Initial import

1 files changed, 1512 insertions, 0 deletions

diff --git a/kernel/power/swap.c b/kernel/power/swap.c
new file mode 100644
index 000000000..570aff817
--- /dev/null
+++ b/kernel/power/swap.c
@@ -0,0 +1,1512 @@
+/*
+ * 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@ucw.cz>
+ * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
+ * Copyright (C) 2010-2012 Bojan Smojver <bojan@rexursive.com>
+ *
+ * This file is released under the GPLv2.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/file.h>
+#include <linux/delay.h>
+#include <linux/bitops.h>
+#include <linux/genhd.h>
+#include <linux/device.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
+#include <linux/pm.h>
+#include <linux/slab.h>
+#include <linux/lzo.h>
+#include <linux/vmalloc.h>
+#include <linux/cpumask.h>
+#include <linux/atomic.h>
+#include <linux/kthread.h>
+#include <linux/crc32.h>
+#include <linux/ktime.h>
+
+#include "power.h"
+
+#define HIBERNATE_SIG	"S1SUSPEND"
+
+/*
+ *	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_ENTRIES 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 pick up all swap_map_page structures into a list.
+ */
+
+#define MAP_PAGE_ENTRIES	(PAGE_SIZE / sizeof(sector_t) - 1)
+
+/*
+ * Number of free pages that are not high.
+ */
+static inline unsigned long low_free_pages(void)
+{
+	return nr_free_pages() - nr_free_highpages();
+}
+
+/*
+ * Number of pages required to be kept free while writing the image. Always
+ * half of all available low pages before the writing starts.
+ */
+static inline unsigned long reqd_free_pages(void)
+{
+	return low_free_pages() / 2;
+}
+
+struct swap_map_page {
+	sector_t entries[MAP_PAGE_ENTRIES];
+	sector_t next_swap;
+};
+
+struct swap_map_page_list {
+	struct swap_map_page *map;
+	struct swap_map_page_list *next;
+};
+
+/**
+ *	The swap_map_handle structure is used for handling swap in
+ *	a file-alike way
+ */
+
+struct swap_map_handle {
+	struct swap_map_page *cur;
+	struct swap_map_page_list *maps;
+	sector_t cur_swap;
+	sector_t first_sector;
+	unsigned int k;
+	unsigned long reqd_free_pages;
+	u32 crc32;
+};
+
+struct swsusp_header {
+	char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int) -
+	              sizeof(u32)];
+	u32	crc32;
+	sector_t image;
+	unsigned int flags;	/* Flags to pass to the "boot" kernel */
+	char	orig_sig[10];
+	char	sig[10];
+} __packed;
+
+static struct swsusp_header *swsusp_header;
+
+/**
+ *	The following functions are used for tracing the allocated
+ *	swap pages, so that they can be freed in case of an error.
+ */
+
+struct swsusp_extent {
+	struct rb_node node;
+	unsigned long start;
+	unsigned long end;
+};
+
+static struct rb_root swsusp_extents = RB_ROOT;
+
+static int swsusp_extents_insert(unsigned long swap_offset)
+{
+	struct rb_node **new = &(swsusp_extents.rb_node);
+	struct rb_node *parent = NULL;
+	struct swsusp_extent *ext;
+
+	/* Figure out where to put the new node */
+	while (*new) {
+		ext = rb_entry(*new, struct swsusp_extent, node);
+		parent = *new;
+		if (swap_offset < ext->start) {
+			/* Try to merge */
+			if (swap_offset == ext->start - 1) {
+				ext->start--;
+				return 0;
+			}
+			new = &((*new)->rb_left);
+		} else if (swap_offset > ext->end) {
+			/* Try to merge */
+			if (swap_offset == ext->end + 1) {
+				ext->end++;
+				return 0;
+			}
+			new = &((*new)->rb_right);
+		} else {
+			/* It already is in the tree */
+			return -EINVAL;
+		}
+	}
+	/* Add the new node and rebalance the tree. */
+	ext = kzalloc(sizeof(struct swsusp_extent), GFP_KERNEL);
+	if (!ext)
+		return -ENOMEM;
+
+	ext->start = swap_offset;
+	ext->end = swap_offset;
+	rb_link_node(&ext->node, parent, new);
+	rb_insert_color(&ext->node, &swsusp_extents);
+	return 0;
+}
+
+/**
+ *	alloc_swapdev_block - allocate a swap page and register that it has
+ *	been allocated, so that it can be freed in case of an error.
