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-rw-r--r--drivers/md/dm.c44
-rw-r--r--include/linux/device-mapper.h6
-rw-r--r--include/linux/dm-ioctl.h4
3 files changed, 52 insertions, 2 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index efe96907492..bca448e1187 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -829,6 +829,49 @@ static int __split_bio(struct mapped_device *md, struct bio *bio)
* CRUD END
*---------------------------------------------------------------*/
+static int dm_merge_bvec(struct request_queue *q,
+ struct bvec_merge_data *bvm,
+ struct bio_vec *biovec)
+{
+ struct mapped_device *md = q->queuedata;
+ struct dm_table *map = dm_get_table(md);
+ struct dm_target *ti;
+ sector_t max_sectors;
+ int max_size;
+
+ if (unlikely(!map))
+ return 0;
+
+ ti = dm_table_find_target(map, bvm->bi_sector);
+
+ /*
+ * Find maximum amount of I/O that won't need splitting
+ */
+ max_sectors = min(max_io_len(md, bvm->bi_sector, ti),
+ (sector_t) BIO_MAX_SECTORS);
+ max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
+ if (max_size < 0)
+ max_size = 0;
+
+ /*
+ * merge_bvec_fn() returns number of bytes
+ * it can accept at this offset
+ * max is precomputed maximal io size
+ */
+ if (max_size && ti->type->merge)
+ max_size = ti->type->merge(ti, bvm, biovec, max_size);
+
+ /*
+ * Always allow an entire first page
+ */
+ if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
+ max_size = biovec->bv_len;
+
+ dm_table_put(map);
+
+ return max_size;
+}
+
/*
* The request function that just remaps the bio built up by
* dm_merge_bvec.
@@ -1032,6 +1075,7 @@ static struct mapped_device *alloc_dev(int minor)
blk_queue_make_request(md->queue, dm_request);
blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
md->queue->unplug_fn = dm_unplug_all;
+ blk_queue_merge_bvec(md->queue, dm_merge_bvec);
md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache);
if (!md->io_pool)
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 0d8d419d191..a90222e3297 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -9,11 +9,13 @@
#define _LINUX_DEVICE_MAPPER_H
#include <linux/bio.h>
+#include <linux/blkdev.h>
struct dm_target;
struct dm_table;
struct dm_dev;
struct mapped_device;
+struct bio_vec;
typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
@@ -72,6 +74,9 @@ typedef int (*dm_ioctl_fn) (struct dm_target *ti, struct inode *inode,
struct file *filp, unsigned int cmd,
unsigned long arg);
+typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
+ struct bio_vec *biovec, int max_size);
+
void dm_error(const char *message);
/*
@@ -107,6 +112,7 @@ struct target_type {
dm_status_fn status;
dm_message_fn message;
dm_ioctl_fn ioctl;
+ dm_merge_fn merge;
};
struct io_restrictions {
diff --git a/include/linux/dm-ioctl.h b/include/linux/dm-ioctl.h
index b03c41bbfa1..28c2940eb30 100644
--- a/include/linux/dm-ioctl.h
+++ b/include/linux/dm-ioctl.h
@@ -256,9 +256,9 @@ enum {
#define DM_DEV_SET_GEOMETRY _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)
#define DM_VERSION_MAJOR 4
-#define DM_VERSION_MINOR 13
+#define DM_VERSION_MINOR 14
#define DM_VERSION_PATCHLEVEL 0
-#define DM_VERSION_EXTRA "-ioctl (2007-10-18)"
+#define DM_VERSION_EXTRA "-ioctl (2008-04-23)"
/* Status bits */
#define DM_READONLY_FLAG (1 << 0) /* In/Out */