block: Consolidate duplicated bio_trim() implementations

Someone cut and pasted md's md_trim_bio() into xen-blkfront.c. Come on,
we should know better than this.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Neil Brown <neilb@suse.de>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

7 files changed, 61 insertions, 108 deletions

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index a4660bbee8a6..8d53ed293606 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1336,57 +1336,6 @@ static int blkfront_probe(struct xenbus_device *dev,
         return 0;
 }
 
-/*
- * This is a clone of md_trim_bio, used to split a bio into smaller ones
- */
-static void trim_bio(struct bio *bio, int offset, int size)
-{
-        /* 'bio' is a cloned bio which we need to trim to match
-         * the given offset and size.
-         * This requires adjusting bi_sector, bi_size, and bi_io_vec
-         */
-        int i;
-        struct bio_vec *bvec;
-        int sofar = 0;
-
-        size <<= 9;
-        if (offset == 0 && size == bio->bi_size)
-                return;
-
-        bio->bi_sector += offset;
-        bio->bi_size = size;
-        offset <<= 9;
-        clear_bit(BIO_SEG_VALID, &bio->bi_flags);
-
-        while (bio->bi_idx < bio->bi_vcnt &&
-               bio->bi_io_vec[bio->bi_idx].bv_len <= offset) {
-                /* remove this whole bio_vec */
-                offset -= bio->bi_io_vec[bio->bi_idx].bv_len;
-                bio->bi_idx++;
-        }
-        if (bio->bi_idx < bio->bi_vcnt) {
-                bio->bi_io_vec[bio->bi_idx].bv_offset += offset;
-                bio->bi_io_vec[bio->bi_idx].bv_len -= offset;
-        }
-        /* avoid any complications with bi_idx being non-zero*/
-        if (bio->bi_idx) {
-                memmove(bio->bi_io_vec, bio->bi_io_vec+bio->bi_idx,
-                        (bio->bi_vcnt - bio->bi_idx) * sizeof(struct bio_vec));
-                bio->bi_vcnt -= bio->bi_idx;
-                bio->bi_idx = 0;
-        }
-        /* Make sure vcnt and last bv are not too big */
-        bio_for_each_segment(bvec, bio, i) {
-                if (sofar + bvec->bv_len > size)
-                        bvec->bv_len = size - sofar;
-                if (bvec->bv_len == 0) {
-                        bio->bi_vcnt = i;
-                        break;
-                }
-                sofar += bvec->bv_len;
-        }
-}
-
 static void split_bio_end(struct bio *bio, int error)
 {
         struct split_bio *split_bio = bio->bi_private;
@@ -1522,7 +1471,7 @@ static int blkif_recover(struct blkfront_info *info)
                                            (unsigned int)(bio->bi_size >> 9) - offset);
                                 cloned_bio = bio_clone(bio, GFP_NOIO);
                                 BUG_ON(cloned_bio == NULL);
-                                trim_bio(cloned_bio, offset, size);
+                                bio_trim(cloned_bio, offset, size);
                                 cloned_bio->bi_private = split_bio;
                                 cloned_bio->bi_end_io = split_bio_end;
                                 submit_bio(cloned_bio->bi_rw, cloned_bio);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 561a65f82e26..752119068d66 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -183,46 +183,6 @@ struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
 }
 EXPORT_SYMBOL_GPL(bio_clone_mddev);
 
