[linux-2.6-block.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/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);
	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 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);
	while (1) {
		ret = snapshot_read_next(snapshot, PAGE_SIZE);
		if (ret <= 0)
			break;
		ret = swap_write_page(handle, data_of(*snapshot), &bio);
		if (ret)
			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 (!ret)
		ret = err2;
	if (!ret)
		printk("\b\b\b\bdone\n");
	else
		printk("\n");
	swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
	return ret;
}

/**
 *	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;
	} else
		printk("\n");
	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);

	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)
			goto put;

		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 {
			error = -EINVAL;
		}

put:
		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	15	#include <linux/file.h>
61159a31 RW	16	#include <linux/delay.h>
	17	#include <linux/bitops.h>
	18	#include <linux/genhd.h>
	19	#include <linux/device.h>
	20	#include <linux/buffer_head.h>
	21	#include <linux/bio.h>
546e0d27	22	#include <linux/blkdev.h>
61159a31 RW	23	#include <linux/swap.h>
	24	#include <linux/swapops.h>
	25	#include <linux/pm.h>
	26
	27	#include "power.h"
	28
61159a31 RW	29	#define SWSUSP_SIG "S1SUSPEND"
61159a31 RW	30
1b29c164	31	struct swsusp_header {
a634cc10	32	char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int)];
3aef83e0	33	sector_t image;
a634cc10	34	unsigned int flags; /* Flags to pass to the "boot" kernel */
61159a31 RW	35	char orig_sig[10];
61159a31 RW	36	char sig[10];
1b29c164 VG	37	} __attribute__((packed));
	38
	39	static struct swsusp_header *swsusp_header;
61159a31 RW	40
61159a31 RW	41	/*
3fc6b34f	42	* General things
61159a31 RW	43	*/
	44
	45	static unsigned short root_swap = 0xffff;
3fc6b34f RW	46	static struct block_device *resume_bdev;
	47
	48	/**
	49	* submit - submit BIO request.
	50	* @rw: READ or WRITE.
	51	* @off physical offset of page.
	52	* @page: page we're reading or writing.
	53	* @bio_chain: list of pending biod (for async reading)
	54	*
	55	* Straight from the textbook - allocate and initialize the bio.
	56	* If we're reading, make sure the page is marked as dirty.
	57	* Then submit it and, if @bio_chain == NULL, wait.
	58	*/
	59	static int submit(int rw, pgoff_t page_off, struct page *page,
	60	struct bio **bio_chain)
	61	{
93dbb393	62	const int bio_rw = rw \| (1 << BIO_RW_SYNCIO) \| (1 << BIO_RW_UNPLUG);
3fc6b34f RW	63	struct bio *bio;
3fc6b34f RW	64
85949121	65	bio = bio_alloc(__GFP_WAIT \| __GFP_HIGH, 1);
3fc6b34f RW	66	bio->bi_sector = page_off * (PAGE_SIZE >> 9);
	67	bio->bi_bdev = resume_bdev;
	68	bio->bi_end_io = end_swap_bio_read;
	69
	70	if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
23976728 RW	71	printk(KERN_ERR "PM: Adding page to bio failed at %ld\n",
23976728 RW	72	page_off);
3fc6b34f RW	73	bio_put(bio);
	74	return -EFAULT;
	75	}
	76
	77	lock_page(page);
	78	bio_get(bio);
	79
	80	if (bio_chain == NULL) {
93dbb393	81	submit_bio(bio_rw, bio);
3fc6b34f RW	82	wait_on_page_locked(page);
	83	if (rw == READ)
	84	bio_set_pages_dirty(bio);
	85	bio_put(bio);
	86	} else {
	87	if (rw == READ)
	88	get_page(page); /* These pages are freed later */
	89	bio->bi_private = *bio_chain;
	90	*bio_chain = bio;
93dbb393	91	submit_bio(bio_rw, bio);
3fc6b34f RW	92	}
	93	return 0;
	94	}
	95
	96	static int bio_read_page(pgoff_t page_off, void addr, struct bio *bio_chain)
	97	{
