[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/version.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"

extern char resume_file[];

#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)
{
	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("swsusp: ERROR: adding page to bio at %ld\n", page_off);
		bio_put(bio);
		return -EFAULT;
	}

	lock_page(page);
	bio_get(bio);

	if (bio_chain == NULL) {
		submit_bio(rw | (1 << BIO_RW_SYNC), 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(rw | (1 << BIO_RW_SYNC), 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 "swsusp: 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, O_RDWR);
	if (res)
		return res;

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

	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("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("swsusp: 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 "swsusp: 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 "swsusp: 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("S");
			error = mark_swapfiles(start, flags);
			printk("|\n");
		}
	}
	if (error)
		free_all_swap_pages(root_swap);

	release_swap_writer(&handle);
 out:
	swsusp_close();
	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("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("swsusp: block 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);

	if (!error)
		pr_debug("swsusp: Reading resume file was successful\n");
	else
		pr_debug("swsusp: 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);
		else
			pr_debug("swsusp: Signature found, resuming\n");
	} else {
		error = PTR_ERR(resume_bdev);
	}

	if (error)
		pr_debug("swsusp: Error %d check for resume file\n", error);

	return error;
}

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

void swsusp_close(void)
{
	if (IS_ERR(resume_bdev)) {
		pr_debug("swsusp: block device not initialised\n");
		return;
	}

