[PATCH] swsusp: Fix mark_free_pages

Clean up mm/page_alloc.c#mark_free_pages() and make it avoid clearing
PageNosaveFree for PageNosave pages.  This allows us to get rid of an ugly
hack in kernel/power/snapshot.c#copy_data_pages().

Additionally, the page-copying loop in copy_data_pages() is moved to an
inline function.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 29 insertions, 22 deletions

diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 81fe8de9e604..4afb7900002b 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -208,37 +208,36 @@ unsigned int count_data_pages(void)
         return n;
 }
 
+static inline void copy_data_page(long *dst, long *src)
+{
+        int n;
+
+        /* copy_page and memcpy are not usable for copying task structs. */
+        for (n = PAGE_SIZE / sizeof(long); n; n--)
+                *dst++ = *src++;
+}
+
 static void copy_data_pages(struct pbe *pblist)
 {
         struct zone *zone;
         unsigned long pfn, max_zone_pfn;
-        struct pbe *pbe, *p;
+        struct pbe *pbe;
 
         pbe = pblist;
         for_each_zone (zone) {
                 if (is_highmem(zone))
                         continue;
                 mark_free_pages(zone);
-                /* This is necessary for swsusp_free() */
-                for_each_pb_page (p, pblist)
-                        SetPageNosaveFree(virt_to_page(p));
-                for_each_pbe (p, pblist)
-                        SetPageNosaveFree(virt_to_page(p->address));
                 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
                 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) {
                         struct page *page = saveable_page(pfn);
 
                         if (page) {
-                                long *src, *dst;
-                                int n;
+                                void *ptr = page_address(page);
 
                                 BUG_ON(!pbe);
-                                pbe->orig_address = (unsigned long)page_address(page);
-                                /* copy_page and memcpy are not usable for copying task structs. */
-                                dst = (long *)pbe->address;
-                                src = (long *)pbe->orig_address;
-                                for (n = PAGE_SIZE / sizeof(long); n; n--)
-                                        *dst++ = *src++;
+                                copy_data_page((void *)pbe->address, ptr);
+                                pbe->orig_address = (unsigned long)ptr;
                                 pbe = pbe->next;
                         }
                 }
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 51070b6d593f..9810f0a60db7 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -694,7 +694,8 @@ static void __drain_pages(unsigned int cpu)
 
 void mark_free_pages(struct zone *zone)
 {
-        unsigned long zone_pfn, flags;
+        unsigned long pfn, max_zone_pfn;
+        unsigned long flags;
         int order;
         struct list_head *curr;
 
@@ -702,18 +703,25 @@ void mark_free_pages(struct zone *zone)
                 return;
 
         spin_lock_irqsave(&zone->lock, flags);
-        for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
-                ClearPageNosaveFree(pfn_to_page(zone_pfn + zone->zone_start_pfn));
+
+        max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
+        for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
+                if (pfn_valid(pfn)) {
+                        struct page *page = pfn_to_page(pfn);
+
+                        if (!PageNosave(page))
+                                ClearPageNosaveFree(page);
+                }
 
         for (order = MAX_ORDER - 1; order >= 0; --order)
                 list_for_each(curr, &zone->free_area[order].free_list) {
-                        unsigned long start_pfn, i;
+                        unsigned long i;
 
-                        start_pfn = page_to_pfn(list_entry(curr, struct page, lru));
+                        pfn = page_to_pfn(list_entry(curr, struct page, lru));
+                        for (i = 0; i < (1UL << order); i++)
+                                SetPageNosaveFree(pfn_to_page(pfn + i));
+                }
 
-                        for (i=0; i < (1<<order); i++)
-                                SetPageNosaveFree(pfn_to_page(start_pfn+i));
-        }
         spin_unlock_irqrestore(&zone->lock, flags);
 }