[deliverable/linux.git] / kernel / power / swap.c

/*
 * linux/kernel/power/swap.c
 *
 * This file provides functions for reading the suspend image from
 * and writing it to a swap partition.
 *
 * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@suse.cz>
 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
 *
 * This file is released under the GPLv2.
 *
 */

#include <linux/module.h>
#include <linux/file.h>
#include <linux/utsname.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/genhd.h>
#include <linux/device.h>
#include <linux/buffer_head.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/pm.h>

#include "power.h"

#define SWSUSP_SIG	"S1SUSPEND"

struct swsusp_header {
	char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int)];
	sector_t image;
	unsigned int flags;	/* Flags to pass to the "boot" kernel */
	char	orig_sig[10];
	char	sig[10];
} __attribute__((packed));

static struct swsusp_header *swsusp_header;

/*
 * General things
 */

static unsigned short root_swap = 0xffff;
static struct block_device *resume_bdev;

/**
 *	submit - submit BIO request.
 *	@rw:	READ or WRITE.
 *	@off	physical offset of page.
 *	@page:	page we're reading or writing.
 *	@bio_chain: list of pending biod (for async reading)
 *
 *	Straight from the textbook - allocate and initialize the bio.
 *	If we're reading, make sure the page is marked as dirty.
 *	Then submit it and, if @bio_chain == NULL, wait.
 */
static int submit(int rw, pgoff_t page_off, struct page *page,
			struct bio **bio_chain)
{
	const int bio_rw = rw | (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG);
	struct bio *bio;

	bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
	if (!bio)
		return -ENOMEM;
	bio->bi_sector = page_off * (PAGE_SIZE >> 9);
	bio->bi_bdev = resume_bdev;
	bio->bi_end_io = end_swap_bio_read;

	if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
		printk(KERN_ERR "PM: Adding page to bio failed at %ld\n",
			page_off);
		bio_put(bio);
		return -EFAULT;
	}

	lock_page(page);
	bio_get(bio);

	if (bio_chain == NULL) {
		submit_bio(bio_rw, bio);
		wait_on_page_locked(page);
		if (rw == READ)
			bio_set_pages_dirty(bio);
		bio_put(bio);
	} else {
		if (rw == READ)
			get_page(page);	/* These pages are freed later */
		bio->bi_private = *bio_chain;
		*bio_chain = bio;
		submit_bio(bio_rw, bio);
	}
	return 0;
}

static int bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
{
	return submit(READ, page_off, virt_to_page(addr), bio_chain);
}

static int bio_write_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
{
	return submit(WRITE, page_off, virt_to_page(addr), bio_chain);
}

static int wait_on_bio_chain(struct bio **bio_chain)
{
	struct bio *bio;
	struct bio *next_bio;
	int ret = 0;

	if (bio_chain == NULL)
		return 0;

	bio = *bio_chain;
	if (bio == NULL)
		return 0;
	while (bio) {
		struct page *page;

		next_bio = bio->bi_private;
		page = bio->bi_io_vec[0].bv_page;
		wait_on_page_locked(page);
		if (!PageUptodate(page) || PageError(page))
			ret = -EIO;
		put_page(page);
		bio_put(bio);
		bio = next_bio;
	}
	*bio_chain = NULL;
	return ret;
}

/*
 * Saving part
 */

static int mark_swapfiles(sector_t start, unsigned int flags)
{
	int error;

	bio_read_page(swsusp_resume_block, swsusp_header, NULL);
	if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
	    !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
		memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
		memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
		swsusp_header->image = start;
		swsusp_header->flags = flags;
		error = bio_write_page(swsusp_resume_block,
					swsusp_header, NULL);
	} else {
		printk(KERN_ERR "PM: Swap header not found!\n");
		error = -ENODEV;
	}
	return error;
}

/**
 *	swsusp_swap_check - check if the resume device is a swap device
 *	and get its index (if so)
 */

static int swsusp_swap_check(void) /* This is called before saving image */
{
	int res;

	res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
			&resume_bdev);
	if (res < 0)
		return res;

	root_swap = res;
	res = blkdev_get(resume_bdev, FMODE_WRITE);
	if (res)
		return res;

	res = set_blocksize(resume_bdev, PAGE_SIZE);
	if (res < 0)
		blkdev_put(resume_bdev, FMODE_WRITE);

	return res;
}

/**
 *	write_page - Write one page to given swap location.
 *	@buf:		Address we're writing.
 *	@offset:	Offset of the swap page we're writing to.
 *	@bio_chain:	Link the next write BIO here
 */

static int write_page(void *buf, sector_t offset, struct bio **bio_chain)
{
	void *src;

	if (!offset)
		return -ENOSPC;

	if (bio_chain) {
		src = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
		if (src) {
			memcpy(src, buf, PAGE_SIZE);
		} else {
			WARN_ON_ONCE(1);
			bio_chain = NULL;	/* Go synchronous */
			src = buf;
		}
	} else {
		src = buf;
	}
	return bio_write_page(offset, src, bio_chain);
}

