1 files changed, 637 insertions, 214 deletions

diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 99f9b7d177d6..fd8251d40eb8 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -1,15 +1,15 @@
 /*
  * linux/kernel/power/snapshot.c
  *
- * This file provide system snapshot/restore functionality.
+ * This file provides system snapshot/restore functionality for swsusp.
  *
  * Copyright (C) 1998-2005 Pavel Machek <pavel@suse.cz>
+ * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
  *
- * This file is released under the GPLv2, and is based on swsusp.c.
+ * This file is released under the GPLv2.
  *
  */
 
-
 #include <linux/version.h>
 #include <linux/module.h>
 #include <linux/mm.h>
@@ -34,137 +34,24 @@
 
 #include "power.h"
 
-/* List of PBEs used for creating and restoring the suspend image */
+/* List of PBEs needed for restoring the pages that were allocated before
+ * the suspend and included in the suspend image, but have also been
+ * allocated by the "resume" kernel, so their contents cannot be written
+ * directly to their "original" page frames.
+ */
 struct pbe *restore_pblist;
 
-static unsigned int nr_copy_pages;
-static unsigned int nr_meta_pages;
+/* Pointer to an auxiliary buffer (1 page) */
 static void *buffer;
 
-#ifdef CONFIG_HIGHMEM
-unsigned int count_highmem_pages(void)
-{
-	struct zone *zone;
-	unsigned long zone_pfn;
-	unsigned int n = 0;
-
-	for_each_zone (zone)
-		if (is_highmem(zone)) {
-			mark_free_pages(zone);
-			for (zone_pfn = 0; zone_pfn < zone->spanned_pages; zone_pfn++) {
-				struct page *page;
-				unsigned long pfn = zone_pfn + zone->zone_start_pfn;
-				if (!pfn_valid(pfn))
-					continue;
-				page = pfn_to_page(pfn);
-				if (PageReserved(page))
-					continue;
-				if (PageNosaveFree(page))
-					continue;
-				n++;
-			}
-		}
-	return n;
-}
-
-struct highmem_page {
-	char *data;
-	struct page *page;
-	struct highmem_page *next;
-};
-
-static struct highmem_page *highmem_copy;
-
-static int save_highmem_zone(struct zone *zone)
-{
-	unsigned long zone_pfn;
-	mark_free_pages(zone);
-	for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
-		struct page *page;
-		struct highmem_page *save;
-		void *kaddr;
-		unsigned long pfn = zone_pfn + zone->zone_start_pfn;
-
-		if (!(pfn%10000))
-			printk(".");
-		if (!pfn_valid(pfn))
-			continue;
-		page = pfn_to_page(pfn);
-		/*
-		 * This condition results from rvmalloc() sans vmalloc_32()
-		 * and architectural memory reservations. This should be
-		 * corrected eventually when the cases giving rise to this
-		 * are better understood.
-		 */
-		if (PageReserved(page))
-			continue;
-		BUG_ON(PageNosave(page));
-		if (PageNosaveFree(page))
-			continue;
-		save = kmalloc(sizeof(struct highmem_page), GFP_ATOMIC);
-		if (!save)
-			return -ENOMEM;
-		save->next = highmem_copy;
-		save->page = page;
-		save->data = (void *) get_zeroed_page(GFP_ATOMIC);
-		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;
-}
-
-int save_highmem(void)
-{
-	struct zone *zone;
-	int res = 0;
-
-	pr_debug("swsusp: Saving Highmem");
-	drain_local_pages();
-	for_each_zone (zone) {
-		if (is_highmem(zone))
-			res = save_highmem_zone(zone);
-		if (res)
-			return res;
-	}
-	printk("\n");
-	return 0;
-}
-
-int restore_highmem(void)
-{
-	printk("swsusp: Restoring Highmem\n");
-	while (highmem_copy) {
-		struct highmem_page *save = highmem_copy;
-		void *kaddr;
-		highmem_copy = save->next;
-
-		kaddr = kmap_atomic(save->page, KM_USER0);
-		memcpy(kaddr, save->data, PAGE_SIZE);
-		kunmap_atomic(kaddr, KM_USER0);
-		free_page((long) save->data);
-		kfree(save);
-	}
-	return 0;
-}
-#else
-static inline unsigned int count_highmem_pages(void) {return 0;}
-static inline int save_highmem(void) {return 0;}
-static inline int restore_highmem(void) {return 0;}
-#endif
-
 /**
  *	@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
- *	used before suspend.
+ *	used before suspend.  The unsafe pages have PageNosaveFree set
+ *	and we count them using unsafe_pages.
  *
- *	The unsafe pages are marked with the PG_nosave_free flag
- *	and we count them using unsafe_pages
+ *	Each allocated image page is marked as PageNosave and PageNosaveFree
+ *	so that swsusp_free() can release it.
  */
 
 #define PG_ANY		0
@@ -174,7 +61,7 @@ static inline int restore_highmem(void) {return 0;}
 
 static unsigned int allocated_unsafe_pages;
 
-static void *alloc_image_page(gfp_t gfp_mask, int safe_needed)
+static void *get_image_page(gfp_t gfp_mask, int safe_needed)
 {
 	void *res;
 