+ */
+
+sector_t alloc_swapdev_block(int swap)
+{
+	unsigned long offset;
+
+	offset = swp_offset(get_swap_page_of_type(swap));
+	if (offset) {
+		if (swsusp_extents_insert(offset))
+			swap_free(swp_entry(swap, offset));
+		else
+			return swapdev_block(swap, offset);
+	}
+	return 0;
+}
+
+/**
+ *	free_all_swap_pages - free swap pages allocated for saving image data.
+ *	It also frees the extents used to register which swap entries had been
+ *	allocated.
+ */
+
+void free_all_swap_pages(int swap)
+{
+	struct rb_node *node;
+
+	while ((node = swsusp_extents.rb_node)) {
+		struct swsusp_extent *ext;
+		unsigned long offset;
+
+		ext = container_of(node, struct swsusp_extent, node);
+		rb_erase(node, &swsusp_extents);
+		for (offset = ext->start; offset <= ext->end; offset++)
+			swap_free(swp_entry(swap, offset));
+
+		kfree(ext);
+	}
+}
+
+int swsusp_swap_in_use(void)
+{
+	return (swsusp_extents.rb_node != NULL);
+}
+
+/*
+ * General things
+ */
+
+static unsigned short root_swap = 0xffff;
+struct block_device *hib_resume_bdev;
+
+/*
+ * Saving part
+ */
+
+static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags)
+{
+	int error;
+
+	hib_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, HIBERNATE_SIG, 10);
+		swsusp_header->image = handle->first_sector;
+		swsusp_header->flags = flags;
+		if (flags & SF_CRC32_MODE)
+			swsusp_header->crc32 = handle->crc32;
+		error = hib_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)
+ *
+ *	This is called before saving image
+ */
+static int swsusp_swap_check(void)
+{
+	int res;
+
+	res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
+			&hib_resume_bdev);
+	if (res < 0)
+		return res;
+
+	root_swap = res;
+	res = blkdev_get(hib_resume_bdev, FMODE_WRITE, NULL);
+	if (res)
+		return res;
+
+	res = set_blocksize(hib_resume_bdev, PAGE_SIZE);
+	if (res < 0)
+		blkdev_put(hib_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;
+	int ret;
+
+	if (!offset)
+		return -ENOSPC;
+
+	if (bio_chain) {
+		src = (void *)__get_free_page(__GFP_WAIT | __GFP_NOWARN |
+		                              __GFP_NORETRY);
+		if (src) {
+			copy_page(src, buf);
+		} else {
+			ret = hib_wait_on_bio_chain(bio_chain); /* Free pages */
+			if (ret)
+				return ret;
+			src = (void *)__get_free_page(__GFP_WAIT |
+			                              __GFP_NOWARN |
+			                              __GFP_NORETRY);
+			if (src) {
+				copy_page(src, buf);
+			} else {
+				WARN_ON_ONCE(1);
+				bio_chain = NULL;	/* Go synchronous */
+				src = buf;
+			}
+		}
+	} else {
+		src = buf;
+	}
+	return hib_bio_write_page(offset, src, bio_chain);
+}
+
+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)
+{
+	int ret;
+
+	ret = swsusp_swap_check();
+	if (ret) {
+		if (ret != -ENOSPC)
+			printk(KERN_ERR "PM: Cannot find swap device, try "
+					"swapon -a.\n");
+		return ret;
+	}
+	handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
+	if (!handle->cur) {
+		ret = -ENOMEM;
+		goto err_close;
+	}
+	handle->cur_swap = alloc_swapdev_block(root_swap);
+	if (!handle->cur_swap) {
+		ret = -ENOSPC;
+		goto err_rel;
+	}
+	handle->k = 0;
+	handle->reqd_free_pages = reqd_free_pages();
+	handle->first_sector = handle->cur_swap;
+	return 0;
+err_rel:
+	release_swap_writer(handle);
+err_close:
+	swsusp_close(FMODE_WRITE);
+	return ret;
+}
+
+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) {
+		offset = alloc_swapdev_block(root_swap);
+		if (!offset)
+			return -ENOSPC;
+		handle->cur->next_swap = offset;
+		error = write_page(handle->cur, handle->cur_swap, bio_chain);
+		if (error)
+			goto out;
+		clear_page(handle->cur);
+		handle->cur_swap = offset;
+		handle->k = 0;
+
+		if (bio_chain && low_free_pages() <= handle->reqd_free_pages) {
+			error = hib_wait_on_bio_chain(bio_chain);
+			if (error)
+				goto out;
+			/*
+			 * Recalculate the number of required free pages, to
+			 * make sure we never take more than half.
