[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)
{
	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(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 "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	{
	63	struct bio *bio;
	64
85949121	65	bio = bio_alloc(__GFP_WAIT \| __GFP_HIGH, 1);
3fc6b34f RW	66	if (!bio)
	67	return -ENOMEM;
	68	bio->bi_sector = page_off * (PAGE_SIZE >> 9);
	69	bio->bi_bdev = resume_bdev;
	70	bio->bi_end_io = end_swap_bio_read;
	71
	72	if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
23976728 RW	73	printk(KERN_ERR "PM: Adding page to bio failed at %ld\n",
23976728 RW	74	page_off);
3fc6b34f RW	75	bio_put(bio);
	76	return -EFAULT;
	77	}
	78
	79	lock_page(page);
	80	bio_get(bio);
	81
	82	if (bio_chain == NULL) {
	83	submit_bio(rw \| (1 << BIO_RW_SYNC), bio);
	84	wait_on_page_locked(page);
	85	if (rw == READ)
	86	bio_set_pages_dirty(bio);
	87	bio_put(bio);
	88	} else {
	89	if (rw == READ)
	90	get_page(page); /* These pages are freed later */
	91	bio->bi_private = *bio_chain;
	92	*bio_chain = bio;
	93	submit_bio(rw \| (1 << BIO_RW_SYNC), bio);
	94	}
	95	return 0;
	96	}
	97
	98	static int bio_read_page(pgoff_t page_off, void addr, struct bio *bio_chain)
	99	{
	100	return submit(READ, page_off, virt_to_page(addr), bio_chain);
	101	}
	102
3aef83e0	103	static int bio_write_page(pgoff_t page_off, void addr, struct bio *bio_chain)
3fc6b34f	104	{
3aef83e0	105	return submit(WRITE, page_off, virt_to_page(addr), bio_chain);
3fc6b34f RW	106	}
	107
	108	static int wait_on_bio_chain(struct bio **bio_chain)
	109	{
	110	struct bio *bio;
	111	struct bio *next_bio;
	112	int ret = 0;
	113
	114	if (bio_chain == NULL)
	115	return 0;
	116
	117	bio = *bio_chain;
	118	if (bio == NULL)
	119	return 0;
	120	while (bio) {
	121	struct page *page;
	122
	123	next_bio = bio->bi_private;
	124	page = bio->bi_io_vec[0].bv_page;
	125	wait_on_page_locked(page);
	126	if (!PageUptodate(page) \|\| PageError(page))
	127	ret = -EIO;
	128	put_page(page);
	129	bio_put(bio);
	130	bio = next_bio;
	131	}
	132	*bio_chain = NULL;
	133	return ret;
	134	}
	135
3fc6b34f RW	136	/*
	137	* Saving part
	138	*/
61159a31	139
a634cc10	140	static int mark_swapfiles(sector_t start, unsigned int flags)
61159a31 RW	141	{
	142	int error;
	143
1b29c164 VG	144	bio_read_page(swsusp_resume_block, swsusp_header, NULL);
	145	if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) \|\|
	146	!memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
	147	memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
	148	memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
	149	swsusp_header->image = start;
a634cc10	150	swsusp_header->flags = flags;
9a154d9d	151	error = bio_write_page(swsusp_resume_block,
1b29c164	152	swsusp_header, NULL);
61159a31	153	} else {
23976728	154	printk(KERN_ERR "PM: Swap header not found!\n");
61159a31 RW	155	error = -ENODEV;
	156	}
	157	return error;
	158	}
	159
	160	/**
	161	* swsusp_swap_check - check if the resume device is a swap device
	162	* and get its index (if so)
	163	*/
	164
	165	static int swsusp_swap_check(void) /* This is called before saving image */
	166	{
3aef83e0 RW	167	int res;
3aef83e0 RW	168
7bf23687 RW	169	res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
7bf23687 RW	170	&resume_bdev);
3aef83e0 RW	171	if (res < 0)
	172	return res;
	173
	174	root_swap = res;
572c4892	175	res = blkdev_get(resume_bdev, FMODE_WRITE);
7bf23687 RW	176	if (res)
7bf23687 RW	177	return res;
3aef83e0 RW	178
	179	res = set_blocksize(resume_bdev, PAGE_SIZE);
	180	if (res < 0)
9a1c3542	181	blkdev_put(resume_bdev, FMODE_WRITE);
61159a31	182
61159a31 RW	183	return res;
	184	}
	185
	186	/**
	187	* write_page - Write one page to given swap location.
	188	* @buf: Address we're writing.