@@ -195,20 +82,38 @@ static void *alloc_image_page(gfp_t gfp_mask, int safe_needed)
 
 unsigned long get_safe_page(gfp_t gfp_mask)
 {
-	return (unsigned long)alloc_image_page(gfp_mask, PG_SAFE);
+	return (unsigned long)get_image_page(gfp_mask, PG_SAFE);
+}
+
+static struct page *alloc_image_page(gfp_t gfp_mask) {
+	struct page *page;
+
+	page = alloc_page(gfp_mask);
+	if (page) {
+		SetPageNosave(page);
+		SetPageNosaveFree(page);
+	}
+	return page;
 }
 
 /**
  *	free_image_page - free page represented by @addr, allocated with
- *	alloc_image_page (page flags set by it must be cleared)
+ *	get_image_page (page flags set by it must be cleared)
  */
 
 static inline void free_image_page(void *addr, int clear_nosave_free)
 {
-	ClearPageNosave(virt_to_page(addr));
+	struct page *page;
+
+	BUG_ON(!virt_addr_valid(addr));
+
+	page = virt_to_page(addr);
+
+	ClearPageNosave(page);
 	if (clear_nosave_free)
-		ClearPageNosaveFree(virt_to_page(addr));
-	free_page((unsigned long)addr);
+		ClearPageNosaveFree(page);
+
+	__free_page(page);
 }
 
 /* struct linked_page is used to build chains of pages */
@@ -269,7 +174,7 @@ static void *chain_alloc(struct chain_allocator *ca, unsigned int size)
 	if (LINKED_PAGE_DATA_SIZE - ca->used_space < size) {
 		struct linked_page *lp;
 
-		lp = alloc_image_page(ca->gfp_mask, ca->safe_needed);
+		lp = get_image_page(ca->gfp_mask, ca->safe_needed);
 		if (!lp)
 			return NULL;
 
@@ -446,8 +351,8 @@ memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask, int safe_needed)
 
 	/* Compute the number of zones */
 	nr = 0;
-	for_each_zone (zone)
-		if (populated_zone(zone) && !is_highmem(zone))
+	for_each_zone(zone)
+		if (populated_zone(zone))
 			nr++;
 
 	/* Allocate the list of zones bitmap objects */
@@ -459,10 +364,10 @@ memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask, int safe_needed)
 	}
 
 	/* Initialize the zone bitmap objects */
-	for_each_zone (zone) {
+	for_each_zone(zone) {
 		unsigned long pfn;
 
-		if (!populated_zone(zone) || is_highmem(zone))
+		if (!populated_zone(zone))
 			continue;
 
 		zone_bm->start_pfn = zone->zone_start_pfn;
@@ -481,7 +386,7 @@ memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask, int safe_needed)
 		while (bb) {
 			unsigned long *ptr;
 
-			ptr = alloc_image_page(gfp_mask, safe_needed);
+			ptr = get_image_page(gfp_mask, safe_needed);
 			bb->data = ptr;
 			if (!ptr)
 				goto Free;
@@ -669,9 +574,81 @@ unsigned int snapshot_additional_pages(struct zone *zone)
 
 	res = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
 	res += DIV_ROUND_UP(res * sizeof(struct bm_block), PAGE_SIZE);
-	return res;
+	return 2 * res;
 }
 
+#ifdef CONFIG_HIGHMEM
+/**
+ *	count_free_highmem_pages - compute the total number of free highmem
+ *	pages, system-wide.
+ */
+
+static unsigned int count_free_highmem_pages(void)
+{
+	struct zone *zone;
+	unsigned int cnt = 0;
+
+	for_each_zone(zone)
+		if (populated_zone(zone) && is_highmem(zone))
+			cnt += zone->free_pages;
+
+	return cnt;
+}
+
+/**
+ *	saveable_highmem_page - Determine whether a highmem page should be
+ *	included in the suspend image.
+ *
+ *	We should save the page if it isn't Nosave or NosaveFree, or Reserved,
+ *	and it isn't a part of a free chunk of pages.
+ */
+
+static struct page *saveable_highmem_page(unsigned long pfn)
+{
+	struct page *page;
+
+	if (!pfn_valid(pfn))
+		return NULL;
+
+	page = pfn_to_page(pfn);
+
+	BUG_ON(!PageHighMem(page));
+
+	if (PageNosave(page) || PageReserved(page) || PageNosaveFree(page))
+		return NULL;
+
+	return page;
+}
+
+/**
+ *	count_highmem_pages - compute the total number of saveable highmem
+ *	pages.
+ */
+
+unsigned int count_highmem_pages(void)
+{
+	struct zone *zone;
+	unsigned int n = 0;
+
+	for_each_zone(zone) {
+		unsigned long pfn, max_zone_pfn;
+
+		if (!is_highmem(zone))
+			continue;
+
+		mark_free_pages(zone);
+		max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
+		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
+			if (saveable_highmem_page(pfn))
+				n++;
+	}
+	return n;
+}
+#else
+static inline void *saveable_highmem_page(unsigned long pfn) { return NULL; }
+static inline unsigned int count_highmem_pages(void) { return 0; }
+#endif /* CONFIG_HIGHMEM */
+
 /**
  *	pfn_is_nosave - check if given pfn is in the 'nosave' section
  */
@@ -684,12 +661,12 @@ static inline int pfn_is_nosave(unsigned long pfn)
 }
 
