[net-next-2.6.git] / kernel / power / snapshot.c

/*
 * linux/kernel/power/snapshot.c
 *
 * This file provide system snapshot/restore functionality.
 *
 * Copyright (C) 1998-2005 Pavel Machek <pavel@suse.cz>
 *
 * This file is released under the GPLv2, and is based on swsusp.c.
 *
 */


#include <linux/module.h>
#include <linux/mm.h>
#include <linux/suspend.h>
#include <linux/smp_lock.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/kernel.h>
#include <linux/pm.h>
#include <linux/device.h>
#include <linux/bootmem.h>
#include <linux/syscalls.h>
#include <linux/console.h>
#include <linux/highmem.h>

#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/io.h>

#include "power.h"

struct pbe *pagedir_nosave;
unsigned int nr_copy_pages;

#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%1000))
			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)) {
			printk("highmem reserved page?!\n");
			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\n");
	for_each_zone (zone) {
		if (is_highmem(zone))
			res = save_highmem_zone(zone);
		if (res)
			return res;
	}
	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;
}
#endif

static int pfn_is_nosave(unsigned long pfn)
{
	unsigned long nosave_begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
	unsigned long nosave_end_pfn = PAGE_ALIGN(__pa(&__nosave_end)) >> PAGE_SHIFT;
	return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
}

/**
 *	saveable - Determine whether a page should be cloned or not.
 *	@pfn:	The page
 *
 *	We save a page if it's Reserved, and not in the range of pages
 *	statically defined as 'unsaveable', or if it isn't reserved, and
 *	isn't part of a free chunk of pages.
 */

static int saveable(struct zone *zone, unsigned long *zone_pfn)
{
	unsigned long pfn = *zone_pfn + zone->zone_start_pfn;
	struct page *page;

	if (!pfn_valid(pfn))
		return 0;

	page = pfn_to_page(pfn);
	BUG_ON(PageReserved(page) && PageNosave(page));
	if (PageNosave(page))
		return 0;
	if (PageReserved(page) && pfn_is_nosave(pfn))
		return 0;
	if (PageNosaveFree(page))
		return 0;

	return 1;
}

unsigned int count_data_pages(void)
{
	struct zone *zone;
	unsigned long zone_pfn;
	unsigned int 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)
			n += saveable(zone, &zone_pfn);
	}
	return n;
}

static void copy_data_pages(struct pbe *pblist)
{
	struct zone *zone;
	unsigned long zone_pfn;
	struct pbe *pbe, *p;

	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, pblist)
			SetPageNosaveFree(virt_to_page(p));
		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)) {
				struct page *page;
				page = pfn_to_page(zone_pfn + zone->zone_start_pfn);
				BUG_ON(!pbe);
				pbe->orig_address = (unsigned long)page_address(page);
				/* copy_page is not usable for copying task structs. */
				memcpy((void *)pbe->address, (void *)pbe->orig_address, PAGE_SIZE);
				pbe = pbe->next;
			}
		}
	}
	BUG_ON(pbe);
}


/**
 *	free_pagedir - free pages allocated with alloc_pagedir()
 */

void free_pagedir(struct pbe *pblist)
{
	struct pbe *pbe;

	while (pblist) {
		pbe = (pblist + PB_PAGE_SKIP)->next;
		ClearPageNosave(virt_to_page(pblist));
		ClearPageNosaveFree(virt_to_page(pblist));
		free_page((unsigned long)pblist);
		pblist = pbe;
	}
}

/**
 *	fill_pb_page - Create a list of PBEs on a given memory page
 */

static inline void fill_pb_page(struct pbe *pbpage)
{
	struct pbe *p;

	p = pbpage;
	pbpage += PB_PAGE_SKIP;
	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()
 */

static inline void create_pbe_list(struct pbe *pblist, unsigned int nr_pages)
{
	struct pbe *pbpage, *p;
	unsigned int num = PBES_PER_PAGE;

	for_each_pb_page (pbpage, pblist) {
		if (num >= nr_pages)
			break;

		fill_pb_page(pbpage);
		num += PBES_PER_PAGE;
	}
	if (pbpage) {
		for (num -= PBES_PER_PAGE - 1, p = pbpage; num < nr_pages; p++, num++)
			p->next = p + 1;
		p->next = NULL;
	}
}

