memory unplug: memory hotplug cleanup

A clean up patch for "scanning memory resource [start, end)" operation.

Now, find_next_system_ram() function is used in memory hotplug, but this
interface is not easy to use and codes are complicated.

This patch adds walk_memory_resouce(start,len,arg,func) function.
The function 'func' is called per valid memory resouce range in [start,pfn).

[pbadari@us.ibm.com: Error handling in walk_memory_resource()]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index b573d1ec871..0a14dad9545 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -63,6 +63,14 @@ extern int online_pages(unsigned long, unsigned long);
 extern int __add_pages(struct zone *zone, unsigned long start_pfn,
         unsigned long nr_pages);
 
+/*
+ * Walk thorugh all memory which is registered as resource.
+ * arg is (start_pfn, nr_pages, private_arg_pointer)
+ */
+extern int walk_memory_resource(unsigned long start_pfn,
+                        unsigned long nr_pages, void *arg,
+                        int (*func)(unsigned long, unsigned long, void *));
+
 #ifdef CONFIG_NUMA
 extern int memory_add_physaddr_to_nid(u64 start);
 #else