/*
 *	The swap map is a data structure used for keeping track of each page
 *	written to a swap partition.  It consists of many swap_map_page
 *	structures that contain each an array of MAP_PAGE_SIZE swap entries.
 *	These structures are stored on the swap and linked together with the
 *	help of the .next_swap member.
 *
 *	The swap map is created during suspend.  The swap map pages are
 *	allocated and populated one at a time, so we only need one memory
 *	page to set up the entire structure.
 *
 *	During resume we also only need to use one swap_map_page structure
 *	at a time.
 */

#define MAP_PAGE_ENTRIES	(PAGE_SIZE / sizeof(sector_t) - 1)

struct swap_map_page {
	sector_t entries[MAP_PAGE_ENTRIES];
	sector_t next_swap;
};

/**
 *	The swap_map_handle structure is used for handling swap in
 *	a file-alike way
 */

struct swap_map_handle {
	struct swap_map_page *cur;
	sector_t cur_swap;
	unsigned int k;
};

static void release_swap_writer(struct swap_map_handle *handle)
{
	if (handle->cur)
		free_page((unsigned long)handle->cur);
	handle->cur = NULL;
}

static int get_swap_writer(struct swap_map_handle *handle)
{
	handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
	if (!handle->cur)
		return -ENOMEM;
	handle->cur_swap = alloc_swapdev_block(root_swap);
	if (!handle->cur_swap) {
		release_swap_writer(handle);
		return -ENOSPC;
	}
	handle->k = 0;
	return 0;
}

static int swap_write_page(struct swap_map_handle *handle, void *buf,
				struct bio **bio_chain)
{
	int error = 0;
	sector_t offset;

	if (!handle->cur)
		return -EINVAL;
	offset = alloc_swapdev_block(root_swap);
	error = write_page(buf, offset, bio_chain);
	if (error)
		return error;
	handle->cur->entries[handle->k++] = offset;
	if (handle->k >= MAP_PAGE_ENTRIES) {
		error = wait_on_bio_chain(bio_chain);
		if (error)
			goto out;
		offset = alloc_swapdev_block(root_swap);
		if (!offset)
			return -ENOSPC;
		handle->cur->next_swap = offset;
		error = write_page(handle->cur, handle->cur_swap, NULL);
		if (error)
			goto out;
		memset(handle->cur, 0, PAGE_SIZE);
		handle->cur_swap = offset;
		handle->k = 0;
	}
 out:
	return error;
}

static int flush_swap_writer(struct swap_map_handle *handle)
{
	if (handle->cur && handle->cur_swap)
		return write_page(handle->cur, handle->cur_swap, NULL);
	else
		return -EINVAL;
}

/**
 *	save_image - save the suspend image data
 */

static int save_image(struct swap_map_handle *handle,
                      struct snapshot_handle *snapshot,
                      unsigned int nr_to_write)
{
	unsigned int m;
	int ret;
	int error = 0;
	int nr_pages;
	int err2;
	struct bio *bio;
	struct timeval start;
	struct timeval stop;

	printk(KERN_INFO "PM: Saving image data pages (%u pages) ...     ",
		nr_to_write);
	m = nr_to_write / 100;
	if (!m)
		m = 1;
	nr_pages = 0;
	bio = NULL;
	do_gettimeofday(&start);
	do {
		ret = snapshot_read_next(snapshot, PAGE_SIZE);
		if (ret > 0) {
			error = swap_write_page(handle, data_of(*snapshot),
						&bio);
			if (error)
				break;
			if (!(nr_pages % m))
				printk("\b\b\b\b%3d%%", nr_pages / m);
			nr_pages++;
		}
	} while (ret > 0);
	err2 = wait_on_bio_chain(&bio);
	do_gettimeofday(&stop);
	if (!error)
		error = err2;
	if (!error)
		printk("\b\b\b\bdone\n");
	swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
	return error;
}

/**
 *	enough_swap - Make sure we have enough swap to save the image.
 *
 *	Returns TRUE or FALSE after checking the total amount of swap
 *	space avaiable from the resume partition.
 */

static int enough_swap(unsigned int nr_pages)
{
	unsigned int free_swap = count_swap_pages(root_swap, 1);

	pr_debug("PM: Free swap pages: %u\n", free_swap);
	return free_swap > nr_pages + PAGES_FOR_IO;
}

/**
 *	swsusp_write - Write entire image and metadata.
 *	@flags: flags to pass to the "boot" kernel in the image header
 *
 *	It is important _NOT_ to umount filesystems at this point. We want
 *	them synced (in case something goes wrong) but we DO not want to mark
 *	filesystem clean: it is not. (And it does not matter, if we resume
 *	correctly, we'll mark system clean, anyway.)
 */

int swsusp_write(unsigned int flags)
{
	struct swap_map_handle handle;
	struct snapshot_handle snapshot;
	struct swsusp_info *header;
	int error;

	error = swsusp_swap_check();
	if (error) {
		printk(KERN_ERR "PM: Cannot find swap device, try "
				"swapon -a.\n");
		return error;
	}
	memset(&snapshot, 0, sizeof(struct snapshot_handle));
	error = snapshot_read_next(&snapshot, PAGE_SIZE);
	if (error < PAGE_SIZE) {
		if (error >= 0)
			error = -EFAULT;

		goto out;
	}
	header = (struct swsusp_info *)data_of(snapshot);
	if (!enough_swap(header->pages)) {
		printk(KERN_ERR "PM: Not enough free swap\n");
		error = -ENOSPC;
		goto out;
	}
	error = get_swap_writer(&handle);
	if (!error) {
		sector_t start = handle.cur_swap;