/**
 *	On resume it is necessary to trace and eventually free the unsafe
 *	pages that have been allocated, because they are needed for I/O
 *	(on x86-64 we likely will "eat" these pages once again while
 *	creating the temporary page translation tables)
 */

struct eaten_page {
	struct eaten_page *next;
	char padding[PAGE_SIZE - sizeof(void *)];
};

static struct eaten_page *eaten_pages = NULL;

void release_eaten_pages(void)
{
	struct eaten_page *p, *q;

	p = eaten_pages;
	while (p) {
		q = p->next;
		/* We don't want swsusp_free() to free this page again */
		ClearPageNosave(virt_to_page(p));
		free_page((unsigned long)p);
		p = q;
	}
	eaten_pages = NULL;
}

/**
 *	@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
 *	which had been used before suspend.
 *
 *	The unsafe pages are marked with the PG_nosave_free flag
 *
 *	Allocated but unusable (ie eaten) memory pages should be marked
 *	so that swsusp_free() can release them
 */

static inline void *alloc_image_page(gfp_t gfp_mask, int safe_needed)
{
	void *res;

	if (safe_needed)
		do {
			res = (void *)get_zeroed_page(gfp_mask);
			if (res && PageNosaveFree(virt_to_page(res))) {
				/* This is for swsusp_free() */
				SetPageNosave(virt_to_page(res));
				((struct eaten_page *)res)->next = eaten_pages;
				eaten_pages = res;
			}
		} while (res && PageNosaveFree(virt_to_page(res)));
	else
		res = (void *)get_zeroed_page(gfp_mask);
	if (res) {
		SetPageNosave(virt_to_page(res));
		SetPageNosaveFree(virt_to_page(res));
	}
	return res;
}

unsigned long get_safe_page(gfp_t gfp_mask)
{
	return (unsigned long)alloc_image_page(gfp_mask, 1);
}

/**
 *	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.
 */

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;

	pr_debug("alloc_pagedir(): nr_pages = %d\n", nr_pages);
	pblist = alloc_image_page(gfp_mask, safe_needed);
	/* FIXME: rewrite this ugly loop */
	for (pbe = pblist, num = PBES_PER_PAGE; pbe && num < nr_pages;
        		pbe = pbe->next, num += PBES_PER_PAGE) {
		pbe += PB_PAGE_SKIP;
		pbe->next = alloc_image_page(gfp_mask, safe_needed);
	}
	if (!pbe) { /* get_zeroed_page() failed */
		free_pagedir(pblist);
		pblist = NULL;
        } else
        	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.
 */

void swsusp_free(void)
{
	struct zone *zone;
	unsigned long zone_pfn;

	for_each_zone(zone) {
		for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
			if (pfn_valid(zone_pfn + zone->zone_start_pfn)) {
				struct page *page;
				page = pfn_to_page(zone_pfn + zone->zone_start_pfn);
				if (PageNosave(page) && PageNosaveFree(page)) {
					ClearPageNosave(page);
					ClearPageNosaveFree(page);
					free_page((long) page_address(page));
				}
			}
	}
}


/**
 *	enough_free_mem - Make sure we enough free memory to snapshot.
 *
 *	Returns TRUE or FALSE after checking the number of available
 *	free pages.
 */

static int enough_free_mem(unsigned int nr_pages)
{
	pr_debug("swsusp: available memory: %u pages\n", nr_free_pages());
	return nr_free_pages() > (nr_pages + PAGES_FOR_IO +
		(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
}

int alloc_data_pages(struct pbe *pblist, gfp_t gfp_mask, int safe_needed)
{
	struct pbe *p;

	for_each_pbe (p, pblist) {
		p->address = (unsigned long)alloc_image_page(gfp_mask, safe_needed);
		if (!p->address)
			return -ENOMEM;
	}
	return 0;
}

static struct pbe *swsusp_alloc(unsigned int nr_pages)
{
	struct pbe *pblist;

	if (!(pblist = alloc_pagedir(nr_pages, GFP_ATOMIC | __GFP_COLD, 0))) {
		printk(KERN_ERR "suspend: Allocating pagedir failed.\n");
		return NULL;
	}

	if (alloc_data_pages(pblist, GFP_ATOMIC | __GFP_COLD, 0)) {
		printk(KERN_ERR "suspend: Allocating image pages failed.\n");
		swsusp_free();
		return NULL;
	}

	return pblist;
}

asmlinkage int swsusp_save(void)
{
	unsigned int nr_pages;

	pr_debug("swsusp: critical section: \n");

	drain_local_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_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;
	}