 /**
- *	saveable - Determine whether a page should be cloned or not.
- *	@pfn:	The page
+ *	saveable - Determine whether a non-highmem page should be included in
+ *	the suspend image.
  *
- *	We save a page if it isn't Nosave, and is not in the range of pages
- *	statically defined as 'unsaveable', and it
- *	isn't a part of a free chunk of pages.
+ *	We should save the page if it isn't Nosave, and is not in the range
+ *	of pages statically defined as 'unsaveable', and it isn't a part of
+ *	a free chunk of pages.
  */
 
 static struct page *saveable_page(unsigned long pfn)
@@ -701,76 +678,130 @@ static struct page *saveable_page(unsigned long pfn)
 
 	page = pfn_to_page(pfn);
 
-	if (PageNosave(page))
+	BUG_ON(PageHighMem(page));
+
+	if (PageNosave(page) || PageNosaveFree(page))
 		return NULL;
+
 	if (PageReserved(page) && pfn_is_nosave(pfn))
 		return NULL;
-	if (PageNosaveFree(page))
-		return NULL;
 
 	return page;
 }
 
+/**
+ *	count_data_pages - compute the total number of saveable non-highmem
+ *	pages.
+ */
+
 unsigned int count_data_pages(void)
 {
 	struct zone *zone;
 	unsigned long pfn, max_zone_pfn;
 	unsigned int n = 0;
 
-	for_each_zone (zone) {
+	for_each_zone(zone) {
 		if (is_highmem(zone))
 			continue;
+
 		mark_free_pages(zone);
 		max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
 		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
-			n += !!saveable_page(pfn);
+			if(saveable_page(pfn))
+				n++;
 	}
 	return n;
 }
 
-static inline void copy_data_page(long *dst, long *src)
+/* This is needed, because copy_page and memcpy are not usable for copying
+ * task structs.
+ */
+static inline void do_copy_page(long *dst, long *src)
 {
 	int n;
 
-	/* copy_page and memcpy are not usable for copying task structs. */
 	for (n = PAGE_SIZE / sizeof(long); n; n--)
 		*dst++ = *src++;
 }
 
+#ifdef CONFIG_HIGHMEM
+static inline struct page *
+page_is_saveable(struct zone *zone, unsigned long pfn)
+{
+	return is_highmem(zone) ?
+			saveable_highmem_page(pfn) : saveable_page(pfn);
+}
+
+static inline void
+copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
+{
+	struct page *s_page, *d_page;
+	void *src, *dst;
+
+	s_page = pfn_to_page(src_pfn);
+	d_page = pfn_to_page(dst_pfn);
+	if (PageHighMem(s_page)) {
+		src = kmap_atomic(s_page, KM_USER0);
+		dst = kmap_atomic(d_page, KM_USER1);
+		do_copy_page(dst, src);
+		kunmap_atomic(src, KM_USER0);
+		kunmap_atomic(dst, KM_USER1);
+	} else {
+		src = page_address(s_page);
+		if (PageHighMem(d_page)) {
+			/* Page pointed to by src may contain some kernel
+			 * data modified by kmap_atomic()
+			 */
+			do_copy_page(buffer, src);
+			dst = kmap_atomic(pfn_to_page(dst_pfn), KM_USER0);
+			memcpy(dst, buffer, PAGE_SIZE);
+			kunmap_atomic(dst, KM_USER0);
+		} else {
+			dst = page_address(d_page);
+			do_copy_page(dst, src);
+		}
+	}
+}
+#else
+#define page_is_saveable(zone, pfn)	saveable_page(pfn)
+
+static inline void
+copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
+{
+	do_copy_page(page_address(pfn_to_page(dst_pfn)),
+			page_address(pfn_to_page(src_pfn)));
+}
+#endif /* CONFIG_HIGHMEM */
+
 static void
 copy_data_pages(struct memory_bitmap *copy_bm, struct memory_bitmap *orig_bm)
 {
 	struct zone *zone;
 	unsigned long pfn;
 
-	for_each_zone (zone) {
+	for_each_zone(zone) {
 		unsigned long max_zone_pfn;
 
-		if (is_highmem(zone))
-			continue;
-
 		mark_free_pages(zone);
 		max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
 		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
-			if (saveable_page(pfn))
+			if (page_is_saveable(zone, pfn))
 				memory_bm_set_bit(orig_bm, pfn);
 	}
 	memory_bm_position_reset(orig_bm);
 	memory_bm_position_reset(copy_bm);
 	do {
 		pfn = memory_bm_next_pfn(orig_bm);
-		if (likely(pfn != BM_END_OF_MAP)) {
-			struct page *page;
-			void *src;
-
-			page = pfn_to_page(pfn);
-			src = page_address(page);
-			page = pfn_to_page(memory_bm_next_pfn(copy_bm));
-			copy_data_page(page_address(page), src);
-		}
+		if (likely(pfn != BM_END_OF_MAP))
+			copy_data_page(memory_bm_next_pfn(copy_bm), pfn);
 	} while (pfn != BM_END_OF_MAP);
 }
 
