From 0f0acd565561b48bb1df5ce38712b314d0d147de Mon Sep 17 00:00:00 2001
From: Dave Hansen <haveblue@us.ibm.com>
Date: Sat, 29 Oct 2005 18:16:51 -0700
Subject: [PATCH] --- yaml --- r: 11387 b: refs/heads/master c:
 4ca644d970bf2542623228a4624af356d20ca267 h: refs/heads/master i:   11385:
 76849428bde23f35efb1562420c6f08402c295bc   11383:
 c2d45457e6334ddbb4ba7a818cb827906e9136a4 v: v3

---
 [refs]                       |  2 +-
 trunk/include/linux/mmzone.h |  1 +
 trunk/mm/sparse.c            | 25 +++++++++++++++++++++++++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index fc43fef07162..26f3cdf583c7 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ed8ece2ec8d3c2031b1a1a0737568bb0d49454e0
+refs/heads/master: 4ca644d970bf2542623228a4624af356d20ca267
diff --git a/trunk/include/linux/mmzone.h b/trunk/include/linux/mmzone.h
index 7519eb4191e7..4674145bb63d 100644
--- a/trunk/include/linux/mmzone.h
+++ b/trunk/include/linux/mmzone.h
@@ -509,6 +509,7 @@ static inline struct mem_section *__nr_to_section(unsigned long nr)
 		return NULL;
 	return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];
 }
+extern int __section_nr(struct mem_section* ms);
 
 /*
  * We use the lower bits of the mem_map pointer to store
diff --git a/trunk/mm/sparse.c b/trunk/mm/sparse.c
index 347249a4917a..0d3bd4bf3aaa 100644
--- a/trunk/mm/sparse.c
+++ b/trunk/mm/sparse.c
@@ -72,6 +72,31 @@ static inline int sparse_index_init(unsigned long section_nr, int nid)
 }
 #endif
 
+/*
+ * Although written for the SPARSEMEM_EXTREME case, this happens
+ * to also work for the flat array case becase
+ * NR_SECTION_ROOTS==NR_MEM_SECTIONS.
+ */
+int __section_nr(struct mem_section* ms)
+{
+	unsigned long root_nr;
+	struct mem_section* root;
+
+	for (root_nr = 0;
+	     root_nr < NR_MEM_SECTIONS;
+	     root_nr += SECTIONS_PER_ROOT) {
+		root = __nr_to_section(root_nr);
+
+		if (!root)
+			continue;
+
+		if ((ms >= root) && (ms < (root + SECTIONS_PER_ROOT)))
+		     break;
+	}
+
+	return (root_nr * SECTIONS_PER_ROOT) + (ms - root);
+}
+
 /* Record a memory area against a node. */
 void memory_present(int nid, unsigned long start, unsigned long end)
 {