	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(pagedir_nosave);

	/*
	 * End of critical section. From now on, we can write to memory,
	 * but we should not touch disk. This specially means we must _not_
	 * touch swap space! Except we must write out our image of course.
	 */

	nr_copy_pages = nr_pages;

	printk("swsusp: critical section/: done (%d pages copied)\n", nr_pages);
	return 0;
}
Commit	Line	Data
25761b6e	1	/*
96bc7aec	2	* linux/kernel/power/snapshot.c
25761b6e	3	*
96bc7aec	4	* This file provide system snapshot/restore functionality.
25761b6e RW	5	*
	6	* Copyright (C) 1998-2005 Pavel Machek <pavel@suse.cz>
	7	*
	8	* This file is released under the GPLv2, and is based on swsusp.c.
	9	*
	10	*/
	11
	12
	13	#include <linux/module.h>
	14	#include <linux/mm.h>
	15	#include <linux/suspend.h>
	16	#include <linux/smp_lock.h>
25761b6e	17	#include <linux/delay.h>
25761b6e	18	#include <linux/bitops.h>
25761b6e	19	#include <linux/spinlock.h>
25761b6e	20	#include <linux/kernel.h>
25761b6e RW	21	#include <linux/pm.h>
25761b6e RW	22	#include <linux/device.h>
25761b6e RW	23	#include <linux/bootmem.h>
	24	#include <linux/syscalls.h>
	25	#include <linux/console.h>
	26	#include <linux/highmem.h>
25761b6e RW	27
	28	#include <asm/uaccess.h>
	29	#include <asm/mmu_context.h>
	30	#include <asm/pgtable.h>
	31	#include <asm/tlbflush.h>
	32	#include <asm/io.h>
	33
25761b6e RW	34	#include "power.h"
25761b6e RW	35
7088a5c0 RW	36	struct pbe *pagedir_nosave;
	37	unsigned int nr_copy_pages;
	38
25761b6e	39	#ifdef CONFIG_HIGHMEM
72a97e08 RW	40	unsigned int count_highmem_pages(void)
	41	{
	42	struct zone *zone;
	43	unsigned long zone_pfn;
	44	unsigned int n = 0;
	45
	46	for_each_zone (zone)
	47	if (is_highmem(zone)) {
	48	mark_free_pages(zone);
	49	for (zone_pfn = 0; zone_pfn < zone->spanned_pages; zone_pfn++) {
	50	struct page *page;
	51	unsigned long pfn = zone_pfn + zone->zone_start_pfn;
	52	if (!pfn_valid(pfn))
	53	continue;
	54	page = pfn_to_page(pfn);
	55	if (PageReserved(page))
	56	continue;
	57	if (PageNosaveFree(page))
	58	continue;
	59	n++;
	60	}
	61	}
	62	return n;
	63	}
	64
25761b6e RW	65	struct highmem_page {
	66	char *data;
	67	struct page *page;
	68	struct highmem_page *next;
	69	};
	70
	71	static struct highmem_page *highmem_copy;
	72
	73	static int save_highmem_zone(struct zone *zone)
	74	{
	75	unsigned long zone_pfn;
	76	mark_free_pages(zone);
	77	for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
	78	struct page *page;
	79	struct highmem_page *save;
	80	void *kaddr;
	81	unsigned long pfn = zone_pfn + zone->zone_start_pfn;
	82
	83	if (!(pfn%1000))
	84	printk(".");
	85	if (!pfn_valid(pfn))
	86	continue;
	87	page = pfn_to_page(pfn);
	88	/*
	89	* This condition results from rvmalloc() sans vmalloc_32()
	90	* and architectural memory reservations. This should be
	91	* corrected eventually when the cases giving rise to this
	92	* are better understood.
	93	*/
	94	if (PageReserved(page)) {
	95	printk("highmem reserved page?!\n");
	96	continue;
	97	}
	98	BUG_ON(PageNosave(page));
	99	if (PageNosaveFree(page))
