diff options
| -rw-r--r-- | drivers/md/dm.c | 164 |
1 files changed, 96 insertions, 68 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 02079cfccaf..0890abd9dff 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1087,7 +1087,7 @@ static void clone_split_bio(struct dm_target_io *tio, struct bio *bio, */ 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) + unsigned short bv_count, unsigned len) { struct bio *clone = &tio->clone; unsigned trim = 0; @@ -1159,17 +1159,23 @@ static int __send_empty_flush(struct clone_info *ci) return 0; } -static void __clone_and_map_data_bio(struct clone_info *ci, - struct dm_target *ti) +static void __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti, + sector_t sector, int nr_iovecs, + unsigned short idx, unsigned short bv_count, + unsigned offset, unsigned len, + unsigned split_bvec) { struct bio *bio = ci->bio; struct dm_target_io *tio; - 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); + tio = alloc_tio(ci, ti, nr_iovecs, 0); + + if (split_bvec) + clone_split_bio(tio, bio, sector, idx, offset, len); + else + clone_bio(tio, bio, sector, idx, bv_count, len); + __map_bio(tio); - ci->sector_count = 0; } typedef unsigned (*get_num_bios_fn)(struct dm_target *ti); @@ -1238,12 +1244,69 @@ static int __send_write_same(struct clone_info *ci) return __send_changing_extent_only(ci, get_num_write_same_bios, NULL); } +/* + * Find maximum number of sectors / bvecs we can process with a single bio. + */ +static sector_t __len_within_target(struct clone_info *ci, sector_t max, int *idx) +{ + struct bio *bio = ci->bio; + sector_t bv_len, total_len = 0; + + for (*idx = ci->idx; max && (*idx < bio->bi_vcnt); (*idx)++) { + bv_len = to_sector(bio->bi_io_vec[*idx].bv_len); + + if (bv_len > max) + break; + + max -= bv_len; + total_len += bv_len; + } + + return total_len; +} + +static int __split_bvec_across_targets(struct clone_info *ci, + struct dm_target *ti, sector_t max) +{ + struct bio *bio = ci->bio; + struct bio_vec *bv = bio->bi_io_vec + ci->idx; + sector_t remaining = to_sector(bv->bv_len); + unsigned offset = 0; + sector_t len; + + do { + if (offset) { + ti = dm_table_find_target(ci->map, ci->sector); + if (!dm_target_is_valid(ti)) + return -EIO; + + max = max_io_len(ci->sector, ti); + } + + len = min(remaining, max); + + __clone_and_map_data_bio(ci, ti, ci->sector, 1, ci->idx, 0, + bv->bv_offset + offset, len, 1); + + ci->sector += len; + ci->sector_count -= len; + offset += to_bytes(len); + } while (remaining -= len); + + ci->idx++; + + return 0; +} + +/* + * Select the correct strategy for processing a non-flush bio. + */ static int __split_and_process_non_flush(struct clone_info *ci) { struct bio *bio = ci->bio; struct dm_target *ti; - sector_t len = 0, max; - struct dm_target_io *tio; + sector_t len, max; + int idx; if (unlikely(bio->bi_rw & REQ_DISCARD)) return __send_discard(ci); @@ -1256,74 +1319,39 @@ static int __split_and_process_non_flush(struct clone_info *ci) max = max_io_len(ci->sector, ti); + /* + * Optimise for the simple case where we can do all of + * the remaining io with a single clone. + */ if (ci->sector_count <= max) { - /* - * Optimise for the simple case where we can do all of - * the remaining io with a single clone. - */ - __clone_and_map_data_bio(ci, ti); - - } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) { - /* - * There are some bvecs that don't span targets. - * Do as many of these as possible. - */ - int i; - sector_t remaining = max; - sector_t bv_len; - - for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) { - bv_len = to_sector(bio->bi_io_vec[i].bv_len); - - if (bv_len > remaining) - break; + __clone_and_map_data_bio(ci, ti, ci->sector, bio->bi_max_vecs, + ci->idx, bio->bi_vcnt - ci->idx, 0, + ci->sector_count, 0); + ci->sector_count = 0; + return 0; + } - remaining -= bv_len; - len += bv_len; - } + /* + * There are some bvecs that don't span targets. + * Do as many of these as possible. + */ + if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) { + len = __len_within_target(ci, max, &idx); - 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); + __clone_and_map_data_bio(ci, ti, ci->sector, bio->bi_max_vecs, + ci->idx, idx - ci->idx, 0, len, 0); ci->sector += len; ci->sector_count -= len; - ci->idx = i; - - } else { - /* - * Handle a bvec that must be split between two or more targets. - */ - struct bio_vec *bv = bio->bi_io_vec + ci->idx; - sector_t remaining = to_sector(bv->bv_len); - unsigned int offset = 0; - - do { - if (offset) { - ti = dm_table_find_target(ci->map, ci->sector); - if (!dm_target_is_valid(ti)) - return -EIO; - - max = max_io_len(ci->sector, ti); - } - - len = min(remaining, max); + ci->idx = idx; - tio = alloc_tio(ci, ti, 1, 0); - clone_split_bio(tio, bio, ci->sector, ci->idx, - bv->bv_offset + offset, len); - - __map_bio(tio); - - ci->sector += len; - ci->sector_count -= len; - offset += to_bytes(len); - } while (remaining -= len); - - ci->idx++; + return 0; } - return 0; + /* + * Handle a bvec that must be split between two or more targets. + */ + return __split_bvec_across_targets(ci, ti, max); } /* |