From 1c3b13e64cf70d652fb04e32d13ae3e36810c2e4 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Tue, 29 Oct 2013 17:17:49 -0700 Subject: [PATCH] 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 Cc: Jens Axboe Cc: Alasdair Kergon Cc: dm-devel@redhat.com Reviewed-by: Mike Snitzer --- drivers/md/dm-bio-record.h | 25 ------ drivers/md/dm.c | 174 +++++-------------------------------- fs/bio.c | 72 --------------- include/linux/bio.h | 2 - 4 files changed, 20 insertions(+), 253 deletions(-) diff --git a/drivers/md/dm-bio-record.h b/drivers/md/dm-bio-record.h index 4f46e8e528de..dd3646111561 100644 --- a/drivers/md/dm-bio-record.h +++ b/drivers/md/dm-bio-record.h @@ -17,49 +17,24 @@ * original bio state. */ -struct dm_bio_vec_details { -#if PAGE_SIZE < 65536 - __u16 bv_len; - __u16 bv_offset; -#else - unsigned bv_len; - unsigned bv_offset; -#endif -}; - struct dm_bio_details { struct block_device *bi_bdev; unsigned long bi_flags; struct bvec_iter bi_iter; - struct dm_bio_vec_details bi_io_vec[BIO_MAX_PAGES]; }; static inline void dm_bio_record(struct dm_bio_details *bd, struct bio *bio) { - unsigned i; - bd->bi_bdev = bio->bi_bdev; bd->bi_flags = bio->bi_flags; bd->bi_iter = bio->bi_iter; - - for (i = 0; i < bio->bi_vcnt; i++) { - bd->bi_io_vec[i].bv_len = bio->bi_io_vec[i].bv_len; - bd->bi_io_vec[i].bv_offset = bio->bi_io_vec[i].bv_offset; - } } static inline void dm_bio_restore(struct dm_bio_details *bd, struct bio *bio) { - unsigned i; - bio->bi_bdev = bd->bi_bdev; bio->bi_flags = bd->bi_flags; bio->bi_iter = bd->bi_iter; - - for (i = 0; i < bio->bi_vcnt; i++) { - bio->bi_io_vec[i].bv_len = bd->bi_io_vec[i].bv_len; - bio->bi_io_vec[i].bv_offset = bd->bi_io_vec[i].bv_offset; - } } #endif 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); } } @@ -1379,60 +1328,6 @@ 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. */ @@ -1440,8 +1335,7 @@ 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); diff --git a/fs/bio.c b/fs/bio.c index 00dc1893c6ee..6e42b68ab0ac 100644 --- a/fs/bio.c +++ b/fs/bio.c @@ -514,40 +514,6 @@ inline int bio_phys_segments(struct request_queue *q, struct bio *bio) } EXPORT_SYMBOL(bio_phys_segments); -/** - * __bio_clone - clone a bio - * @bio: destination bio - * @bio_src: bio to clone - * - * Clone a &bio. Caller will own the returned bio, but not - * the actual data it points to. Reference count of returned - * bio will be one. - */ -void __bio_clone(struct bio *bio, struct bio *bio_src) -{ - if (bio_is_rw(bio_src)) { - struct bio_vec bv; - struct bvec_iter iter; - - bio_for_each_segment(bv, bio_src, iter) - bio->bi_io_vec[bio->bi_vcnt++] = bv; - } else if (bio_has_data(bio_src)) { - memcpy(bio->bi_io_vec, bio_src->bi_io_vec, - bio_src->bi_max_vecs * sizeof(struct bio_vec)); - bio->bi_vcnt = bio_src->bi_vcnt; - } - - /* - * most users will be overriding ->bi_bdev with a new target, - * so we don't set nor calculate new physical/hw segment counts here - */ - bio->bi_bdev = bio_src->bi_bdev; - bio->bi_flags |= 1 << BIO_CLONED; - bio->bi_rw = bio_src->bi_rw; - bio->bi_iter = bio_src->bi_iter; -} -EXPORT_SYMBOL(__bio_clone); - /** * __bio_clone_fast - clone a bio that shares the original bio's biovec * @bio: destination bio @@ -1921,44 +1887,6 @@ void bio_trim(struct bio *bio, int offset, int size) } EXPORT_SYMBOL_GPL(bio_trim); -/** - * bio_sector_offset - Find hardware sector offset in bio - * @bio: bio to inspect - * @index: bio_vec index - * @offset: offset in bv_page - * - * Return the number of hardware sectors between beginning of bio - * and an end point indicated by a bio_vec index and an offset - * within that vector's page. - */ -sector_t bio_sector_offset(struct bio *bio, unsigned short index, - unsigned int offset) -{ - unsigned int sector_sz; - struct bio_vec *bv; - sector_t sectors; - int i; - - sector_sz = queue_logical_block_size(bio->bi_bdev->bd_disk->queue); - sectors = 0; - - if (index >= bio->bi_iter.bi_idx) - index = bio->bi_vcnt - 1; - - bio_for_each_segment_all(bv, bio, i) { - if (i == index) { - if (offset > bv->bv_offset) - sectors += (offset - bv->bv_offset) / sector_sz; - break; - } - - sectors += bv->bv_len / sector_sz; - } - - return sectors; -} -EXPORT_SYMBOL(bio_sector_offset); - /* * create memory pools for biovec's in a bio_set. * use the global biovec slabs created for general use. diff --git a/include/linux/bio.h b/include/linux/bio.h index 1f83f4a3083e..0c32a45a419c 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -330,7 +330,6 @@ extern void bio_put(struct bio *); extern void __bio_clone_fast(struct bio *, struct bio *); extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *); -extern void __bio_clone(struct bio *, struct bio *); extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs); extern struct bio_set *fs_bio_set; @@ -370,7 +369,6 @@ extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int); extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *, unsigned int, unsigned int); extern int bio_get_nr_vecs(struct block_device *); -extern sector_t bio_sector_offset(struct bio *, unsigned short, unsigned int); extern struct bio *bio_map_user(struct request_queue *, struct block_device *, unsigned long, unsigned int, int, gfp_t); struct sg_iovec; -- 2.20.1