forked from luck/tmp_suning_uos_patched
dm: store dm_target_io in bio front_pad
Use the recently-added bio front_pad field to allocate struct dm_target_io. Prior to this patch, dm_target_io was allocated from a mempool. For each dm_target_io, there is exactly one bio allocated from a bioset. This patch merges these two allocations into one allocation: we create a bioset with front_pad equal to the size of dm_target_io so that every bio allocated from the bioset has sizeof(struct dm_target_io) bytes before it. We allocate a bio and use the bytes before the bio as dm_target_io. _tio_cache is removed and the tio_pool mempool is now only used for request-based devices. This idea was introduced by Kent Overstreet. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: tj@kernel.org Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Bill Pemberton <wfp5p@viridian.itc.virginia.edu> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
parent
4f81a41762
commit
dba141601d
108
drivers/md/dm.c
108
drivers/md/dm.c
@ -71,6 +71,7 @@ struct dm_target_io {
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struct dm_io *io;
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struct dm_target *ti;
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union map_info info;
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struct bio clone;
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};
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/*
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@ -214,7 +215,6 @@ struct dm_md_mempools {
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#define MIN_IOS 256
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static struct kmem_cache *_io_cache;
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static struct kmem_cache *_tio_cache;
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static struct kmem_cache *_rq_tio_cache;
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/*
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@ -232,14 +232,9 @@ static int __init local_init(void)
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if (!_io_cache)
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return r;
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/* allocate a slab for the target ios */
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_tio_cache = KMEM_CACHE(dm_target_io, 0);
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if (!_tio_cache)
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goto out_free_io_cache;
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_rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0);
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if (!_rq_tio_cache)
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goto out_free_tio_cache;
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goto out_free_io_cache;
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_rq_bio_info_cache = KMEM_CACHE(dm_rq_clone_bio_info, 0);
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if (!_rq_bio_info_cache)
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@ -265,8 +260,6 @@ static int __init local_init(void)
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kmem_cache_destroy(_rq_bio_info_cache);
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out_free_rq_tio_cache:
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kmem_cache_destroy(_rq_tio_cache);
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out_free_tio_cache:
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kmem_cache_destroy(_tio_cache);
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out_free_io_cache:
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kmem_cache_destroy(_io_cache);
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@ -277,7 +270,6 @@ static void local_exit(void)
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{
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kmem_cache_destroy(_rq_bio_info_cache);
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kmem_cache_destroy(_rq_tio_cache);
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kmem_cache_destroy(_tio_cache);
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kmem_cache_destroy(_io_cache);
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unregister_blkdev(_major, _name);
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dm_uevent_exit();
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@ -463,7 +455,7 @@ static void free_io(struct mapped_device *md, struct dm_io *io)
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static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
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{
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mempool_free(tio, md->tio_pool);
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bio_put(&tio->clone);
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}
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static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md,
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@ -682,7 +674,6 @@ static void clone_endio(struct bio *bio, int error)
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}
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free_tio(md, tio);
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bio_put(bio);
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dec_pending(io, error);
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}
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@ -1002,12 +993,12 @@ int dm_set_target_max_io_len(struct dm_target *ti, sector_t len)
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}
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EXPORT_SYMBOL_GPL(dm_set_target_max_io_len);
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static void __map_bio(struct dm_target *ti, struct bio *clone,
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struct dm_target_io *tio)
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static void __map_bio(struct dm_target *ti, struct dm_target_io *tio)
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{
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int r;
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sector_t sector;
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struct mapped_device *md;
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struct bio *clone = &tio->clone;
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clone->bi_end_io = clone_endio;
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clone->bi_private = tio;
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@ -1031,7 +1022,6 @@ static void __map_bio(struct dm_target *ti, struct bio *clone,
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/* error the io and bail out, or requeue it if needed */
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md = tio->io->md;
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dec_pending(tio->io, r);
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bio_put(clone);
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free_tio(md, tio);
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} else if (r) {
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DMWARN("unimplemented target map return value: %d", r);
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@ -1052,14 +1042,13 @@ struct clone_info {
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/*
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* Creates a little bio that just does part of a bvec.