	189	* @offset: Offset of the swap page we're writing to.
ab954160	190	* @bio_chain: Link the next write BIO here
61159a31 RW	191	*/
61159a31 RW	192
3aef83e0	193	static int write_page(void buf, sector_t offset, struct bio *bio_chain)
61159a31	194	{
3aef83e0 RW	195	void *src;
	196
	197	if (!offset)
	198	return -ENOSPC;
	199
	200	if (bio_chain) {
85949121	201	src = (void *)__get_free_page(__GFP_WAIT \| __GFP_HIGH);
3aef83e0 RW	202	if (src) {
	203	memcpy(src, buf, PAGE_SIZE);
	204	} else {
	205	WARN_ON_ONCE(1);
	206	bio_chain = NULL; /* Go synchronous */
	207	src = buf;
ab954160	208	}
3aef83e0 RW	209	} else {
3aef83e0 RW	210	src = buf;
61159a31	211	}
3aef83e0	212	return bio_write_page(offset, src, bio_chain);
61159a31 RW	213	}
	214
	215	/*
	216	* The swap map is a data structure used for keeping track of each page
	217	* written to a swap partition. It consists of many swap_map_page
	218	* structures that contain each an array of MAP_PAGE_SIZE swap entries.
	219	* These structures are stored on the swap and linked together with the
	220	* help of the .next_swap member.
	221	*
	222	* The swap map is created during suspend. The swap map pages are
	223	* allocated and populated one at a time, so we only need one memory
	224	* page to set up the entire structure.
	225	*
	226	* During resume we also only need to use one swap_map_page structure
	227	* at a time.
	228	*/
	229
3aef83e0	230	#define MAP_PAGE_ENTRIES (PAGE_SIZE / sizeof(sector_t) - 1)
61159a31 RW	231
61159a31 RW	232	struct swap_map_page {
3aef83e0 RW	233	sector_t entries[MAP_PAGE_ENTRIES];
3aef83e0 RW	234	sector_t next_swap;
61159a31 RW	235	};
	236
	237	/**
	238	* The swap_map_handle structure is used for handling swap in
	239	* a file-alike way
	240	*/
	241
	242	struct swap_map_handle {
	243	struct swap_map_page *cur;
3aef83e0	244	sector_t cur_swap;
61159a31 RW	245	unsigned int k;
	246	};
	247
	248	static void release_swap_writer(struct swap_map_handle *handle)
	249	{
	250	if (handle->cur)
	251	free_page((unsigned long)handle->cur);
	252	handle->cur = NULL;
61159a31 RW	253	}
	254
	255	static int get_swap_writer(struct swap_map_handle *handle)
	256	{
	257	handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
	258	if (!handle->cur)
	259	return -ENOMEM;
d1d241cc	260	handle->cur_swap = alloc_swapdev_block(root_swap);
61159a31 RW	261	if (!handle->cur_swap) {
	262	release_swap_writer(handle);
	263	return -ENOSPC;
	264	}
	265	handle->k = 0;
	266	return 0;
	267	}
	268
ab954160 AM	269	static int swap_write_page(struct swap_map_handle handle, void buf,
	270	struct bio **bio_chain)
	271	{
	272	int error = 0;
3aef83e0	273	sector_t offset;
61159a31 RW	274
	275	if (!handle->cur)
	276	return -EINVAL;
d1d241cc	277	offset = alloc_swapdev_block(root_swap);
ab954160	278	error = write_page(buf, offset, bio_chain);
61159a31 RW	279	if (error)
	280	return error;
	281	handle->cur->entries[handle->k++] = offset;
	282	if (handle->k >= MAP_PAGE_ENTRIES) {
ab954160 AM	283	error = wait_on_bio_chain(bio_chain);
	284	if (error)
	285	goto out;
d1d241cc	286	offset = alloc_swapdev_block(root_swap);
61159a31 RW	287	if (!offset)
	288	return -ENOSPC;
	289	handle->cur->next_swap = offset;
ab954160	290	error = write_page(handle->cur, handle->cur_swap, NULL);
61159a31	291	if (error)
ab954160	292	goto out;
61159a31 RW	293	memset(handle->cur, 0, PAGE_SIZE);
	294	handle->cur_swap = offset;
	295	handle->k = 0;
	296	}
59a49335	297	out:
ab954160	298	return error;
61159a31 RW	299	}
	300
	301	static int flush_swap_writer(struct swap_map_handle *handle)
	302	{
	303	if (handle->cur && handle->cur_swap)
ab954160	304	return write_page(handle->cur, handle->cur_swap, NULL);
61159a31 RW	305	else
	306	return -EINVAL;
	307	}
	308
	309	/**
	310	* save_image - save the suspend image data
