dm: Use bvec_iter for dm_bio_record()

This patch doesn't itself have any functional changes, but immutable
biovecs are going to add a bi_bvec_done member to bi_iter, which will
need to be saved too here.
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: dm-devel@redhat.com
Reviewed-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-bio-record.h

@@ -28,11 +28,9 @@ struct dm_bio_vec_details {
 };
 
 struct dm_bio_details {
-	sector_t bi_sector;
 	struct block_device *bi_bdev;
-	unsigned int bi_size;
-	unsigned short bi_idx;
 	unsigned long bi_flags;
+	struct bvec_iter bi_iter;
 	struct dm_bio_vec_details bi_io_vec[BIO_MAX_PAGES];
 };
 
@@ -40,11 +38,9 @@ static inline void dm_bio_record(struct dm_bio_details *bd, struct bio *bio)
 {
 	unsigned i;
 
-	bd->bi_sector = bio->bi_iter.bi_sector;
 	bd->bi_bdev = bio->bi_bdev;
-	bd->bi_size = bio->bi_iter.bi_size;
-	bd->bi_idx = bio->bi_iter.bi_idx;
 	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;
@@ -56,11 +52,9 @@ static inline void dm_bio_restore(struct dm_bio_details *bd, struct bio *bio)
 {
 	unsigned i;
 
-	bio->bi_iter.bi_sector = bd->bi_sector;
 	bio->bi_bdev = bd->bi_bdev;
-	bio->bi_iter.bi_size = bd->bi_size;
-	bio->bi_iter.bi_idx = bd->bi_idx;
 	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;