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*/
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static struct bio *split_bvec(struct bio *bio, sector_t sector,
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unsigned short idx, unsigned int offset,
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unsigned int len, struct bio_set *bs)
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static void split_bvec(struct dm_target_io *tio, struct bio *bio,
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sector_t sector, unsigned short idx, unsigned int offset,
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unsigned int len, struct bio_set *bs)
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{
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struct bio *clone;
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struct bio *clone = &tio->clone;
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struct bio_vec *bv = bio->bi_io_vec + idx;
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clone = bio_alloc_bioset(GFP_NOIO, 1, bs);
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*clone->bi_io_vec = *bv;
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clone->bi_sector = sector;
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@ -1076,20 +1065,18 @@ static struct bio *split_bvec(struct bio *bio, sector_t sector,
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bio_integrity_trim(clone,
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bio_sector_offset(bio, idx, offset), len);
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}
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return clone;
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}
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/*
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* Creates a bio that consists of range of complete bvecs.
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*/
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static struct bio *clone_bio(struct bio *bio, sector_t sector,
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unsigned short idx, unsigned short bv_count,
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unsigned int len, struct bio_set *bs)
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static void clone_bio(struct dm_target_io *tio, struct bio *bio,
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sector_t sector, unsigned short idx,
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unsigned short bv_count, unsigned int len,
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struct bio_set *bs)
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{
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struct bio *clone;
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struct bio *clone = &tio->clone;
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clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs);
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__bio_clone(clone, bio);
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clone->bi_sector = sector;
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clone->bi_idx = idx;
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@ -1104,14 +1091,16 @@ static struct bio *clone_bio(struct bio *bio, sector_t sector,
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bio_integrity_trim(clone,
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bio_sector_offset(bio, idx, 0), len);
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}
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return clone;
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}
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static struct dm_target_io *alloc_tio(struct clone_info *ci,
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struct dm_target *ti)
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struct dm_target *ti, int nr_iovecs)
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{
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struct dm_target_io *tio = mempool_alloc(ci->md->tio_pool, GFP_NOIO);
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struct dm_target_io *tio;
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struct bio *clone;
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clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, ci->md->bs);
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tio = container_of(clone, struct dm_target_io, clone);
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tio->io = ci->io;
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tio->ti = ti;
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@ -1123,8 +1112,8 @@ static struct dm_target_io *alloc_tio(struct clone_info *ci,
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static void __issue_target_request(struct clone_info *ci, struct dm_target *ti,
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unsigned request_nr, sector_t len)
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{
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struct dm_target_io *tio = alloc_tio(ci, ti);
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struct bio *clone;
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struct dm_target_io *tio = alloc_tio(ci, ti, ci->bio->bi_max_vecs);
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struct bio *clone = &tio->clone;
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tio->info.target_request_nr = request_nr;
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@ -1133,14 +1122,14 @@ static void __issue_target_request(struct clone_info *ci, struct dm_target *ti,
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* ci->bio->bi_max_vecs is BIO_INLINE_VECS anyway, for both flush
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* and discard, so no need for concern about wasted bvec allocations.