	100	continue;
	101	save = kmalloc(sizeof(struct highmem_page), GFP_ATOMIC);
	102	if (!save)
	103	return -ENOMEM;
	104	save->next = highmem_copy;
	105	save->page = page;
	106	save->data = (void *) get_zeroed_page(GFP_ATOMIC);
	107	if (!save->data) {
	108	kfree(save);
	109	return -ENOMEM;
	110	}
	111	kaddr = kmap_atomic(page, KM_USER0);
	112	memcpy(save->data, kaddr, PAGE_SIZE);
	113	kunmap_atomic(kaddr, KM_USER0);
	114	highmem_copy = save;
	115	}
	116	return 0;
	117	}
25761b6e	118
0fbeb5a4	119	int save_highmem(void)
25761b6e	120	{
25761b6e RW	121	struct zone *zone;
	122	int res = 0;
	123
	124	pr_debug("swsusp: Saving Highmem\n");
	125	for_each_zone (zone) {
	126	if (is_highmem(zone))
	127	res = save_highmem_zone(zone);
	128	if (res)
	129	return res;
	130	}
25761b6e RW	131	return 0;
	132	}
	133
	134	int restore_highmem(void)
	135	{
25761b6e RW	136	printk("swsusp: Restoring Highmem\n");
	137	while (highmem_copy) {
	138	struct highmem_page *save = highmem_copy;
	139	void *kaddr;
	140	highmem_copy = save->next;
	141
	142	kaddr = kmap_atomic(save->page, KM_USER0);
	143	memcpy(kaddr, save->data, PAGE_SIZE);
	144	kunmap_atomic(kaddr, KM_USER0);
	145	free_page((long) save->data);
	146	kfree(save);
	147	}
25761b6e RW	148	return 0;
25761b6e RW	149	}
0fbeb5a4	150	#endif
25761b6e RW	151
	152	static int pfn_is_nosave(unsigned long pfn)
	153	{
	154	unsigned long nosave_begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
	155	unsigned long nosave_end_pfn = PAGE_ALIGN(__pa(&__nosave_end)) >> PAGE_SHIFT;
	156	return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
	157	}
	158
	159	/**
	160	* saveable - Determine whether a page should be cloned or not.
	161	* @pfn: The page
	162	*
	163	* We save a page if it's Reserved, and not in the range of pages
	164	* statically defined as 'unsaveable', or if it isn't reserved, and
	165	* isn't part of a free chunk of pages.
	166	*/
	167
de491861	168	static int saveable(struct zone zone, unsigned long zone_pfn)
25761b6e RW	169	{
25761b6e RW	170	unsigned long pfn = *zone_pfn + zone->zone_start_pfn;
de491861	171	struct page *page;
25761b6e RW	172
	173	if (!pfn_valid(pfn))
	174	return 0;
	175
	176	page = pfn_to_page(pfn);
	177	BUG_ON(PageReserved(page) && PageNosave(page));
	178	if (PageNosave(page))
	179	return 0;
72a97e08	180	if (PageReserved(page) && pfn_is_nosave(pfn))
25761b6e	181	return 0;
25761b6e RW	182	if (PageNosaveFree(page))
	183	return 0;
	184
	185	return 1;
	186	}
	187
72a97e08	188	unsigned int count_data_pages(void)
25761b6e RW	189	{
	190	struct zone *zone;
	191	unsigned long zone_pfn;
dc19d507	192	unsigned int n = 0;
25761b6e	193
25761b6e RW	194	for_each_zone (zone) {
	195	if (is_highmem(zone))
	196	continue;
	197	mark_free_pages(zone);
	198	for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
a0f49651	199	n += saveable(zone, &zone_pfn);
25761b6e	200	}
a0f49651	201	return n;
25761b6e RW	202	}
25761b6e RW	203
a0f49651	204	static void copy_data_pages(struct pbe *pblist)
25761b6e RW	205	{
	206	struct zone *zone;
	207	unsigned long zone_pfn;
a0f49651	208	struct pbe pbe, p;