		error = swap_write_page(&handle, header, NULL);
		if (!error)
			error = save_image(&handle, &snapshot,
					header->pages - 1);

		if (!error) {
			flush_swap_writer(&handle);
			printk(KERN_INFO "PM: S");
			error = mark_swapfiles(start, flags);
			printk("|\n");
		}
	}
	if (error)
		free_all_swap_pages(root_swap);

	release_swap_writer(&handle);
 out:
	swsusp_close(FMODE_WRITE);
	return error;
}

/**
 *	The following functions allow us to read data using a swap map
 *	in a file-alike way
 */

static void release_swap_reader(struct swap_map_handle *handle)
{
	if (handle->cur)
		free_page((unsigned long)handle->cur);
	handle->cur = NULL;
}

static int get_swap_reader(struct swap_map_handle *handle, sector_t start)
{
	int error;

	if (!start)
		return -EINVAL;

	handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT | __GFP_HIGH);
	if (!handle->cur)
		return -ENOMEM;

	error = bio_read_page(start, handle->cur, NULL);
	if (error) {
		release_swap_reader(handle);
		return error;
	}
	handle->k = 0;
	return 0;
}

static int swap_read_page(struct swap_map_handle *handle, void *buf,
				struct bio **bio_chain)
{
	sector_t offset;
	int error;

	if (!handle->cur)
		return -EINVAL;
	offset = handle->cur->entries[handle->k];
	if (!offset)
		return -EFAULT;
	error = bio_read_page(offset, buf, bio_chain);
	if (error)
		return error;
	if (++handle->k >= MAP_PAGE_ENTRIES) {
		error = wait_on_bio_chain(bio_chain);
		handle->k = 0;
		offset = handle->cur->next_swap;
		if (!offset)
			release_swap_reader(handle);
		else if (!error)
			error = bio_read_page(offset, handle->cur, NULL);
	}
	return error;
}

/**
 *	load_image - load the image using the swap map handle
 *	@handle and the snapshot handle @snapshot
 *	(assume there are @nr_pages pages to load)
 */

static int load_image(struct swap_map_handle *handle,
                      struct snapshot_handle *snapshot,
                      unsigned int nr_to_read)
{
	unsigned int m;
	int error = 0;
	struct timeval start;
	struct timeval stop;
	struct bio *bio;
	int err2;
	unsigned nr_pages;

	printk(KERN_INFO "PM: Loading image data pages (%u pages) ...     ",
		nr_to_read);
	m = nr_to_read / 100;
	if (!m)
		m = 1;
	nr_pages = 0;
	bio = NULL;
	do_gettimeofday(&start);
	for ( ; ; ) {
		error = snapshot_write_next(snapshot, PAGE_SIZE);
		if (error <= 0)
			break;
		error = swap_read_page(handle, data_of(*snapshot), &bio);
		if (error)
			break;
		if (snapshot->sync_read)
			error = wait_on_bio_chain(&bio);
		if (error)
			break;
		if (!(nr_pages % m))
			printk("\b\b\b\b%3d%%", nr_pages / m);
		nr_pages++;
	}
	err2 = wait_on_bio_chain(&bio);
	do_gettimeofday(&stop);
	if (!error)
		error = err2;
	if (!error) {
		printk("\b\b\b\bdone\n");
		snapshot_write_finalize(snapshot);
		if (!snapshot_image_loaded(snapshot))
			error = -ENODATA;
	}
	swsusp_show_speed(&start, &stop, nr_to_read, "Read");
	return error;
}

/**
 *	swsusp_read - read the hibernation image.
 *	@flags_p: flags passed by the "frozen" kernel in the image header should
 *		  be written into this memeory location
 */

int swsusp_read(unsigned int *flags_p)
{
	int error;
	struct swap_map_handle handle;
	struct snapshot_handle snapshot;
	struct swsusp_info *header;

	*flags_p = swsusp_header->flags;
	if (IS_ERR(resume_bdev)) {
		pr_debug("PM: Image device not initialised\n");
		return PTR_ERR(resume_bdev);
	}

	memset(&snapshot, 0, sizeof(struct snapshot_handle));
	error = snapshot_write_next(&snapshot, PAGE_SIZE);
	if (error < PAGE_SIZE)
		return error < 0 ? error : -EFAULT;
	header = (struct swsusp_info *)data_of(snapshot);
	error = get_swap_reader(&handle, swsusp_header->image);
	if (!error)
		error = swap_read_page(&handle, header, NULL);
	if (!error)
		error = load_image(&handle, &snapshot, header->pages - 1);
	release_swap_reader(&handle);

	blkdev_put(resume_bdev, FMODE_READ);

	if (!error)
		pr_debug("PM: Image successfully loaded\n");
	else
		pr_debug("PM: Error %d resuming\n", error);
	return error;
}