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*/
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clone = bio_clone_bioset(ci->bio, GFP_NOIO, ci->md->bs);
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__bio_clone(clone, ci->bio);
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if (len) {
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clone->bi_sector = ci->sector;
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clone->bi_size = to_bytes(len);
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}
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__map_bio(ti, clone, tio);
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__map_bio(ti, tio);
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}
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static void __issue_target_requests(struct clone_info *ci, struct dm_target *ti,
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@ -1169,14 +1158,13 @@ static int __clone_and_map_empty_flush(struct clone_info *ci)
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*/
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static void __clone_and_map_simple(struct clone_info *ci, struct dm_target *ti)
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{
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struct bio *clone, *bio = ci->bio;
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struct bio *bio = ci->bio;
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struct dm_target_io *tio;
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tio = alloc_tio(ci, ti);
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clone = clone_bio(bio, ci->sector, ci->idx,
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bio->bi_vcnt - ci->idx, ci->sector_count,
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ci->md->bs);
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__map_bio(ti, clone, tio);
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tio = alloc_tio(ci, ti, bio->bi_max_vecs);
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clone_bio(tio, bio, ci->sector, ci->idx, bio->bi_vcnt - ci->idx,
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ci->sector_count, ci->md->bs);
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__map_bio(ti, tio);
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ci->sector_count = 0;
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}
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@ -1214,7 +1202,7 @@ static int __clone_and_map_discard(struct clone_info *ci)
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static int __clone_and_map(struct clone_info *ci)
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{
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struct bio *clone, *bio = ci->bio;
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struct bio *bio = ci->bio;
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struct dm_target *ti;
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sector_t len = 0, max;
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struct dm_target_io *tio;
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@ -1254,10 +1242,10 @@ static int __clone_and_map(struct clone_info *ci)
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len += bv_len;
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}
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tio = alloc_tio(ci, ti);
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clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len,
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ci->md->bs);
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__map_bio(ti, clone, tio);
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tio = alloc_tio(ci, ti, bio->bi_max_vecs);
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clone_bio(tio, bio, ci->sector, ci->idx, i - ci->idx, len,
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ci->md->bs);
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__map_bio(ti, tio);
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ci->sector += len;
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ci->sector_count -= len;
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@ -1282,12 +1270,11 @@ static int __clone_and_map(struct clone_info *ci)
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len = min(remaining, max);
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tio = alloc_tio(ci, ti);
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clone = split_bvec(bio, ci->sector, ci->idx,
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bv->bv_offset + offset, len,
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ci->md->bs);
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tio = alloc_tio(ci, ti, 1);
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split_bvec(tio, bio, ci->sector, ci->idx,
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bv->bv_offset + offset, len, ci->md->bs);
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__map_bio(ti, clone, tio);
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__map_bio(ti, tio);
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ci->sector += len;
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ci->sector_count -= len;
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@ -1955,7 +1942,7 @@ static void __bind_mempools(struct mapped_device *md, struct dm_table *t)
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{
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struct dm_md_mempools *p;
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if (md->io_pool && md->tio_pool && md->bs)
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if (md->io_pool && (md->tio_pool || dm_table_get_type(t) == DM_TYPE_BIO_BASED) && md->bs)
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/* the md already has necessary mempools */
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goto out;
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@ -2732,14 +2719,16 @@ struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity)
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if (!pools->io_pool)
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goto free_pools_and_out;
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pools->tio_pool = (type == DM_TYPE_BIO_BASED) ?
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mempool_create_slab_pool(MIN_IOS, _tio_cache) :
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mempool_create_slab_pool(MIN_IOS, _rq_tio_cache);
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if (!pools->tio_pool)
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goto free_io_pool_and_out;
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pools->tio_pool = NULL;
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if (type == DM_TYPE_REQUEST_BASED) {
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pools->tio_pool = mempool_create_slab_pool(MIN_IOS, _rq_tio_cache);
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if (!pools->tio_pool)
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goto free_io_pool_and_out;
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}
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pools->bs = (type == DM_TYPE_BIO_BASED) ?
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bioset_create(pool_size, 0) :
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bioset_create(pool_size,
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offsetof(struct dm_target_io, clone)) :
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bioset_create(pool_size,
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offsetof(struct dm_rq_clone_bio_info, clone));
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if (!pools->bs)
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@ -2754,7 +2743,8 @@ struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity)
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bioset_free(pools->bs);
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free_tio_pool_and_out:
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mempool_destroy(pools->tio_pool);
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if (pools->tio_pool)
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mempool_destroy(pools->tio_pool);
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free_io_pool_and_out:
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mempool_destroy(pools->io_pool);
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