4 files changed, 186 insertions, 246 deletions

diff --git a/kernel/power/power.h b/kernel/power/power.h
index 6e9e2acc34f..bfe999f7b27 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -81,16 +81,6 @@ struct snapshot_handle {
 	unsigned int	prev;	/* number of the block of PAGE_SIZE bytes that
 				 * was the current one previously
 				 */
-	struct pbe	*pbe;	/* PBE that corresponds to 'buffer' */
-	struct pbe	*last_pbe;	/* When the image is restored (eg. read
-					 * from disk) we can store some image
-					 * data directly in the page frames
-					 * in which they were before suspend.
-					 * In such a case the PBEs that
-					 * correspond to them will be unused.
-					 * This is the last PBE, so far, that
-					 * does not correspond to such data.
-					 */
 	void		*buffer;	/* address of the block to read from
 					 * or write to
 					 */
@@ -113,6 +103,7 @@ extern unsigned int snapshot_additional_pages(struct zone *zone);
 extern int snapshot_read_next(struct snapshot_handle *handle, size_t count);
 extern int snapshot_write_next(struct snapshot_handle *handle, size_t count);
 extern int snapshot_image_loaded(struct snapshot_handle *handle);
+extern void snapshot_free_unused_memory(struct snapshot_handle *handle);
 
 #define SNAPSHOT_IOC_MAGIC	'3'
 #define SNAPSHOT_FREEZE			_IO(SNAPSHOT_IOC_MAGIC, 1)
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 852e0df4171..1b84313cbab 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -39,7 +39,7 @@ struct pbe *restore_pblist;
 
 static unsigned int nr_copy_pages;
 static unsigned int nr_meta_pages;
-static unsigned long *buffer;
+static void *buffer;
 
 #ifdef CONFIG_HIGHMEM
 unsigned int count_highmem_pages(void)
@@ -172,7 +172,7 @@ static inline int restore_highmem(void) {return 0;}
 #define PG_UNSAFE_CLEAR	1
 #define PG_UNSAFE_KEEP	0
 
-static unsigned int unsafe_pages;
+static unsigned int allocated_unsafe_pages;
 
 static void *alloc_image_page(gfp_t gfp_mask, int safe_needed)
 {
@@ -183,7 +183,7 @@ static void *alloc_image_page(gfp_t gfp_mask, int safe_needed)
 		while (res && PageNosaveFree(virt_to_page(res))) {
 			/* The page is unsafe, mark it for swsusp_free() */
 			SetPageNosave(virt_to_page(res));
-			unsafe_pages++;
+			allocated_unsafe_pages++;
 			res = (void *)get_zeroed_page(gfp_mask);
 		}
 	if (res) {
@@ -772,101 +772,10 @@ copy_data_pages(struct memory_bitmap *copy_bm, struct memory_bitmap *orig_bm)
 }
 
 /**
- *	free_pagedir - free pages allocated with alloc_pagedir()
- */
-
-static void free_pagedir(struct pbe *pblist, int clear_nosave_free)
-{
-	struct pbe *pbe;
-
-	while (pblist) {
-		pbe = (pblist + PB_PAGE_SKIP)->next;
-		free_image_page(pblist, clear_nosave_free);
-		pblist = pbe;
-	}
-}
-
-/**
- *	fill_pb_page - Create a list of PBEs on a given memory page
- */
-
-static inline void fill_pb_page(struct pbe *pbpage, unsigned int n)
-{
-	struct pbe *p;
-
-	p = pbpage;
-	pbpage += n - 1;
-	do
-		p->next = p + 1;
-	while (++p < pbpage);
-}
-
-/**
- *	create_pbe_list - Create a list of PBEs on top of a given chain
- *	of memory pages allocated with alloc_pagedir()
+ *	swsusp_free - free pages allocated for the suspend.
  *
- *	This function assumes that pages allocated by alloc_image_page() will
- *	always be zeroed.
- */
-
-static inline void create_pbe_list(struct pbe *pblist, unsigned int nr_pages)
-{
-	struct pbe *pbpage;
-	unsigned int num = PBES_PER_PAGE;
-
-	for_each_pb_page (pbpage, pblist) {
-		if (num >= nr_pages)
-			break;
-
-		fill_pb_page(pbpage, PBES_PER_PAGE);
-		num += PBES_PER_PAGE;
-	}
-	if (pbpage) {
-		num -= PBES_PER_PAGE;
-		fill_pb_page(pbpage, nr_pages - num);
-	}
-}
-
-/**
- *	alloc_pagedir - Allocate the page directory.
- *
- *	First, determine exactly how many pages we need and
- *	allocate them.
- *
- *	We arrange the pages in a chain: each page is an array of PBES_PER_PAGE
- *	struct pbe elements (pbes) and the last element in the page points
- *	to the next page.
- *
- *	On each page we set up a list of struct_pbe elements.
- */
-
-static struct pbe *alloc_pagedir(unsigned int nr_pages, gfp_t gfp_mask,
-				 int safe_needed)
-{
-	unsigned int num;
-	struct pbe *pblist, *pbe;
-
-	if (!nr_pages)
-		return NULL;
-
-	pblist = alloc_image_page(gfp_mask, safe_needed);
-	pbe = pblist;
-	for (num = PBES_PER_PAGE; num < nr_pages; num += PBES_PER_PAGE) {
-		if (!pbe) {
-			free_pagedir(pblist, PG_UNSAFE_CLEAR);
-			return NULL;
-		}
-		pbe += PB_PAGE_SKIP;
-		pbe->next = alloc_image_page(gfp_mask, safe_needed);
-		pbe = pbe->next;
-	}
-	create_pbe_list(pblist, nr_pages);
-	return pblist;
-}
-
-/**
- * Free pages we allocated for suspend. Suspend pages are alocated
- * before atomic copy, so we need to free them after resume.
+ *	Suspend pages are alocated before the atomic copy is made, so we
+ *	need to release them after the resume.
  */
 