	98	return submit(READ, page_off, virt_to_page(addr), bio_chain);
	99	}
	100
3aef83e0	101	static int bio_write_page(pgoff_t page_off, void addr, struct bio *bio_chain)
3fc6b34f	102	{
3aef83e0	103	return submit(WRITE, page_off, virt_to_page(addr), bio_chain);
3fc6b34f RW	104	}
	105
	106	static int wait_on_bio_chain(struct bio **bio_chain)
	107	{
	108	struct bio *bio;
	109	struct bio *next_bio;
	110	int ret = 0;
	111
	112	if (bio_chain == NULL)
	113	return 0;
	114
	115	bio = *bio_chain;
	116	if (bio == NULL)
	117	return 0;
	118	while (bio) {
	119	struct page *page;
	120
	121	next_bio = bio->bi_private;
	122	page = bio->bi_io_vec[0].bv_page;
	123	wait_on_page_locked(page);
	124	if (!PageUptodate(page) \|\| PageError(page))
	125	ret = -EIO;
	126	put_page(page);
	127	bio_put(bio);
	128	bio = next_bio;
	129	}
	130	*bio_chain = NULL;
	131	return ret;
	132	}
	133
3fc6b34f RW	134	/*
	135	* Saving part
	136	*/
61159a31	137
a634cc10	138	static int mark_swapfiles(sector_t start, unsigned int flags)
61159a31 RW	139	{
	140	int error;
	141
1b29c164 VG	142	bio_read_page(swsusp_resume_block, swsusp_header, NULL);
	143	if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) \|\|
	144	!memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
	145	memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
	146	memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
	147	swsusp_header->image = start;
a634cc10	148	swsusp_header->flags = flags;
9a154d9d	149	error = bio_write_page(swsusp_resume_block,
1b29c164	150	swsusp_header, NULL);
61159a31	151	} else {
23976728	152	printk(KERN_ERR "PM: Swap header not found!\n");
61159a31 RW	153	error = -ENODEV;
	154	}
	155	return error;
	156	}
	157
	158	/**
	159	* swsusp_swap_check - check if the resume device is a swap device
	160	* and get its index (if so)
	161	*/
	162
	163	static int swsusp_swap_check(void) /* This is called before saving image */
	164	{
3aef83e0 RW	165	int res;
3aef83e0 RW	166
7bf23687 RW	167	res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
7bf23687 RW	168	&resume_bdev);
3aef83e0 RW	169	if (res < 0)
	170	return res;
	171
	172	root_swap = res;
572c4892	173	res = blkdev_get(resume_bdev, FMODE_WRITE);
7bf23687 RW	174	if (res)
7bf23687 RW	175	return res;
3aef83e0 RW	176
	177	res = set_blocksize(resume_bdev, PAGE_SIZE);
	178	if (res < 0)
9a1c3542	179	blkdev_put(resume_bdev, FMODE_WRITE);
61159a31	180
61159a31 RW	181	return res;
	182	}
	183
	184	/**
	185	* write_page - Write one page to given swap location.
	186	* @buf: Address we're writing.
	187	* @offset: Offset of the swap page we're writing to.
ab954160	188	* @bio_chain: Link the next write BIO here
61159a31 RW	189	*/
61159a31 RW	190
3aef83e0	191	static int write_page(void buf, sector_t offset, struct bio *bio_chain)
61159a31	192	{
3aef83e0 RW	193	void *src;
	194
	195	if (!offset)
	196	return -ENOSPC;
	197
	198	if (bio_chain) {
85949121	199	src = (void *)__get_free_page(__GFP_WAIT \| __GFP_HIGH);
3aef83e0 RW	200	if (src) {
	201	memcpy(src, buf, PAGE_SIZE);
	202	} else {
	203	WARN_ON_ONCE(1);
	204	bio_chain = NULL; /* Go synchronous */
	205	src = buf;
ab954160	206	}
3aef83e0 RW	207	} else {
3aef83e0 RW	208	src = buf;
61159a31	209	}
3aef83e0	210	return bio_write_page(offset, src, bio_chain);
61159a31 RW	211	}
	212
	213	/*
	214	* The swap map is a data structure used for keeping track of each page
	215	* written to a swap partition. It consists of many swap_map_page
	216	* structures that contain each an array of MAP_PAGE_SIZE swap entries.
	217	* These structures are stored on the swap and linked together with the
	218	* help of the .next_swap member.