-void md_trim_bio(struct bio *bio, int offset, int size)
-{
-        /* 'bio' is a cloned bio which we need to trim to match
-         * the given offset and size.
-         * This requires adjusting bi_sector, bi_size, and bi_io_vec
-         */
-        int i;
-        struct bio_vec *bvec;
-        int sofar = 0;
-
-        size <<= 9;
-        if (offset == 0 && size == bio->bi_size)
-                return;
-
-        clear_bit(BIO_SEG_VALID, &bio->bi_flags);
-
-        bio_advance(bio, offset << 9);
-
-        bio->bi_size = size;
-
-        /* avoid any complications with bi_idx being non-zero*/
-        if (bio->bi_idx) {
-                memmove(bio->bi_io_vec, bio->bi_io_vec+bio->bi_idx,
-                        (bio->bi_vcnt - bio->bi_idx) * sizeof(struct bio_vec));
-                bio->bi_vcnt -= bio->bi_idx;
-                bio->bi_idx = 0;
-        }
-        /* Make sure vcnt and last bv are not too big */
-        bio_for_each_segment(bvec, bio, i) {
-                if (sofar + bvec->bv_len > size)
-                        bvec->bv_len = size - sofar;
-                if (bvec->bv_len == 0) {
-                        bio->bi_vcnt = i;
-                        break;
-                }
-                sofar += bvec->bv_len;
-        }
-}
-EXPORT_SYMBOL_GPL(md_trim_bio);
-
 /*
  * We have a system wide 'event count' that is incremented
  * on any 'interesting' event, and readers of /proc/mdstat
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 608050c43f17..c96456c16700 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -617,7 +617,6 @@ extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
                                    struct mddev *mddev);
 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
                                    struct mddev *mddev);
-extern void md_trim_bio(struct bio *bio, int offset, int size);
 
 extern void md_unplug(struct blk_plug_cb *cb, bool from_schedule);
 static inline int mddev_check_plugged(struct mddev *mddev)
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index aacf6bf352d8..af6681b19776 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1097,8 +1097,8 @@ read_again:
                 r1_bio->read_disk = rdisk;
 
                 read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
-                md_trim_bio(read_bio, r1_bio->sector - bio->bi_sector,
-                            max_sectors);
+                bio_trim(read_bio, r1_bio->sector - bio->bi_sector,
+                         max_sectors);
 
                 r1_bio->bios[rdisk] = read_bio;
 
@@ -1266,7 +1266,7 @@ read_again:
                         continue;
 
                 mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
-                md_trim_bio(mbio, r1_bio->sector - bio->bi_sector, max_sectors);
+                bio_trim(mbio, r1_bio->sector - bio->bi_sector, max_sectors);
 
                 if (first_clone) {
                         /* do behind I/O ?
@@ -2126,7 +2126,7 @@ static int narrow_write_error(struct r1bio *r1_bio, int i)
                 wbio->bi_sector = r1_bio->sector;
                 wbio->bi_size = r1_bio->sectors << 9;
 
-                md_trim_bio(wbio, sector - r1_bio->sector, sectors);
+                bio_trim(wbio, sector - r1_bio->sector, sectors);
                 wbio->bi_sector += rdev->data_offset;
                 wbio->bi_bdev = rdev->bdev;
                 if (submit_bio_wait(WRITE, wbio) == 0)
@@ -2241,7 +2241,7 @@ read_more:
                 }
                 r1_bio->read_disk = disk;
                 bio = bio_clone_mddev(r1_bio->master_bio, GFP_NOIO, mddev);
-                md_trim_bio(bio, r1_bio->sector - bio->bi_sector, max_sectors);
+                bio_trim(bio, r1_bio->sector - bio->bi_sector, max_sectors);
                 r1_bio->bios[r1_bio->read_disk] = bio;
                 rdev = conf->mirrors[disk].rdev;
                 printk_ratelimited(KERN_ERR
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 73dc8a377522..7c3508abb5e1 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1302,8 +1302,8 @@ read_again:
                 slot = r10_bio->read_slot;
 
                 read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
-                md_trim_bio(read_bio, r10_bio->sector - bio->bi_sector,
-                            max_sectors);
+                bio_trim(read_bio, r10_bio->sector - bio->bi_sector,
+                         max_sectors);
 
                 r10_bio->devs[slot].bio = read_bio;
                 r10_bio->devs[slot].rdev = rdev;
@@ -1510,8 +1510,8 @@ retry_write:
                 if (r10_bio->devs[i].bio) {
                         struct md_rdev *rdev = conf->mirrors[d].rdev;
                         mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
-                        md_trim_bio(mbio, r10_bio->sector - bio->bi_sector,
-                                    max_sectors);
+                        bio_trim(mbio, r10_bio->sector - bio->bi_sector,
+                                 max_sectors);
                         r10_bio->devs[i].bio = mbio;
 