	blkdev_put(resume_bdev);
}

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>
	16	#include <linux/utsname.h>
	17	#include <linux/version.h>
	18	#include <linux/delay.h>
	19	#include <linux/bitops.h>
	20	#include <linux/genhd.h>
	21	#include <linux/device.h>
	22	#include <linux/buffer_head.h>
	23	#include <linux/bio.h>
546e0d27	24	#include <linux/blkdev.h>
61159a31 RW	25	#include <linux/swap.h>
	26	#include <linux/swapops.h>
	27	#include <linux/pm.h>
	28
	29	#include "power.h"
	30
	31	extern char resume_file[];
	32
	33	#define SWSUSP_SIG "S1SUSPEND"
	34
1b29c164	35	struct swsusp_header {
a634cc10	36	char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int)];
3aef83e0	37	sector_t image;
a634cc10	38	unsigned int flags; /* Flags to pass to the "boot" kernel */
61159a31 RW	39	char orig_sig[10];
61159a31 RW	40	char sig[10];
1b29c164 VG	41	} __attribute__((packed));
	42
	43	static struct swsusp_header *swsusp_header;
61159a31 RW	44
61159a31 RW	45	/*
3fc6b34f	46	* General things
61159a31 RW	47	*/
	48
	49	static unsigned short root_swap = 0xffff;
3fc6b34f RW	50	static struct block_device *resume_bdev;
	51
	52	/**
	53	* submit - submit BIO request.
	54	* @rw: READ or WRITE.
	55	* @off physical offset of page.
	56	* @page: page we're reading or writing.
	57	* @bio_chain: list of pending biod (for async reading)
	58	*
	59	* Straight from the textbook - allocate and initialize the bio.
	60	* If we're reading, make sure the page is marked as dirty.
	61	* Then submit it and, if @bio_chain == NULL, wait.
	62	*/
	63	static int submit(int rw, pgoff_t page_off, struct page *page,
	64	struct bio **bio_chain)
	65	{
	66	struct bio *bio;
	67
85949121	68	bio = bio_alloc(__GFP_WAIT \| __GFP_HIGH, 1);
3fc6b34f RW	69	if (!bio)
	70	return -ENOMEM;
	71	bio->bi_sector = page_off * (PAGE_SIZE >> 9);
	72	bio->bi_bdev = resume_bdev;
	73	bio->bi_end_io = end_swap_bio_read;
	74
	75	if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
	76	printk("swsusp: ERROR: adding page to bio at %ld\n", page_off);
	77	bio_put(bio);
	78	return -EFAULT;
	79	}
	80
	81	lock_page(page);
	82	bio_get(bio);
	83
	84	if (bio_chain == NULL) {
	85	submit_bio(rw \| (1 << BIO_RW_SYNC), bio);
	86	wait_on_page_locked(page);
	87	if (rw == READ)
	88	bio_set_pages_dirty(bio);
	89	bio_put(bio);
	90	} else {
	91	if (rw == READ)
	92	get_page(page); /* These pages are freed later */
	93	bio->bi_private = *bio_chain;
	94	*bio_chain = bio;
	95	submit_bio(rw \| (1 << BIO_RW_SYNC), bio);
	96	}
	97	return 0;
	98	}
	99
	100	static int bio_read_page(pgoff_t page_off, void addr, struct bio *bio_chain)
	101	{
	102	return submit(READ, page_off, virt_to_page(addr), bio_chain);
	103	}
	104
3aef83e0	105	static int bio_write_page(pgoff_t page_off, void addr, struct bio *bio_chain)
3fc6b34f	106	{
3aef83e0	107	return submit(WRITE, page_off, virt_to_page(addr), bio_chain);
3fc6b34f RW	108	}
	109
	110	static int wait_on_bio_chain(struct bio **bio_chain)
	111	{
	112	struct bio *bio;
	113	struct bio *next_bio;
	114	int ret = 0;
	115
	116	if (bio_chain == NULL)
	117	return 0;
	118
	119	bio = *bio_chain;
	120	if (bio == NULL)
	121	return 0;
	122	while (bio) {
	123	struct page *page;
	124
	125	next_bio = bio->bi_private;
	126	page = bio->bi_io_vec[0].bv_page;
	127	wait_on_page_locked(page);
	128	if (!PageUptodate(page) \|\| PageError(page))
	129	ret = -EIO;
	130	put_page(page);
	131	bio_put(bio);
	132	bio = next_bio;
	133	}
	134	*bio_chain = NULL;
	135	return ret;
	136	}
	137
3fc6b34f RW	138	/*
	139	* Saving part
	140	*/
61159a31	141
a634cc10	142	static int mark_swapfiles(sector_t start, unsigned int flags)
61159a31 RW	143	{
	144	int error;
	145
1b29c164 VG	146	bio_read_page(swsusp_resume_block, swsusp_header, NULL);
	147	if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) \|\|
	148	!memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
	149	memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
	150	memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
	151	swsusp_header->image = start;
a634cc10	152	swsusp_header->flags = flags;
9a154d9d	153	error = bio_write_page(swsusp_resume_block,
1b29c164	154	swsusp_header, NULL);
61159a31	155	} else {
3aef83e0	156	printk(KERN_ERR "swsusp: Swap header not found!\n");
61159a31 RW	157	error = -ENODEV;
	158	}
	159	return error;
	160	}
	161
	162	/**
	163	* swsusp_swap_check - check if the resume device is a swap device
	164	* and get its index (if so)
	165	*/
	166
	167	static int swsusp_swap_check(void) /* This is called before saving image */
	168	{
3aef83e0 RW	169	int res;
3aef83e0 RW	170
7bf23687 RW	171	res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
7bf23687 RW	172	&resume_bdev);
