block: Abstract out bvec iterator

Immutable biovecs are going to require an explicit iterator. To
implement immutable bvecs, a later patch is going to add a bi_bvec_done
member to this struct; for now, this patch effectively just renames
things.

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: Matthew Wilcox <[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: Rusty Russell <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Konrad Rzeszutek Wilk <[email protected]>
Cc: Jeremy Fitzhardinge <[email protected]>
Cc: Neil Brown <[email protected]>
Cc: Alasdair Kergon <[email protected]>
Cc: Mike Snitzer <[email protected]>
Cc: [email protected]
Cc: Martin Schwidefsky <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: [email protected]
Cc: Boaz Harrosh <[email protected]>
Cc: Benny Halevy <[email protected]>
Cc: "James E.J. Bottomley" <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: "Nicholas A. Bellinger" <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: Chris Mason <[email protected]>
Cc: "Theodore Ts'o" <[email protected]>
Cc: Andreas Dilger <[email protected]>
Cc: Jaegeuk Kim <[email protected]>
Cc: Steven Whitehouse <[email protected]>
Cc: Dave Kleikamp <[email protected]>
Cc: Joern Engel <[email protected]>
Cc: Prasad Joshi <[email protected]>
Cc: Trond Myklebust <[email protected]>
Cc: KONISHI Ryusuke <[email protected]>
Cc: Mark Fasheh <[email protected]>
Cc: Joel Becker <[email protected]>
Cc: Ben Myers <[email protected]>
Cc: [email protected]
Cc: Steven Rostedt <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Pavel Machek <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Herton Ronaldo Krzesinski <[email protected]>
Cc: Ben Hutchings <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Guo Chao <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Asai Thambi S P <[email protected]>
Cc: Selvan Mani <[email protected]>
Cc: Sam Bradshaw <[email protected]>
Cc: Wei Yongjun <[email protected]>
Cc: "Roger Pau Monné" <[email protected]>
Cc: Jan Beulich <[email protected]>
Cc: Stefano Stabellini <[email protected]>
Cc: Ian Campbell <[email protected]>
Cc: Sebastian Ott <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Jiang Liu <[email protected]>
Cc: Nitin Gupta <[email protected]>
Cc: Jerome Marchand <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Peng Tao <[email protected]>
Cc: Andy Adamson <[email protected]>
Cc: fanchaoting <[email protected]>
Cc: Jie Liu <[email protected]>
Cc: Sunil Mushran <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Namjae Jeon <[email protected]>
Cc: Pankaj Kumar <[email protected]>
Cc: Dan Magenheimer <[email protected]>
Cc: Mel Gorman <[email protected]>6

2 files changed, 20 insertions, 15 deletions

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 060ff695085c..e2e0bc642ed1 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -62,19 +62,19 @@
  * 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_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_segments(bio)	((bio)->bi_vcnt - (bio)->bi_idx)
-#define bio_sectors(bio)	((bio)->bi_size >> 9)
-#define bio_end_sector(bio)	((bio)->bi_sector + bio_sectors((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)))
 
 static inline unsigned int bio_cur_bytes(struct bio *bio)
 {
 	if (bio->bi_vcnt)
 		return bio_iovec(bio)->bv_len;
 	else /* dataless requests such as discard */
-		return bio->bi_size;
+		return bio->bi_iter.bi_size;
 }
 
 static inline void *bio_data(struct bio *bio)
@@ -108,7 +108,7 @@ static inline void *bio_data(struct bio *bio)
  */
 
 #define __BVEC_END(bio)		bio_iovec_idx((bio), (bio)->bi_vcnt - 1)
-#define __BVEC_START(bio)	bio_iovec_idx((bio), (bio)->bi_idx)
+#define __BVEC_START(bio)	bio_iovec_idx((bio), (bio)->bi_iter.bi_idx)
 
 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)	\
@@ -150,7 +150,7 @@ static inline void *bio_data(struct bio *bio)
 	     i++)
 
 #define bio_for_each_segment(bvl, bio, i)				\
-	for (i = (bio)->bi_idx;						\
+	for (i = (bio)->bi_iter.bi_idx;					\
 	     bvl = bio_iovec_idx((bio), (i)), i < (bio)->bi_vcnt;	\
 	     i++)
 
@@ -365,7 +365,7 @@ static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
 #define __bio_kunmap_irq(buf, flags)	bvec_kunmap_irq(buf, flags)
 
 #define bio_kmap_irq(bio, flags) \
-	__bio_kmap_irq((bio), (bio)->bi_idx, (flags))
+	__bio_kmap_irq((bio), (bio)->bi_iter.bi_idx, (flags))
 #define bio_kunmap_irq(buf,flags)	__bio_kunmap_irq(buf, flags)
 
 /*
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 238ef0ed62f8..29b5b84d8a29 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -28,13 +28,19 @@ struct bio_vec {
 	unsigned int	bv_offset;
 };
 
+struct bvec_iter {
+	sector_t		bi_sector;	/* device address in 512 byte
+						   sectors */
+	unsigned int		bi_size;	/* residual I/O count */
+
+	unsigned int		bi_idx;		/* current index into bvl_vec */
+};
+
 /*
  * main unit of I/O for the block layer and lower layers (ie drivers and
  * stacking drivers)
  */
 struct bio {
-	sector_t		bi_sector;	/* device address in 512 byte
-						   sectors */
 	struct bio		*bi_next;	/* request queue link */
 	struct block_device	*bi_bdev;
 	unsigned long		bi_flags;	/* status, command, etc */
@@ -42,16 +48,13 @@ struct bio {
 						 * top bits priority
 						 */
 
-	unsigned short		bi_vcnt;	/* how many bio_vec's */
-	unsigned short		bi_idx;		/* current index into bvl_vec */
+	struct bvec_iter	bi_iter;
 
 	/* Number of segments in this BIO after
 	 * physical address coalescing is performed.
 	 */
 	unsigned int		bi_phys_segments;
 
-	unsigned int		bi_size;	/* residual I/O count */
-
 	/*
 	 * To keep track of the max segment size, we account for the
 	 * sizes of the first and last mergeable segments in this bio.
@@ -74,11 +77,13 @@ struct bio {
 	struct bio_integrity_payload *bi_integrity;  /* data integrity */
 #endif
 
+	unsigned short		bi_vcnt;	/* how many bio_vec's */
+
 	/*
 	 * Everything starting with bi_max_vecs will be preserved by bio_reset()
 	 */
 
-	unsigned int		bi_max_vecs;	/* max bvl_vecs we can hold */
+	unsigned short		bi_max_vecs;	/* max bvl_vecs we can hold */
 
 	atomic_t		bi_cnt;		/* pin count */