	219	*
	220	* The swap map is created during suspend. The swap map pages are
	221	* allocated and populated one at a time, so we only need one memory
	222	* page to set up the entire structure.
	223	*
	224	* During resume we also only need to use one swap_map_page structure
	225	* at a time.
	226	*/
	227
3aef83e0	228	#define MAP_PAGE_ENTRIES (PAGE_SIZE / sizeof(sector_t) - 1)
61159a31 RW	229
61159a31 RW	230	struct swap_map_page {
3aef83e0 RW	231	sector_t entries[MAP_PAGE_ENTRIES];
3aef83e0 RW	232	sector_t next_swap;
61159a31 RW	233	};
	234
	235	/**
	236	* The swap_map_handle structure is used for handling swap in
	237	* a file-alike way
	238	*/
	239
	240	struct swap_map_handle {
	241	struct swap_map_page *cur;
3aef83e0	242	sector_t cur_swap;
61159a31 RW	243	unsigned int k;
	244	};
	245
	246	static void release_swap_writer(struct swap_map_handle *handle)
	247	{
	248	if (handle->cur)
	249	free_page((unsigned long)handle->cur);
	250	handle->cur = NULL;
61159a31 RW	251	}
	252
	253	static int get_swap_writer(struct swap_map_handle *handle)
	254	{
	255	handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
	256	if (!handle->cur)
	257	return -ENOMEM;
d1d241cc	258	handle->cur_swap = alloc_swapdev_block(root_swap);
61159a31 RW	259	if (!handle->cur_swap) {
	260	release_swap_writer(handle);
	261	return -ENOSPC;
	262	}
	263	handle->k = 0;
	264	return 0;
	265	}
	266
ab954160 AM	267	static int swap_write_page(struct swap_map_handle handle, void buf,
	268	struct bio **bio_chain)
	269	{
	270	int error = 0;
3aef83e0	271	sector_t offset;
61159a31 RW	272
	273	if (!handle->cur)
	274	return -EINVAL;
d1d241cc	275	offset = alloc_swapdev_block(root_swap);
ab954160	276	error = write_page(buf, offset, bio_chain);
61159a31 RW	277	if (error)
	278	return error;
	279	handle->cur->entries[handle->k++] = offset;
	280	if (handle->k >= MAP_PAGE_ENTRIES) {
ab954160 AM	281	error = wait_on_bio_chain(bio_chain);
	282	if (error)
	283	goto out;
d1d241cc	284	offset = alloc_swapdev_block(root_swap);
61159a31 RW	285	if (!offset)
	286	return -ENOSPC;
	287	handle->cur->next_swap = offset;
ab954160	288	error = write_page(handle->cur, handle->cur_swap, NULL);
61159a31	289	if (error)
ab954160	290	goto out;
61159a31 RW	291	memset(handle->cur, 0, PAGE_SIZE);
	292	handle->cur_swap = offset;
	293	handle->k = 0;
	294	}
59a49335	295	out:
ab954160	296	return error;
61159a31 RW	297	}
	298
	299	static int flush_swap_writer(struct swap_map_handle *handle)
	300	{
	301	if (handle->cur && handle->cur_swap)
ab954160	302	return write_page(handle->cur, handle->cur_swap, NULL);
61159a31 RW	303	else
	304	return -EINVAL;
	305	}
	306
	307	/**
	308	* save_image - save the suspend image data
	309	*/
	310
	311	static int save_image(struct swap_map_handle *handle,
	312	struct snapshot_handle *snapshot,
3a4f7577	313	unsigned int nr_to_write)
61159a31 RW	314	{
	315	unsigned int m;
	316	int ret;
3a4f7577	317	int nr_pages;
ab954160 AM	318	int err2;
ab954160 AM	319	struct bio *bio;
3a4f7577 AM	320	struct timeval start;
3a4f7577 AM	321	struct timeval stop;
61159a31	322
23976728 RW	323	printk(KERN_INFO "PM: Saving image data pages (%u pages) ... ",
23976728 RW	324	nr_to_write);
3a4f7577	325	m = nr_to_write / 100;
61159a31 RW	326	if (!m)
	327	m = 1;
	328	nr_pages = 0;
ab954160	329	bio = NULL;
3a4f7577	330	do_gettimeofday(&start);
4ff277f9	331	while (1) {
61159a31	332	ret = snapshot_read_next(snapshot, PAGE_SIZE);
4ff277f9 JS	333	if (ret <= 0)
	334	break;
	335	ret = swap_write_page(handle, data_of(*snapshot), &bio);
	336	if (ret)
	337	break;
	338	if (!(nr_pages % m))
	339	printk("\b\b\b\b%3d%%", nr_pages / m);
	340	nr_pages++;
	341	}
ab954160	342	err2 = wait_on_bio_chain(&bio);
3a4f7577	343	do_gettimeofday(&stop);
4ff277f9 JS	344	if (!ret)
	345	ret = err2;
	346	if (!ret)
61159a31	347	printk("\b\b\b\bdone\n");
4ff277f9 JS	348	else
4ff277f9 JS	349	printk("\n");
0d3a9abe	350	swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
4ff277f9	351	return ret;
61159a31 RW	352	}
	353
	354	/**
	355	* enough_swap - Make sure we have enough swap to save the image.