+/* Total number of image pages */
+static unsigned int nr_copy_pages;
+/* Number of pages needed for saving the original pfns of the image pages */
+static unsigned int nr_meta_pages;
+
 /**
  *	swsusp_free - free pages allocated for the suspend.
  *
@@ -792,7 +823,7 @@ void swsusp_free(void)
 				if (PageNosave(page) && PageNosaveFree(page)) {
 					ClearPageNosave(page);
 					ClearPageNosaveFree(page);
-					free_page((long) page_address(page));
+					__free_page(page);
 				}
 			}
 	}
@@ -802,34 +833,108 @@ void swsusp_free(void)
 	buffer = NULL;
 }
 
+#ifdef CONFIG_HIGHMEM
+/**
+  *	count_pages_for_highmem - compute the number of non-highmem pages
+  *	that will be necessary for creating copies of highmem pages.
+  */
+
+static unsigned int count_pages_for_highmem(unsigned int nr_highmem)
+{
+	unsigned int free_highmem = count_free_highmem_pages();
+
+	if (free_highmem >= nr_highmem)
+		nr_highmem = 0;
+	else
+		nr_highmem -= free_highmem;
+
+	return nr_highmem;
+}
+#else
+static unsigned int
+count_pages_for_highmem(unsigned int nr_highmem) { return 0; }
+#endif /* CONFIG_HIGHMEM */
 
 /**
- *	enough_free_mem - Make sure we enough free memory to snapshot.
- *
- *	Returns TRUE or FALSE after checking the number of available
- *	free pages.
+ *	enough_free_mem - Make sure we have enough free memory for the
+ *	snapshot image.
  */
 
-static int enough_free_mem(unsigned int nr_pages)
+static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem)
 {
 	struct zone *zone;
 	unsigned int free = 0, meta = 0;
 
-	for_each_zone (zone)
-		if (!is_highmem(zone)) {
+	for_each_zone(zone) {
+		meta += snapshot_additional_pages(zone);
+		if (!is_highmem(zone))
 			free += zone->free_pages;
-			meta += snapshot_additional_pages(zone);
-		}
+	}
 
-	pr_debug("swsusp: pages needed: %u + %u + %u, available pages: %u\n",
+	nr_pages += count_pages_for_highmem(nr_highmem);
+	pr_debug("swsusp: Normal pages needed: %u + %u + %u, available pages: %u\n",
 		nr_pages, PAGES_FOR_IO, meta, free);
 
 	return free > nr_pages + PAGES_FOR_IO + meta;
 }
 
+#ifdef CONFIG_HIGHMEM
+/**
+ *	get_highmem_buffer - if there are some highmem pages in the suspend
+ *	image, we may need the buffer to copy them and/or load their data.
+ */
+
+static inline int get_highmem_buffer(int safe_needed)
+{
+	buffer = get_image_page(GFP_ATOMIC | __GFP_COLD, safe_needed);
+	return buffer ? 0 : -ENOMEM;
+}
+
+/**
+ *	alloc_highmem_image_pages - allocate some highmem pages for the image.
+ *	Try to allocate as many pages as needed, but if the number of free
+ *	highmem pages is lesser than that, allocate them all.
+ */
+
+static inline unsigned int
+alloc_highmem_image_pages(struct memory_bitmap *bm, unsigned int nr_highmem)
+{
+	unsigned int to_alloc = count_free_highmem_pages();
+
+	if (to_alloc > nr_highmem)
+		to_alloc = nr_highmem;
+
+	nr_highmem -= to_alloc;
+	while (to_alloc-- > 0) {
+		struct page *page;
+
+		page = alloc_image_page(__GFP_HIGHMEM);
+		memory_bm_set_bit(bm, page_to_pfn(page));
+	}
+	return nr_highmem;
+}
+#else
+static inline int get_highmem_buffer(int safe_needed) { return 0; }
+
+static inline unsigned int
+alloc_highmem_image_pages(struct memory_bitmap *bm, unsigned int n) { return 0; }
+#endif /* CONFIG_HIGHMEM */
+
+/**
+ *	swsusp_alloc - allocate memory for the suspend image
+ *
+ *	We first try to allocate as many highmem pages as there are
+ *	saveable highmem pages in the system.  If that fails, we allocate
+ *	non-highmem pages for the copies of the remaining highmem ones.
+ *
+ *	In this approach it is likely that the copies of highmem pages will
+ *	also be located in the high memory, because of the way in which
+ *	copy_data_pages() works.
+ */
+
 static int
 swsusp_alloc(struct memory_bitmap *orig_bm, struct memory_bitmap *copy_bm,
-		unsigned int nr_pages)
+		unsigned int nr_pages, unsigned int nr_highmem)
 {
 	int error;
 
@@ -841,13 +946,19 @@ swsusp_alloc(struct memory_bitmap *orig_bm, struct memory_bitmap *copy_bm,
 	if (error)
 		goto Free;
 
