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Subject[PATCH 1/3] swsusp: reduce code duplication
Date
The changes made by this patch are necessary for the pagedir relocation
simplification in the next patch.  Additionally, these changes allow us to
drop check_pagedir() and make get_safe_page() be a one-line wrapper around
alloc_image_page() (get_safe_page() goes to snapshot.c, because
alloc_image_page() is static and it does not make sense to export
it).

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

kernel/power/power.h | 3 +-
kernel/power/snapshot.c | 62 +++++++++++++++++++++++++++++++++++++-----------
kernel/power/swsusp.c | 57 +-------------------------------------------
3 files changed, 52 insertions(+), 70 deletions(-)
Index: linux-2.6.14-git4/kernel/power/power.h
===================================================================
--- linux-2.6.14-git4.orig/kernel/power/power.h 2005-11-01 18:18:31.000000000 +0100
+++ linux-2.6.14-git4/kernel/power/power.h 2005-11-01 18:20:28.000000000 +0100
@@ -66,7 +66,8 @@
extern asmlinkage int swsusp_arch_resume(void);

extern int restore_highmem(void);
-extern struct pbe * alloc_pagedir(unsigned nr_pages);
+extern struct pbe *alloc_pagedir(unsigned nr_pages, gfp_t gfp_mask, int safe_needed);
extern void create_pbe_list(struct pbe *pblist, unsigned nr_pages);
extern void swsusp_free(void);
+extern int alloc_data_pages(struct pbe *pblist, gfp_t gfp_mask, int safe_needed);
extern int enough_swap(unsigned nr_pages);
Index: linux-2.6.14-git4/kernel/power/snapshot.c
===================================================================
--- linux-2.6.14-git4.orig/kernel/power/snapshot.c 2005-11-01 18:18:31.000000000 +0100
+++ linux-2.6.14-git4/kernel/power/snapshot.c 2005-11-01 18:20:28.000000000 +0100
@@ -270,9 +270,30 @@
pr_debug("create_pbe_list(): initialized %d PBEs\n", num);
}

-static void *alloc_image_page(void)
+/**
+ * @safe_needed - on resume, for storing the PBE list and the image,
+ * we can only use memory pages that do not conflict with the pages
+ * which had been used before suspend.
+ *
+ * The unsafe pages are marked with the PG_nosave_free flag
+ *
+ * Allocated but unusable (ie eaten) memory pages should be marked
+ * so that swsusp_free() can release them
+ */
+
+static inline void *alloc_image_page(gfp_t gfp_mask, int safe_needed)
{
- void *res = (void *)get_zeroed_page(GFP_ATOMIC | __GFP_COLD);
+ void *res;
+
+ if (safe_needed)
+ do {
+ res = (void *)get_zeroed_page(gfp_mask);
+ if (res && PageNosaveFree(virt_to_page(res)))
+ /* This is for swsusp_free() */
+ SetPageNosave(virt_to_page(res));
+ } while (res && PageNosaveFree(virt_to_page(res)));
+ else
+ res = (void *)get_zeroed_page(gfp_mask);
if (res) {
SetPageNosave(virt_to_page(res));
SetPageNosaveFree(virt_to_page(res));
@@ -280,6 +301,11 @@
return res;
}

+unsigned long get_safe_page(gfp_t gfp_mask)
+{
+ return (unsigned long)alloc_image_page(gfp_mask, 1);
+}
+
/**
* alloc_pagedir - Allocate the page directory.
*
@@ -293,7 +319,7 @@
* On each page we set up a list of struct_pbe elements.
*/

-struct pbe *alloc_pagedir(unsigned nr_pages)
+struct pbe *alloc_pagedir(unsigned nr_pages, gfp_t gfp_mask, int safe_needed)
{
unsigned num;
struct pbe *pblist, *pbe;
@@ -302,12 +328,12 @@
return NULL;

pr_debug("alloc_pagedir(): nr_pages = %d\n", nr_pages);
- pblist = alloc_image_page();
+ 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 += PB_PAGE_SKIP;
- pbe->next = alloc_image_page();
+ pbe->next = alloc_image_page(gfp_mask, safe_needed);
}
if (!pbe) { /* get_zeroed_page() failed */
free_pagedir(pblist);
@@ -355,24 +381,32 @@
(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
}