                         mbio->bi_sector = (r10_bio->devs[i].addr+
@@ -1553,8 +1553,8 @@ retry_write:
                                 rdev = conf->mirrors[d].rdev;
                         }
                         mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
-                        md_trim_bio(mbio, r10_bio->sector - bio->bi_sector,
-                                    max_sectors);
+                        bio_trim(mbio, r10_bio->sector - bio->bi_sector,
+                                 max_sectors);
                         r10_bio->devs[i].repl_bio = mbio;
 
                         mbio->bi_sector = (r10_bio->devs[i].addr +
@@ -2614,7 +2614,7 @@ static int narrow_write_error(struct r10bio *r10_bio, int i)
                         sectors = sect_to_write;
                 /* Write at 'sector' for 'sectors' */
                 wbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
-                md_trim_bio(wbio, sector - bio->bi_sector, sectors);
+                bio_trim(wbio, sector - bio->bi_sector, sectors);
                 wbio->bi_sector = (r10_bio->devs[i].addr+
                                    choose_data_offset(r10_bio, rdev) +
                                    (sector - r10_bio->sector));
@@ -2687,9 +2687,7 @@ read_more:
                 (unsigned long long)r10_bio->sector);
         bio = bio_clone_mddev(r10_bio->master_bio,
                               GFP_NOIO, mddev);
-        md_trim_bio(bio,
-                    r10_bio->sector - bio->bi_sector,
-                    max_sectors);
+        bio_trim(bio, r10_bio->sector - bio->bi_sector, max_sectors);
         r10_bio->devs[slot].bio = bio;
         r10_bio->devs[slot].rdev = rdev;
         bio->bi_sector = r10_bio->devs[slot].addr
diff --git a/fs/bio.c b/fs/bio.c
index ea5035da4d9a..2bdb4e25ee77 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -1805,6 +1805,52 @@ struct bio_pair *bio_split(struct bio *bi, int first_sectors)
 EXPORT_SYMBOL(bio_split);
 
 /**
+ * bio_trim - trim a bio
+ * @bio:        bio to trim
+ * @offset:     number of sectors to trim from the front of @bio
+ * @size:       size we want to trim @bio to, in sectors
+ */
+void bio_trim(struct bio *bio, int offset, int size)
+{
+        /* 'bio' is a cloned bio which we need to trim to match
+         * the given offset and size.
+         * This requires adjusting bi_sector, bi_size, and bi_io_vec
+         */
+        int i;
+        struct bio_vec *bvec;
+        int sofar = 0;
+
+        size <<= 9;
+        if (offset == 0 && size == bio->bi_size)
+                return;
+
+        clear_bit(BIO_SEG_VALID, &bio->bi_flags);
+
+        bio_advance(bio, offset << 9);
+
+        bio->bi_size = size;
+
+        /* avoid any complications with bi_idx being non-zero*/
+        if (bio->bi_idx) {
+                memmove(bio->bi_io_vec, bio->bi_io_vec+bio->bi_idx,
+                        (bio->bi_vcnt - bio->bi_idx) * sizeof(struct bio_vec));
+                bio->bi_vcnt -= bio->bi_idx;
+                bio->bi_idx = 0;
+        }
+        /* Make sure vcnt and last bv are not too big */
+        bio_for_each_segment(bvec, bio, i) {
+                if (sofar + bvec->bv_len > size)
+                        bvec->bv_len = size - sofar;
+                if (bvec->bv_len == 0) {
+                        bio->bi_vcnt = i;
+                        break;
+                }
+                sofar += bvec->bv_len;
+        }
+}
+EXPORT_SYMBOL_GPL(bio_trim);
+
+/**
  *      bio_sector_offset - Find hardware sector offset in bio
  *      @bio:           bio to inspect
  *      @index:         bio_vec index
diff --git a/include/linux/bio.h b/include/linux/bio.h
index ec48bac5b039..162036aca741 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -218,6 +218,7 @@ struct bio_pair {
 };
 extern struct bio_pair *bio_split(struct bio *bi, int first_sectors);
 extern void bio_pair_release(struct bio_pair *dbio);
+extern void bio_trim(struct bio *bio, int offset, int size);
 
 extern struct bio_set *bioset_create(unsigned int, unsigned int);
 extern void bioset_free(struct bio_set *);