 void swsusp_free(void)
@@ -904,14 +813,18 @@ void swsusp_free(void)
 static int enough_free_mem(unsigned int nr_pages)
 {
 	struct zone *zone;
-	unsigned int n = 0;
+	unsigned int free = 0, meta = 0;
 
 	for_each_zone (zone)
-		if (!is_highmem(zone))
-			n += zone->free_pages;
-	pr_debug("swsusp: available memory: %u pages\n", n);
-	return n > (nr_pages + PAGES_FOR_IO +
-		(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
+		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, PAGES_FOR_IO, meta, free);
+
+	return free > nr_pages + PAGES_FOR_IO + meta;
 }
 
 static int
@@ -961,11 +874,6 @@ asmlinkage int swsusp_save(void)
 	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_pages,
-		 (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE,
-		 PAGES_FOR_IO, nr_free_pages());
-
 	if (!enough_free_mem(nr_pages)) {
 		printk(KERN_ERR "swsusp: Not enough free memory\n");
 		return -ENOMEM;
@@ -1007,22 +915,19 @@ static void init_header(struct swsusp_info *info)
 }
 
 /**
- *	pack_addresses - the addresses corresponding to pfns found in the
- *	bitmap @bm are stored in the array @buf[] (1 page)
+ *	pack_pfns - pfns corresponding to the set bits found in the bitmap @bm
+ *	are stored in the array @buf[] (1 page at a time)
  */
 
 static inline void
-pack_addresses(unsigned long *buf, struct memory_bitmap *bm)
+pack_pfns(unsigned long *buf, struct memory_bitmap *bm)
 {
 	int j;
 
 	for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
-		unsigned long pfn = memory_bm_next_pfn(bm);
-
-		if (unlikely(pfn == BM_END_OF_MAP))
+		buf[j] = memory_bm_next_pfn(bm);
+		if (unlikely(buf[j] == BM_END_OF_MAP))
 			break;
-
-		buf[j] = (unsigned long)page_address(pfn_to_page(pfn));
 	}
 }
 
@@ -1068,7 +973,7 @@ int snapshot_read_next(struct snapshot_handle *handle, size_t count)
 	if (handle->prev < handle->cur) {
 		if (handle->cur <= nr_meta_pages) {
 			memset(buffer, 0, PAGE_SIZE);
-			pack_addresses(buffer, &orig_bm);
+			pack_pfns(buffer, &orig_bm);
 		} else {
 			unsigned long pfn = memory_bm_next_pfn(&copy_bm);
 
@@ -1094,14 +999,10 @@ int snapshot_read_next(struct snapshot_handle *handle, size_t count)
  *	had been used before suspend
  */
 
-static int mark_unsafe_pages(struct pbe *pblist)
+static int mark_unsafe_pages(struct memory_bitmap *bm)
 {
 	struct zone *zone;
 	unsigned long pfn, max_zone_pfn;
-	struct pbe *p;
-
-	if (!pblist) /* a sanity check */
-		return -EINVAL;
 
 	/* Clear page flags */
 	for_each_zone (zone) {
@@ -1111,30 +1012,37 @@ static int mark_unsafe_pages(struct pbe *pblist)
 				ClearPageNosaveFree(pfn_to_page(pfn));
 	}
 
