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 <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Yehuda Sadeh <yehuda@inktank.com>
Cc: Sage Weil <sage@inktank.com>
Cc: Alex Elder <elder@inktank.com>
Cc: ceph-devel@vger.kernel.org
Cc: Joshua Morris <josh.h.morris@us.ibm.com>
Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: Boaz Harrosh <bharrosh@panasas.com>
Cc: Benny Halevy <bhalevy@tonian.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Dave Kleikamp <shaggy@kernel.org>
Cc: Joern Engel <joern@logfs.org>
Cc: Prasad Joshi <prasadjoshi.linux@gmail.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Ben Myers <bpm@sgi.com>
Cc: xfs@oss.sgi.com
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Guo Chao <yan@linux.vnet.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Asai Thambi S P <asamymuthupa@micron.com>
Cc: Selvan Mani <smani@micron.com>
Cc: Sam Bradshaw <sbradshaw@micron.com>
Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Jerome Marchand <jmarchand@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Peng Tao <tao.peng@emc.com>
Cc: Andy Adamson <andros@netapp.com>
Cc: fanchaoting <fanchaoting@cn.fujitsu.com>
Cc: Jie Liu <jeff.liu@oracle.com>
Cc: Sunil Mushran <sunil.mushran@gmail.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Namjae Jeon <namjae.jeon@samsung.com>
Cc: Pankaj Kumar <pankaj.km@samsung.com>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Mel Gorman <mgorman@suse.de>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 */