[PATCH] swsusp: rework memory freeing on resume

The following patch makes swsusp use the PG_nosave and PG_nosave_free flags to
mark pages that should be freed in case of an error during resume.

This allows us to simplify the code and to use swsusp_free() in all of the
swsusp's resume error paths, which makes them actually work.

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>

1 files changed, 19 insertions, 65 deletions

diff --git a/arch/x86_64/kernel/suspend.c b/arch/x86_64/kernel/suspend.c
index 02516823f514..fd2bef780882 100644
--- a/arch/x86_64/kernel/suspend.c
+++ b/arch/x86_64/kernel/suspend.c
@@ -147,57 +147,7 @@ extern int restore_image(void);
 
 pgd_t *temp_level4_pgt;
 
-static void **pages;
-
-static inline void *__add_page(void)
-{
-        void **c;
-
-        c = (void **)get_usable_page(GFP_ATOMIC);
-        if (c) {
-                *c = pages;
-                pages = c;
-        }
-        return c;
-}
-
-static inline void *__next_page(void)
-{
-        void **c;
-
-        c = pages;
-        if (c) {
-                pages = *c;
-                *c = NULL;
-        }
-        return c;
-}
-
-/*
- * Try to allocate as many usable pages as needed and daisy chain them.
- * If one allocation fails, free the pages allocated so far
- */
-static int alloc_usable_pages(unsigned long n)
-{
-        void *p;
-
-        pages = NULL;
-        do
-                if (!__add_page())
-                        break;
-        while (--n);
-        if (n) {
-                p = __next_page();
-                while (p) {
-                        free_page((unsigned long)p);
-                        p = __next_page();
-                }
-                return -ENOMEM;
-        }
-        return 0;
-}
-
-static void res_phys_pud_init(pud_t *pud, unsigned long address, unsigned long end)
+static int res_phys_pud_init(pud_t *pud, unsigned long address, unsigned long end)
 {
         long i, j;
 
@@ -211,7 +161,9 @@ static void res_phys_pud_init(pud_t *pud, unsigned long address, unsigned long e
                 if (paddr >= end)
                         break;
 
-                pmd = (pmd_t *)__next_page();
+                pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
+                if (!pmd)
+                        return -ENOMEM;
                 set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
                 for (j = 0; j < PTRS_PER_PMD; pmd++, j++, paddr += PMD_SIZE) {
                         unsigned long pe;
@@ -223,13 +175,17 @@ static void res_phys_pud_init(pud_t *pud, unsigned long address, unsigned long e
                         set_pmd(pmd, __pmd(pe));
                 }
         }
+        return 0;
 }
 
-static void set_up_temporary_mappings(void)
+static int set_up_temporary_mappings(void)
 {
         unsigned long start, end, next;
+        int error;
 
-        temp_level4_pgt = (pgd_t *)__next_page();
+        temp_level4_pgt = (pgd_t *)get_safe_page(GFP_ATOMIC);
+        if (!temp_level4_pgt)
+                return -ENOMEM;
 
         /* It is safe to reuse the original kernel mapping */
         set_pgd(temp_level4_pgt + pgd_index(__START_KERNEL_map),
@@ -240,29 +196,27 @@ static void set_up_temporary_mappings(void)
         end = (unsigned long)pfn_to_kaddr(end_pfn);
 
         for (; start < end; start = next) {
-                pud_t *pud = (pud_t *)__next_page();
+                pud_t *pud = (pud_t *)get_safe_page(GFP_ATOMIC);
+                if (!pud)
+                        return -ENOMEM;
                 next = start + PGDIR_SIZE;
                 if (next > end)
                         next = end;
-                res_phys_pud_init(pud, __pa(start), __pa(next));
+                if ((error = res_phys_pud_init(pud, __pa(start), __pa(next))))
+                        return error;
                 set_pgd(temp_level4_pgt + pgd_index(start),
                         mk_kernel_pgd(__pa(pud)));
         }
+        return 0;
 }
 
 int swsusp_arch_resume(void)
 {
-        unsigned long n;
+        int error;
 
-        n = ((end_pfn << PAGE_SHIFT) + PUD_SIZE - 1) >> PUD_SHIFT;
-        n += (n + PTRS_PER_PUD - 1) / PTRS_PER_PUD + 1;
-        pr_debug("swsusp_arch_resume(): pages needed = %lu\n", n);
-        if (alloc_usable_pages(n)) {
-                free_eaten_memory();
-                return -ENOMEM;
-        }
         /* We have got enough memory and from now on we cannot recover */
-        set_up_temporary_mappings();
+        if ((error = set_up_temporary_mappings()))
+                return error;
         restore_image();
         return 0;
 }