[PATCH] swsusp: Fix alloc_pagedir

Get rid of the FIXME in kernel/power/snapshot.c#alloc_pagedir() and
simplify the functions called by it.

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

1 files changed, 17 insertions, 15 deletions

diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 7ad0c0465524..4ca372f2bc14 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -316,12 +316,12 @@ static void free_pagedir(struct pbe *pblist, int clear_nosave_free)
  *      fill_pb_page - Create a list of PBEs on a given memory page
  */
 
-static inline void fill_pb_page(struct pbe *pbpage)
+static inline void fill_pb_page(struct pbe *pbpage, unsigned int n)
 {
         struct pbe *p;
 
         p = pbpage;
-        pbpage += PB_PAGE_SKIP;
+        pbpage += n - 1;
         do
                 p->next = p + 1;
         while (++p < pbpage);
@@ -330,24 +330,26 @@ static inline void fill_pb_page(struct pbe *pbpage)
 /**
  *      create_pbe_list - Create a list of PBEs on top of a given chain
  *      of memory pages allocated with alloc_pagedir()
+ *
+ *      This function assumes that pages allocated by alloc_image_page() will
+ *      always be zeroed.
  */
 
 static inline void create_pbe_list(struct pbe *pblist, unsigned int nr_pages)
 {
-        struct pbe *pbpage, *p;
+        struct pbe *pbpage;
         unsigned int num = PBES_PER_PAGE;
 
         for_each_pb_page (pbpage, pblist) {
                 if (num >= nr_pages)
                         break;
 
-                fill_pb_page(pbpage);
+                fill_pb_page(pbpage, PBES_PER_PAGE);
                 num += PBES_PER_PAGE;
         }
         if (pbpage) {
-                for (num -= PBES_PER_PAGE - 1, p = pbpage; num < nr_pages; p++, num++)
-                        p->next = p + 1;
-                p->next = NULL;
+                num -= PBES_PER_PAGE;
+                fill_pb_page(pbpage, nr_pages - num);
         }
 }
 
@@ -374,17 +376,17 @@ static struct pbe *alloc_pagedir(unsigned int nr_pages, gfp_t gfp_mask,
                 return NULL;
 
         pblist = alloc_image_page(gfp_mask, safe_needed);
-        /* FIXME: rewrite this ugly loop */
-        for (pbe = pblist, num = PBES_PER_PAGE; pbe && num < nr_pages;
-                        pbe = pbe->next, num += PBES_PER_PAGE) {
+        pbe = pblist;
+        for (num = PBES_PER_PAGE; num < nr_pages; num += PBES_PER_PAGE) {
+                if (!pbe) {
+                        free_pagedir(pblist, 1);
+                        return NULL;
+                }
                 pbe += PB_PAGE_SKIP;
                 pbe->next = alloc_image_page(gfp_mask, safe_needed);
+                pbe = pbe->next;
         }
-        if (!pbe) { /* get_zeroed_page() failed */
-                free_pagedir(pblist, 1);
-                pblist = NULL;
-        } else
-                create_pbe_list(pblist, nr_pages);
+        create_pbe_list(pblist, nr_pages);
         return pblist;
 }