block: Convert bio_iovec() to bvec_iter

For immutable biovecs, we'll be introducing a new bio_iovec() that uses
our new bvec iterator to construct a biovec, taking into account
bvec_iter->bi_bvec_done - this patch updates existing users for the new
usage.

Some of the existing users really do need a pointer into the bvec array
- those uses are all going to be removed, but we'll need the
functionality from immutable to remove them - so for now rename the
existing bio_iovec() -> __bio_iovec(), and it'll be removed in a couple
patches.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: dm-devel@redhat.com
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/include/linux/bio.h b/include/linux/bio.h
index e2e0bc642ed1..9f182fcbe714 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -62,9 +62,11 @@
  * on highmem page vectors
  */
 #define bio_iovec_idx(bio, idx) (&((bio)->bi_io_vec[(idx)]))
-#define bio_iovec(bio)          bio_iovec_idx((bio), (bio)->bi_iter.bi_idx)
-#define bio_page(bio)           bio_iovec((bio))->bv_page
-#define bio_offset(bio)         bio_iovec((bio))->bv_offset
+#define __bio_iovec(bio)        bio_iovec_idx((bio), (bio)->bi_iter.bi_idx)
+#define bio_iovec(bio)          (*__bio_iovec(bio))
+
+#define bio_page(bio)           (bio_iovec((bio)).bv_page)
+#define bio_offset(bio)         (bio_iovec((bio)).bv_offset)
 #define bio_segments(bio)       ((bio)->bi_vcnt - (bio)->bi_iter.bi_idx)
 #define bio_sectors(bio)        ((bio)->bi_iter.bi_size >> 9)
 #define bio_end_sector(bio)     ((bio)->bi_iter.bi_sector + bio_sectors((bio)))
@@ -72,7 +74,7 @@
 static inline unsigned int bio_cur_bytes(struct bio *bio)
 {
         if (bio->bi_vcnt)
-                return bio_iovec(bio)->bv_len;
+                return bio_iovec(bio).bv_len;
         else /* dataless requests such as discard */
                 return bio->bi_iter.bi_size;
 }