-	/* Mark orig addresses */
-	for_each_pbe (p, pblist) {
-		if (virt_addr_valid(p->orig_address))
-			SetPageNosaveFree(virt_to_page(p->orig_address));
-		else
-			return -EFAULT;
-	}
+	/* Mark pages that correspond to the "original" pfns as "unsafe" */
+	memory_bm_position_reset(bm);
+	do {
+		pfn = memory_bm_next_pfn(bm);
+		if (likely(pfn != BM_END_OF_MAP)) {
+			if (likely(pfn_valid(pfn)))
+				SetPageNosaveFree(pfn_to_page(pfn));
+			else
+				return -EFAULT;
+		}
+	} while (pfn != BM_END_OF_MAP);
 
-	unsafe_pages = 0;
+	allocated_unsafe_pages = 0;
 
 	return 0;
 }
 
-static void copy_page_backup_list(struct pbe *dst, struct pbe *src)
+static void
+duplicate_memory_bitmap(struct memory_bitmap *dst, struct memory_bitmap *src)
 {
-	/* We assume both lists contain the same number of elements */
-	while (src) {
-		dst->orig_address = src->orig_address;
-		dst = dst->next;
-		src = src->next;
+	unsigned long pfn;
+
+	memory_bm_position_reset(src);
+	pfn = memory_bm_next_pfn(src);
+	while (pfn != BM_END_OF_MAP) {
+		memory_bm_set_bit(dst, pfn);
+		pfn = memory_bm_next_pfn(src);
 	}
 }
 
-static int check_header(struct swsusp_info *info)
+static inline int check_header(struct swsusp_info *info)
 {
 	char *reason = NULL;
 
@@ -1161,19 +1069,14 @@ static int check_header(struct swsusp_info *info)
  *	load header - check the image header and copy data from it
  */
 
-static int load_header(struct snapshot_handle *handle,
-                              struct swsusp_info *info)
+static int
+load_header(struct swsusp_info *info)
 {
 	int error;
-	struct pbe *pblist;
 
+	restore_pblist = NULL;
 	error = check_header(info);
 	if (!error) {
-		pblist = alloc_pagedir(info->image_pages, GFP_ATOMIC, PG_ANY);
-		if (!pblist)
-			return -ENOMEM;
-		restore_pblist = pblist;
-		handle->pbe = pblist;
 		nr_copy_pages = info->image_pages;
 		nr_meta_pages = info->pages - info->image_pages - 1;
 	}
@@ -1181,108 +1084,137 @@ static int load_header(struct snapshot_handle *handle,
 }
 
 /**
- *	unpack_orig_addresses - copy the elements of @buf[] (1 page) to
- *	the PBEs in the list starting at @pbe
+ *	unpack_orig_pfns - for each element of @buf[] (1 page at a time) set
+ *	the corresponding bit in the memory bitmap @bm
  */
 
-static inline struct pbe *unpack_orig_addresses(unsigned long *buf,
-                                                struct pbe *pbe)
+static inline void
+unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
 {
 	int j;
 
-	for (j = 0; j < PAGE_SIZE / sizeof(long) && pbe; j++) {
-		pbe->orig_address = buf[j];
-		pbe = pbe->next;
+	for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
+		if (unlikely(buf[j] == BM_END_OF_MAP))
+			break;
+
+		memory_bm_set_bit(bm, buf[j]);
 	}
-	return pbe;
 }
 
 /**
- *	prepare_image - use metadata contained in the PBE list
- *	pointed to by restore_pblist to mark the pages that will
- *	be overwritten in the process of restoring the system
- *	memory state from the image ("unsafe" pages) and allocate
- *	memory for the image
+ *	prepare_image - use the memory bitmap @bm to mark the pages that will
+ *	be overwritten in the process of restoring the system memory state
+ *	from the suspend image ("unsafe" pages) and allocate memory for the
+ *	image.
  *
- *	The idea is to allocate the PBE list first and then
- *	allocate as many pages as it's needed for the image data,
- *	but not to assign these pages to the PBEs initially.
- *	Instead, we just mark them as allocated and create a list
- *	of "safe" which will be used later
+ *	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.
  */
 
-static struct linked_page *safe_pages;
+#define PBES_PER_LINKED_PAGE	(LINKED_PAGE_DATA_SIZE / sizeof(struct pbe))
+
+static struct linked_page *safe_pages_list;
 