+	if (nr_highmem > 0) {
+		error = get_highmem_buffer(PG_ANY);
+		if (error)
+			goto Free;
+
+		nr_pages += alloc_highmem_image_pages(copy_bm, nr_highmem);
+	}
 	while (nr_pages-- > 0) {
-		struct page *page = alloc_page(GFP_ATOMIC | __GFP_COLD);
+		struct page *page = alloc_image_page(GFP_ATOMIC | __GFP_COLD);
+
 		if (!page)
 			goto Free;
 
-		SetPageNosave(page);
-		SetPageNosaveFree(page);
 		memory_bm_set_bit(copy_bm, page_to_pfn(page));
 	}
 	return 0;
@@ -857,30 +968,39 @@ Free:
 	return -ENOMEM;
 }
 
-/* Memory bitmap used for marking saveable pages */
+/* Memory bitmap used for marking saveable pages (during suspend) or the
+ * suspend image pages (during resume)
+ */
 static struct memory_bitmap orig_bm;
-/* Memory bitmap used for marking allocated pages that will contain the copies
- * of saveable pages
+/* Memory bitmap used on suspend for marking allocated pages that will contain
+ * the copies of saveable pages.  During resume it is initially used for
+ * marking the suspend image pages, but then its set bits are duplicated in
+ * @orig_bm and it is released.  Next, on systems with high memory, it may be
+ * used for marking "safe" highmem pages, but it has to be reinitialized for
+ * this purpose.
  */
 static struct memory_bitmap copy_bm;
 
 asmlinkage int swsusp_save(void)
 {
-	unsigned int nr_pages;
+	unsigned int nr_pages, nr_highmem;
 
-	pr_debug("swsusp: critical section: \n");
+	printk("swsusp: critical section: \n");
 
 	drain_local_pages();
 	nr_pages = count_data_pages();
-	printk("swsusp: Need to copy %u pages\n", nr_pages);
+	nr_highmem = count_highmem_pages();
+	printk("swsusp: Need to copy %u pages\n", nr_pages + nr_highmem);
 
-	if (!enough_free_mem(nr_pages)) {
+	if (!enough_free_mem(nr_pages, nr_highmem)) {
 		printk(KERN_ERR "swsusp: Not enough free memory\n");
 		return -ENOMEM;
 	}
 
-	if (swsusp_alloc(&orig_bm, &copy_bm, nr_pages))
+	if (swsusp_alloc(&orig_bm, &copy_bm, nr_pages, nr_highmem)) {
+		printk(KERN_ERR "swsusp: Memory allocation failed\n");
 		return -ENOMEM;
+	}
 
 	/* During allocating of suspend pagedir, new cold pages may appear.
 	 * Kill them.
@@ -894,10 +1014,12 @@ asmlinkage int swsusp_save(void)
 	 * touch swap space! Except we must write out our image of course.
 	 */
 
+	nr_pages += nr_highmem;
 	nr_copy_pages = nr_pages;
-	nr_meta_pages = (nr_pages * sizeof(long) + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	nr_meta_pages = DIV_ROUND_UP(nr_pages * sizeof(long), PAGE_SIZE);
 
 	printk("swsusp: critical section/: done (%d pages copied)\n", nr_pages);
+
 	return 0;
 }
 
@@ -960,7 +1082,7 @@ int snapshot_read_next(struct snapshot_handle *handle, size_t count)
 
 	if (!buffer) {
 		/* This makes the buffer be freed by swsusp_free() */
-		buffer = alloc_image_page(GFP_ATOMIC, PG_ANY);
+		buffer = get_image_page(GFP_ATOMIC, PG_ANY);
 		if (!buffer)
 			return -ENOMEM;
 	}
@@ -975,9 +1097,23 @@ int snapshot_read_next(struct snapshot_handle *handle, size_t count)
 			memset(buffer, 0, PAGE_SIZE);
 			pack_pfns(buffer, &orig_bm);
 		} else {
-			unsigned long pfn = memory_bm_next_pfn(&copy_bm);
+			struct page *page;
 
-			handle->buffer = page_address(pfn_to_page(pfn));
+			page = pfn_to_page(memory_bm_next_pfn(&copy_bm));
+			if (PageHighMem(page)) {
+				/* Highmem pages are copied to the buffer,
+				 * because we can't return with a kmapped
+				 * highmem page (we may not be called again).
+				 */
+				void *kaddr;
+
+				kaddr = kmap_atomic(page, KM_USER0);
+				memcpy(buffer, kaddr, PAGE_SIZE);
+				kunmap_atomic(kaddr, KM_USER0);
+				handle->buffer = buffer;
+			} else {
+				handle->buffer = page_address(page);
+			}
 		}
 		handle->prev = handle->cur;
 	}
@@ -1005,7 +1141,7 @@ static int mark_unsafe_pages(struct memory_bitmap *bm)
 	unsigned long pfn, max_zone_pfn;
 
 	/* Clear page flags */
-	for_each_zone (zone) {
+	for_each_zone(zone) {
 		max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
 		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
 			if (pfn_valid(pfn))
@@ -1101,6 +1237,218 @@ unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
 	}
 }
 
