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 <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: Paul Clements <Paul.Clements@steeleye.com>
Cc: Jim Paris <jim@jtan.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: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: Nagalakshmi Nandigama <Nagalakshmi.Nandigama@lsi.com>
Cc: Sreekanth Reddy <Sreekanth.Reddy@lsi.com>
Cc: support@lsi.com
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Guo Chao <yan@linux.vnet.ibm.com>
Cc: Asai Thambi S P <asamymuthupa@micron.com>
Cc: Selvan Mani <smani@micron.com>
Cc: Sam Bradshaw <sbradshaw@micron.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Quoc-Son Anh <quoc-sonx.anh@intel.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Jan Kara <jack@suse.cz>
Cc: linux-m68k@lists.linux-m68k.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: drbd-user@lists.linbit.com
Cc: nbd-general@lists.sourceforge.net
Cc: cbe-oss-dev@lists.ozlabs.org
Cc: xen-devel@lists.xensource.com
Cc: virtualization@lists.linux-foundation.org
Cc: linux-raid@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: DL-MPTFusionLinux@lsi.com
Cc: linux-scsi@vger.kernel.org
Cc: devel@driverdev.osuosl.org
Cc: linux-fsdevel@vger.kernel.org
Cc: cluster-devel@redhat.com
Cc: linux-mm@kvack.org
Acked-by: Geoff Levand <geoff@infradead.org>

1 files changed, 23 insertions, 26 deletions

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 03bc083c28cf..a1ead9049ed6 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -12,10 +12,11 @@
 static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
                                              struct bio *bio)
 {
-        struct bio_vec *bv, *bvprv = NULL;
-        int cluster, i, high, highprv = 1;
+        struct bio_vec bv, bvprv = { NULL };
+        int cluster, high, highprv = 1;
         unsigned int seg_size, nr_phys_segs;
         struct bio *fbio, *bbio;
+        struct bvec_iter iter;
 
         if (!bio)
                 return 0;
@@ -25,25 +26,23 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
         seg_size = 0;
         nr_phys_segs = 0;
         for_each_bio(bio) {
-                bio_for_each_segment(bv, bio, i) {
+                bio_for_each_segment(bv, bio, iter) {
                         /*
                          * the trick here is making sure that a high page is
                          * never considered part of another segment, since that
                          * might change with the bounce page.
                          */
-                        high = page_to_pfn(bv->bv_page) > queue_bounce_pfn(q);
-                        if (high || highprv)
-                                goto new_segment;
-                        if (cluster) {
-                                if (seg_size + bv->bv_len
+                        high = page_to_pfn(bv.bv_page) > queue_bounce_pfn(q);
+                        if (!high && !highprv && cluster) {
+                                if (seg_size + bv.bv_len
                                     > queue_max_segment_size(q))
                                         goto new_segment;
-                                if (!BIOVEC_PHYS_MERGEABLE(bvprv, bv))
+                                if (!BIOVEC_PHYS_MERGEABLE(&bvprv, &bv))
                                         goto new_segment;
-                                if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bv))
+                                if (!BIOVEC_SEG_BOUNDARY(q, &bvprv, &bv))
                                         goto new_segment;
 
-                                seg_size += bv->bv_len;
+                                seg_size += bv.bv_len;
                                 bvprv = bv;
                                 continue;
                         }
@@ -54,7 +53,7 @@ new_segment:
 
                         nr_phys_segs++;
                         bvprv = bv;
-                        seg_size = bv->bv_len;
+                        seg_size = bv.bv_len;
                         highprv = high;
                 }
                 bbio = bio;
@@ -110,21 +109,21 @@ static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio,
         return 0;
 }
 
-static void
+static inline void
 __blk_segment_map_sg(struct request_queue *q, struct bio_vec *bvec,
-                     struct scatterlist *sglist, struct bio_vec **bvprv,
+                     struct scatterlist *sglist, struct bio_vec *bvprv,
                      struct scatterlist **sg, int *nsegs, int *cluster)
 {
 
         int nbytes = bvec->bv_len;
 
-        if (*bvprv && *cluster) {
+        if (*sg && *cluster) {
                 if ((*sg)->length + nbytes > queue_max_segment_size(q))
                         goto new_segment;
 
-                if (!BIOVEC_PHYS_MERGEABLE(*bvprv, bvec))
+                if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec))
                         goto new_segment;
-                if (!BIOVEC_SEG_BOUNDARY(q, *bvprv, bvec))
+                if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec))
                         goto new_segment;
 
                 (*sg)->length += nbytes;
@@ -150,7 +149,7 @@ new_segment:
                 sg_set_page(*sg, bvec->bv_page, nbytes, bvec->bv_offset);
                 (*nsegs)++;
         }
-        *bvprv = bvec;
+        *bvprv = *bvec;
 }
 
 /*
@@ -160,7 +159,7 @@ new_segment:
 int blk_rq_map_sg(struct request_queue *q, struct request *rq,
                   struct scatterlist *sglist)
 {
-        struct bio_vec *bvec, *bvprv;
+        struct bio_vec bvec, bvprv;
         struct req_iterator iter;
         struct scatterlist *sg;
         int nsegs, cluster;
@@ -171,10 +170,9 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,
         /*
          * for each bio in rq
          */
-        bvprv = NULL;
         sg = NULL;
         rq_for_each_segment(bvec, rq, iter) {
-                __blk_segment_map_sg(q, bvec, sglist, &bvprv, &sg,
+                __blk_segment_map_sg(q, &bvec, sglist, &bvprv, &sg,
                                      &nsegs, &cluster);
         } /* segments in rq */
 
@@ -223,18 +221,17 @@ EXPORT_SYMBOL(blk_rq_map_sg);
 int blk_bio_map_sg(struct request_queue *q, struct bio *bio,
                    struct scatterlist *sglist)
 {
-        struct bio_vec *bvec, *bvprv;
+        struct bio_vec bvec, bvprv;
         struct scatterlist *sg;
         int nsegs, cluster;
-        unsigned long i;
+        struct bvec_iter iter;
 
         nsegs = 0;
         cluster = blk_queue_cluster(q);
 
-        bvprv = NULL;
         sg = NULL;
-        bio_for_each_segment(bvec, bio, i) {
-                __blk_segment_map_sg(q, bvec, sglist, &bvprv, &sg,
+        bio_for_each_segment(bvec, bio, iter) {
+                __blk_segment_map_sg(q, &bvec, sglist, &bvprv, &sg,
                                      &nsegs, &cluster);
         } /* segments in bio */