+int alloc_data_pages(struct pbe *pblist, gfp_t gfp_mask, int safe_needed)
+{
+ struct pbe *p;
+
+ for_each_pbe (p, pblist) {
+ p->address = (unsigned long)alloc_image_page(gfp_mask, safe_needed);
+ if (!p->address)
+ return -ENOMEM;
+ }
+ return 0;
+}

static struct pbe *swsusp_alloc(unsigned nr_pages)
{
- struct pbe *pblist, *p;
+ struct pbe *pblist;

- if (!(pblist = alloc_pagedir(nr_pages))) {
+ if (!(pblist = alloc_pagedir(nr_pages, GFP_ATOMIC | __GFP_COLD, 0))) {
printk(KERN_ERR "suspend: Allocating pagedir failed.\n");
return NULL;
}
create_pbe_list(pblist, nr_pages);

- for_each_pbe (p, pblist) {
- p->address = (unsigned long)alloc_image_page();
- if (!p->address) {
- printk(KERN_ERR "suspend: Allocating image pages failed.\n");
- swsusp_free();
- return NULL;
- }
+ if (alloc_data_pages(pblist, GFP_ATOMIC | __GFP_COLD, 0)) {
+ printk(KERN_ERR "suspend: Allocating image pages failed.\n");
+ swsusp_free();
+ return NULL;
}

return pblist;
Index: linux-2.6.14-git4/kernel/power/swsusp.c
===================================================================
--- linux-2.6.14-git4.orig/kernel/power/swsusp.c 2005-11-01 18:18:31.000000000 +0100
+++ linux-2.6.14-git4/kernel/power/swsusp.c 2005-11-01 18:20:28.000000000 +0100
@@ -636,59 +636,6 @@
}

/**
- * On resume, for storing the PBE list and the image,
- * we can only use memory pages that do not conflict with the pages
- * which had been used before suspend.
- *
- * We don't know which pages are usable until we allocate them.
- *
- * Allocated but unusable (ie eaten) memory pages are marked so that
- * swsusp_free() can release them
- */
-
-unsigned long get_safe_page(gfp_t gfp_mask)
-{
- unsigned long m;
-
- do {
- m = get_zeroed_page(gfp_mask);
- if (m && PageNosaveFree(virt_to_page(m)))
- /* This is for swsusp_free() */
- SetPageNosave(virt_to_page(m));
- } while (m && PageNosaveFree(virt_to_page(m)));
- if (m) {
- /* This is for swsusp_free() */
- SetPageNosave(virt_to_page(m));
- SetPageNosaveFree(virt_to_page(m));
- }
- return m;
-}
-
-/**
- * check_pagedir - We ensure here that pages that the PBEs point to
- * won't collide with pages where we're going to restore from the loaded
- * pages later
- */
-
-static int check_pagedir(struct pbe *pblist)
-{
- struct pbe *p;
-
- /* This is necessary, so that we can free allocated pages
- * in case of failure
- */
- for_each_pbe (p, pblist)
- p->address = 0UL;
-
- for_each_pbe (p, pblist) {
- p->address = get_safe_page(GFP_ATOMIC);
- if (!p->address)
- return -ENOMEM;
- }
- return 0;
-}
-
-/**
* swsusp_pagedir_relocate - It is possible, that some memory pages
* occupied by the list of PBEs collide with pages where we're going to
* restore from the loaded pages later. We relocate them here.
@@ -997,7 +944,7 @@
int error = 0;
struct pbe *p;

- if (!(p = alloc_pagedir(nr_copy_pages)))
+ if (!(p = alloc_pagedir(nr_copy_pages, GFP_ATOMIC, 0)))
return -ENOMEM;

if ((error = read_pagedir(p)))
@@ -1010,7 +957,7 @@

/* Allocate memory for the image and read the data from swap */

- error = check_pagedir(pagedir_nosave);
+ error = alloc_data_pages(pagedir_nosave, GFP_ATOMIC, 1);

if (!error)
error = data_read(pagedir_nosave);
-
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