	311	*/
	312
	313	static int save_image(struct swap_map_handle *handle,
	314	struct snapshot_handle *snapshot,
3a4f7577	315	unsigned int nr_to_write)
61159a31 RW	316	{
	317	unsigned int m;
	318	int ret;
	319	int error = 0;
3a4f7577	320	int nr_pages;
ab954160 AM	321	int err2;
ab954160 AM	322	struct bio *bio;
3a4f7577 AM	323	struct timeval start;
3a4f7577 AM	324	struct timeval stop;
61159a31	325
23976728 RW	326	printk(KERN_INFO "PM: Saving image data pages (%u pages) ... ",
23976728 RW	327	nr_to_write);
3a4f7577	328	m = nr_to_write / 100;
61159a31 RW	329	if (!m)
	330	m = 1;
	331	nr_pages = 0;
ab954160	332	bio = NULL;
3a4f7577	333	do_gettimeofday(&start);
61159a31 RW	334	do {
	335	ret = snapshot_read_next(snapshot, PAGE_SIZE);
	336	if (ret > 0) {
ab954160 AM	337	error = swap_write_page(handle, data_of(*snapshot),
ab954160 AM	338	&bio);
61159a31 RW	339	if (error)
	340	break;
	341	if (!(nr_pages % m))
	342	printk("\b\b\b\b%3d%%", nr_pages / m);
	343	nr_pages++;
	344	}
	345	} while (ret > 0);
ab954160	346	err2 = wait_on_bio_chain(&bio);
3a4f7577	347	do_gettimeofday(&stop);
ab954160 AM	348	if (!error)
ab954160 AM	349	error = err2;
61159a31 RW	350	if (!error)
61159a31 RW	351	printk("\b\b\b\bdone\n");
0d3a9abe	352	swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
61159a31 RW	353	return error;
	354	}
	355
	356	/**
	357	* enough_swap - Make sure we have enough swap to save the image.
	358	*
	359	* Returns TRUE or FALSE after checking the total amount of swap
	360	* space avaiable from the resume partition.
	361	*/
	362
	363	static int enough_swap(unsigned int nr_pages)
	364	{
	365	unsigned int free_swap = count_swap_pages(root_swap, 1);
	366
23976728	367	pr_debug("PM: Free swap pages: %u\n", free_swap);
940864dd	368	return free_swap > nr_pages + PAGES_FOR_IO;
61159a31 RW	369	}
	370
	371	/**
	372	* swsusp_write - Write entire image and metadata.
a634cc10	373	* @flags: flags to pass to the "boot" kernel in the image header
61159a31 RW	374	*
	375	* It is important _NOT_ to umount filesystems at this point. We want
	376	* them synced (in case something goes wrong) but we DO not want to mark
	377	* filesystem clean: it is not. (And it does not matter, if we resume
	378	* correctly, we'll mark system clean, anyway.)
	379	*/
	380
a634cc10	381	int swsusp_write(unsigned int flags)
61159a31 RW	382	{
	383	struct swap_map_handle handle;
	384	struct snapshot_handle snapshot;
	385	struct swsusp_info *header;
61159a31 RW	386	int error;
61159a31 RW	387
3aef83e0 RW	388	error = swsusp_swap_check();
3aef83e0 RW	389	if (error) {
23976728	390	printk(KERN_ERR "PM: Cannot find swap device, try "
546e0d27	391	"swapon -a.\n");
61159a31 RW	392	return error;
	393	}
	394	memset(&snapshot, 0, sizeof(struct snapshot_handle));
	395	error = snapshot_read_next(&snapshot, PAGE_SIZE);
3aef83e0 RW	396	if (error < PAGE_SIZE) {
	397	if (error >= 0)
	398	error = -EFAULT;
	399
	400	goto out;
	401	}
61159a31 RW	402	header = (struct swsusp_info *)data_of(snapshot);
61159a31 RW	403	if (!enough_swap(header->pages)) {
23976728	404	printk(KERN_ERR "PM: Not enough free swap\n");
3aef83e0 RW	405	error = -ENOSPC;
3aef83e0 RW	406	goto out;
61159a31 RW	407	}
	408	error = get_swap_writer(&handle);
	409	if (!error) {
3aef83e0 RW	410	sector_t start = handle.cur_swap;
3aef83e0 RW	411
ab954160	412	error = swap_write_page(&handle, header, NULL);
712f403a AM	413	if (!error)
	414	error = save_image(&handle, &snapshot,
	415	header->pages - 1);
3aef83e0	416
712f403a AM	417	if (!error) {
712f403a AM	418	flush_swap_writer(&handle);
23976728	419	printk(KERN_INFO "PM: S");
a634cc10	420	error = mark_swapfiles(start, flags);
712f403a AM	421	printk("\|\n");
712f403a AM	422	}
61159a31 RW	423	}
61159a31 RW	424	if (error)