	356	*
	357	* Returns TRUE or FALSE after checking the total amount of swap
	358	* space avaiable from the resume partition.
	359	*/
	360
	361	static int enough_swap(unsigned int nr_pages)
	362	{
	363	unsigned int free_swap = count_swap_pages(root_swap, 1);
	364
23976728	365	pr_debug("PM: Free swap pages: %u\n", free_swap);
940864dd	366	return free_swap > nr_pages + PAGES_FOR_IO;
61159a31 RW	367	}
	368
	369	/**
	370	* swsusp_write - Write entire image and metadata.
a634cc10	371	* @flags: flags to pass to the "boot" kernel in the image header
61159a31 RW	372	*
	373	* It is important _NOT_ to umount filesystems at this point. We want
	374	* them synced (in case something goes wrong) but we DO not want to mark
	375	* filesystem clean: it is not. (And it does not matter, if we resume
	376	* correctly, we'll mark system clean, anyway.)
	377	*/
	378
a634cc10	379	int swsusp_write(unsigned int flags)
61159a31 RW	380	{
	381	struct swap_map_handle handle;
	382	struct snapshot_handle snapshot;
	383	struct swsusp_info *header;
61159a31 RW	384	int error;
61159a31 RW	385
3aef83e0 RW	386	error = swsusp_swap_check();
3aef83e0 RW	387	if (error) {
23976728	388	printk(KERN_ERR "PM: Cannot find swap device, try "
546e0d27	389	"swapon -a.\n");
61159a31 RW	390	return error;
	391	}
	392	memset(&snapshot, 0, sizeof(struct snapshot_handle));
	393	error = snapshot_read_next(&snapshot, PAGE_SIZE);
3aef83e0 RW	394	if (error < PAGE_SIZE) {
	395	if (error >= 0)
	396	error = -EFAULT;
	397
	398	goto out;
	399	}
61159a31 RW	400	header = (struct swsusp_info *)data_of(snapshot);
61159a31 RW	401	if (!enough_swap(header->pages)) {
23976728	402	printk(KERN_ERR "PM: Not enough free swap\n");
3aef83e0 RW	403	error = -ENOSPC;
3aef83e0 RW	404	goto out;
61159a31 RW	405	}
	406	error = get_swap_writer(&handle);
	407	if (!error) {
3aef83e0 RW	408	sector_t start = handle.cur_swap;
3aef83e0 RW	409
ab954160	410	error = swap_write_page(&handle, header, NULL);
712f403a AM	411	if (!error)
	412	error = save_image(&handle, &snapshot,
	413	header->pages - 1);
3aef83e0	414
712f403a AM	415	if (!error) {
712f403a AM	416	flush_swap_writer(&handle);
23976728	417	printk(KERN_INFO "PM: S");
a634cc10	418	error = mark_swapfiles(start, flags);
712f403a AM	419	printk("\|\n");
712f403a AM	420	}
61159a31 RW	421	}
61159a31 RW	422	if (error)
d1d241cc RW	423	free_all_swap_pages(root_swap);
d1d241cc RW	424
61159a31	425	release_swap_writer(&handle);
59a49335	426	out:
c2dd0dae	427	swsusp_close(FMODE_WRITE);
61159a31 RW	428	return error;
	429	}
	430
61159a31 RW	431	/**
	432	* The following functions allow us to read data using a swap map
	433	* in a file-alike way
	434	*/
	435
	436	static void release_swap_reader(struct swap_map_handle *handle)
	437	{
	438	if (handle->cur)
	439	free_page((unsigned long)handle->cur);
	440	handle->cur = NULL;
	441	}
	442
3aef83e0	443	static int get_swap_reader(struct swap_map_handle *handle, sector_t start)
61159a31 RW	444	{
	445	int error;
	446
3aef83e0	447	if (!start)