/**
 *      swsusp_check - Check for swsusp signature in the resume device
 */

int swsusp_check(void)
{
	int error;

	resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
	if (!IS_ERR(resume_bdev)) {
		set_blocksize(resume_bdev, PAGE_SIZE);
		memset(swsusp_header, 0, PAGE_SIZE);
		error = bio_read_page(swsusp_resume_block,
					swsusp_header, NULL);
		if (error)
			return error;

		if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
			memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
			/* Reset swap signature now */
			error = bio_write_page(swsusp_resume_block,
						swsusp_header, NULL);
		} else {
			return -EINVAL;
		}
		if (error)
			blkdev_put(resume_bdev, FMODE_READ);
		else
			pr_debug("PM: Signature found, resuming\n");
	} else {
		error = PTR_ERR(resume_bdev);
	}

	if (error)
		pr_debug("PM: Error %d checking image file\n", error);

	return error;
}

/**
 *	swsusp_close - close swap device.
 */

void swsusp_close(fmode_t mode)
{
	if (IS_ERR(resume_bdev)) {
		pr_debug("PM: Image device not initialised\n");
		return;
	}

	blkdev_put(resume_bdev, mode);
}

static int swsusp_header_init(void)
{
	swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
	if (!swsusp_header)
		panic("Could not allocate memory for swsusp_header\n");
	return 0;
}