+			 */
+			handle->reqd_free_pages = reqd_free_pages();
+		}
+	}
+ 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;
+}
+
+static int swap_writer_finish(struct swap_map_handle *handle,
+		unsigned int flags, int error)
+{
+	if (!error) {
+		flush_swap_writer(handle);
+		printk(KERN_INFO "PM: S");
+		error = mark_swapfiles(handle, flags);
+		printk("|\n");
+	}
+
+	if (error)
+		free_all_swap_pages(root_swap);
+	release_swap_writer(handle);
+	swsusp_close(FMODE_WRITE);
+
+	return error;
+}
+
+/* We need to remember how much compressed data we need to read. */
+#define LZO_HEADER	sizeof(size_t)
+
+/* Number of pages/bytes we'll compress at one time. */
+#define LZO_UNC_PAGES	32
+#define LZO_UNC_SIZE	(LZO_UNC_PAGES * PAGE_SIZE)
+
+/* Number of pages/bytes we need for compressed data (worst case). */
+#define LZO_CMP_PAGES	DIV_ROUND_UP(lzo1x_worst_compress(LZO_UNC_SIZE) + \
+			             LZO_HEADER, PAGE_SIZE)
+#define LZO_CMP_SIZE	(LZO_CMP_PAGES * PAGE_SIZE)
+
+/* Maximum number of threads for compression/decompression. */
+#define LZO_THREADS	3
+
+/* Minimum/maximum number of pages for read buffering. */
+#define LZO_MIN_RD_PAGES	1024
+#define LZO_MAX_RD_PAGES	8192
+
+
+/**
+ *	save_image - save the suspend image data
+ */
+
+static int save_image(struct swap_map_handle *handle,
+                      struct snapshot_handle *snapshot,
+                      unsigned int nr_to_write)
+{
+	unsigned int m;
+	int ret;
+	int nr_pages;
+	int err2;
+	struct bio *bio;
+	ktime_t start;
+	ktime_t stop;
+
+	printk(KERN_INFO "PM: Saving image data pages (%u pages)...\n",
+		nr_to_write);
+	m = nr_to_write / 10;
+	if (!m)
+		m = 1;
+	nr_pages = 0;
+	bio = NULL;
+	start = ktime_get();
+	while (1) {
+		ret = snapshot_read_next(snapshot);
+		if (ret <= 0)
+			break;
+		ret = swap_write_page(handle, data_of(*snapshot), &bio);
+		if (ret)
+			break;
+		if (!(nr_pages % m))
+			printk(KERN_INFO "PM: Image saving progress: %3d%%\n",
+			       nr_pages / m * 10);
+		nr_pages++;
+	}
+	err2 = hib_wait_on_bio_chain(&bio);
+	stop = ktime_get();
+	if (!ret)
+		ret = err2;
+	if (!ret)
+		printk(KERN_INFO "PM: Image saving done.\n");
+	swsusp_show_speed(start, stop, nr_to_write, "Wrote");
+	return ret;
+}
+
+/**
+ * Structure used for CRC32.
+ */
+struct crc_data {
+	struct task_struct *thr;                  /* thread */
+	atomic_t ready;                           /* ready to start flag */
+	atomic_t stop;                            /* ready to stop flag */
+	unsigned run_threads;                     /* nr current threads */
+	wait_queue_head_t go;                     /* start crc update */
+	wait_queue_head_t done;                   /* crc update done */
+	u32 *crc32;                               /* points to handle's crc32 */
+	size_t *unc_len[LZO_THREADS];             /* uncompressed lengths */
+	unsigned char *unc[LZO_THREADS];          /* uncompressed data */
+};
+
+/**
+ * CRC32 update function that runs in its own thread.
+ */
+static int crc32_threadfn(void *data)
+{
+	struct crc_data *d = data;
+	unsigned i;
+
+	while (1) {
+		wait_event(d->go, atomic_read(&d->ready) ||
+		                  kthread_should_stop());
+		if (kthread_should_stop()) {
+			d->thr = NULL;
+			atomic_set(&d->stop, 1);
+			wake_up(&d->done);
+			break;
+		}
+		atomic_set(&d->ready, 0);
+
+		for (i = 0; i < d->run_threads; i++)
+			*d->crc32 = crc32_le(*d->crc32,
+			                     d->unc[i], *d->unc_len[i]);
+		atomic_set(&d->stop, 1);
+		wake_up(&d->done);
+	}
+	return 0;
+}
+/**
+ * Structure used for LZO data compression.
