[net-next-2.6.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_ATOMIC, 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;
}

static void show_speed(struct timeval *start, struct timeval *stop,
			unsigned nr_pages, char *msg)
{
	s64 elapsed_centisecs64;
	int centisecs;
	int k;
	int kps;

	elapsed_centisecs64 = timeval_to_ns(stop) - timeval_to_ns(start);
	do_div(elapsed_centisecs64, NSEC_PER_SEC / 100);
	centisecs = elapsed_centisecs64;
	if (centisecs == 0)
		centisecs = 1;	/* avoid div-by-zero */
	k = nr_pages * (PAGE_SIZE / 1024);
	kps = (k * 100) / centisecs;
	printk("%s %d kbytes in %d.%02d seconds (%d.%02d MB/s)\n", msg, k,
			centisecs / 100, centisecs % 100,
			kps / 1000, (kps % 1000) / 10);
}

/*
 * 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);
	if (res < 0)
		return res;

	root_swap = res;
	resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_WRITE);
	if (IS_ERR(resume_bdev))
		return PTR_ERR(resume_bdev);

	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_ATOMIC);
		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");
	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_ATOMIC);
	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_free_unused_memory(snapshot);
		if (!snapshot_image_loaded(snapshot))
			error = -ENODATA;
	}
	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
	66	bio = bio_alloc(GFP_ATOMIC, 1);
	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
	136	static void show_speed(struct timeval start, struct timeval stop,
	137	unsigned nr_pages, char *msg)
	138	{
	139	s64 elapsed_centisecs64;
	140	int centisecs;
	141	int k;
	142	int kps;
	143
	144	elapsed_centisecs64 = timeval_to_ns(stop) - timeval_to_ns(start);
	145	do_div(elapsed_centisecs64, NSEC_PER_SEC / 100);
	146	centisecs = elapsed_centisecs64;
	147	if (centisecs == 0)
	148	centisecs = 1; /* avoid div-by-zero */
	149	k = nr_pages * (PAGE_SIZE / 1024);
	150	kps = (k * 100) / centisecs;
	151	printk("%s %d kbytes in %d.%02d seconds (%d.%02d MB/s)\n", msg, k,
	152	centisecs / 100, centisecs % 100,
	153	kps / 1000, (kps % 1000) / 10);
	154	}
	155
	156	/*
	157	* Saving part
	158	*/
61159a31	159
3aef83e0	160	static int mark_swapfiles(sector_t start)
61159a31 RW	161	{
	162	int error;
	163
9a154d9d	164	bio_read_page(swsusp_resume_block, &swsusp_header, NULL);
61159a31 RW	165	if (!memcmp("SWAP-SPACE",swsusp_header.sig, 10) \|\|
	166	!memcmp("SWAPSPACE2",swsusp_header.sig, 10)) {
	167	memcpy(swsusp_header.orig_sig,swsusp_header.sig, 10);
	168	memcpy(swsusp_header.sig,SWSUSP_SIG, 10);
	169	swsusp_header.image = start;
9a154d9d RW	170	error = bio_write_page(swsusp_resume_block,
9a154d9d RW	171	&swsusp_header, NULL);
61159a31	172	} else {
3aef83e0	173	printk(KERN_ERR "swsusp: Swap header not found!\n");
61159a31 RW	174	error = -ENODEV;
	175	}
	176	return error;
	177	}
	178
	179	/**
	180	* swsusp_swap_check - check if the resume device is a swap device
	181	* and get its index (if so)
	182	*/
	183
	184	static int swsusp_swap_check(void) /* This is called before saving image */
	185	{
3aef83e0 RW	186	int res;
3aef83e0 RW	187
9a154d9d	188	res = swap_type_of(swsusp_resume_device, swsusp_resume_block);
3aef83e0 RW	189	if (res < 0)
	190	return res;
	191
	192	root_swap = res;
	193	resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_WRITE);
	194	if (IS_ERR(resume_bdev))
	195	return PTR_ERR(resume_bdev);
	196
	197	res = set_blocksize(resume_bdev, PAGE_SIZE);
	198	if (res < 0)
	199	blkdev_put(resume_bdev);
61159a31	200
61159a31 RW	201	return res;
	202	}
	203
	204	/**
	205	* write_page - Write one page to given swap location.