core_initcall(swsusp_header_init);
Commit	Line	Data
61159a31 RW	1	/*
	2	* linux/kernel/power/swap.c
	3	*
	4	* This file provides functions for reading the suspend image from
	5	* and writing it to a swap partition.
	6	*
	7	* Copyright (C) 1998,2001-2005 Pavel Machek <pavel@suse.cz>
	8	* Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
	9	*
	10	* This file is released under the GPLv2.
	11	*
	12	*/
	13
	14	#include <linux/module.h>
61159a31 RW	15	#include <linux/file.h>
61159a31 RW	16	#include <linux/utsname.h>
61159a31 RW	17	#include <linux/delay.h>
	18	#include <linux/bitops.h>
	19	#include <linux/genhd.h>
	20	#include <linux/device.h>
	21	#include <linux/buffer_head.h>
	22	#include <linux/bio.h>
546e0d27	23	#include <linux/blkdev.h>
61159a31 RW	24	#include <linux/swap.h>
	25	#include <linux/swapops.h>
	26	#include <linux/pm.h>
	27
	28	#include "power.h"
	29
61159a31 RW	30	#define SWSUSP_SIG "S1SUSPEND"
61159a31 RW	31
1b29c164	32	struct swsusp_header {
a634cc10	33	char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int)];
3aef83e0	34	sector_t image;
a634cc10	35	unsigned int flags; /* Flags to pass to the "boot" kernel */
61159a31 RW	36	char orig_sig[10];
61159a31 RW	37	char sig[10];
1b29c164 VG	38	} __attribute__((packed));
	39
	40	static struct swsusp_header *swsusp_header;
61159a31 RW	41
61159a31 RW	42	/*
3fc6b34f	43	* General things
61159a31 RW	44	*/
	45
	46	static unsigned short root_swap = 0xffff;
3fc6b34f RW	47	static struct block_device *resume_bdev;
	48
	49	/**
	50	* submit - submit BIO request.
	51	* @rw: READ or WRITE.
	52	* @off physical offset of page.
	53	* @page: page we're reading or writing.
	54	* @bio_chain: list of pending biod (for async reading)
	55	*
	56	* Straight from the textbook - allocate and initialize the bio.
	57	* If we're reading, make sure the page is marked as dirty.
	58	* Then submit it and, if @bio_chain == NULL, wait.
	59	*/
	60	static int submit(int rw, pgoff_t page_off, struct page *page,
	61	struct bio **bio_chain)
	62	{
93dbb393	63	const int bio_rw = rw \| (1 << BIO_RW_SYNCIO) \| (1 << BIO_RW_UNPLUG);
3fc6b34f RW	64	struct bio *bio;
3fc6b34f RW	65
85949121	66	bio = bio_alloc(__GFP_WAIT \| __GFP_HIGH, 1);
3fc6b34f RW	67	if (!bio)
	68	return -ENOMEM;
	69	bio->bi_sector = page_off * (PAGE_SIZE >> 9);
	70	bio->bi_bdev = resume_bdev;
	71	bio->bi_end_io = end_swap_bio_read;
	72
	73	if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
23976728 RW	74	printk(KERN_ERR "PM: Adding page to bio failed at %ld\n",
23976728 RW	75	page_off);
3fc6b34f RW	76	bio_put(bio);
	77	return -EFAULT;
	78	}
	79
	80	lock_page(page);
	81	bio_get(bio);
	82
	83	if (bio_chain == NULL) {
93dbb393	84	submit_bio(bio_rw, bio);
3fc6b34f RW	85	wait_on_page_locked(page);
	86	if (rw == READ)
	87	bio_set_pages_dirty(bio);
	88	bio_put(bio);
	89	} else {
	90	if (rw == READ)
	91	get_page(page); /* These pages are freed later */
	92	bio->bi_private = *bio_chain;
	93	*bio_chain = bio;
93dbb393	94	submit_bio(bio_rw, bio);
3fc6b34f RW	95	}
	96	return 0;
	97	}
	98
	99	static int bio_read_page(pgoff_t page_off, void addr, struct bio *bio_chain)
	100	{
	101	return submit(READ, page_off, virt_to_page(addr), bio_chain);
	102	}
	103
3aef83e0	104	static int bio_write_page(pgoff_t page_off, void addr, struct bio *bio_chain)
3fc6b34f	105	{
3aef83e0	106	return submit(WRITE, page_off, virt_to_page(addr), bio_chain);
3fc6b34f RW	107	}
	108
	109	static int wait_on_bio_chain(struct bio **bio_chain)
	110	{
	111	struct bio *bio;
	112	struct bio *next_bio;
	113	int ret = 0;
	114
	115	if (bio_chain == NULL)
	116	return 0;
	117
	118	bio = *bio_chain;
	119	if (bio == NULL)
	120	return 0;
	121	while (bio) {
	122	struct page *page;
	123
	124	next_bio = bio->bi_private;
	125	page = bio->bi_io_vec[0].bv_page;
	126	wait_on_page_locked(page);
	127	if (!PageUptodate(page) \|\| PageError(page))
	128	ret = -EIO;
	129	put_page(page);
	130	bio_put(bio);
	131	bio = next_bio;
	132	}
	133	*bio_chain = NULL;
	134	return ret;
	135	}
	136
3fc6b34f RW	137	/*
	138	* Saving part
	139	*/
61159a31	140
a634cc10	141	static int mark_swapfiles(sector_t start, unsigned int flags)
61159a31 RW	142	{
	143	int error;
	144
1b29c164 VG	145	bio_read_page(swsusp_resume_block, swsusp_header, NULL);
	146	if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) \|\|
	147	!memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
	148	memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
	149	memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
	150	swsusp_header->image = start;
a634cc10	151	swsusp_header->flags = flags;
9a154d9d	152	error = bio_write_page(swsusp_resume_block,
1b29c164	153	swsusp_header, NULL);
61159a31	154	} else {
23976728	155	printk(KERN_ERR "PM: Swap header not found!\n");
61159a31 RW	156	error = -ENODEV;
	157	}
	158	return error;
	159	}
	160
	161	/**
	162	* swsusp_swap_check - check if the resume device is a swap device
	163	* and get its index (if so)
	164	*/
	165
