[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/smp_lock.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"

static struct swsusp_header {
	char reserved[PAGE_SIZE - 20 - sizeof(sector_t)];
	sector_t image;
	char	orig_sig[10];
	char	sig[10];
} __attribute__((packed, aligned(PAGE_SIZE))) 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)
{
	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;
		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;
	struct bitmap_page *bitmap;
	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;
	if (handle->bitmap)
		free_bitmap(handle->bitmap);
	handle->bitmap = 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->bitmap = alloc_bitmap(count_swap_pages(root_swap, 0));
	if (!handle->bitmap) {
		release_swap_writer(handle);
		return -ENOMEM;
	}
	handle->cur_swap = alloc_swapdev_block(root_swap, handle->bitmap);
	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, handle->bitmap);
	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, handle->bitmap);
		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.
 *
 *	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(void)
{
	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);
			printk("|\n");
		}
	}
	if (error)
		free_all_swap_pages(root_swap, handle.bitmap);
	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;
}

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

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