	206	* @buf: Address we're writing.
	207	* @offset: Offset of the swap page we're writing to.
ab954160	208	* @bio_chain: Link the next write BIO here
61159a31 RW	209	*/
61159a31 RW	210
3aef83e0	211	static int write_page(void buf, sector_t offset, struct bio *bio_chain)
61159a31	212	{
3aef83e0 RW	213	void *src;
	214
	215	if (!offset)
	216	return -ENOSPC;
	217
	218	if (bio_chain) {
	219	src = (void *)__get_free_page(GFP_ATOMIC);
	220	if (src) {
	221	memcpy(src, buf, PAGE_SIZE);
	222	} else {
	223	WARN_ON_ONCE(1);
	224	bio_chain = NULL; /* Go synchronous */
	225	src = buf;
ab954160	226	}
3aef83e0 RW	227	} else {
3aef83e0 RW	228	src = buf;
61159a31	229	}
3aef83e0	230	return bio_write_page(offset, src, bio_chain);
61159a31 RW	231	}
	232
	233	/*
	234	* The swap map is a data structure used for keeping track of each page
	235	* written to a swap partition. It consists of many swap_map_page
	236	* structures that contain each an array of MAP_PAGE_SIZE swap entries.
	237	* These structures are stored on the swap and linked together with the
	238	* help of the .next_swap member.
	239	*
	240	* The swap map is created during suspend. The swap map pages are
	241	* allocated and populated one at a time, so we only need one memory
	242	* page to set up the entire structure.
	243	*
	244	* During resume we also only need to use one swap_map_page structure
	245	* at a time.
	246	*/
	247
3aef83e0	248	#define MAP_PAGE_ENTRIES (PAGE_SIZE / sizeof(sector_t) - 1)
61159a31 RW	249
61159a31 RW	250	struct swap_map_page {
3aef83e0 RW	251	sector_t entries[MAP_PAGE_ENTRIES];
3aef83e0 RW	252	sector_t next_swap;
61159a31 RW	253	};
	254
	255	/**
	256	* The swap_map_handle structure is used for handling swap in
	257	* a file-alike way
	258	*/
	259
	260	struct swap_map_handle {
	261	struct swap_map_page *cur;
3aef83e0	262	sector_t cur_swap;
61159a31 RW	263	struct bitmap_page *bitmap;
	264	unsigned int k;
	265	};
	266
	267	static void release_swap_writer(struct swap_map_handle *handle)
	268	{
	269	if (handle->cur)
	270	free_page((unsigned long)handle->cur);
	271	handle->cur = NULL;
	272	if (handle->bitmap)
	273	free_bitmap(handle->bitmap);
	274	handle->bitmap = NULL;
	275	}
	276
	277	static int get_swap_writer(struct swap_map_handle *handle)
	278	{
	279	handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
	280	if (!handle->cur)
	281	return -ENOMEM;
	282	handle->bitmap = alloc_bitmap(count_swap_pages(root_swap, 0));
	283	if (!handle->bitmap) {
	284	release_swap_writer(handle);
	285	return -ENOMEM;
	286	}
3aef83e0	287	handle->cur_swap = alloc_swapdev_block(root_swap, handle->bitmap);
61159a31 RW	288	if (!handle->cur_swap) {
	289	release_swap_writer(handle);
	290	return -ENOSPC;
	291	}
	292	handle->k = 0;
	293	return 0;
	294	}
	295
ab954160 AM	296	static int swap_write_page(struct swap_map_handle handle, void buf,
	297	struct bio **bio_chain)
	298	{
	299	int error = 0;
3aef83e0	300	sector_t offset;
61159a31 RW	301
	302	if (!handle->cur)
	303	return -EINVAL;
3aef83e0	304	offset = alloc_swapdev_block(root_swap, handle->bitmap);
ab954160	305	error = write_page(buf, offset, bio_chain);
