[PATCH] swsusp update: supports discontingmem/highmem fixes

From: Pavel Machek <pavel@ucw.cz>

It makes swsusp behave correctly w.r.t.  discontingmem, and adds highmem
handling.

diff --git a/arch/i386/power/swsusp.S b/arch/i386/power/swsusp.S
index 6fad0ed51f9fcd471a0c4609c3c06b9a3302f8b7..ac2b57d7a045b9ff624c56174a02726f29b9c31f 100644 (file)
--- a/arch/i386/power/swsusp.S
+++ b/arch/i386/power/swsusp.S
@@ -1,6 +1,13 @@
 .text
 
-/* Originally gcc generated, modified by hand */
+/* Originally gcc generated, modified by hand
+ *
+ * This may not use any stack, nor any variable that is not "NoSave":
+ *
+ * Its rewriting one kernel image with another. What is stack in "old"
+ * image could very well be data page in "new" image, and overwriting
+ * your own stack under you is bad idea.
+ */
 
 #include <linux/linkage.h>
 #include <asm/segment.h>

diff --git a/kernel/power/swsusp.c b/kernel/power/swsusp.c
index 23e577559fd9766100dbac9e64d14e3cb42fb223..8f78d68075764e7ad6a6fc61790c83b259abae04 100644 (file)
--- a/kernel/power/swsusp.c
+++ b/kernel/power/swsusp.c
@@ -225,7 +225,7 @@ static void mark_swapfiles(swp_entry_t prev, int mode)
 static void read_swapfiles(void) /* This is called before saving image */
 {
        int i, len;
-       char buff[sizeof(resume_file)], *sname;
+       static char buff[sizeof(resume_file)], *sname;
        
        len=strlen(resume_file);
        root_swap = 0xFFFF;
@@ -366,6 +366,7 @@ static int write_suspend_image(void)
        return 0;
 }
 
+#ifdef CONFIG_HIGHMEM
 struct highmem_page {
        char *data;
        struct page *page;
@@ -374,7 +375,7 @@ struct highmem_page {
 
 struct highmem_page *highmem_copy = NULL;
 
-static void save_highmem_zone(struct zone *zone)
+static int save_highmem_zone(struct zone *zone)
 {
        unsigned long zone_pfn;
        for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
@@ -384,7 +385,7 @@ static void save_highmem_zone(struct zone *zone)
                unsigned long pfn = zone_pfn + zone->zone_start_pfn;
                int chunk_size;
 
-               if (!(pfn%200))
+               if (!(pfn%1000))
                        printk(".");
                if (!pfn_valid(pfn))
                        continue;
@@ -397,7 +398,7 @@ static void save_highmem_zone(struct zone *zone)
                 */
                if (PageReserved(page)) {
                        printk("highmem reserved page?!\n");
-                       BUG();
+                       continue;
                }
                if ((chunk_size = is_head_of_free_region(page))) {
                        pfn += chunk_size - 1;
@@ -406,26 +407,33 @@ static void save_highmem_zone(struct zone *zone)
                }
                save = kmalloc(sizeof(struct highmem_page), GFP_ATOMIC);
                if (!save)
-                       panic("Not enough memory");
+                       return -ENOMEM;
                save->next = highmem_copy;
                save->page = page;
                save->data = (void *) get_zeroed_page(GFP_ATOMIC);
-               if (!save->data)
-                       panic("Not enough memory");
+               if (!save->data) {
+                       kfree(save);
+                       return -ENOMEM;
+               }
                kaddr = kmap_atomic(page, KM_USER0);
                memcpy(save->data, kaddr, PAGE_SIZE);
                kunmap_atomic(kaddr, KM_USER0);
                highmem_copy = save;
        }
+       return 0;
 }
 
