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dm: rename bio cloning functions

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Rename functions involved in splitting and cloning bios.

The sequence of functions is now:
  (1) __split_and_process* - entry point that selects the processing strategy
  (2) __send* - prepare the details for each bio needed and loop through them
  (3) __clone_and_map* - creates a clone and maps it

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
tirimbino
Alasdair G Kergon 12 years ago
parent 55a62eef8d
commit 14fe594d67
1 changed files with 31 additions and 32 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 63
      drivers/md/dm.c

63
drivers/md/dm.c
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@ -1061,9 +1061,9 @@ static void clone_bio_integrity(struct bio *bio, struct bio *clone,
/*
* 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)
static void clone_split_bio(struct dm_target_io *tio, struct bio *bio,
sector_t sector, unsigned short idx,
unsigned offset, unsigned len)
{
struct bio *clone = &tio->clone;
struct bio_vec *bv = bio->bi_io_vec + idx;
@ -1119,8 +1119,9 @@ static struct dm_target_io *alloc_tio(struct clone_info *ci,
return tio;
}
static void __issue_target_request(struct clone_info *ci, struct dm_target *ti,
unsigned target_bio_nr, sector_t len)
static void __clone_and_map_simple_bio(struct clone_info *ci,
struct dm_target *ti,
unsigned target_bio_nr, sector_t len)
{
struct dm_target_io *tio = alloc_tio(ci, ti, ci->bio->bi_max_vecs, target_bio_nr);
struct bio *clone = &tio->clone;
@ -1137,31 +1138,29 @@ static void __issue_target_request(struct clone_info *ci, struct dm_target *ti,
__map_bio(tio);
}
static void __issue_target_bios(struct clone_info *ci, struct dm_target *ti,
unsigned num_bios, sector_t len)
static void __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
unsigned num_bios, sector_t len)
{
unsigned target_bio_nr;
for (target_bio_nr = 0; target_bio_nr < num_bios; target_bio_nr++)
__issue_target_request(ci, ti, target_bio_nr, len);
__clone_and_map_simple_bio(ci, ti, target_bio_nr, len);
}
static int __clone_and_map_empty_flush(struct clone_info *ci)
static int __send_empty_flush(struct clone_info *ci)
{
unsigned target_nr = 0;
struct dm_target *ti;
BUG_ON(bio_has_data(ci->bio));
while ((ti = dm_table_get_target(ci->map, target_nr++)))
__issue_target_bios(ci, ti, ti->num_flush_bios, 0);
__send_duplicate_bios(ci, ti, ti->num_flush_bios, 0);
return 0;
}
/*
* Perform all io with a single clone.
*/
static void __clone_and_map_simple(struct clone_info *ci, struct dm_target *ti)
static void __clone_and_map_data_bio(struct clone_info *ci,
struct dm_target *ti)
{
struct bio *bio = ci->bio;
struct dm_target_io *tio;
@ -1192,9 +1191,9 @@ static bool is_split_required_for_discard(struct dm_target *ti)
return ti->split_discard_bios;
}
static int __clone_and_map_changing_extent_only(struct clone_info *ci,
get_num_bios_fn get_num_bios,
is_split_required_fn is_split_required)
static int __send_changing_extent_only(struct clone_info *ci,
get_num_bios_fn get_num_bios,
is_split_required_fn is_split_required)
{
struct dm_target *ti;
sector_t len;
@ -1220,7 +1219,7 @@ static int __clone_and_map_changing_extent_only(struct clone_info *ci,
else
len = min(ci->sector_count, max_io_len(ci->sector, ti));
__issue_target_bios(ci, ti, num_bios, len);
__send_duplicate_bios(ci, ti, num_bios, len);
ci->sector += len;
} while (ci->sector_count -= len);
@ -1228,18 +1227,18 @@ static int __clone_and_map_changing_extent_only(struct clone_info *ci,
return 0;
}
static int __clone_and_map_discard(struct clone_info *ci)
static int __send_discard(struct clone_info *ci)
{
return __clone_and_map_changing_extent_only(ci, get_num_discard_bios,
is_split_required_for_discard);
return __send_changing_extent_only(ci, get_num_discard_bios,
is_split_required_for_discard);
}
static int __clone_and_map_write_same(struct clone_info *ci)
static int __send_write_same(struct clone_info *ci)
{
return __clone_and_map_changing_extent_only(ci, get_num_write_same_bios, NULL);
return __send_changing_extent_only(ci, get_num_write_same_bios, NULL);
}
static int __clone_and_map(struct clone_info *ci)
static int __split_and_process_non_flush(struct clone_info *ci)
{
struct bio *bio = ci->bio;
struct dm_target *ti;
@ -1247,9 +1246,9 @@ static int __clone_and_map(struct clone_info *ci)
struct dm_target_io *tio;
if (unlikely(bio->bi_rw & REQ_DISCARD))
return __clone_and_map_discard(ci);
return __send_discard(ci);
else if (unlikely(bio->bi_rw & REQ_WRITE_SAME))
return __clone_and_map_write_same(ci);
return __send_write_same(ci);
ti = dm_table_find_target(ci->map, ci->sector);
if (!dm_target_is_valid(ti))
@ -1262,7 +1261,7 @@ static int __clone_and_map(struct clone_info *ci)
* Optimise for the simple case where we can do all of
* the remaining io with a single clone.
*/
__clone_and_map_simple(ci, ti);
__clone_and_map_data_bio(ci, ti);
} else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) {
/*
@ -1311,8 +1310,8 @@ static int __clone_and_map(struct clone_info *ci)
len = min(remaining, max);
tio = alloc_tio(ci, ti, 1, 0);
split_bvec(tio, bio, ci->sector, ci->idx,
bv->bv_offset + offset, len);
clone_split_bio(tio, bio, ci->sector, ci->idx,
bv->bv_offset + offset, len);
__map_bio(tio);
@ -1328,7 +1327,7 @@ static int __clone_and_map(struct clone_info *ci)
}
/*
* Split the bio into several clones and submit it to targets.
* Entry point to split a bio into clones and submit them to the targets.
*/
static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
{
@ -1356,13 +1355,13 @@ static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
if (bio->bi_rw & REQ_FLUSH) {
ci.bio = &ci.md->flush_bio;
ci.sector_count = 0;
error = __clone_and_map_empty_flush(&ci);
error = __send_empty_flush(&ci);
/* dec_pending submits any data associated with flush */
} else {
ci.bio = bio;
ci.sector_count = bio_sectors(bio);
while (ci.sector_count && !error)
error = __clone_and_map(&ci);
error = __split_and_process_non_flush(&ci);
}
/* drop the extra reference count */

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