61159a31 RW	306	if (error)
	307	return error;
	308	handle->cur->entries[handle->k++] = offset;
	309	if (handle->k >= MAP_PAGE_ENTRIES) {
ab954160 AM	310	error = wait_on_bio_chain(bio_chain);
	311	if (error)
	312	goto out;
3aef83e0	313	offset = alloc_swapdev_block(root_swap, handle->bitmap);
61159a31 RW	314	if (!offset)
	315	return -ENOSPC;
	316	handle->cur->next_swap = offset;
ab954160	317	error = write_page(handle->cur, handle->cur_swap, NULL);
61159a31	318	if (error)
ab954160	319	goto out;
61159a31 RW	320	memset(handle->cur, 0, PAGE_SIZE);
	321	handle->cur_swap = offset;
	322	handle->k = 0;
	323	}
ab954160 AM	324	out:
ab954160 AM	325	return error;
61159a31 RW	326	}
	327
	328	static int flush_swap_writer(struct swap_map_handle *handle)
	329	{
	330	if (handle->cur && handle->cur_swap)
ab954160	331	return write_page(handle->cur, handle->cur_swap, NULL);
61159a31 RW	332	else
	333	return -EINVAL;
	334	}
	335
	336	/**
	337	* save_image - save the suspend image data
	338	*/
	339
	340	static int save_image(struct swap_map_handle *handle,
	341	struct snapshot_handle *snapshot,
3a4f7577	342	unsigned int nr_to_write)
61159a31 RW	343	{
	344	unsigned int m;
	345	int ret;
	346	int error = 0;
3a4f7577	347	int nr_pages;
ab954160 AM	348	int err2;
ab954160 AM	349	struct bio *bio;
3a4f7577 AM	350	struct timeval start;
3a4f7577 AM	351	struct timeval stop;
61159a31	352
3a4f7577 AM	353	printk("Saving image data pages (%u pages) ... ", nr_to_write);
3a4f7577 AM	354	m = nr_to_write / 100;
61159a31 RW	355	if (!m)
	356	m = 1;
	357	nr_pages = 0;
ab954160	358	bio = NULL;
3a4f7577	359	do_gettimeofday(&start);
61159a31 RW	360	do {
	361	ret = snapshot_read_next(snapshot, PAGE_SIZE);
	362	if (ret > 0) {
ab954160 AM	363	error = swap_write_page(handle, data_of(*snapshot),
ab954160 AM	364	&bio);
61159a31 RW	365	if (error)
	366	break;
	367	if (!(nr_pages % m))
	368	printk("\b\b\b\b%3d%%", nr_pages / m);
	369	nr_pages++;
	370	}
	371	} while (ret > 0);
ab954160	372	err2 = wait_on_bio_chain(&bio);
3a4f7577	373	do_gettimeofday(&stop);
ab954160 AM	374	if (!error)
ab954160 AM	375	error = err2;
61159a31 RW	376	if (!error)
61159a31 RW	377	printk("\b\b\b\bdone\n");
3a4f7577	378	show_speed(&start, &stop, nr_to_write, "Wrote");
61159a31 RW	379	return error;
	380	}
	381
	382	/**
	383	* enough_swap - Make sure we have enough swap to save the image.
	384	*
	385	* Returns TRUE or FALSE after checking the total amount of swap
	386	* space avaiable from the resume partition.
	387	*/
	388
	389	static int enough_swap(unsigned int nr_pages)
	390	{
	391	unsigned int free_swap = count_swap_pages(root_swap, 1);
	392
	393	pr_debug("swsusp: free swap pages: %u\n", free_swap);
940864dd	394	return free_swap > nr_pages + PAGES_FOR_IO;
61159a31 RW	395	}
	396
	397	/**
	398	* swsusp_write - Write entire image and metadata.
	399	*
	400	* It is important _NOT_ to umount filesystems at this point. We want
	401	* them synced (in case something goes wrong) but we DO not want to mark
	402	* filesystem clean: it is not. (And it does not matter, if we resume
	403	* correctly, we'll mark system clean, anyway.)
