[PATCH] memory hotplug prep: fixup bad_range()
When doing memory hotplug operations, the size of existing zones can obviously
change. This means that zone->zone_{start_pfn,spanned_pages} can change.
There are currently no locks that protect these structure members. However,
they are rarely accessed at runtime. Outside of swsusp, the only place that I
can find is bad_range().
So, split bad_range() up into two pieces: one that needs to be locked and
anther that doesn't.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 9a2fa81..a51ef94 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -78,21 +78,37 @@
unsigned long __initdata nr_kernel_pages;
unsigned long __initdata nr_all_pages;
-/*
- * Temporary debugging check for pages not lying within a given zone.
- */
-static int bad_range(struct zone *zone, struct page *page)
+static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
{
if (page_to_pfn(page) >= zone->zone_start_pfn + zone->spanned_pages)
return 1;
if (page_to_pfn(page) < zone->zone_start_pfn)
return 1;
+
+ return 0;
+}
+
+static int page_is_consistent(struct zone *zone, struct page *page)
+{
#ifdef CONFIG_HOLES_IN_ZONE
if (!pfn_valid(page_to_pfn(page)))
- return 1;
+ return 0;
#endif
if (zone != page_zone(page))
+ return 0;
+
+ return 1;
+}
+/*
+ * Temporary debugging check for pages not lying within a given zone.
+ */
+static int bad_range(struct zone *zone, struct page *page)
+{
+ if (page_outside_zone_boundaries(zone, page))
return 1;
+ if (!page_is_consistent(zone, page))
+ return 1;
+
return 0;
}