[PATCH] swsusp: simplify pagedir relocation
Rafael J. Wysocki [Wed, 9 Nov 2005 05:34:40 +0000 (21:34 -0800)]
This patch simplifies the relocation of the page backup list (aka pagedir)
during resume.

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>

kernel/power/power.h
kernel/power/snapshot.c
kernel/power/swsusp.c

index c98923e..893ee65 100644 (file)
@@ -66,6 +66,7 @@ extern asmlinkage int swsusp_arch_suspend(void);
 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 96cc3e2..b8a2e9a 100644 (file)
@@ -216,7 +216,7 @@ static void copy_data_pages(struct pbe *pblist)
  *     free_pagedir - free pages allocated with alloc_pagedir()
  */
 
-static void free_pagedir(struct pbe *pblist)
+void free_pagedir(struct pbe *pblist)
 {
        struct pbe *pbe;
 
index a456ffe..8511c7f 100644 (file)
@@ -629,74 +629,43 @@ int swsusp_resume(void)
 }
 
 /**
- *     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;
 }
 
 /*
@@ -942,10 +911,15 @@ static int read_suspend_image(void)
 
        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 */