+/* List of "safe" pages that may be used to store data loaded from the suspend
+ * image
+ */
+static struct linked_page *safe_pages_list;
+
+#ifdef CONFIG_HIGHMEM
+/* struct highmem_pbe is used for creating the list of highmem pages that
+ * should be restored atomically during the resume from disk, because the page
+ * frames they have occupied before the suspend are in use.
+ */
+struct highmem_pbe {
+	struct page *copy_page;	/* data is here now */
+	struct page *orig_page;	/* data was here before the suspend */
+	struct highmem_pbe *next;
+};
+
+/* List of highmem PBEs needed for restoring the highmem pages that were
+ * allocated before the suspend and included in the suspend image, but have
+ * also been allocated by the "resume" kernel, so their contents cannot be
+ * written directly to their "original" page frames.
+ */
+static struct highmem_pbe *highmem_pblist;
+
+/**
+ *	count_highmem_image_pages - compute the number of highmem pages in the
+ *	suspend image.  The bits in the memory bitmap @bm that correspond to the
+ *	image pages are assumed to be set.
+ */
+
+static unsigned int count_highmem_image_pages(struct memory_bitmap *bm)
+{
+	unsigned long pfn;
+	unsigned int cnt = 0;
+
+	memory_bm_position_reset(bm);
+	pfn = memory_bm_next_pfn(bm);
+	while (pfn != BM_END_OF_MAP) {
+		if (PageHighMem(pfn_to_page(pfn)))
+			cnt++;
+
+		pfn = memory_bm_next_pfn(bm);
+	}
+	return cnt;
+}
+
+/**
+ *	prepare_highmem_image - try to allocate as many highmem pages as
+ *	there are highmem image pages (@nr_highmem_p points to the variable
+ *	containing the number of highmem image pages).  The pages that are
+ *	"safe" (ie. will not be overwritten when the suspend image is
+ *	restored) have the corresponding bits set in @bm (it must be
+ *	unitialized).
+ *
+ *	NOTE: This function should not be called if there are no highmem
+ *	image pages.
+ */
+
+static unsigned int safe_highmem_pages;
+
+static struct memory_bitmap *safe_highmem_bm;
+
+static int
+prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p)
+{
+	unsigned int to_alloc;
+
+	if (memory_bm_create(bm, GFP_ATOMIC, PG_SAFE))
+		return -ENOMEM;
+
+	if (get_highmem_buffer(PG_SAFE))
+		return -ENOMEM;
+
+	to_alloc = count_free_highmem_pages();
+	if (to_alloc > *nr_highmem_p)
+		to_alloc = *nr_highmem_p;
+	else
+		*nr_highmem_p = to_alloc;
+
+	safe_highmem_pages = 0;
+	while (to_alloc-- > 0) {
+		struct page *page;
+
+		page = alloc_page(__GFP_HIGHMEM);
+		if (!PageNosaveFree(page)) {
+			/* The page is "safe", set its bit the bitmap */
+			memory_bm_set_bit(bm, page_to_pfn(page));
+			safe_highmem_pages++;
+		}
+		/* Mark the page as allocated */
+		SetPageNosave(page);
+		SetPageNosaveFree(page);
+	}
+	memory_bm_position_reset(bm);
+	safe_highmem_bm = bm;
+	return 0;
+}
+
+/**
+ *	get_highmem_page_buffer - for given highmem image page find the buffer
+ *	that suspend_write_next() should set for its caller to write to.
+ *
+ *	If the page is to be saved to its "original" page frame or a copy of
+ *	the page is to be made in the highmem, @buffer is returned.  Otherwise,
+ *	the copy of the page is to be made in normal memory, so the address of
+ *	the copy is returned.
+ *
+ *	If @buffer is returned, the caller of suspend_write_next() will write
+ *	the page's contents to @buffer, so they will have to be copied to the
+ *	right location on the next call to suspend_write_next() and it is done
+ *	with the help of copy_last_highmem_page().  For this purpose, if
+ *	@buffer is returned, @last_highmem page is set to the page to which
+ *	the data will have to be copied from @buffer.
+ */
+
+static struct page *last_highmem_page;
+
+static void *
+get_highmem_page_buffer(struct page *page, struct chain_allocator *ca)
+{
+	struct highmem_pbe *pbe;
+	void *kaddr;
+
+	if (PageNosave(page) && PageNosaveFree(page)) {
+		/* We have allocated the "original" page frame and we can
+		 * use it directly to store the loaded page.
+		 */
+		last_highmem_page = page;
+		return buffer;
+	}
+	/* The "original" page frame has not been allocated and we have to
+	 * use a "safe" page frame to store the loaded page.
+	 */
+	pbe = chain_alloc(ca, sizeof(struct highmem_pbe));
+	if (!pbe) {
+		swsusp_free();
+		return NULL;
+	}
+	pbe->orig_page = page;
+	if (safe_highmem_pages > 0) {
+		struct page *tmp;
+
+		/* Copy of the page will be stored in high memory */
+		kaddr = buffer;
+		tmp = pfn_to_page(memory_bm_next_pfn(safe_highmem_bm));
+		safe_highmem_pages--;
+		last_highmem_page = tmp;
+		pbe->copy_page = tmp;
+	} else {
+		/* Copy of the page will be stored in normal memory */
+		kaddr = safe_pages_list;
+		safe_pages_list = safe_pages_list->next;
+		pbe->copy_page = virt_to_page(kaddr);
+	}
+	pbe->next = highmem_pblist;
+	highmem_pblist = pbe;
+	return kaddr;
+}
+
+/**
+ *	copy_last_highmem_page - copy the contents of a highmem image from
+ *	@buffer, where the caller of snapshot_write_next() has place them,
+ *	to the right location represented by @last_highmem_page .
+ */
+
+static void copy_last_highmem_page(void)
+{
+	if (last_highmem_page) {
+		void *dst;
+
+		dst = kmap_atomic(last_highmem_page, KM_USER0);
+		memcpy(dst, buffer, PAGE_SIZE);
+		kunmap_atomic(dst, KM_USER0);
+		last_highmem_page = NULL;
+	}
+}
+
+static inline int last_highmem_page_copied(void)
+{
+	return !last_highmem_page;
+}
+
+static inline void free_highmem_data(void)
+{
+	if (safe_highmem_bm)
+		memory_bm_free(safe_highmem_bm, PG_UNSAFE_CLEAR);
+
+	if (buffer)
+		free_image_page(buffer, PG_UNSAFE_CLEAR);
+}
+#else
+static inline int get_safe_write_buffer(void) { return 0; }
+
+static unsigned int
+count_highmem_image_pages(struct memory_bitmap *bm) { return 0; }
+
+static inline int
+prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p)
+{
+	return 0;
+}
+
+static inline void *
+get_highmem_page_buffer(struct page *page, struct chain_allocator *ca)
+{
+	return NULL;
+}
+
+static inline void copy_last_highmem_page(void) {}
+static inline int last_highmem_page_copied(void) { return 1; }
+static inline void free_highmem_data(void) {}
+#endif /* CONFIG_HIGHMEM */
+
 /**
  *	prepare_image - use the memory bitmap @bm to mark the pages that will
  *	be overwritten in the process of restoring the system memory state
@@ -1110,20 +1458,25 @@ unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
  *	The idea is to allocate a new memory bitmap first and then allocate
  *	as many pages as needed for the image data, but not to assign these
  *	pages to specific tasks initially.  Instead, we just mark them as
- *	allocated and create a list of "safe" pages that will be used later.
+ *	allocated and create a lists of "safe" pages that will be used
+ *	later.  On systems with high memory a list of "safe" highmem pages is
+ *	also created.
  */
 
