block: Convert bio_for_each_segment() to bvec_iter

More prep work for immutable biovecs - with immutable bvecs drivers
won't be able to use the biovec directly, they'll need to use helpers
that take into account bio->bi_iter.bi_bvec_done.

This updates callers for the new usage without changing the
implementation yet.

Signed-off-by: Kent Overstreet <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: "Ed L. Cashin" <[email protected]>
Cc: Nick Piggin <[email protected]>
Cc: Lars Ellenberg <[email protected]>
Cc: Jiri Kosina <[email protected]>
Cc: Paul Clements <[email protected]>
Cc: Jim Paris <[email protected]>
Cc: Geoff Levand <[email protected]>
Cc: Yehuda Sadeh <[email protected]>
Cc: Sage Weil <[email protected]>
Cc: Alex Elder <[email protected]>
Cc: [email protected]
Cc: Joshua Morris <[email protected]>
Cc: Philip Kelleher <[email protected]>
Cc: Konrad Rzeszutek Wilk <[email protected]>
Cc: Jeremy Fitzhardinge <[email protected]>
Cc: Neil Brown <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: [email protected]
Cc: Nagalakshmi Nandigama <[email protected]>
Cc: Sreekanth Reddy <[email protected]>
Cc: [email protected]
Cc: "James E.J. Bottomley" <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: Steven Whitehouse <[email protected]>
Cc: Herton Ronaldo Krzesinski <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Guo Chao <[email protected]>
Cc: Asai Thambi S P <[email protected]>
Cc: Selvan Mani <[email protected]>
Cc: Sam Bradshaw <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Keith Busch <[email protected]>
Cc: Stephen Hemminger <[email protected]>
Cc: Quoc-Son Anh <[email protected]>
Cc: Sebastian Ott <[email protected]>
Cc: Nitin Gupta <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Jerome Marchand <[email protected]>
Cc: Seth Jennings <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Mike Snitzer <[email protected]>
Cc: Vivek Goyal <[email protected]>
Cc: "Darrick J. Wong" <[email protected]>
Cc: Chris Metcalf <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Acked-by: Geoff Levand <[email protected]>

2 files changed, 18 insertions, 17 deletions

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 9f182fcbe714..c16adb5f69f8 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -63,10 +63,13 @@
  */
 #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_iovec(bio)		(*__bio_iovec(bio))
+
+#define bio_iter_iovec(bio, iter) ((bio)->bi_io_vec[(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(bio))
+
 #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)))
@@ -134,15 +137,6 @@ static inline void *bio_data(struct bio *bio)
 #define bio_io_error(bio) bio_endio((bio), -EIO)
 
 /*
- * drivers should not use the __ version unless they _really_ know what
- * they're doing
- */
-#define __bio_for_each_segment(bvl, bio, i, start_idx)			\
-	for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx);	\
-	     i < (bio)->bi_vcnt;					\
-	     bvl++, i++)
-
-/*
  * drivers should _never_ use the all version - the bio may have been split
  * before it got to the driver and the driver won't own all of it
  */
@@ -151,10 +145,16 @@ static inline void *bio_data(struct bio *bio)
 	     bvl = bio_iovec_idx((bio), (i)), i < (bio)->bi_vcnt;	\
 	     i++)
 
-#define bio_for_each_segment(bvl, bio, i)				\
-	for (i = (bio)->bi_iter.bi_idx;					\
-	     bvl = bio_iovec_idx((bio), (i)), i < (bio)->bi_vcnt;	\
-	     i++)
+#define __bio_for_each_segment(bvl, bio, iter, start)			\
+	for (iter = (start);						\
+	     bvl = bio_iter_iovec((bio), (iter)),			\
+	     (iter).bi_idx < (bio)->bi_vcnt;				\
+	     (iter).bi_idx++)
+
+#define bio_for_each_segment(bvl, bio, iter)				\
+	__bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
+
+#define bio_iter_last(bio, iter) ((iter).bi_idx == (bio)->bi_vcnt - 1)
 
 /*
  * get a reference to a bio, so it won't disappear. the intended use is
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 1b135d49b279..337b92a54658 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -735,7 +735,7 @@ struct rq_map_data {
 };
 
 struct req_iterator {
-	int i;
+	struct bvec_iter iter;
 	struct bio *bio;
 };
 
@@ -748,10 +748,11 @@ struct req_iterator {
 
 #define rq_for_each_segment(bvl, _rq, _iter)			\
 	__rq_for_each_bio(_iter.bio, _rq)			\
-		bio_for_each_segment(bvl, _iter.bio, _iter.i)
+		bio_for_each_segment(bvl, _iter.bio, _iter.iter)
 
 #define rq_iter_last(rq, _iter)					\
-		(_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
+		(_iter.bio->bi_next == NULL &&			\
+		 bio_iter_last(_iter.bio, _iter.iter))
 
 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 # error	"You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"