61159a31	448	return -EINVAL;
3aef83e0	449
85949121	450	handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT \| __GFP_HIGH);
61159a31 RW	451	if (!handle->cur)
61159a31 RW	452	return -ENOMEM;
3aef83e0 RW	453
3aef83e0 RW	454	error = bio_read_page(start, handle->cur, NULL);
61159a31 RW	455	if (error) {
	456	release_swap_reader(handle);
	457	return error;
	458	}
	459	handle->k = 0;
	460	return 0;
	461	}
	462
546e0d27 AM	463	static int swap_read_page(struct swap_map_handle handle, void buf,
546e0d27 AM	464	struct bio **bio_chain)
61159a31	465	{
3aef83e0	466	sector_t offset;
61159a31 RW	467	int error;
	468
	469	if (!handle->cur)
	470	return -EINVAL;
	471	offset = handle->cur->entries[handle->k];
	472	if (!offset)
	473	return -EFAULT;
546e0d27	474	error = bio_read_page(offset, buf, bio_chain);
61159a31 RW	475	if (error)
	476	return error;
	477	if (++handle->k >= MAP_PAGE_ENTRIES) {
546e0d27	478	error = wait_on_bio_chain(bio_chain);
61159a31 RW	479	handle->k = 0;
	480	offset = handle->cur->next_swap;
	481	if (!offset)
	482	release_swap_reader(handle);
546e0d27 AM	483	else if (!error)
546e0d27 AM	484	error = bio_read_page(offset, handle->cur, NULL);
61159a31 RW	485	}
	486	return error;
	487	}
	488
	489	/**
	490	* load_image - load the image using the swap map handle
	491	* @handle and the snapshot handle @snapshot
	492	* (assume there are @nr_pages pages to load)
	493	*/
	494
	495	static int load_image(struct swap_map_handle *handle,
	496	struct snapshot_handle *snapshot,
546e0d27	497	unsigned int nr_to_read)
61159a31 RW	498	{
61159a31 RW	499	unsigned int m;
61159a31	500	int error = 0;
8c002494 AM	501	struct timeval start;
8c002494 AM	502	struct timeval stop;
546e0d27 AM	503	struct bio *bio;
	504	int err2;
	505	unsigned nr_pages;
61159a31	506
23976728 RW	507	printk(KERN_INFO "PM: Loading image data pages (%u pages) ... ",
23976728 RW	508	nr_to_read);
546e0d27	509	m = nr_to_read / 100;
61159a31 RW	510	if (!m)
	511	m = 1;
	512	nr_pages = 0;
546e0d27	513	bio = NULL;
8c002494	514	do_gettimeofday(&start);
546e0d27 AM	515	for ( ; ; ) {
	516	error = snapshot_write_next(snapshot, PAGE_SIZE);
	517	if (error <= 0)
	518	break;
	519	error = swap_read_page(handle, data_of(*snapshot), &bio);
	520	if (error)
	521	break;
	522	if (snapshot->sync_read)
	523	error = wait_on_bio_chain(&bio);
	524	if (error)
	525	break;
	526	if (!(nr_pages % m))
	527	printk("\b\b\b\b%3d%%", nr_pages / m);
	528	nr_pages++;
	529	}
	530	err2 = wait_on_bio_chain(&bio);
8c002494	531	do_gettimeofday(&stop);
546e0d27 AM	532	if (!error)
546e0d27 AM	533	error = err2;
e655a250	534	if (!error) {
61159a31	535	printk("\b\b\b\bdone\n");
8357376d	536	snapshot_write_finalize(snapshot);
e655a250 CK	537	if (!snapshot_image_loaded(snapshot))
e655a250 CK	538	error = -ENODATA;
bf9fd67a JS	539	} else
bf9fd67a JS	540	printk("\n");
0d3a9abe	541	swsusp_show_speed(&start, &stop, nr_to_read, "Read");
61159a31 RW	542	return error;
	543	}
	544
a634cc10 RW	545	/**
	546	* swsusp_read - read the hibernation image.
