1 files changed, 12 insertions, 2 deletions

diff --git a/include/linux/dm-ioctl.h b/include/linux/dm-ioctl.h
index 48e44ee2b466..2ab84c83c31a 100644
--- a/include/linux/dm-ioctl.h
+++ b/include/linux/dm-ioctl.h
@@ -123,6 +123,16 @@ struct dm_ioctl {
         __u32 target_count;     /* in/out */
         __s32 open_count;       /* out */
         __u32 flags;            /* in/out */
+
+        /*
+         * event_nr holds either the event number (input and output) or the
+         * udev cookie value (input only).
+         * The DM_DEV_WAIT ioctl takes an event number as input.
+         * The DM_SUSPEND, DM_DEV_REMOVE and DM_DEV_RENAME ioctls
+         * use the field as a cookie to return in the DM_COOKIE
+         * variable with the uevents they issue.
+         * For output, the ioctls return the event number, not the cookie.
+         */
         __u32 event_nr;         /* in/out */
         __u32 padding;
 
@@ -256,9 +266,9 @@ 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        14
+#define DM_VERSION_MINOR        15
 #define DM_VERSION_PATCHLEVEL   0
-#define DM_VERSION_EXTRA        "-ioctl (2008-04-23)"
+#define DM_VERSION_EXTRA        "-ioctl (2009-04-01)"
 
 /* Status bits */
 #define DM_READONLY_FLAG        (1 << 0) /* In/Out */