	404	*/
	405
	406	int swsusp_write(void)
	407	{
	408	struct swap_map_handle handle;
	409	struct snapshot_handle snapshot;
	410	struct swsusp_info *header;
61159a31 RW	411	int error;
61159a31 RW	412
3aef83e0 RW	413	error = swsusp_swap_check();
3aef83e0 RW	414	if (error) {
546e0d27 AM	415	printk(KERN_ERR "swsusp: Cannot find swap device, try "
546e0d27 AM	416	"swapon -a.\n");
61159a31 RW	417	return error;
	418	}
	419	memset(&snapshot, 0, sizeof(struct snapshot_handle));
	420	error = snapshot_read_next(&snapshot, PAGE_SIZE);
3aef83e0 RW	421	if (error < PAGE_SIZE) {
	422	if (error >= 0)
	423	error = -EFAULT;
	424
	425	goto out;
	426	}
61159a31 RW	427	header = (struct swsusp_info *)data_of(snapshot);
	428	if (!enough_swap(header->pages)) {
	429	printk(KERN_ERR "swsusp: Not enough free swap\n");
3aef83e0 RW	430	error = -ENOSPC;
3aef83e0 RW	431	goto out;
61159a31 RW	432	}
	433	error = get_swap_writer(&handle);
	434	if (!error) {
3aef83e0 RW	435	sector_t start = handle.cur_swap;
3aef83e0 RW	436
ab954160	437	error = swap_write_page(&handle, header, NULL);
712f403a AM	438	if (!error)
	439	error = save_image(&handle, &snapshot,
	440	header->pages - 1);
3aef83e0	441
712f403a AM	442	if (!error) {
	443	flush_swap_writer(&handle);
	444	printk("S");
3aef83e0	445	error = mark_swapfiles(start);
712f403a AM	446	printk("\|\n");
712f403a AM	447	}
61159a31 RW	448	}
	449	if (error)
	450	free_all_swap_pages(root_swap, handle.bitmap);
	451	release_swap_writer(&handle);
3aef83e0 RW	452	out:
3aef83e0 RW	453	swsusp_close();
61159a31 RW	454	return error;
	455	}
	456
61159a31 RW	457	/**
	458	* The following functions allow us to read data using a swap map
	459	* in a file-alike way
	460	*/
	461
	462	static void release_swap_reader(struct swap_map_handle *handle)
	463	{
	464	if (handle->cur)
	465	free_page((unsigned long)handle->cur);
	466	handle->cur = NULL;
	467	}
	468
3aef83e0	469	static int get_swap_reader(struct swap_map_handle *handle, sector_t start)
61159a31 RW	470	{
	471	int error;
	472
3aef83e0	473	if (!start)
61159a31	474	return -EINVAL;
3aef83e0	475
61159a31 RW	476	handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC);
	477	if (!handle->cur)
	478	return -ENOMEM;
3aef83e0 RW	479
3aef83e0 RW	480	error = bio_read_page(start, handle->cur, NULL);
61159a31 RW	481	if (error) {
	482	release_swap_reader(handle);
	483	return error;
	484	}
	485	handle->k = 0;
	486	return 0;
	487	}
	488
546e0d27 AM	489	static int swap_read_page(struct swap_map_handle handle, void buf,
546e0d27 AM	490	struct bio **bio_chain)
61159a31	491	{
3aef83e0	492	sector_t offset;
61159a31 RW	493	int error;
	494
	495	if (!handle->cur)
	496	return -EINVAL;
	497	offset = handle->cur->entries[handle->k];
	498	if (!offset)
	499	return -EFAULT;
546e0d27	500	error = bio_read_page(offset, buf, bio_chain);
61159a31 RW	501	if (error)
	502	return error;
	503	if (++handle->k >= MAP_PAGE_ENTRIES) {
546e0d27	504	error = wait_on_bio_chain(bio_chain);
61159a31 RW	505	handle->k = 0;
	506	offset = handle->cur->next_swap;
	507	if (!offset)
	508	release_swap_reader(handle);
546e0d27 AM	509	else if (!error)
546e0d27 AM	510	error = bio_read_page(offset, handle->cur, NULL);
61159a31 RW	511	}
	512	return error;
	513	}
	514
	515	/**
	516	* load_image - load the image using the swap map handle
	517	* @handle and the snapshot handle @snapshot
	518	* (assume there are @nr_pages pages to load)
	519	*/
	520
	521	static int load_image(struct swap_map_handle *handle,
	522	struct snapshot_handle *snapshot,
546e0d27	523	unsigned int nr_to_read)
61159a31 RW	524	{
61159a31 RW	525	unsigned int m;
61159a31	526	int error = 0;
