diff options
author | Kent Overstreet <kmo@daterainc.com> | 2013-10-29 17:17:49 -0700 |
---|---|---|
committer | Kent Overstreet <kmo@daterainc.com> | 2013-11-23 22:33:55 -0800 |
commit | 1c3b13e64cf70d652fb04e32d13ae3e36810c2e4 (patch) | |
tree | ca3d3fd7d0c6d99fa2bc041ed51bac4aaa9a242a /drivers/md/dm.c | |
parent | 5341a6278bc5d10dbbb2ab6031b41d95c8db7a35 (diff) | |
download | blackbird-op-linux-1c3b13e64cf70d652fb04e32d13ae3e36810c2e4.tar.gz blackbird-op-linux-1c3b13e64cf70d652fb04e32d13ae3e36810c2e4.zip |
dm: Refactor for new bio cloning/splitting
We need to convert the dm code to the new bvec_iter primitives which
respect bi_bvec_done; they also allow us to drastically simplify dm's
bio splitting code.
Also, it's no longer necessary to save/restore the bvec array anymore -
driver conversions for immutable bvecs are done, so drivers should never
be modifying it.
Also kill bio_sector_offset(), dm was the only user and it doesn't make
much sense anymore.
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: dm-devel@redhat.com
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm.c')
-rw-r--r-- | drivers/md/dm.c | 174 |
1 files changed, 20 insertions, 154 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index ccd064ea4fe6..44a2fa6814ce 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1155,7 +1155,6 @@ struct clone_info { struct dm_io *io; sector_t sector; sector_t sector_count; - unsigned short idx; }; static void bio_setup_sector(struct bio *bio, sector_t sector, sector_t len) @@ -1164,68 +1163,24 @@ static void bio_setup_sector(struct bio *bio, sector_t sector, sector_t len) bio->bi_iter.bi_size = to_bytes(len); } -static void bio_setup_bv(struct bio *bio, unsigned short idx, unsigned short bv_count) -{ - bio->bi_iter.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 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; - - *clone->bi_io_vec = *bv; - - bio_setup_sector(clone, sector, len); - - clone->bi_bdev = bio->bi_bdev; - clone->bi_rw = bio->bi_rw; - clone->bi_vcnt = 1; - clone->bi_io_vec->bv_offset = offset; - clone->bi_io_vec->bv_len = clone->bi_iter.bi_size; - clone->bi_flags |= 1 << BIO_CLONED; - - 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 len) + sector_t sector, unsigned len) { struct bio *clone = &tio->clone; - unsigned trim = 0; - __bio_clone(clone, bio); - bio_setup_sector(clone, sector, len); - bio_setup_bv(clone, idx, bv_count); + __bio_clone_fast(clone, bio); + + if (bio_integrity(bio)) + bio_integrity_clone(clone, bio, GFP_NOIO); + + bio_advance(clone, to_bytes(sector - clone->bi_iter.bi_sector)); + clone->bi_iter.bi_size = to_bytes(len); - if (idx != bio->bi_iter.bi_idx || - clone->bi_iter.bi_size < bio->bi_iter.bi_size) - trim = 1; - clone_bio_integrity(bio, clone, idx, len, 0, trim); + if (bio_integrity(bio)) + bio_integrity_trim(clone, 0, len); } static struct dm_target_io *alloc_tio(struct clone_info *ci, @@ -1258,7 +1213,7 @@ static void __clone_and_map_simple_bio(struct clone_info *ci, * 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); + __bio_clone_fast(clone, ci->bio); if (len) bio_setup_sector(clone, ci->sector, len); @@ -1287,10 +1242,7 @@ static int __send_empty_flush(struct clone_info *ci) } 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) + sector_t sector, unsigned len) { struct bio *bio = ci->bio; struct dm_target_io *tio; @@ -1304,11 +1256,8 @@ static void __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti num_target_bios = ti->num_write_bios(ti, bio); for (target_bio_nr = 0; target_bio_nr < num_target_bios; target_bio_nr++) { - tio = alloc_tio(ci, ti, nr_iovecs, target_bio_nr); - if (split_bvec) - clone_split_bio(tio, bio, sector, idx, offset, len); - else - clone_bio(tio, bio, sector, idx, bv_count, len); + tio = alloc_tio(ci, ti, 0, target_bio_nr); + clone_bio(tio, bio, sector, len); __map_bio(tio); } } @@ -1380,68 +1329,13 @@ static int __send_write_same(struct clone_info *ci) } /* - * 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, max; - int idx; + unsigned len; if (unlikely(bio->bi_rw & REQ_DISCARD)) return __send_discard(ci); @@ -1452,41 +1346,14 @@ static int __split_and_process_non_flush(struct clone_info *ci) if (!dm_target_is_valid(ti)) return -EIO; - 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) { - __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; - } - - /* - * 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); - - __clone_and_map_data_bio(ci, ti, ci->sector, bio->bi_max_vecs, - ci->idx, idx - ci->idx, 0, len, 0); + len = min_t(sector_t, max_io_len(ci->sector, ti), ci->sector_count); - ci->sector += len; - ci->sector_count -= len; - ci->idx = idx; + __clone_and_map_data_bio(ci, ti, ci->sector, len); - return 0; - } + ci->sector += len; + ci->sector_count -= len; - /* - * Handle a bvec that must be split between two or more targets. - */ - return __split_bvec_across_targets(ci, ti, max); + return 0; } /* @@ -1512,7 +1379,6 @@ static void __split_and_process_bio(struct mapped_device *md, ci.io->md = md; spin_lock_init(&ci.io->endio_lock); ci.sector = bio->bi_iter.bi_sector; - ci.idx = bio->bi_iter.bi_idx; start_io_acct(ci.io); |