	166	static int swsusp_swap_check(void) /* This is called before saving image */
	167	{
3aef83e0 RW	168	int res;
3aef83e0 RW	169
7bf23687 RW	170	res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
7bf23687 RW	171	&resume_bdev);
3aef83e0 RW	172	if (res < 0)
	173	return res;
	174
	175	root_swap = res;
572c4892	176	res = blkdev_get(resume_bdev, FMODE_WRITE);
7bf23687 RW	177	if (res)
7bf23687 RW	178	return res;
3aef83e0 RW	179
	180	res = set_blocksize(resume_bdev, PAGE_SIZE);
	181	if (res < 0)
9a1c3542	182	blkdev_put(resume_bdev, FMODE_WRITE);
61159a31	183
61159a31 RW	184	return res;
	185	}
	186
	187	/**
	188	* write_page - Write one page to given swap location.
	189	* @buf: Address we're writing.
	190	* @offset: Offset of the swap page we're writing to.
ab954160	191	* @bio_chain: Link the next write BIO here
61159a31 RW	192	*/
61159a31 RW	193
3aef83e0	194	static int write_page(void buf, sector_t offset, struct bio *bio_chain)
61159a31	195	{
3aef83e0 RW	196	void *src;
	197
	198	if (!offset)
	199	return -ENOSPC;
	200
	201	if (bio_chain) {
85949121	202	src = (void *)__get_free_page(__GFP_WAIT \| __GFP_HIGH);
3aef83e0 RW	203	if (src) {
	204	memcpy(src, buf, PAGE_SIZE);
	205	} else {
	206	WARN_ON_ONCE(1);
	207	bio_chain = NULL; /* Go synchronous */
	208	src = buf;
ab954160	209	}
3aef83e0 RW	210	} else {
3aef83e0 RW	211	src = buf;
61159a31	212	}
3aef83e0	213	return bio_write_page(offset, src, bio_chain);
61159a31 RW	214	}
	215
	216	/*
	217	* The swap map is a data structure used for keeping track of each page
	218	* written to a swap partition. It consists of many swap_map_page
	219	* structures that contain each an array of MAP_PAGE_SIZE swap entries.
	220	* These structures are stored on the swap and linked together with the
	221	* help of the .next_swap member.
	222	*
	223	* The swap map is created during suspend. The swap map pages are
	224	* allocated and populated one at a time, so we only need one memory
	225	* page to set up the entire structure.
	226	*
	227	* During resume we also only need to use one swap_map_page structure
	228	* at a time.
	229	*/
	230
3aef83e0	231	#define MAP_PAGE_ENTRIES (PAGE_SIZE / sizeof(sector_t) - 1)
61159a31 RW	232
61159a31 RW	233	struct swap_map_page {
3aef83e0 RW	234	sector_t entries[MAP_PAGE_ENTRIES];
3aef83e0 RW	235	sector_t next_swap;
61159a31 RW	236	};
	237
	238	/**
	239	* The swap_map_handle structure is used for handling swap in
	240	* a file-alike way
	241	*/
	242
	243	struct swap_map_handle {
	244	struct swap_map_page *cur;
3aef83e0	245	sector_t cur_swap;
61159a31 RW	246	unsigned int k;
	247	};
	248
	249	static void release_swap_writer(struct swap_map_handle *handle)
	250	{
	251	if (handle->cur)
	252	free_page((unsigned long)handle->cur);
	253	handle->cur = NULL;
61159a31 RW	254	}
	255
	256	static int get_swap_writer(struct swap_map_handle *handle)
	257	{
	258	handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
	259	if (!handle->cur)
	260	return -ENOMEM;
d1d241cc	261	handle->cur_swap = alloc_swapdev_block(root_swap);
61159a31 RW	262	if (!handle->cur_swap) {
	263	release_swap_writer(handle);
	264	return -ENOSPC;
	265	}
	266	handle->k = 0;
	267	return 0;
	268	}
	269
ab954160 AM	270	static int swap_write_page(struct swap_map_handle handle, void buf,
	271	struct bio **bio_chain)
	272	{
	273	int error = 0;
3aef83e0	274	sector_t offset;
61159a31 RW	275
	276	if (!handle->cur)
	277	return -EINVAL;
d1d241cc	278	offset = alloc_swapdev_block(root_swap);
ab954160	279	error = write_page(buf, offset, bio_chain);
61159a31 RW	280	if (error)
	281	return error;
	282	handle->cur->entries[handle->k++] = offset;
	283	if (handle->k >= MAP_PAGE_ENTRIES) {
ab954160 AM	284	error = wait_on_bio_chain(bio_chain);
	285	if (error)
	286	goto out;
d1d241cc	287	offset = alloc_swapdev_block(root_swap);
61159a31 RW	288	if (!offset)
	289	return -ENOSPC;
	290	handle->cur->next_swap = offset;
ab954160	291	error = write_page(handle->cur, handle->cur_swap, NULL);
61159a31	292	if (error)
ab954160	293	goto out;
61159a31 RW	294	memset(handle->cur, 0, PAGE_SIZE);
	295	handle->cur_swap = offset;
	296	handle->k = 0;
	297	}
59a49335	298	out:
ab954160	299	return error;
61159a31 RW	300	}
	301
	302	static int flush_swap_writer(struct swap_map_handle *handle)
	303	{
	304	if (handle->cur && handle->cur_swap)
ab954160	305	return write_page(handle->cur, handle->cur_swap, NULL);
61159a31 RW	306	else
	307	return -EINVAL;
	308	}
	309
	310	/**
	311	* save_image - save the suspend image data
	312	*/
	313
	314	static int save_image(struct swap_map_handle *handle,
	315	struct snapshot_handle *snapshot,
3a4f7577	316	unsigned int nr_to_write)
61159a31 RW	317	{
	318	unsigned int m;
	319	int ret;
	320	int error = 0;
3a4f7577	321	int nr_pages;
ab954160 AM	322	int err2;
ab954160 AM	323	struct bio *bio;
3a4f7577 AM	324	struct timeval start;
3a4f7577 AM	325	struct timeval stop;
61159a31	326
23976728 RW	327	printk(KERN_INFO "PM: Saving image data pages (%u pages) ... ",
23976728 RW	328	nr_to_write);