3aef83e0 RW	173	if (res < 0)
	174	return res;
	175
	176	root_swap = res;
7bf23687 RW	177	res = blkdev_get(resume_bdev, FMODE_WRITE, O_RDWR);
	178	if (res)
	179	return res;
3aef83e0 RW	180
	181	res = set_blocksize(resume_bdev, PAGE_SIZE);
	182	if (res < 0)
	183	blkdev_put(resume_bdev);
61159a31	184
61159a31 RW	185	return res;
	186	}
	187
	188	/**
	189	* write_page - Write one page to given swap location.
	190	* @buf: Address we're writing.
	191	* @offset: Offset of the swap page we're writing to.
ab954160	192	* @bio_chain: Link the next write BIO here
61159a31 RW	193	*/
61159a31 RW	194
3aef83e0	195	static int write_page(void buf, sector_t offset, struct bio *bio_chain)
61159a31	196	{
3aef83e0 RW	197	void *src;
	198
	199	if (!offset)
	200	return -ENOSPC;
	201
	202	if (bio_chain) {
85949121	203	src = (void *)__get_free_page(__GFP_WAIT \| __GFP_HIGH);
3aef83e0 RW	204	if (src) {
	205	memcpy(src, buf, PAGE_SIZE);
	206	} else {
	207	WARN_ON_ONCE(1);
	208	bio_chain = NULL; /* Go synchronous */
	209	src = buf;
ab954160	210	}
3aef83e0 RW	211	} else {
3aef83e0 RW	212	src = buf;
61159a31	213	}
3aef83e0	214	return bio_write_page(offset, src, bio_chain);
61159a31 RW	215	}
	216
	217	/*
	218	* The swap map is a data structure used for keeping track of each page
	219	* written to a swap partition. It consists of many swap_map_page
	220	* structures that contain each an array of MAP_PAGE_SIZE swap entries.
	221	* These structures are stored on the swap and linked together with the
	222	* help of the .next_swap member.
	223	*
	224	* The swap map is created during suspend. The swap map pages are
	225	* allocated and populated one at a time, so we only need one memory
	226	* page to set up the entire structure.
	227	*
	228	* During resume we also only need to use one swap_map_page structure
	229	* at a time.
	230	*/
	231
3aef83e0	232	#define MAP_PAGE_ENTRIES (PAGE_SIZE / sizeof(sector_t) - 1)
61159a31 RW	233
61159a31 RW	234	struct swap_map_page {
3aef83e0 RW	235	sector_t entries[MAP_PAGE_ENTRIES];
3aef83e0 RW	236	sector_t next_swap;
61159a31 RW	237	};
	238
	239	/**
	240	* The swap_map_handle structure is used for handling swap in
	241	* a file-alike way
	242	*/
	243
	244	struct swap_map_handle {
	245	struct swap_map_page *cur;
3aef83e0	246	sector_t cur_swap;
61159a31 RW	247	unsigned int k;
	248	};
	249
	250	static void release_swap_writer(struct swap_map_handle *handle)
	251	{
	252	if (handle->cur)
	253	free_page((unsigned long)handle->cur);
	254	handle->cur = NULL;
61159a31 RW	255	}
	256
	257	static int get_swap_writer(struct swap_map_handle *handle)
	258	{
	259	handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
	260	if (!handle->cur)
	261	return -ENOMEM;
d1d241cc	262	handle->cur_swap = alloc_swapdev_block(root_swap);
61159a31 RW	263	if (!handle->cur_swap) {
	264	release_swap_writer(handle);
	265	return -ENOSPC;
	266	}
	267	handle->k = 0;
	268	return 0;
	269	}
	270
ab954160 AM	271	static int swap_write_page(struct swap_map_handle handle, void buf,
	272	struct bio **bio_chain)
	273	{
	274	int error = 0;
3aef83e0	275	sector_t offset;
61159a31 RW	276
	277	if (!handle->cur)
	278	return -EINVAL;
d1d241cc	279	offset = alloc_swapdev_block(root_swap);
ab954160	280	error = write_page(buf, offset, bio_chain);
61159a31 RW	281	if (error)
	282	return error;
	283	handle->cur->entries[handle->k++] = offset;
	284	if (handle->k >= MAP_PAGE_ENTRIES) {
ab954160 AM	285	error = wait_on_bio_chain(bio_chain);
	286	if (error)
	287	goto out;
d1d241cc	288	offset = alloc_swapdev_block(root_swap);
61159a31 RW	289	if (!offset)
	290	return -ENOSPC;
	291	handle->cur->next_swap = offset;
ab954160	292	error = write_page(handle->cur, handle->cur_swap, NULL);
61159a31	293	if (error)
ab954160	294	goto out;
61159a31 RW	295	memset(handle->cur, 0, PAGE_SIZE);
	296	handle->cur_swap = offset;
	297	handle->k = 0;
	298	}
59a49335	299	out:
ab954160	300	return error;
61159a31 RW	301	}
	302
	303	static int flush_swap_writer(struct swap_map_handle *handle)
	304	{
	305	if (handle->cur && handle->cur_swap)
ab954160	306	return write_page(handle->cur, handle->cur_swap, NULL);
61159a31 RW	307	else
	308	return -EINVAL;
	309	}
	310
	311	/**
	312	* save_image - save the suspend image data
	313	*/
	314
	315	static int save_image(struct swap_map_handle *handle,
	316	struct snapshot_handle *snapshot,
3a4f7577	317	unsigned int nr_to_write)
61159a31 RW	318	{
	319	unsigned int m;
	320	int ret;
	321	int error = 0;
3a4f7577	322	int nr_pages;
ab954160 AM	323	int err2;
ab954160 AM	324	struct bio *bio;
3a4f7577 AM	325	struct timeval start;
3a4f7577 AM	326	struct timeval stop;
61159a31	327
3a4f7577 AM	328	printk("Saving image data pages (%u pages) ... ", nr_to_write);
