi_size;
clone->bi_flags |= 1 << BIO_CLONED;

if (bio_integrity(bio)) {
bio_integrity_clone(clone, bio, GFP_NOIO);
bio_integrity_trim(clone,
bio_sector_offset(bio, idx, offset), len);
}
clone_bio_integrity(bio, clone, idx, len, offset, 1);
}

/*
* Creates a bio that consists of range of complete bvecs.
*/
static void clone_bio(struct dm_target_io *tio, struct bio *bio,
sector_t sector, unsigned short idx,
unsigned short bv_count, unsigned int len,
struct bio_set *bs)
unsigned short bv_count, unsigned int len)
{
struct bio *clone = &tio->clone;
unsigned trim = 0;

__bio_clone(clone, bio);
clone->bi_sector = sector;
clone->bi_idx = idx;
clone->bi_vcnt = idx + bv_count;
clone->bi_size = to_bytes(len);
clone->bi_flags &= ~(1 << BIO_SEG_VALID);

if (bio_integrity(bio)) {
bio_integrity_clone(clone, bio, GFP_NOIO);

if (idx != bio->bi_idx || clone->bi_size < bio->bi_size)
bio_integrity_trim(clone,
bio_sector_offset(bio, idx, 0), len);
}
bio_setup_sector(clone, sector, len);
bio_setup_bv(clone, idx, bv_count);

if (idx != bio->bi_idx || clone->bi_size < bio->bi_size)
trim = 1;
clone_bio_integrity(bio, clone, idx, len, 0, trim);
}

static struct dm_target_io *alloc_tio(struct clone_info *ci,
struct dm_target *ti, int nr_iovecs)
struct dm_target *ti, int nr_iovecs,
unsigned target_request_nr)
{
struct dm_target_io *tio;
struct bio *clone;
Expand All @@ -1097,32 +1114,27 @@ static struct dm_target_io *alloc_tio(struct clone_info *ci,
tio->io = ci->io;
tio->ti = ti;
memset(&tio->info, 0, sizeof(tio->info));
tio->target_request_nr = 0;
tio->target_request_nr = target_request_nr;

return tio;
}

static void __issue_target_request(struct clone_info *ci, struct dm_target *ti,
unsigned request_nr, sector_t len)
{
struct dm_target_io *tio = alloc_tio(ci, ti, ci->bio->bi_max_vecs);
struct dm_target_io *tio = alloc_tio(ci, ti, ci->bio->bi_max_vecs, request_nr);
struct bio *clone = &tio->clone;

tio->target_request_nr = request_nr;

/*
* Discard requests require the bio's inline iovecs be initialized.
* ci->bio->bi_max_vecs is BIO_INLINE_VECS anyway, for both flush
* and discard, so no need for concern about wasted bvec allocations.
*/

__bio_clone(clone, ci->bio);
if (len) {
clone->bi_sector = ci->sector;
clone->bi_size = to_bytes(len);
}
if (len)
bio_setup_sector(clone, ci->sector, len);

__map_bio(ti, tio);
__map_bio(tio);
}

static void __issue_target_requests(struct clone_info *ci, struct dm_target *ti,
Expand Down Expand Up @@ -1154,10 +1166,10 @@ static void __clone_and_map_simple(struct clone_info *ci, struct dm_target *ti)
struct bio *bio = ci->bio;
struct dm_target_io *tio;

tio = alloc_tio(ci, ti, bio->bi_max_vecs);
tio = alloc_tio(ci, ti, bio->bi_max_vecs, 0);
clone_bio(tio, bio, ci->sector, ci->idx, bio->bi_vcnt - ci->idx,
ci->sector_count, ci->md->bs);
__map_bio(ti, tio);
ci->sector_count);
__map_bio(tio);
ci->sector_count = 0;
}

Expand Down Expand Up @@ -1271,10 +1283,9 @@ static int __clone_and_map(struct clone_info *ci)
len += bv_len;
}

tio = alloc_tio(ci, ti, bio->bi_max_vecs);
clone_bio(tio, bio, ci->sector, ci->idx, i - ci->idx, len,
ci->md->bs);
__map_bio(ti, tio);
tio = alloc_tio(ci, ti, bio->bi_max_vecs, 0);
clone_bio(tio, bio, ci->sector, ci->idx, i - ci->idx, len);
__map_bio(tio);

ci->sector += len;
ci->sector_count -= len;
Expand All @@ -1299,11 +1310,11 @@ static int __clone_and_map(struct clone_info *ci)

len = min(remaining, max);

tio = alloc_tio(ci, ti, 1);
tio = alloc_tio(ci, ti, 1, 0);
split_bvec(tio, bio, ci->sector, ci->idx,
bv->bv_offset + offset, len, ci->md->bs);
bv->bv_offset + offset, len);

__map_bio(ti, tio);
__map_bio(tio);

ci->sector += len;
ci->sector_count -= len;
Expand Down Expand Up @@ -1341,6 +1352,7 @@ static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
ci.idx = bio->bi_idx;

start_io_acct(ci.io);

if (bio->bi_rw & REQ_FLUSH) {
ci.bio = &ci.md->flush_bio;
ci.sector_count = 0;
Expand Down

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