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Subject[PATCH 2/3] swsusp: simplify pagedir relocation
Date
This patch simplifies the relocation of the page backup list (aka pagedir)
during resume.

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

kernel/power/power.h | 1
kernel/power/snapshot.c | 2 -
kernel/power/swsusp.c | 78 ++++++++++++++++--------------------------------
3 files changed, 28 insertions(+), 53 deletions(-)
Index: linux-2.6.14-git4/kernel/power/swsusp.c
===================================================================
--- linux-2.6.14-git4.orig/kernel/power/swsusp.c 2005-11-01 18:20:28.000000000 +0100
+++ linux-2.6.14-git4/kernel/power/swsusp.c 2005-11-01 18:22:12.000000000 +0100
@@ -636,74 +636,43 @@
}

/**
- * 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.
+ * mark_unsafe_pages - mark the pages that cannot be used for storing
+ * the image during resume, because they conflict with the pages that
+ * had been used before suspend
*/

-static struct pbe * swsusp_pagedir_relocate(struct pbe *pblist)
+static void mark_unsafe_pages(struct pbe *pblist)
{
struct zone *zone;
unsigned long zone_pfn;
- struct pbe *pbpage, *tail, *p;
- void *m;
- int rel = 0;
+ struct pbe *p;

if (!pblist) /* a sanity check */
- return NULL;
-
- pr_debug("swsusp: Relocating pagedir (%lu pages to check)\n",
- swsusp_info.pagedir_pages);
+ return;

/* Clear page flags */
-
for_each_zone (zone) {
- for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
- if (pfn_valid(zone_pfn + zone->zone_start_pfn))
- ClearPageNosaveFree(pfn_to_page(zone_pfn +
+ for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
+ if (pfn_valid(zone_pfn + zone->zone_start_pfn))
+ ClearPageNosaveFree(pfn_to_page(zone_pfn +
zone->zone_start_pfn));
}

/* Mark orig addresses */
-
for_each_pbe (p, pblist)
SetPageNosaveFree(virt_to_page(p->orig_address));

- tail = pblist + PB_PAGE_SKIP;
-
- /* Relocate colliding pages */
-
- for_each_pb_page (pbpage, pblist) {
- if (PageNosaveFree(virt_to_page((unsigned long)pbpage))) {
- m = (void *)get_safe_page(GFP_ATOMIC | __GFP_COLD);
- if (!m)
- return NULL;
- memcpy(m, (void *)pbpage, PAGE_SIZE);
- if (pbpage == pblist)
- pblist = (struct pbe *)m;
- else
- tail->next = (struct pbe *)m;
- pbpage = (struct pbe *)m;
-
- /* We have to link the PBEs again */
- for (p = pbpage; p < pbpage + PB_PAGE_SKIP; p++)
- if (p->next) /* needed to save the end */
- p->next = p + 1;
-
- rel++;
- }
- tail = pbpage + PB_PAGE_SKIP;
- }
+}

- /* This is for swsusp_free() */
- for_each_pb_page (pbpage, pblist) {
- SetPageNosave(virt_to_page(pbpage));
- SetPageNosaveFree(virt_to_page(pbpage));
+static void copy_page_backup_list(struct pbe *dst, struct pbe *src)
+{
+ /* We assume both lists contain the same number of elements */
+ while (src) {
+ dst->orig_address = src->orig_address;
+ dst->swap_address = src->swap_address;
+ dst = dst->next;
+ src = src->next;
}
-
- printk("swsusp: Relocated %d pages\n", rel);
-
- return pblist;
}

/*
@@ -949,10 +918,15 @@

if ((error = read_pagedir(p)))
return error;
-
create_pbe_list(p, nr_copy_pages);
-
- if (!(pagedir_nosave = swsusp_pagedir_relocate(p)))
+ mark_unsafe_pages(p);
+ pagedir_nosave = alloc_pagedir(nr_copy_pages, GFP_ATOMIC, 1);
+ if (pagedir_nosave) {
+ create_pbe_list(pagedir_nosave, nr_copy_pages);
+ copy_page_backup_list(pagedir_nosave, p);
+ }
+ free_pagedir(p);
+ if (!pagedir_nosave)
return -ENOMEM;

/* Allocate memory for the image and read the data from swap */
Index: linux-2.6.14-git4/kernel/power/power.h
===================================================================
--- linux-2.6.14-git4.orig/kernel/power/power.h 2005-11-01 18:20:28.000000000 +0100
+++ linux-2.6.14-git4/kernel/power/power.h 2005-11-01 18:22:12.000000000 +0100
@@ -66,6 +66,7 @@
extern asmlinkage int swsusp_arch_resume(void);

extern int restore_highmem(void);
+extern void free_pagedir(struct pbe *pblist);
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);
Index: linux-2.6.14-git4/kernel/power/snapshot.c
===================================================================
--- linux-2.6.14-git4.orig/kernel/power/snapshot.c 2005-11-01 18:20:28.000000000 +0100
+++ linux-2.6.14-git4/kernel/power/snapshot.c 2005-11-01 18:22:12.000000000 +0100
@@ -217,7 +217,7 @@
* free_pagedir - free pages allocated with alloc_pagedir()
*/

-static void free_pagedir(struct pbe *pblist)
+void free_pagedir(struct pbe *pblist)
{
struct pbe *pbe;

-
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