3a4f7577	329	m = nr_to_write / 100;
61159a31 RW	330	if (!m)
	331	m = 1;
	332	nr_pages = 0;
ab954160	333	bio = NULL;
3a4f7577	334	do_gettimeofday(&start);
61159a31 RW	335	do {
	336	ret = snapshot_read_next(snapshot, PAGE_SIZE);
	337	if (ret > 0) {
ab954160 AM	338	error = swap_write_page(handle, data_of(*snapshot),
ab954160 AM	339	&bio);
61159a31 RW	340	if (error)
	341	break;
	342	if (!(nr_pages % m))
	343	printk("\b\b\b\b%3d%%", nr_pages / m);
	344	nr_pages++;
	345	}
	346	} while (ret > 0);
ab954160	347	err2 = wait_on_bio_chain(&bio);
3a4f7577	348	do_gettimeofday(&stop);
ab954160 AM	349	if (!error)
ab954160 AM	350	error = err2;
61159a31 RW	351	if (!error)
61159a31 RW	352	printk("\b\b\b\bdone\n");
0d3a9abe	353	swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
61159a31 RW	354	return error;
	355	}
	356
	357	/**
	358	* enough_swap - Make sure we have enough swap to save the image.
	359	*
	360	* Returns TRUE or FALSE after checking the total amount of swap
	361	* space avaiable from the resume partition.
	362	*/
	363
	364	static int enough_swap(unsigned int nr_pages)
	365	{
	366	unsigned int free_swap = count_swap_pages(root_swap, 1);
	367
23976728	368	pr_debug("PM: Free swap pages: %u\n", free_swap);
940864dd	369	return free_swap > nr_pages + PAGES_FOR_IO;
61159a31 RW	370	}
	371
	372	/**
	373	* swsusp_write - Write entire image and metadata.
a634cc10	374	* @flags: flags to pass to the "boot" kernel in the image header
61159a31 RW	375	*
	376	* It is important _NOT_ to umount filesystems at this point. We want
	377	* them synced (in case something goes wrong) but we DO not want to mark
	378	* filesystem clean: it is not. (And it does not matter, if we resume
	379	* correctly, we'll mark system clean, anyway.)
	380	*/
	381
a634cc10	382	int swsusp_write(unsigned int flags)
61159a31 RW	383	{
	384	struct swap_map_handle handle;
	385	struct snapshot_handle snapshot;
	386	struct swsusp_info *header;
61159a31 RW	387	int error;
61159a31 RW	388
3aef83e0 RW	389	error = swsusp_swap_check();
3aef83e0 RW	390	if (error) {
23976728	391	printk(KERN_ERR "PM: Cannot find swap device, try "
546e0d27	392	"swapon -a.\n");
61159a31 RW	393	return error;
	394	}
	395	memset(&snapshot, 0, sizeof(struct snapshot_handle));
	396	error = snapshot_read_next(&snapshot, PAGE_SIZE);
3aef83e0 RW	397	if (error < PAGE_SIZE) {
	398	if (error >= 0)
	399	error = -EFAULT;
	400
	401	goto out;
	402	}
61159a31 RW	403	header = (struct swsusp_info *)data_of(snapshot);
61159a31 RW	404	if (!enough_swap(header->pages)) {
23976728	405	printk(KERN_ERR "PM: Not enough free swap\n");
3aef83e0 RW	406	error = -ENOSPC;
3aef83e0 RW	407	goto out;
61159a31 RW	408	}
	409	error = get_swap_writer(&handle);
	410	if (!error) {
3aef83e0 RW	411	sector_t start = handle.cur_swap;
3aef83e0 RW	412
ab954160	413	error = swap_write_page(&handle, header, NULL);
712f403a AM	414	if (!error)
	415	error = save_image(&handle, &snapshot,
	416	header->pages - 1);
3aef83e0	417
712f403a AM	418	if (!error) {
712f403a AM	419	flush_swap_writer(&handle);
23976728	420	printk(KERN_INFO "PM: S");
a634cc10	421	error = mark_swapfiles(start, flags);
712f403a AM	422	printk("\|\n");
712f403a AM	423	}
61159a31 RW	424	}
61159a31 RW	425	if (error)
d1d241cc RW	426	free_all_swap_pages(root_swap);
d1d241cc RW	427
61159a31	428	release_swap_writer(&handle);
59a49335	429	out:
c2dd0dae	430	swsusp_close(FMODE_WRITE);
61159a31 RW	431	return error;
	432	}
	433
61159a31 RW	434	/**
	435	* The following functions allow us to read data using a swap map
	436	* in a file-alike way
	437	*/
	438
	439	static void release_swap_reader(struct swap_map_handle *handle)
	440	{
	441	if (handle->cur)
	442	free_page((unsigned long)handle->cur);
	443	handle->cur = NULL;
	444	}
	445
3aef83e0	446	static int get_swap_reader(struct swap_map_handle *handle, sector_t start)
61159a31 RW	447	{
	448	int error;
	449
3aef83e0	450	if (!start)
61159a31	451	return -EINVAL;
3aef83e0	452
85949121	453	handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT \| __GFP_HIGH);
61159a31 RW	454	if (!handle->cur)
61159a31 RW	455	return -ENOMEM;
3aef83e0 RW	456
3aef83e0 RW	457	error = bio_read_page(start, handle->cur, NULL);
61159a31 RW	458	if (error) {
	459	release_swap_reader(handle);
	460	return error;
	461	}
	462	handle->k = 0;
	463	return 0;
	464	}
	465
546e0d27 AM	466	static int swap_read_page(struct swap_map_handle handle, void buf,
546e0d27 AM	467	struct bio **bio_chain)
61159a31	468	{
3aef83e0	469	sector_t offset;
61159a31 RW	470	int error;
	471
	472	if (!handle->cur)
	473	return -EINVAL;
	474	offset = handle->cur->entries[handle->k];
	475	if (!offset)
	476	return -EFAULT;
546e0d27	477	error = bio_read_page(offset, buf, bio_chain);
61159a31 RW	478	if (error)
	479	return error;
	480	if (++handle->k >= MAP_PAGE_ENTRIES) {
546e0d27	481	error = wait_on_bio_chain(bio_chain);
61159a31 RW	482	handle->k = 0;
	483	offset = handle->cur->next_swap;
	484	if (!offset)
	485	release_swap_reader(handle);
546e0d27 AM	486	else if (!error)
