From: Dave Hansen <haveblue@us.ibm.com>
A little helper that we use in the hotplug code.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
include/linux/mmzone.h | 25 +++++++++++++++++++++++++
1 files changed, 25 insertions(+)
diff -puN include/linux/mmzone.h~memory-hotplug-prep-__section_nr-helper include/linux/mmzone.h
--- devel/include/linux/mmzone.h~memory-hotplug-prep-__section_nr-helper 2005-09-07 20:10:27.000000000 -0700
+++ devel-akpm/include/linux/mmzone.h 2005-09-07 20:10:27.000000000 -0700
@@ -513,6 +513,31 @@ static inline struct mem_section *__nr_t
}
/*
+ * Although written for the SPARSEMEM_EXTREME case, this happens
+ * to also work for the flat array case becase
+ * NR_SECTION_ROOTS==NR_MEM_SECTIONS.
+ */
+static inline 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);
+}
+
+/*
* We use the lower bits of the mem_map pointer to store
* a little bit of information. There should be at least
* 3 bits here due to 32-bit alignment.
_