block: Convert drivers to immutable biovecs

Now that we've got a mechanism for immutable biovecs -
bi_iter.bi_bvec_done - we need to convert drivers to use primitives that
respect it instead of using the bvec array directly.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: NeilBrown <neilb@suse.de>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: dm-devel@redhat.com

1 files changed, 11 insertions, 3 deletions

diff --git a/fs/bio.c b/fs/bio.c
index e32f2ffc3f33..a082ce2d197b 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -525,8 +525,17 @@ EXPORT_SYMBOL(bio_phys_segments);
  */
 void __bio_clone(struct bio *bio, struct bio *bio_src)
 {
-	memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
-		bio_src->bi_max_vecs * sizeof(struct bio_vec));
+	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,
@@ -535,7 +544,6 @@ void __bio_clone(struct bio *bio, struct bio *bio_src)
 	bio->bi_bdev = bio_src->bi_bdev;
 	bio->bi_flags |= 1 << BIO_CLONED;
 	bio->bi_rw = bio_src->bi_rw;
-	bio->bi_vcnt = bio_src->bi_vcnt;
 	bio->bi_iter = bio_src->bi_iter;
 }
 EXPORT_SYMBOL(__bio_clone);