546e0d27 AM	487	error = bio_read_page(offset, handle->cur, NULL);
61159a31 RW	488	}
	489	return error;
	490	}
	491
	492	/**
	493	* load_image - load the image using the swap map handle
	494	* @handle and the snapshot handle @snapshot
	495	* (assume there are @nr_pages pages to load)
	496	*/
	497
	498	static int load_image(struct swap_map_handle *handle,
	499	struct snapshot_handle *snapshot,
546e0d27	500	unsigned int nr_to_read)
61159a31 RW	501	{
61159a31 RW	502	unsigned int m;
61159a31	503	int error = 0;
8c002494 AM	504	struct timeval start;
8c002494 AM	505	struct timeval stop;
546e0d27 AM	506	struct bio *bio;
	507	int err2;
	508	unsigned nr_pages;
61159a31	509
23976728 RW	510	printk(KERN_INFO "PM: Loading image data pages (%u pages) ... ",
23976728 RW	511	nr_to_read);
546e0d27	512	m = nr_to_read / 100;
61159a31 RW	513	if (!m)
	514	m = 1;
	515	nr_pages = 0;
546e0d27	516	bio = NULL;
8c002494	517	do_gettimeofday(&start);
546e0d27 AM	518	for ( ; ; ) {
	519	error = snapshot_write_next(snapshot, PAGE_SIZE);
	520	if (error <= 0)
	521	break;
	522	error = swap_read_page(handle, data_of(*snapshot), &bio);
	523	if (error)
	524	break;
	525	if (snapshot->sync_read)
	526	error = wait_on_bio_chain(&bio);
	527	if (error)
	528	break;
	529	if (!(nr_pages % m))
	530	printk("\b\b\b\b%3d%%", nr_pages / m);
	531	nr_pages++;
	532	}
	533	err2 = wait_on_bio_chain(&bio);
8c002494	534	do_gettimeofday(&stop);
546e0d27 AM	535	if (!error)
546e0d27 AM	536	error = err2;
e655a250	537	if (!error) {
61159a31	538	printk("\b\b\b\bdone\n");
8357376d	539	snapshot_write_finalize(snapshot);
e655a250 CK	540	if (!snapshot_image_loaded(snapshot))
	541	error = -ENODATA;
	542	}
0d3a9abe	543	swsusp_show_speed(&start, &stop, nr_to_read, "Read");
61159a31 RW	544	return error;
	545	}
	546
a634cc10 RW	547	/**
	548	* swsusp_read - read the hibernation image.
	549	* @flags_p: flags passed by the "frozen" kernel in the image header should
	550	* be written into this memeory location
	551	*/
	552
	553	int swsusp_read(unsigned int *flags_p)
61159a31 RW	554	{
	555	int error;
	556	struct swap_map_handle handle;
	557	struct snapshot_handle snapshot;
	558	struct swsusp_info *header;
	559
a634cc10	560	*flags_p = swsusp_header->flags;
61159a31	561	if (IS_ERR(resume_bdev)) {
23976728	562	pr_debug("PM: Image device not initialised\n");
61159a31 RW	563	return PTR_ERR(resume_bdev);
	564	}
	565
	566	memset(&snapshot, 0, sizeof(struct snapshot_handle));
	567	error = snapshot_write_next(&snapshot, PAGE_SIZE);
	568	if (error < PAGE_SIZE)
	569	return error < 0 ? error : -EFAULT;
	570	header = (struct swsusp_info *)data_of(snapshot);
1b29c164	571	error = get_swap_reader(&handle, swsusp_header->image);
61159a31	572	if (!error)
546e0d27	573	error = swap_read_page(&handle, header, NULL);
61159a31 RW	574	if (!error)
	575	error = load_image(&handle, &snapshot, header->pages - 1);
	576	release_swap_reader(&handle);
	577
9a1c3542	578	blkdev_put(resume_bdev, FMODE_READ);
61159a31 RW	579
61159a31 RW	580	if (!error)
23976728	581	pr_debug("PM: Image successfully loaded\n");
61159a31	582	else
23976728	583	pr_debug("PM: Error %d resuming\n", error);
61159a31 RW	584	return error;
	585	}
	586
	587	/**
	588	* swsusp_check - Check for swsusp signature in the resume device
	589	*/
	590
	591	int swsusp_check(void)
	592	{
	593	int error;
	594
	595	resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
	596	if (!IS_ERR(resume_bdev)) {
	597	set_blocksize(resume_bdev, PAGE_SIZE);
6373da1f	598	memset(swsusp_header, 0, PAGE_SIZE);
9a154d9d	599	error = bio_read_page(swsusp_resume_block,
1b29c164	600	swsusp_header, NULL);
9a154d9d	601	if (error)
61159a31	602	return error;
9a154d9d	603
1b29c164 VG	604	if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
1b29c164 VG	605	memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
61159a31	606	/* Reset swap signature now */
9a154d9d	607	error = bio_write_page(swsusp_resume_block,
1b29c164	608	swsusp_header, NULL);
61159a31 RW	609	} else {
	610	return -EINVAL;
	611	}
	612	if (error)
9a1c3542	613	blkdev_put(resume_bdev, FMODE_READ);
61159a31	614	else
23976728	615	pr_debug("PM: Signature found, resuming\n");
61159a31 RW	616	} else {
	617	error = PTR_ERR(resume_bdev);
	618	}
	619
	620	if (error)
23976728	621	pr_debug("PM: Error %d checking image file\n", error);
61159a31 RW	622
	623	return error;
	624	}
	625
	626	/**
	627	* swsusp_close - close swap device.
	628	*/
	629
c2dd0dae	630	void swsusp_close(fmode_t mode)
61159a31 RW	631	{
61159a31 RW	632	if (IS_ERR(resume_bdev)) {
23976728	633	pr_debug("PM: Image device not initialised\n");
61159a31 RW	634	return;
	635	}
	636
50c396d3	637	blkdev_put(resume_bdev, mode);
61159a31	638	}
1b29c164 VG	639
	640	static int swsusp_header_init(void)
	641	{
	642	swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
	643	if (!swsusp_header)
	644	panic("Could not allocate memory for swsusp_header\n");
	645	return 0;
	646	}
	647
	648	core_initcall(swsusp_header_init);