mm/memblock: introduce for_each_memblock_type()

We already have the for_each_memblock() macro in <linux/memblock.h>
which provides ability to iterate over memblock regions of a known type.
The for_each_memblock() macro allows us to pass the pointer to the
struct memblock_type, instead we need to pass name of the type.

This patch introduces a new macro for_each_memblock_type() which allows
us iterate over memblock regions with the given type when the type is
unknown.

Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 3a092fb..c0c4208 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -399,6 +399,11 @@
 	     region < (memblock.memblock_type.regions + memblock.memblock_type.cnt);	\
 	     region++)
 
+#define for_each_memblock_type(memblock_type, rgn)			\
+	idx = 0;							\
+	rgn = &memblock_type->regions[idx];				\
+	for (idx = 0; idx < memblock_type->cnt;				\
+	     idx++,rgn = &memblock_type->regions[idx])
 
 #ifdef CONFIG_ARCH_DISCARD_MEMBLOCK
 #define __init_memblock __meminit