25761b6e	209
a0f49651	210	pbe = pblist;
25761b6e RW	211	for_each_zone (zone) {
	212	if (is_highmem(zone))
	213	continue;
	214	mark_free_pages(zone);
	215	/* This is necessary for swsusp_free() */
a0f49651	216	for_each_pb_page (p, pblist)
25761b6e	217	SetPageNosaveFree(virt_to_page(p));
a0f49651	218	for_each_pbe (p, pblist)
25761b6e RW	219	SetPageNosaveFree(virt_to_page(p->address));
	220	for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
	221	if (saveable(zone, &zone_pfn)) {
de491861	222	struct page *page;
25761b6e RW	223	page = pfn_to_page(zone_pfn + zone->zone_start_pfn);
	224	BUG_ON(!pbe);
	225	pbe->orig_address = (unsigned long)page_address(page);
	226	/* copy_page is not usable for copying task structs. */
	227	memcpy((void )pbe->address, (void )pbe->orig_address, PAGE_SIZE);
	228	pbe = pbe->next;
	229	}
	230	}
	231	}
	232	BUG_ON(pbe);
	233	}
	234
	235
	236	/**
	237	* free_pagedir - free pages allocated with alloc_pagedir()
	238	*/
	239
ed14b527	240	void free_pagedir(struct pbe *pblist)
25761b6e RW	241	{
	242	struct pbe *pbe;
	243
	244	while (pblist) {
	245	pbe = (pblist + PB_PAGE_SKIP)->next;
	246	ClearPageNosave(virt_to_page(pblist));
	247	ClearPageNosaveFree(virt_to_page(pblist));
	248	free_page((unsigned long)pblist);
	249	pblist = pbe;
	250	}
	251	}
	252
	253	/**
	254	* fill_pb_page - Create a list of PBEs on a given memory page
	255	*/
	256
	257	static inline void fill_pb_page(struct pbe *pbpage)
	258	{
	259	struct pbe *p;
	260
	261	p = pbpage;
	262	pbpage += PB_PAGE_SKIP;
	263	do
	264	p->next = p + 1;
	265	while (++p < pbpage);
	266	}
	267
	268	/**
	269	* create_pbe_list - Create a list of PBEs on top of a given chain
	270	* of memory pages allocated with alloc_pagedir()
	271	*/
	272
7088a5c0	273	static inline void create_pbe_list(struct pbe *pblist, unsigned int nr_pages)
25761b6e RW	274	{
25761b6e RW	275	struct pbe pbpage, p;
dc19d507	276	unsigned int num = PBES_PER_PAGE;
25761b6e RW	277
	278	for_each_pb_page (pbpage, pblist) {
	279	if (num >= nr_pages)
	280	break;
	281
	282	fill_pb_page(pbpage);
	283	num += PBES_PER_PAGE;
	284	}
	285	if (pbpage) {
	286	for (num -= PBES_PER_PAGE - 1, p = pbpage; num < nr_pages; p++, num++)
	287	p->next = p + 1;
	288	p->next = NULL;
	289	}
25761b6e RW	290	}
25761b6e RW	291
72a97e08 RW	292	/**
	293	* On resume it is necessary to trace and eventually free the unsafe
	294	* pages that have been allocated, because they are needed for I/O
	295	* (on x86-64 we likely will "eat" these pages once again while
	296	* creating the temporary page translation tables)
	297	*/
	298
	299	struct eaten_page {
	300	struct eaten_page *next;
	301	char padding[PAGE_SIZE - sizeof(void *)];
	302	};
	303
	304	static struct eaten_page *eaten_pages = NULL;
	305
	306	void release_eaten_pages(void)
	307	{
	308	struct eaten_page p, q;
	309
	310	p = eaten_pages;
	311	while (p) {
	312	q = p->next;
	313	/* We don't want swsusp_free() to free this page again */
	314	ClearPageNosave(virt_to_page(p));
	315	free_page((unsigned long)p);
	316	p = q;
	317	}
	318	eaten_pages = NULL;
	319	}
	320
