[PATCH] swsusp: reduce the use of global variables
Rafael J. Wysocki [Sun, 30 Oct 2005 22:59:57 +0000 (14:59 -0800)]
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>

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

index e54dd84..28afcb0 100644 (file)
@@ -69,4 +69,4 @@ extern int restore_highmem(void);
 extern void free_pagedir(struct pbe *pblist);
 extern struct pbe * alloc_pagedir(unsigned nr_pages);
 extern void create_pbe_list(struct pbe *pblist, unsigned nr_pages);
-extern int enough_swap(void);
+extern int enough_swap(unsigned nr_pages);
index 0f0a7f3..03916cf 100644 (file)
@@ -187,37 +187,38 @@ static int saveable(struct zone * zone, unsigned long * zone_pfn)
        return 1;
 }
 
-static void count_data_pages(void)
+static unsigned count_data_pages(void)
 {
        struct zone *zone;
        unsigned long zone_pfn;
+       unsigned n;
 
-       nr_copy_pages = 0;
-
+       n = 0;
        for_each_zone (zone) {
                if (is_highmem(zone))
                        continue;
                mark_free_pages(zone);
                for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
-                       nr_copy_pages += saveable(zone, &zone_pfn);
+                       n += saveable(zone, &zone_pfn);
        }
+       return n;
 }
 
-static void copy_data_pages(void)
+static void copy_data_pages(struct pbe *pblist)
 {
        struct zone *zone;
        unsigned long zone_pfn;
-       struct pbe *pbe = pagedir_nosave, *p;
+       struct pbe *pbe, *p;
 
-       pr_debug("copy_data_pages(): pages to copy: %d\n", nr_copy_pages);
+       pbe = pblist;
        for_each_zone (zone) {
                if (is_highmem(zone))
                        continue;
                mark_free_pages(zone);
                /* This is necessary for swsusp_free() */
-               for_each_pb_page (p, pagedir_nosave)
+               for_each_pb_page (p, pblist)
                        SetPageNosaveFree(virt_to_page(p));
-               for_each_pbe(p, pagedir_nosave)
+               for_each_pbe (p, pblist)
                        SetPageNosaveFree(virt_to_page(p->address));
                for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
                        if (saveable(zone, &zone_pfn)) {
@@ -370,46 +371,39 @@ void swsusp_free(void)
  *     free pages.
  */
 
-static int enough_free_mem(void)
+static int enough_free_mem(unsigned nr_pages)
 {
        pr_debug("swsusp: available memory: %u pages\n", nr_free_pages());
-       return nr_free_pages() > (nr_copy_pages + PAGES_FOR_IO +
-               nr_copy_pages/PBES_PER_PAGE + !!(nr_copy_pages%PBES_PER_PAGE));
+       return nr_free_pages() > (nr_pages + PAGES_FOR_IO +
+               (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
 }
 
 
-static int swsusp_alloc(void)
+static struct pbe *swsusp_alloc(unsigned nr_pages)
 {
-       struct pbe * p;
-
-       pagedir_nosave = NULL;
-
-       if (MAX_PBES < nr_copy_pages / PBES_PER_PAGE +
-           !!(nr_copy_pages % PBES_PER_PAGE))
-               return -ENOSPC;
+       struct pbe *pblist, *p;
 
-       if (!(pagedir_save = alloc_pagedir(nr_copy_pages))) {
+       if (!(pblist = alloc_pagedir(nr_pages))) {
                printk(KERN_ERR "suspend: Allocating pagedir failed.\n");
-               return -ENOMEM;
+               return NULL;
        }
-       create_pbe_list(pagedir_save, nr_copy_pages);
-       pagedir_nosave = pagedir_save;
+       create_pbe_list(pblist, nr_pages);
 
-       for_each_pbe (p, pagedir_save) {
+       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 -ENOMEM;
+                       return NULL;
                }
        }
 
-       return 0;
+       return pblist;
 }
 
 static int suspend_prepare_image(void)
 {
-       int error;
+       unsigned nr_pages;
 
        pr_debug("swsusp: critical section: \n");
        if (save_highmem()) {
@@ -419,33 +413,37 @@ static int suspend_prepare_image(void)
        }
 
        drain_local_pages();
-       count_data_pages();
-       printk("swsusp: Need to copy %u pages\n", nr_copy_pages);
+       nr_pages = count_data_pages();
+       printk("swsusp: Need to copy %u pages\n", nr_pages);
 
        pr_debug("swsusp: pages needed: %u + %lu + %u, free: %u\n",
-                nr_copy_pages,
-                nr_copy_pages/PBES_PER_PAGE + !!(nr_copy_pages%PBES_PER_PAGE),
+                nr_pages,
+                (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE,
                 PAGES_FOR_IO, nr_free_pages());
 
-       if (!enough_free_mem()) {
+       /* This is needed because of the fixed size of swsusp_info */
+       if (MAX_PBES < (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE)
+               return -ENOSPC;
+
+       if (!enough_free_mem(nr_pages)) {
                printk(KERN_ERR "swsusp: Not enough free memory\n");
                return -ENOMEM;
        }
 
-       if (!enough_swap()) {
+       if (!enough_swap(nr_pages)) {
                printk(KERN_ERR "swsusp: Not enough free swap\n");
                return -ENOSPC;
        }
 
-       error = swsusp_alloc();
-       if (error)
-               return error;
+       pagedir_nosave = swsusp_alloc(nr_pages);
+       if (!pagedir_nosave)
+               return -ENOMEM;
 
        /* During allocating of suspend pagedir, new cold pages may appear.
         * Kill them.
         */
        drain_local_pages();
-       copy_data_pages();
+       copy_data_pages(pagedir_nosave);
 
        /*
         * End of critical section. From now on, we can write to memory,
@@ -453,7 +451,9 @@ static int suspend_prepare_image(void)
         * touch swap space! Except we must write out our image of course.
         */
 
-       printk("swsusp: critical section/: done (%d pages copied)\n", nr_copy_pages );
+       nr_copy_pages = nr_pages;
+
+       printk("swsusp: critical section/: done (%d pages copied)\n", nr_pages);
        return 0;
 }
 
index fc50b5d..f6abfdb 100644 (file)
@@ -550,14 +550,14 @@ static int write_suspend_image(void)
  *     We should only consider resume_device.
  */
 
-int enough_swap(void)
+int enough_swap(unsigned nr_pages)
 {
        struct sysinfo i;
 
        si_swapinfo(&i);
        pr_debug("swsusp: available swap: %lu pages\n", i.freeswap);
-       return i.freeswap > (nr_copy_pages + PAGES_FOR_IO +
-               nr_copy_pages/PBES_PER_PAGE + !!(nr_copy_pages%PBES_PER_PAGE));
+       return i.freeswap > (nr_pages + PAGES_FOR_IO +
+               (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
 }