	547	* @flags_p: flags passed by the "frozen" kernel in the image header should
	548	* be written into this memeory location
	549	*/
	550
	551	int swsusp_read(unsigned int *flags_p)
61159a31 RW	552	{
	553	int error;
	554	struct swap_map_handle handle;
	555	struct snapshot_handle snapshot;
	556	struct swsusp_info *header;
	557
a634cc10	558	*flags_p = swsusp_header->flags;
61159a31	559	if (IS_ERR(resume_bdev)) {
23976728	560	pr_debug("PM: Image device not initialised\n");
61159a31 RW	561	return PTR_ERR(resume_bdev);
	562	}
	563
	564	memset(&snapshot, 0, sizeof(struct snapshot_handle));
	565	error = snapshot_write_next(&snapshot, PAGE_SIZE);
	566	if (error < PAGE_SIZE)
	567	return error < 0 ? error : -EFAULT;
	568	header = (struct swsusp_info *)data_of(snapshot);
1b29c164	569	error = get_swap_reader(&handle, swsusp_header->image);
61159a31	570	if (!error)
546e0d27	571	error = swap_read_page(&handle, header, NULL);
61159a31 RW	572	if (!error)
	573	error = load_image(&handle, &snapshot, header->pages - 1);
	574	release_swap_reader(&handle);
	575
61159a31	576	if (!error)
23976728	577	pr_debug("PM: Image successfully loaded\n");
61159a31	578	else
23976728	579	pr_debug("PM: Error %d resuming\n", error);
61159a31 RW	580	return error;
	581	}
	582
	583	/**
	584	* swsusp_check - Check for swsusp signature in the resume device
	585	*/
	586
	587	int swsusp_check(void)
	588	{
	589	int error;
	590
	591	resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
	592	if (!IS_ERR(resume_bdev)) {
	593	set_blocksize(resume_bdev, PAGE_SIZE);
6373da1f	594	memset(swsusp_header, 0, PAGE_SIZE);
9a154d9d	595	error = bio_read_page(swsusp_resume_block,
1b29c164	596	swsusp_header, NULL);
9a154d9d	597	if (error)
76b57e61	598	goto put;
9a154d9d	599
1b29c164 VG	600	if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
1b29c164 VG	601	memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
61159a31	602	/* Reset swap signature now */
9a154d9d	603	error = bio_write_page(swsusp_resume_block,
1b29c164	604	swsusp_header, NULL);
61159a31	605	} else {
76b57e61	606	error = -EINVAL;
61159a31	607	}
76b57e61 JS	608
76b57e61 JS	609	put:
61159a31	610	if (error)
9a1c3542	611	blkdev_put(resume_bdev, FMODE_READ);
61159a31	612	else
23976728	613	pr_debug("PM: Signature found, resuming\n");
61159a31 RW	614	} else {
	615	error = PTR_ERR(resume_bdev);
	616	}
	617
	618	if (error)
23976728	619	pr_debug("PM: Error %d checking image file\n", error);
61159a31 RW	620
	621	return error;
	622	}
	623
	624	/**
	625	* swsusp_close - close swap device.
	626	*/
	627
c2dd0dae	628	void swsusp_close(fmode_t mode)
61159a31 RW	629	{
61159a31 RW	630	if (IS_ERR(resume_bdev)) {
23976728	631	pr_debug("PM: Image device not initialised\n");
61159a31 RW	632	return;
	633	}
	634
50c396d3	635	blkdev_put(resume_bdev, mode);
61159a31	636	}
1b29c164 VG	637
	638	static int swsusp_header_init(void)
	639	{
	640	swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
	641	if (!swsusp_header)
	642	panic("Could not allocate memory for swsusp_header\n");
	643	return 0;
	644	}
	645
	646	core_initcall(swsusp_header_init);