054bd4c1 RW	321	/**
	322	* @safe_needed - on resume, for storing the PBE list and the image,
	323	* we can only use memory pages that do not conflict with the pages
	324	* which had been used before suspend.
	325	*
	326	* The unsafe pages are marked with the PG_nosave_free flag
	327	*
	328	* Allocated but unusable (ie eaten) memory pages should be marked
	329	* so that swsusp_free() can release them
	330	*/
	331
	332	static inline void *alloc_image_page(gfp_t gfp_mask, int safe_needed)
25761b6e	333	{
054bd4c1 RW	334	void *res;
	335
	336	if (safe_needed)
	337	do {
	338	res = (void *)get_zeroed_page(gfp_mask);
72a97e08	339	if (res && PageNosaveFree(virt_to_page(res))) {
054bd4c1 RW	340	/* This is for swsusp_free() */
054bd4c1 RW	341	SetPageNosave(virt_to_page(res));
72a97e08 RW	342	((struct eaten_page *)res)->next = eaten_pages;
	343	eaten_pages = res;
	344	}
054bd4c1 RW	345	} while (res && PageNosaveFree(virt_to_page(res)));
	346	else
	347	res = (void *)get_zeroed_page(gfp_mask);
25761b6e RW	348	if (res) {
	349	SetPageNosave(virt_to_page(res));
	350	SetPageNosaveFree(virt_to_page(res));
	351	}
	352	return res;
	353	}
	354
054bd4c1 RW	355	unsigned long get_safe_page(gfp_t gfp_mask)
	356	{
	357	return (unsigned long)alloc_image_page(gfp_mask, 1);
	358	}
	359
25761b6e RW	360	/**
	361	* alloc_pagedir - Allocate the page directory.
	362	*
	363	* First, determine exactly how many pages we need and
	364	* allocate them.
	365	*
	366	* We arrange the pages in a chain: each page is an array of PBES_PER_PAGE
	367	* struct pbe elements (pbes) and the last element in the page points
	368	* to the next page.
	369	*
	370	* On each page we set up a list of struct_pbe elements.
	371	*/
	372
054bd4c1	373	struct pbe *alloc_pagedir(unsigned int nr_pages, gfp_t gfp_mask, int safe_needed)
25761b6e	374	{
dc19d507	375	unsigned int num;
25761b6e RW	376	struct pbe pblist, pbe;
	377
	378	if (!nr_pages)
	379	return NULL;
	380
	381	pr_debug("alloc_pagedir(): nr_pages = %d\n", nr_pages);
054bd4c1	382	pblist = alloc_image_page(gfp_mask, safe_needed);
25761b6e RW	383	/* FIXME: rewrite this ugly loop */
	384	for (pbe = pblist, num = PBES_PER_PAGE; pbe && num < nr_pages;
	385	pbe = pbe->next, num += PBES_PER_PAGE) {
	386	pbe += PB_PAGE_SKIP;
054bd4c1	387	pbe->next = alloc_image_page(gfp_mask, safe_needed);
25761b6e RW	388	}
	389	if (!pbe) { /* get_zeroed_page() failed */
	390	free_pagedir(pblist);
	391	pblist = NULL;
7088a5c0 RW	392	} else
7088a5c0 RW	393	create_pbe_list(pblist, nr_pages);
25761b6e RW	394	return pblist;
	395	}
	396
	397	/**
	398	* Free pages we allocated for suspend. Suspend pages are alocated
	399	* before atomic copy, so we need to free them after resume.
	400	*/
	401
	402	void swsusp_free(void)
	403	{
	404	struct zone *zone;
	405	unsigned long zone_pfn;
	406
	407	for_each_zone(zone) {
	408	for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
	409	if (pfn_valid(zone_pfn + zone->zone_start_pfn)) {
dc19d507	410	struct page *page;
25761b6e RW	411	page = pfn_to_page(zone_pfn + zone->zone_start_pfn);
	412	if (PageNosave(page) && PageNosaveFree(page)) {
