dm: use dm_target_offset macro

Use new dm_target_offset() macro to avoid most references to ti->begin
in dm targets.
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

drivers/md/dm-crypt.c

@@ -1284,7 +1284,7 @@ static int crypt_map(struct dm_target *ti, struct bio *bio,
 		return DM_MAPIO_REMAPPED;
 	}
 
-	io = crypt_io_alloc(ti, bio, bio->bi_sector - ti->begin);
+	io = crypt_io_alloc(ti, bio, dm_target_offset(ti, bio->bi_sector));
 
 	if (bio_data_dir(io->base_bio) == READ)
 		kcryptd_queue_io(io);
@@ -1406,7 +1406,7 @@ static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
 		return max_size;
 
 	bvm->bi_bdev = cc->dev->bdev;
-	bvm->bi_sector = cc->start + bvm->bi_sector - ti->begin;
+	bvm->bi_sector = cc->start + dm_target_offset(ti, bvm->bi_sector);
 
 	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
 }

drivers/md/dm-delay.c

@@ -281,14 +281,13 @@ static int delay_map(struct dm_target *ti, struct bio *bio,
 		bio->bi_bdev = dc->dev_write->bdev;
 		if (bio_sectors(bio))
 			bio->bi_sector = dc->start_write +
-					 (bio->bi_sector - ti->begin);
+					 dm_target_offset(ti, bio->bi_sector);
 
 		return delay_bio(dc, dc->write_delay, bio);
 	}
 
 	bio->bi_bdev = dc->dev_read->bdev;
-	bio->bi_sector = dc->start_read +
-			 (bio->bi_sector - ti->begin);
+	bio->bi_sector = dc->start_read + dm_target_offset(ti, bio->bi_sector);
 
 	return delay_bio(dc, dc->read_delay, bio);
 }

drivers/md/dm-linear.c

@@ -74,7 +74,7 @@ static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector)
 {
 	struct linear_c *lc = ti->private;
 
-	return lc->start + (bi_sector - ti->begin);
+	return lc->start + dm_target_offset(ti, bi_sector);
 }
 
 static void linear_map_bio(struct dm_target *ti, struct bio *bio)

drivers/md/dm-raid1.c

@@ -445,7 +445,7 @@ static sector_t map_sector(struct mirror *m, struct bio *bio)
 {
 	if (unlikely(!bio->bi_size))
 		return 0;
-	return m->offset + (bio->bi_sector - m->ms->ti->begin);
+	return m->offset + dm_target_offset(m->ms->ti, bio->bi_sector);
 }
 
 static void map_bio(struct mirror *m, struct bio *bio)

drivers/md/dm-stripe.c

@@ -222,7 +222,7 @@ static int stripe_map(struct dm_target *ti, struct bio *bio,
 		return DM_MAPIO_REMAPPED;
 	}
 
-	offset = bio->bi_sector - ti->begin;
+	offset = dm_target_offset(ti, bio->bi_sector);
 	chunk = offset >> sc->chunk_shift;
 	stripe = sector_div(chunk, sc->stripes);