-static void save_highmem(void)
+static int save_highmem(void)
 {
        struct zone *zone;
+       int res = 0;
        for_each_zone(zone) {
                if (is_highmem(zone))
-                       save_highmem_zone(zone);
+                       res = save_highmem_zone(zone);
+               if (res)
+                       return res;
        }
+       return 0;
 }
 
 static int restore_highmem(void)
@@ -443,6 +451,7 @@ static int restore_highmem(void)
        }
        return 0;
 }
+#endif
 
 static int pfn_is_nosave(unsigned long pfn)
 {
@@ -460,7 +469,7 @@ static int count_and_copy_zone(struct zone *zone, struct pbe **pagedir_p)
                struct page *page;
                unsigned long pfn = zone_pfn + zone->zone_start_pfn;
 
-               if (!(pfn%200))
+               if (!(pfn%1000))
                        printk(".");
                if (!pfn_valid(pfn))
                        continue;
@@ -548,7 +557,7 @@ static suspend_pagedir_t *create_suspend_pagedir(int nr_copy_pages)
                
        while(nr_copy_pages--) {
                p->address = get_zeroed_page(GFP_ATOMIC | __GFP_COLD);
-               if(!p->address) {
+               if (!p->address) {
                        free_suspend_pagedir((unsigned long) pagedir);
                        return NULL;
                }
@@ -589,10 +598,17 @@ static int suspend_prepare_image(void)
        unsigned int nr_needed_pages = 0;
 
        pagedir_nosave = NULL;
-       printk( "/critical section: Handling highmem" );
-       save_highmem();
+       printk( "/critical section: ");
+#ifdef CONFIG_HIGHMEM
+       printk( "handling highmem" );
+       if (save_highmem()) {
+               printk(KERN_CRIT "%sNot enough free pages for highmem\n", name_suspend);
+               return -ENOMEM;
+       }
+       printk(", ");
+#endif
 
-       printk(", counting pages to copy" );
+       printk("counting pages to copy" );
        drain_local_pages();
        nr_copy_pages = count_and_copy_data_pages(NULL);
        nr_needed_pages = nr_copy_pages + PAGES_FOR_IO;
@@ -602,23 +618,22 @@ static int suspend_prepare_image(void)
                printk(KERN_CRIT "%sCouldn't get enough free pages, on %d pages short\n",
                       name_suspend, nr_needed_pages-nr_free_pages());
                root_swap = 0xFFFF;
-               return 1;
+               return -ENOMEM;
        }
        si_swapinfo(&i);        /* FIXME: si_swapinfo(&i) returns all swap devices information.
                                   We should only consider resume_device. */
        if (i.freeswap < nr_needed_pages)  {
                printk(KERN_CRIT "%sThere's not enough swap space available, on %ld pages short\n",
                       name_suspend, nr_needed_pages-i.freeswap);
-               return 1;
+               return -ENOSPC;
        }
 
        PRINTK( "Alloc pagedir\n" ); 
        pagedir_save = pagedir_nosave = create_suspend_pagedir(nr_copy_pages);
-       if(!pagedir_nosave) {
-               /* Shouldn't happen */
-               printk(KERN_CRIT "%sCouldn't allocate enough pages\n",name_suspend);
-               panic("Really should not happen");
-               return 1;
+       if (!pagedir_nosave) {
+               /* Pagedir is big, one-chunk allocation. It is easily possible for this allocation to fail */
+               printk(KERN_CRIT "%sCouldn't allocate continuous pagedir\n", name_suspend);
+               return -ENOMEM;
        }
        nr_copy_pages_check = nr_copy_pages;
        pagedir_order_check = pagedir_order;
@@ -702,8 +717,10 @@ asmlinkage void do_magic_resume_2(void)
        PRINTK( "Freeing prev allocated pagedir\n" );
        free_suspend_pagedir((unsigned long) pagedir_save);
 
+#ifdef CONFIG_HIGHMEM
        printk( "Restoring highmem\n" );
        restore_highmem();
+#endif
        printk("done, devices\n");
 
        device_power_up();