walk system ram range

Originally, walk_memory_resource() was introduced to traverse all memory
of "System RAM" for detecting memory hotplug/unplug range.  For doing so,
flags of IORESOUCE_MEM|IORESOURCE_BUSY was used and this was enough for
memory hotplug.

But for using other purpose, /proc/kcore, this may includes some firmware
area marked as IORESOURCE_BUSY | IORESOUCE_MEM.  This patch makes the
check strict to find out busy "System RAM".

Note: PPC64 keeps their own walk_memory_resouce(), which walk through
ppc64's lmb informaton.  Because old kclist_add() is called per lmb, this
patch makes no difference in behavior, finally.

And this patch removes CONFIG_MEMORY_HOTPLUG check from this function.
Because pfn_valid() just show "there is memmap or not* and cannot be used
for "there is physical memory or not", this function is useful in generic
to scan physical memory range.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Américo Wang <xiyou.wangcong@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 0e5c59b995ef..59736317bf0e 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -143,8 +143,8 @@ int arch_add_memory(int nid, u64 start, u64 size)
  * memory regions, find holes and callback for contiguous regions.
  */
 int
-walk_memory_resource(unsigned long start_pfn, unsigned long nr_pages, void *arg,
-                        int (*func)(unsigned long, unsigned long, void *))
+walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
+                void *arg, int (*func)(unsigned long, unsigned long, void *))
 {
         struct lmb_property res;
         unsigned long pfn, len;
@@ -166,7 +166,7 @@ walk_memory_resource(unsigned long start_pfn, unsigned long nr_pages, void *arg,
         }
         return ret;
 }
-EXPORT_SYMBOL_GPL(walk_memory_resource);
+EXPORT_SYMBOL_GPL(walk_system_ram_range);
 
 /*
  * Initialize the bootmem system and give it all the memory we