3a4f7577 AM	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
	368	pr_debug("swsusp: 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) {
546e0d27 AM	391	printk(KERN_ERR "swsusp: Cannot find swap device, try "
546e0d27 AM	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);
	404	if (!enough_swap(header->pages)) {
	405	printk(KERN_ERR "swsusp: 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) {
	419	flush_swap_writer(&handle);
	420	printk("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:
3aef83e0	430	swsusp_close();
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
546e0d27 AM	510	printk("Loading image data pages (%u pages) ... ", nr_to_read);
546e0d27 AM	511	m = nr_to_read / 100;
61159a31 RW	512	if (!m)
	513	m = 1;
	514	nr_pages = 0;
546e0d27	515	bio = NULL;
8c002494	516	do_gettimeofday(&start);
546e0d27 AM	517	for ( ; ; ) {
	518	error = snapshot_write_next(snapshot, PAGE_SIZE);
	519	if (error <= 0)
	520	break;
	521	error = swap_read_page(handle, data_of(*snapshot), &bio);
	522	if (error)
	523	break;
	524	if (snapshot->sync_read)
	525	error = wait_on_bio_chain(&bio);
	526	if (error)
	527	break;
	528	if (!(nr_pages % m))
	529	printk("\b\b\b\b%3d%%", nr_pages / m);
	530	nr_pages++;
	531	}
	532	err2 = wait_on_bio_chain(&bio);
8c002494	533	do_gettimeofday(&stop);
546e0d27 AM	534	if (!error)
546e0d27 AM	535	error = err2;
e655a250	536	if (!error) {
61159a31	537	printk("\b\b\b\bdone\n");
8357376d	538	snapshot_write_finalize(snapshot);
e655a250 CK	539	if (!snapshot_image_loaded(snapshot))
	540	error = -ENODATA;
	541	}
0d3a9abe	542	swsusp_show_speed(&start, &stop, nr_to_read, "Read");
61159a31 RW	543	return error;
	544	}
	545
a634cc10 RW	546	/**
	547	* swsusp_read - read the hibernation image.
	548	* @flags_p: flags passed by the "frozen" kernel in the image header should
	549	* be written into this memeory location
	550	*/
	551
	552	int swsusp_read(unsigned int *flags_p)
61159a31 RW	553	{
	554	int error;
	555	struct swap_map_handle handle;
	556	struct snapshot_handle snapshot;
	557	struct swsusp_info *header;
	558
a634cc10	559	*flags_p = swsusp_header->flags;
61159a31 RW	560	if (IS_ERR(resume_bdev)) {
	561	pr_debug("swsusp: block device not initialised\n");
	562	return PTR_ERR(resume_bdev);
	563	}
	564
	565	memset(&snapshot, 0, sizeof(struct snapshot_handle));
	566	error = snapshot_write_next(&snapshot, PAGE_SIZE);
	567	if (error < PAGE_SIZE)
	568	return error < 0 ? error : -EFAULT;
	569	header = (struct swsusp_info *)data_of(snapshot);
1b29c164	570	error = get_swap_reader(&handle, swsusp_header->image);
61159a31	571	if (!error)
546e0d27	572	error = swap_read_page(&handle, header, NULL);
61159a31 RW	573	if (!error)
	574	error = load_image(&handle, &snapshot, header->pages - 1);
	575	release_swap_reader(&handle);
	576
	577	blkdev_put(resume_bdev);
	578
	579	if (!error)
	580	pr_debug("swsusp: Reading resume file was successful\n");
	581	else
	582	pr_debug("swsusp: Error %d resuming\n", error);
	583	return error;
	584	}
	585
	586	/**
	587	* swsusp_check - Check for swsusp signature in the resume device
	588	*/
	589
	590	int swsusp_check(void)
	591	{
	592	int error;
	593
	594	resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
	595	if (!IS_ERR(resume_bdev)) {
	596	set_blocksize(resume_bdev, PAGE_SIZE);
6373da1f	597	memset(swsusp_header, 0, PAGE_SIZE);
9a154d9d	598	error = bio_read_page(swsusp_resume_block,
1b29c164	599	swsusp_header, NULL);
9a154d9d	600	if (error)
61159a31	601	return error;
9a154d9d	602
1b29c164 VG	603	if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
1b29c164 VG	604	memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
61159a31	605	/* Reset swap signature now */
9a154d9d	606	error = bio_write_page(swsusp_resume_block,
1b29c164	607	swsusp_header, NULL);
61159a31 RW	608	} else {
	609	return -EINVAL;
	610	}
	611	if (error)
	612	blkdev_put(resume_bdev);
	613	else
	614	pr_debug("swsusp: Signature found, resuming\n");
	615	} else {
	616	error = PTR_ERR(resume_bdev);
	617	}
	618
	619	if (error)
	620	pr_debug("swsusp: Error %d check for resume file\n", error);
	621
	622	return error;
	623	}
	624
	625	/**
	626	* swsusp_close - close swap device.
	627	*/
	628
	629	void swsusp_close(void)
	630	{
	631	if (IS_ERR(resume_bdev)) {
	632	pr_debug("swsusp: block device not initialised\n");
	633	return;
	634	}
	635
	636	blkdev_put(resume_bdev);
	637	}
1b29c164 VG	638
	639	static int swsusp_header_init(void)
	640	{
	641	swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
	642	if (!swsusp_header)
	643	panic("Could not allocate memory for swsusp_header\n");
	644	return 0;
	645	}
	646
	647	core_initcall(swsusp_header_init);