	413	ClearPageNosave(page);
	414	ClearPageNosaveFree(page);
	415	free_page((long) page_address(page));
	416	}
	417	}
	418	}
	419	}
	420
	421
	422	/**
	423	* enough_free_mem - Make sure we enough free memory to snapshot.
	424	*
	425	* Returns TRUE or FALSE after checking the number of available
	426	* free pages.
	427	*/
	428
dc19d507	429	static int enough_free_mem(unsigned int nr_pages)
25761b6e RW	430	{
25761b6e RW	431	pr_debug("swsusp: available memory: %u pages\n", nr_free_pages());
a0f49651 RW	432	return nr_free_pages() > (nr_pages + PAGES_FOR_IO +
a0f49651 RW	433	(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
25761b6e RW	434	}
25761b6e RW	435
054bd4c1 RW	436	int alloc_data_pages(struct pbe *pblist, gfp_t gfp_mask, int safe_needed)
	437	{
	438	struct pbe *p;
	439
	440	for_each_pbe (p, pblist) {
	441	p->address = (unsigned long)alloc_image_page(gfp_mask, safe_needed);
	442	if (!p->address)
	443	return -ENOMEM;
	444	}
	445	return 0;
	446	}
25761b6e	447
dc19d507	448	static struct pbe *swsusp_alloc(unsigned int nr_pages)
25761b6e	449	{
054bd4c1	450	struct pbe *pblist;
25761b6e	451
054bd4c1	452	if (!(pblist = alloc_pagedir(nr_pages, GFP_ATOMIC \| __GFP_COLD, 0))) {
25761b6e	453	printk(KERN_ERR "suspend: Allocating pagedir failed.\n");
a0f49651	454	return NULL;
25761b6e	455	}
25761b6e	456
054bd4c1 RW	457	if (alloc_data_pages(pblist, GFP_ATOMIC \| __GFP_COLD, 0)) {
	458	printk(KERN_ERR "suspend: Allocating image pages failed.\n");
	459	swsusp_free();
	460	return NULL;
25761b6e RW	461	}
25761b6e RW	462
a0f49651	463	return pblist;
25761b6e RW	464	}
25761b6e RW	465
2e32a43e	466	asmlinkage int swsusp_save(void)
25761b6e	467	{
dc19d507	468	unsigned int nr_pages;
25761b6e RW	469
25761b6e RW	470	pr_debug("swsusp: critical section: \n");
25761b6e RW	471
25761b6e RW	472	drain_local_pages();
a0f49651 RW	473	nr_pages = count_data_pages();
a0f49651 RW	474	printk("swsusp: Need to copy %u pages\n", nr_pages);
25761b6e RW	475
25761b6e RW	476	pr_debug("swsusp: pages needed: %u + %lu + %u, free: %u\n",
a0f49651 RW	477	nr_pages,
a0f49651 RW	478	(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE,
25761b6e RW	479	PAGES_FOR_IO, nr_free_pages());
25761b6e RW	480
a0f49651	481	if (!enough_free_mem(nr_pages)) {
25761b6e RW	482	printk(KERN_ERR "swsusp: Not enough free memory\n");
	483	return -ENOMEM;
	484	}
	485
a0f49651 RW	486	pagedir_nosave = swsusp_alloc(nr_pages);
	487	if (!pagedir_nosave)
	488	return -ENOMEM;
25761b6e RW	489
	490	/* During allocating of suspend pagedir, new cold pages may appear.
	491	* Kill them.
	492	*/
	493	drain_local_pages();
a0f49651	494	copy_data_pages(pagedir_nosave);
25761b6e RW	495
	496	/*
	497	* End of critical section. From now on, we can write to memory,
	498	* but we should not touch disk. This specially means we must _not_
	499	* touch swap space! Except we must write out our image of course.
	500	*/
	501
a0f49651 RW	502	nr_copy_pages = nr_pages;
	503
	504	printk("swsusp: critical section/: done (%d pages copied)\n", nr_pages);
25761b6e RW	505	return 0;
25761b6e RW	506	}