 #define PBES_PER_LINKED_PAGE	(LINKED_PAGE_DATA_SIZE / sizeof(struct pbe))
 
-static struct linked_page *safe_pages_list;
-
 static int
 prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm)
 {
-	unsigned int nr_pages;
+	unsigned int nr_pages, nr_highmem;
 	struct linked_page *sp_list, *lp;
 	int error;
 
+	/* If there is no highmem, the buffer will not be necessary */
+	free_image_page(buffer, PG_UNSAFE_CLEAR);
+	buffer = NULL;
+
+	nr_highmem = count_highmem_image_pages(bm);
 	error = mark_unsafe_pages(bm);
 	if (error)
 		goto Free;
@@ -1134,6 +1487,11 @@ prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm)
 
 	duplicate_memory_bitmap(new_bm, bm);
 	memory_bm_free(bm, PG_UNSAFE_KEEP);
+	if (nr_highmem > 0) {
+		error = prepare_highmem_image(bm, &nr_highmem);
+		if (error)
+			goto Free;
+	}
 	/* Reserve some safe pages for potential later use.
 	 *
 	 * NOTE: This way we make sure there will be enough safe pages for the
@@ -1142,10 +1500,10 @@ prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm)
 	 */
 	sp_list = NULL;
 	/* nr_copy_pages cannot be lesser than allocated_unsafe_pages */
-	nr_pages = nr_copy_pages - allocated_unsafe_pages;
+	nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
 	nr_pages = DIV_ROUND_UP(nr_pages, PBES_PER_LINKED_PAGE);
 	while (nr_pages > 0) {
-		lp = alloc_image_page(GFP_ATOMIC, PG_SAFE);
+		lp = get_image_page(GFP_ATOMIC, PG_SAFE);
 		if (!lp) {
 			error = -ENOMEM;
 			goto Free;
@@ -1156,7 +1514,7 @@ prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm)
 	}
 	/* Preallocate memory for the image */
 	safe_pages_list = NULL;
-	nr_pages = nr_copy_pages - allocated_unsafe_pages;
+	nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
 	while (nr_pages > 0) {
 		lp = (struct linked_page *)get_zeroed_page(GFP_ATOMIC);
 		if (!lp) {
@@ -1196,6 +1554,9 @@ static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
 	struct pbe *pbe;
 	struct page *page = pfn_to_page(memory_bm_next_pfn(bm));
 