8c002494 AM	527	struct timeval start;
8c002494 AM	528	struct timeval stop;
546e0d27 AM	529	struct bio *bio;
	530	int err2;
	531	unsigned nr_pages;
61159a31	532
546e0d27 AM	533	printk("Loading image data pages (%u pages) ... ", nr_to_read);
546e0d27 AM	534	m = nr_to_read / 100;
61159a31 RW	535	if (!m)
	536	m = 1;
	537	nr_pages = 0;
546e0d27	538	bio = NULL;
8c002494	539	do_gettimeofday(&start);
546e0d27 AM	540	for ( ; ; ) {
	541	error = snapshot_write_next(snapshot, PAGE_SIZE);
	542	if (error <= 0)
	543	break;
	544	error = swap_read_page(handle, data_of(*snapshot), &bio);
	545	if (error)
	546	break;
	547	if (snapshot->sync_read)
	548	error = wait_on_bio_chain(&bio);
	549	if (error)
	550	break;
	551	if (!(nr_pages % m))
	552	printk("\b\b\b\b%3d%%", nr_pages / m);
	553	nr_pages++;
	554	}
	555	err2 = wait_on_bio_chain(&bio);
8c002494	556	do_gettimeofday(&stop);
546e0d27 AM	557	if (!error)
546e0d27 AM	558	error = err2;
e655a250	559	if (!error) {
61159a31	560	printk("\b\b\b\bdone\n");
940864dd	561	snapshot_free_unused_memory(snapshot);
e655a250 CK	562	if (!snapshot_image_loaded(snapshot))
	563	error = -ENODATA;
	564	}
546e0d27	565	show_speed(&start, &stop, nr_to_read, "Read");
61159a31 RW	566	return error;
	567	}
	568
	569	int swsusp_read(void)
	570	{
	571	int error;
	572	struct swap_map_handle handle;
	573	struct snapshot_handle snapshot;
	574	struct swsusp_info *header;
	575
	576	if (IS_ERR(resume_bdev)) {
	577	pr_debug("swsusp: block device not initialised\n");
	578	return PTR_ERR(resume_bdev);
	579	}
	580
	581	memset(&snapshot, 0, sizeof(struct snapshot_handle));
	582	error = snapshot_write_next(&snapshot, PAGE_SIZE);
	583	if (error < PAGE_SIZE)
	584	return error < 0 ? error : -EFAULT;
	585	header = (struct swsusp_info *)data_of(snapshot);
	586	error = get_swap_reader(&handle, swsusp_header.image);
	587	if (!error)
546e0d27	588	error = swap_read_page(&handle, header, NULL);
61159a31 RW	589	if (!error)
	590	error = load_image(&handle, &snapshot, header->pages - 1);
	591	release_swap_reader(&handle);
	592
	593	blkdev_put(resume_bdev);
	594
	595	if (!error)
	596	pr_debug("swsusp: Reading resume file was successful\n");
	597	else
	598	pr_debug("swsusp: Error %d resuming\n", error);
	599	return error;
	600	}
	601
	602	/**
	603	* swsusp_check - Check for swsusp signature in the resume device
	604	*/
	605
	606	int swsusp_check(void)
	607	{
	608	int error;
	609
	610	resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
	611	if (!IS_ERR(resume_bdev)) {
	612	set_blocksize(resume_bdev, PAGE_SIZE);
	613	memset(&swsusp_header, 0, sizeof(swsusp_header));
9a154d9d RW	614	error = bio_read_page(swsusp_resume_block,
	615	&swsusp_header, NULL);
	616	if (error)
61159a31	617	return error;
9a154d9d	618
61159a31 RW	619	if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) {
	620	memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10);
	621	/* Reset swap signature now */
9a154d9d RW	622	error = bio_write_page(swsusp_resume_block,
9a154d9d RW	623	&swsusp_header, NULL);
61159a31 RW	624	} else {
	625	return -EINVAL;
	626	}
	627	if (error)
	628	blkdev_put(resume_bdev);
	629	else
	630	pr_debug("swsusp: Signature found, resuming\n");
	631	} else {
	632	error = PTR_ERR(resume_bdev);
	633	}
	634
	635	if (error)
	636	pr_debug("swsusp: Error %d check for resume file\n", error);
	637
	638	return error;
	639	}
	640
	641	/**
	642	* swsusp_close - close swap device.
	643	*/
	644
	645	void swsusp_close(void)
	646	{
	647	if (IS_ERR(resume_bdev)) {
	648	pr_debug("swsusp: block device not initialised\n");
	649	return;
	650	}
	651
	652	blkdev_put(resume_bdev);
	653	}