3 files changed, 64 insertions, 21 deletions

diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index bf6afa2fc432..1e483fa7afb4 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -68,8 +68,8 @@ typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
 typedef int (*dm_preresume_fn) (struct dm_target *ti);
 typedef void (*dm_resume_fn) (struct dm_target *ti);
 
-typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
-                             unsigned status_flags, char *result, unsigned maxlen);
+typedef void (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
+                              unsigned status_flags, char *result, unsigned maxlen);
 
 typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
 
@@ -175,6 +175,14 @@ struct target_type {
 #define DM_TARGET_IMMUTABLE             0x00000004
 #define dm_target_is_immutable(type)    ((type)->features & DM_TARGET_IMMUTABLE)
 
+/*
+ * Some targets need to be sent the same WRITE bio severals times so
+ * that they can send copies of it to different devices.  This function
+ * examines any supplied bio and returns the number of copies of it the
+ * target requires.
+ */
+typedef unsigned (*dm_num_write_bios_fn) (struct dm_target *ti, struct bio *bio);
+
 struct dm_target {
         struct dm_table *table;
         struct target_type *type;
@@ -187,26 +195,26 @@ struct dm_target {
         uint32_t max_io_len;
 
         /*
-         * A number of zero-length barrier requests that will be submitted
+         * A number of zero-length barrier bios that will be submitted
          * to the target for the purpose of flushing cache.
          *
-         * The request number can be accessed with dm_bio_get_target_request_nr.
-         * It is a responsibility of the target driver to remap these requests
+         * The bio number can be accessed with dm_bio_get_target_bio_nr.
+         * It is a responsibility of the target driver to remap these bios
          * to the real underlying devices.
          */
-        unsigned num_flush_requests;
+        unsigned num_flush_bios;
 
         /*
-         * The number of discard requests that will be submitted to the target.
-         * The request number can be accessed with dm_bio_get_target_request_nr.
+         * The number of discard bios that will be submitted to the target.
+         * The bio number can be accessed with dm_bio_get_target_bio_nr.
          */
-        unsigned num_discard_requests;
+        unsigned num_discard_bios;
 
         /*
-         * The number of WRITE SAME requests that will be submitted to the target.
-         * The request number can be accessed with dm_bio_get_target_request_nr.
+         * The number of WRITE SAME bios that will be submitted to the target.
+         * The bio number can be accessed with dm_bio_get_target_bio_nr.
          */
-        unsigned num_write_same_requests;
+        unsigned num_write_same_bios;
 
         /*
          * The minimum number of extra bytes allocated in each bio for the
@@ -214,6 +222,13 @@ struct dm_target {
          */
         unsigned per_bio_data_size;
 
+        /*
+         * If defined, this function is called to find out how many
+         * duplicate bios should be sent to the target when writing
+         * data.
+         */
+        dm_num_write_bios_fn num_write_bios;
+
         /* target specific data */
         void *private;
 
@@ -233,10 +248,10 @@ struct dm_target {
         bool discards_supported:1;
 
         /*
-         * Set if the target required discard request to be split
+         * Set if the target required discard bios to be split
          * on max_io_len boundary.
          */
-        bool split_discard_requests:1;
+        bool split_discard_bios:1;
 
         /*
          * Set if this target does not return zeroes on discarded blocks.
@@ -261,7 +276,7 @@ struct dm_target_io {
         struct dm_io *io;
         struct dm_target *ti;
         union map_info info;
-        unsigned target_request_nr;
+        unsigned target_bio_nr;
         struct bio clone;
 };
 
@@ -275,9 +290,9 @@ static inline struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size)
         return (struct bio *)((char *)data + data_size + offsetof(struct dm_target_io, clone));
 }
 
-static inline unsigned dm_bio_get_target_request_nr(const struct bio *bio)
+static inline unsigned dm_bio_get_target_bio_nr(const struct bio *bio)
 {
-        return container_of(bio, struct dm_target_io, clone)->target_request_nr;
+        return container_of(bio, struct dm_target_io, clone)->target_bio_nr;
 }
 
 int dm_register_target(struct target_type *t);
diff --git a/include/linux/dm-kcopyd.h b/include/linux/dm-kcopyd.h
index 47d9d376e4e7..f486d636b82e 100644
--- a/include/linux/dm-kcopyd.h
+++ b/include/linux/dm-kcopyd.h
@@ -21,11 +21,34 @@
 
 #define DM_KCOPYD_IGNORE_ERROR 1
 
+struct dm_kcopyd_throttle {
+        unsigned throttle;
+        unsigned num_io_jobs;
+        unsigned io_period;
+        unsigned total_period;
+        unsigned last_jiffies;
+};
+
+/*
+ * kcopyd clients that want to support throttling must pass an initialised
+ * dm_kcopyd_throttle struct into dm_kcopyd_client_create().
+ * Two or more clients may share the same instance of this struct between
+ * them if they wish to be throttled as a group.
+ *
+ * This macro also creates a corresponding module parameter to configure
+ * the amount of throttling.
+ */
+#define DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(name, description)  \
+static struct dm_kcopyd_throttle dm_kcopyd_throttle = { 100, 0, 0, 0, 0 }; \
+module_param_named(name, dm_kcopyd_throttle.throttle, uint, 0644); \
+MODULE_PARM_DESC(name, description)
+
 /*
  * To use kcopyd you must first create a dm_kcopyd_client object.
+ * throttle can be NULL if you don't want any throttling.
  */
 struct dm_kcopyd_client;
-struct dm_kcopyd_client *dm_kcopyd_client_create(void);
+struct dm_kcopyd_client *dm_kcopyd_client_create(struct dm_kcopyd_throttle *throttle);
 void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc);
 
 /*
diff --git a/include/uapi/linux/dm-ioctl.h b/include/uapi/linux/dm-ioctl.h
index 539b179b349c..7e75b6fd8d45 100644
--- a/include/uapi/linux/dm-ioctl.h
+++ b/include/uapi/linux/dm-ioctl.h
@@ -267,9 +267,9 @@ 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        23
-#define DM_VERSION_PATCHLEVEL   1
-#define DM_VERSION_EXTRA        "-ioctl (2012-12-18)"
+#define DM_VERSION_MINOR        24
+#define DM_VERSION_PATCHLEVEL   0
+#define DM_VERSION_EXTRA        "-ioctl (2013-01-15)"
 
 /* Status bits */
 #define DM_READONLY_FLAG        (1 << 0) /* In/Out */
@@ -336,4 +336,9 @