[PATCH] swsusp: fix enough_free_mem

This patch fixes a problem with the function enough_free_mem() used by
swsusp to verify if there is a sufficient number of memory pages available
to it to create and save the suspend image.

Namely, enough_free_mem() uses nr_free_pages() to obtain the number of free
memory pages, which is incorrect, because this function returns the total
number of free pages, including free highmem pages, and the highmem pages
cannot be used by swsusp for storing the image data.

The patch makes enough_free_mem() avoid counting the free highmem
pages as available to swsusp.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

kernel/power/snapshot.c

@@ -428,8 +428,14 @@ void swsusp_free(void)
 
 static int enough_free_mem(unsigned int nr_pages)
 {
-	pr_debug("swsusp: available memory: %u pages\n", nr_free_pages());
-	return nr_free_pages() > (nr_pages + PAGES_FOR_IO +
+	struct zone *zone;
+	unsigned int n = 0;
+
+	for_each_zone (zone)
+		if (!is_highmem(zone))
+			n += zone->free_pages;
+	pr_debug("swsusp: available memory: %u pages\n", n);
+	return n > (nr_pages + PAGES_FOR_IO +
 		(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
 }