-static int prepare_image(struct snapshot_handle *handle)
+static int
+prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm)
 {
-	int error = 0;
-	unsigned int nr_pages = nr_copy_pages;
-	struct pbe *p, *pblist = NULL;
+	unsigned int nr_pages;
+	struct linked_page *sp_list, *lp;
+	int error;
 
-	p = restore_pblist;
-	error = mark_unsafe_pages(p);
-	if (!error) {
-		pblist = alloc_pagedir(nr_pages, GFP_ATOMIC, PG_SAFE);
-		if (pblist)
-			copy_page_backup_list(pblist, p);
-		free_pagedir(p, PG_UNSAFE_KEEP);
-		if (!pblist)
+	error = mark_unsafe_pages(bm);
+	if (error)
+		goto Free;
+
+	error = memory_bm_create(new_bm, GFP_ATOMIC, PG_SAFE);
+	if (error)
+		goto Free;
+
+	duplicate_memory_bitmap(new_bm, bm);
+	memory_bm_free(bm, PG_UNSAFE_KEEP);
+	/* Reserve some safe pages for potential later use.
+	 *
+	 * NOTE: This way we make sure there will be enough safe pages for the
+	 * chain_alloc() in get_buffer().  It is a bit wasteful, but
+	 * nr_copy_pages cannot be greater than 50% of the memory anyway.
+	 */
+	sp_list = NULL;
+	/* nr_copy_pages cannot be lesser than allocated_unsafe_pages */
+	nr_pages = nr_copy_pages - 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);
+		if (!lp) {
 			error = -ENOMEM;
+			goto Free;
+		}
+		lp->next = sp_list;
+		sp_list = lp;
+		nr_pages--;
 	}
-	safe_pages = NULL;
-	if (!error && nr_pages > unsafe_pages) {
-		nr_pages -= unsafe_pages;
-		while (nr_pages--) {
-			struct linked_page *ptr;
-
-			ptr = (void *)get_zeroed_page(GFP_ATOMIC);
-			if (!ptr) {
-				error = -ENOMEM;
-				break;
-			}
-			if (!PageNosaveFree(virt_to_page(ptr))) {
-				/* The page is "safe", add it to the list */
-				ptr->next = safe_pages;
-				safe_pages = ptr;
-			}
-			/* Mark the page as allocated */
-			SetPageNosave(virt_to_page(ptr));
-			SetPageNosaveFree(virt_to_page(ptr));
+	/* Preallocate memory for the image */
+	safe_pages_list = NULL;
+	nr_pages = nr_copy_pages - allocated_unsafe_pages;
+	while (nr_pages > 0) {
+		lp = (struct linked_page *)get_zeroed_page(GFP_ATOMIC);
+		if (!lp) {
+			error = -ENOMEM;
+			goto Free;
+		}
+		if (!PageNosaveFree(virt_to_page(lp))) {
+			/* The page is "safe", add it to the list */
+			lp->next = safe_pages_list;
+			safe_pages_list = lp;
 		}
+		/* Mark the page as allocated */
+		SetPageNosave(virt_to_page(lp));
+		SetPageNosaveFree(virt_to_page(lp));
+		nr_pages--;
 	}
-	if (!error) {
-		restore_pblist = pblist;
-	} else {
-		handle->pbe = NULL;
-		swsusp_free();
+	/* Free the reserved safe pages so that chain_alloc() can use them */
+	while (sp_list) {
+		lp = sp_list->next;
+		free_image_page(sp_list, PG_UNSAFE_CLEAR);
+		sp_list = lp;
 	}
+	return 0;
+
+Free:
+	swsusp_free();
 	return error;
 }
 
-static void *get_buffer(struct snapshot_handle *handle)
+/**
+ *	get_buffer - compute the address that snapshot_write_next() should
+ *	set for its caller to write to.
+ */
+
+static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
 {
-	struct pbe *pbe = handle->pbe, *last = handle->last_pbe;
-	struct page *page = virt_to_page(pbe->orig_address);
+	struct pbe *pbe;
+	struct page *page = pfn_to_page(memory_bm_next_pfn(bm));
 