d1d241cc RW	425	free_all_swap_pages(root_swap);
d1d241cc RW	426
61159a31	427	release_swap_writer(&handle);
59a49335	428	out:
c2dd0dae	429	swsusp_close(FMODE_WRITE);
61159a31 RW	430	return error;
	431	}
	432
61159a31 RW	433	/**
	434	* The following functions allow us to read data using a swap map
	435	* in a file-alike way
	436	*/
	437
	438	static void release_swap_reader(struct swap_map_handle *handle)
	439	{
	440	if (handle->cur)
	441	free_page((unsigned long)handle->cur);
	442	handle->cur = NULL;
	443	}
	444
3aef83e0	445	static int get_swap_reader(struct swap_map_handle *handle, sector_t start)
61159a31 RW	446	{
	447	int error;
	448
3aef83e0	449	if (!start)
61159a31	450	return -EINVAL;
3aef83e0	451
85949121	452	handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT \| __GFP_HIGH);
61159a31 RW	453	if (!handle->cur)
61159a31 RW	454	return -ENOMEM;
3aef83e0 RW	455
3aef83e0 RW	456	error = bio_read_page(start, handle->cur, NULL);
61159a31 RW	457	if (error) {
	458	release_swap_reader(handle);
	459	return error;
	460	}
	461	handle->k = 0;
	462	return 0;
	463	}
	464
546e0d27 AM	465	static int swap_read_page(struct swap_map_handle handle, void buf,
546e0d27 AM	466	struct bio **bio_chain)
61159a31	467	{
3aef83e0	468	sector_t offset;
61159a31 RW	469	int error;
	470
	471	if (!handle->cur)
	472	return -EINVAL;
	473	offset = handle->cur->entries[handle->k];
	474	if (!offset)
	475	return -EFAULT;
546e0d27	476	error = bio_read_page(offset, buf, bio_chain);
61159a31 RW	477	if (error)
	478	return error;
	479	if (++handle->k >= MAP_PAGE_ENTRIES) {
546e0d27	480	error = wait_on_bio_chain(bio_chain);
61159a31 RW	481	handle->k = 0;
	482	offset = handle->cur->next_swap;
	483	if (!offset)
	484	release_swap_reader(handle);
546e0d27 AM	485	else if (!error)
546e0d27 AM	486	error = bio_read_page(offset, handle->cur, NULL);
61159a31 RW	487	}
	488	return error;
	489	}
	490
	491	/**
	492	* load_image - load the image using the swap map handle
	493	* @handle and the snapshot handle @snapshot
	494	* (assume there are @nr_pages pages to load)
	495	*/
	496
	497	static int load_image(struct swap_map_handle *handle,
	498	struct snapshot_handle *snapshot,
546e0d27	499	unsigned int nr_to_read)
61159a31 RW	500	{
61159a31 RW	501	unsigned int m;
61159a31	502	int error = 0;
8c002494 AM	503	struct timeval start;
8c002494 AM	504	struct timeval stop;
546e0d27 AM	505	struct bio *bio;
	506	int err2;
	507	unsigned nr_pages;
61159a31	508
23976728 RW	509	printk(KERN_INFO "PM: Loading image data pages (%u pages) ... ",
23976728 RW	510	nr_to_read);
546e0d27	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	560	if (IS_ERR(resume_bdev)) {
23976728	561	pr_debug("PM: Image device not initialised\n");
61159a31 RW	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
9a1c3542	577	blkdev_put(resume_bdev, FMODE_READ);
61159a31 RW	578
61159a31 RW	579	if (!error)
23976728	580	pr_debug("PM: Image successfully loaded\n");
61159a31	581	else
23976728	582	pr_debug("PM: Error %d resuming\n", error);
61159a31 RW	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)
9a1c3542	612	blkdev_put(resume_bdev, FMODE_READ);
61159a31	613	else
23976728	614	pr_debug("PM: Signature found, resuming\n");
61159a31 RW	615	} else {
	616	error = PTR_ERR(resume_bdev);
	617	}
	618
	619	if (error)
23976728	620	pr_debug("PM: Error %d checking image file\n", error);
61159a31 RW	621
	622	return error;
	623	}
	624
	625	/**
	626	* swsusp_close - close swap device.
	627	*/
	628
c2dd0dae	629	void swsusp_close(fmode_t mode)
61159a31 RW	630	{
61159a31 RW	631	if (IS_ERR(resume_bdev)) {
23976728	632	pr_debug("PM: Image device not initialised\n");
61159a31 RW	633	return;
	634	}
	635
50c396d3	636	blkdev_put(resume_bdev, mode);
61159a31	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);