A function to decrement consecutive chunk counter.
Will be needed for snapshot merging.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

Index: linux-2.6.26-rc5-devel/drivers/md/dm-snap.h
===================================================================
--- linux-2.6.26-rc5-devel.orig/drivers/md/dm-snap.h	2008-06-16 22:00:04.000000000 +0200
+++ linux-2.6.26-rc5-devel/drivers/md/dm-snap.h	2008-06-16 22:00:53.000000000 +0200
@@ -64,6 +64,13 @@
 	BUG_ON(!dm_consecutive_chunk_count(e));
 }
 
+static inline void dm_consecutive_chunk_count_dec(struct dm_snap_exception *e)
+{
+	BUG_ON(!dm_consecutive_chunk_count(e));
+
+	e->new_chunk -= (1ULL << DM_CHUNK_NUMBER_BITS);
+}
+
 #  else
 #    define DM_CHUNK_CONSECUTIVE_BITS 0
 
@@ -81,6 +88,10 @@
 {
 }
 
+static inline void dm_consecutive_chunk_count_dec(struct dm_snap_exception *e)
+{
+}
+
 #  endif
 
 /*