-	if (PageNosave(page) && PageNosaveFree(page)) {
-		/*
-		 * We have allocated the "original" page frame and we can
-		 * use it directly to store the read page
+	if (PageNosave(page) && PageNosaveFree(page))
+		/* We have allocated the "original" page frame and we can
+		 * use it directly to store the loaded page.
 		 */
-		pbe->address = 0;
-		if (last && last->next)
-			last->next = NULL;
-		return (void *)pbe->orig_address;
-	}
-	/*
-	 * The "original" page frame has not been allocated and we have to
-	 * use a "safe" page frame to store the read page
+		return page_address(page);
+
+	/* The "original" page frame has not been allocated and we have to
+	 * use a "safe" page frame to store the loaded page.
 	 */
-	pbe->address = (unsigned long)safe_pages;
-	safe_pages = safe_pages->next;
-	if (last)
-		last->next = pbe;
-	handle->last_pbe = pbe;
+	pbe = chain_alloc(ca, sizeof(struct pbe));
+	if (!pbe) {
+		swsusp_free();
+		return NULL;
+	}
+	pbe->orig_address = (unsigned long)page_address(page);
+	pbe->address = (unsigned long)safe_pages_list;
+	safe_pages_list = safe_pages_list->next;
+	pbe->next = restore_pblist;
+	restore_pblist = pbe;
 	return (void *)pbe->address;
 }
 
@@ -1310,10 +1242,13 @@ static void *get_buffer(struct snapshot_handle *handle)
 
 int snapshot_write_next(struct snapshot_handle *handle, size_t count)
 {
+	static struct chain_allocator ca;
 	int error = 0;
 
+	/* Check if we have already loaded the entire image */
 	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);
@@ -1324,26 +1259,32 @@ int snapshot_write_next(struct snapshot_handle *handle, size_t count)
 		handle->buffer = buffer;
 	handle->sync_read = 1;
 	if (handle->prev < handle->cur) {
-		if (!handle->prev) {
-			error = load_header(handle,
-					(struct swsusp_info *)buffer);
+		if (handle->prev == 0) {
+			error = load_header(buffer);
+			if (error)
+				return error;
+
+			error = memory_bm_create(&copy_bm, GFP_ATOMIC, PG_ANY);
 			if (error)
 				return error;
+
 		} else if (handle->prev <= nr_meta_pages) {
-			handle->pbe = unpack_orig_addresses(buffer,
-							handle->pbe);
-			if (!handle->pbe) {
-				error = prepare_image(handle);
+			unpack_orig_pfns(buffer, &copy_bm);
+			if (handle->prev == nr_meta_pages) {
+				error = prepare_image(&orig_bm, &copy_bm);
 				if (error)
 					return error;
-				handle->pbe = restore_pblist;
-				handle->last_pbe = NULL;
-				handle->buffer = get_buffer(handle);
+
+				chain_init(&ca, GFP_ATOMIC, PG_SAFE);
+				memory_bm_position_reset(&orig_bm);
+				restore_pblist = NULL;
+				handle->buffer = get_buffer(&orig_bm, &ca);
 				handle->sync_read = 0;
+				if (!handle->buffer)
+					return -ENOMEM;
 			}
 		} else {
-			handle->pbe = handle->pbe->next;
-			handle->buffer = get_buffer(handle);
+			handle->buffer = get_buffer(&orig_bm, &ca);
 			handle->sync_read = 0;
 		}
 		handle->prev = handle->cur;
@@ -1362,6 +1303,13 @@ int snapshot_write_next(struct snapshot_handle *handle, size_t count)
 
 int snapshot_image_loaded(struct snapshot_handle *handle)
 {
-	return !(!handle->pbe || handle->pbe->next || !nr_copy_pages ||
-		handle->cur <= nr_meta_pages + nr_copy_pages);
+	return !(!nr_copy_pages ||
+			handle->cur <= nr_meta_pages + nr_copy_pages);
+}
+
+void snapshot_free_unused_memory(struct snapshot_handle *handle)
+{
+	/* 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);
 }
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 8309d20b256..9b2ee5344de 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -331,8 +331,7 @@ static int enough_swap(unsigned int nr_pages)
 	unsigned int free_swap = count_swap_pages(root_swap, 1);
 
 	pr_debug("swsusp: free swap pages: %u\n", free_swap);
-	return free_swap > (nr_pages + PAGES_FOR_IO +
-		(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
+	return free_swap > nr_pages + PAGES_FOR_IO;
 }
 
 /**
@@ -547,6 +546,7 @@ static int load_image(struct swap_map_handle *handle,
 		error = err2;
 	if (!error) {
 		printk("\b\b\b\bdone\n");
+		snapshot_free_unused_memory(snapshot);
 		if (!snapshot_image_loaded(snapshot))
 			error = -ENODATA;
 	}
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 0ef5e4ba39e..2e4499f3e4d 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -193,6 +193,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
 			error = -EPERM;
 			break;
 		}
+		snapshot_free_unused_memory(&data->handle);
 		down(&pm_sem);
 		pm_prepare_console();
 		error = device_suspend(PMSG_FREEZE);