+	if (PageHighMem(page))
+		return get_highmem_page_buffer(page, ca);
+
 	if (PageNosave(page) && PageNosaveFree(page))
 		/* We have allocated the "original" page frame and we can
 		 * use it directly to store the loaded page.
@@ -1210,12 +1571,12 @@ static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
 		swsusp_free();
 		return NULL;
 	}
-	pbe->orig_address = (unsigned long)page_address(page);
-	pbe->address = (unsigned long)safe_pages_list;
+	pbe->orig_address = page_address(page);
+	pbe->address = safe_pages_list;
 	safe_pages_list = safe_pages_list->next;
 	pbe->next = restore_pblist;
 	restore_pblist = pbe;
-	return (void *)pbe->address;
+	return pbe->address;
 }
 
 /**
@@ -1249,14 +1610,16 @@ int snapshot_write_next(struct snapshot_handle *handle, size_t count)
 	if (handle->prev && handle->cur > nr_meta_pages + nr_copy_pages)
 		return 0;
 
-	if (!buffer) {
-		/* This makes the buffer be freed by swsusp_free() */
-		buffer = alloc_image_page(GFP_ATOMIC, PG_ANY);
+	if (handle->offset == 0) {
+		if (!buffer)
+			/* This makes the buffer be freed by swsusp_free() */
+			buffer = get_image_page(GFP_ATOMIC, PG_ANY);
+
 		if (!buffer)
 			return -ENOMEM;
-	}
-	if (!handle->offset)
+
 		handle->buffer = buffer;
+	}
 	handle->sync_read = 1;
 	if (handle->prev < handle->cur) {
 		if (handle->prev == 0) {
@@ -1284,8 +1647,10 @@ int snapshot_write_next(struct snapshot_handle *handle, size_t count)
 					return -ENOMEM;
 			}
 		} else {
+			copy_last_highmem_page();
 			handle->buffer = get_buffer(&orig_bm, &ca);
-			handle->sync_read = 0;
+			if (handle->buffer != buffer)
+				handle->sync_read = 0;
 		}
 		handle->prev = handle->cur;
 	}
@@ -1301,15 +1666,73 @@ int snapshot_write_next(struct snapshot_handle *handle, size_t count)
 	return count;
 }
 
+/**
+ *	snapshot_write_finalize - must be called after the last call to
+ *	snapshot_write_next() in case the last page in the image happens
+ *	to be a highmem page and its contents should be stored in the
+ *	highmem.  Additionally, it releases the memory that will not be
+ *	used any more.
+ */
+
+void snapshot_write_finalize(struct snapshot_handle *handle)
+{
+	copy_last_highmem_page();
+	/* Free only if we have loaded the image entirely */
+	if (handle->prev && handle->cur > nr_meta_pages + nr_copy_pages) {
+		memory_bm_free(&orig_bm, PG_UNSAFE_CLEAR);
+		free_highmem_data();
+	}
+}
+
 int snapshot_image_loaded(struct snapshot_handle *handle)
 {
-	return !(!nr_copy_pages ||
+	return !(!nr_copy_pages || !last_highmem_page_copied() ||
 			handle->cur <= nr_meta_pages + nr_copy_pages);
 }
 
-void snapshot_free_unused_memory(struct snapshot_handle *handle)
+#ifdef CONFIG_HIGHMEM
+/* Assumes that @buf is ready and points to a "safe" page */
+static inline void
+swap_two_pages_data(struct page *p1, struct page *p2, void *buf)
 {
-	/* Free only if we have loaded the image entirely */
-	if (handle->prev && handle->cur > nr_meta_pages + nr_copy_pages)
-		memory_bm_free(&orig_bm, PG_UNSAFE_CLEAR);
+	void *kaddr1, *kaddr2;
+
+	kaddr1 = kmap_atomic(p1, KM_USER0);
+	kaddr2 = kmap_atomic(p2, KM_USER1);
+	memcpy(buf, kaddr1, PAGE_SIZE);
+	memcpy(kaddr1, kaddr2, PAGE_SIZE);
+	memcpy(kaddr2, buf, PAGE_SIZE);
+	kunmap_atomic(kaddr1, KM_USER0);
+	kunmap_atomic(kaddr2, KM_USER1);
+}
+
+/**
+ *	restore_highmem - for each highmem page that was allocated before
+ *	the suspend and included in the suspend image, and also has been
+ *	allocated by the "resume" kernel swap its current (ie. "before
+ *	resume") contents with the previous (ie. "before suspend") one.
+ *
+ *	If the resume eventually fails, we can call this function once
+ *	again and restore the "before resume" highmem state.
+ */
+
+int restore_highmem(void)
+{
+	struct highmem_pbe *pbe = highmem_pblist;
+	void *buf;
+
+	if (!pbe)
+		return 0;
+
+	buf = get_image_page(GFP_ATOMIC, PG_SAFE);
+	if (!buf)
+		return -ENOMEM;
+
+	while (pbe) {
+		swap_two_pages_data(pbe->copy_page, pbe->orig_page, buf);
+		pbe = pbe->next;
+	}
+	free_image_page(buf, PG_UNSAFE_CLEAR);
+	return 0;
 }
+#endif /* CONFIG_HIGHMEM */