+ */
+struct cmp_data {
+	struct task_struct *thr;                  /* thread */
+	atomic_t ready;                           /* ready to start flag */
+	atomic_t stop;                            /* ready to stop flag */
+	int ret;                                  /* return code */
+	wait_queue_head_t go;                     /* start compression */
+	wait_queue_head_t done;                   /* compression done */
+	size_t unc_len;                           /* uncompressed length */
+	size_t cmp_len;                           /* compressed length */
+	unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
+	unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
+	unsigned char wrk[LZO1X_1_MEM_COMPRESS];  /* compression workspace */
+};
+
+/**
+ * Compression function that runs in its own thread.
+ */
+static int lzo_compress_threadfn(void *data)
+{
+	struct cmp_data *d = data;
+
+	while (1) {
+		wait_event(d->go, atomic_read(&d->ready) ||
+		                  kthread_should_stop());
+		if (kthread_should_stop()) {
+			d->thr = NULL;
+			d->ret = -1;
+			atomic_set(&d->stop, 1);
+			wake_up(&d->done);
+			break;
+		}
+		atomic_set(&d->ready, 0);
+
+		d->ret = lzo1x_1_compress(d->unc, d->unc_len,
+		                          d->cmp + LZO_HEADER, &d->cmp_len,
+		                          d->wrk);
+		atomic_set(&d->stop, 1);
+		wake_up(&d->done);
+	}
+	return 0;
+}
+
+/**
+ * save_image_lzo - Save the suspend image data compressed with LZO.
+ * @handle: Swap map handle to use for saving the image.
+ * @snapshot: Image to read data from.
+ * @nr_to_write: Number of pages to save.
+ */
+static int save_image_lzo(struct swap_map_handle *handle,
+                          struct snapshot_handle *snapshot,
+                          unsigned int nr_to_write)
+{
+	unsigned int m;
+	int ret = 0;
+	int nr_pages;
+	int err2;
+	struct bio *bio;
+	ktime_t start;
+	ktime_t stop;
+	size_t off;
+	unsigned thr, run_threads, nr_threads;
+	unsigned char *page = NULL;
+	struct cmp_data *data = NULL;
+	struct crc_data *crc = NULL;
+
+	/*
+	 * We'll limit the number of threads for compression to limit memory
+	 * footprint.
+	 */
+	nr_threads = num_online_cpus() - 1;
+	nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
+
+	page = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
+	if (!page) {
+		printk(KERN_ERR "PM: Failed to allocate LZO page\n");
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+
+	data = vmalloc(sizeof(*data) * nr_threads);
+	if (!data) {
+		printk(KERN_ERR "PM: Failed to allocate LZO data\n");
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+	for (thr = 0; thr < nr_threads; thr++)
+		memset(&data[thr], 0, offsetof(struct cmp_data, go));
+
+	crc = kmalloc(sizeof(*crc), GFP_KERNEL);
+	if (!crc) {
+		printk(KERN_ERR "PM: Failed to allocate crc\n");
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+	memset(crc, 0, offsetof(struct crc_data, go));
+
+	/*
+	 * Start the compression threads.
+	 */
+	for (thr = 0; thr < nr_threads; thr++) {
+		init_waitqueue_head(&data[thr].go);
+		init_waitqueue_head(&data[thr].done);
+
+		data[thr].thr = kthread_run(lzo_compress_threadfn,
+		                            &data[thr],
+		                            "image_compress/%u", thr);
+		if (IS_ERR(data[thr].thr)) {
+			data[thr].thr = NULL;
+			printk(KERN_ERR
+			       "PM: Cannot start compression threads\n");
+			ret = -ENOMEM;
+			goto out_clean;
+		}
+	}
+
+	/*
+	 * Start the CRC32 thread.
+	 */
+	init_waitqueue_head(&crc->go);
+	init_waitqueue_head(&crc->done);
+
+	handle->crc32 = 0;
+	crc->crc32 = &handle->crc32;
+	for (thr = 0; thr < nr_threads; thr++) {
+		crc->unc[thr] = data[thr].unc;
+		crc->unc_len[thr] = &data[thr].unc_len;
+	}
+
+	crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
+	if (IS_ERR(crc->thr)) {
+		crc->thr = NULL;
+		printk(KERN_ERR "PM: Cannot start CRC32 thread\n");
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+
+	/*
+	 * Adjust the number of required free pages after all allocations have
+	 * been done. We don't want to run out of pages when writing.
+	 */
+	handle->reqd_free_pages = reqd_free_pages();
+
+	printk(KERN_INFO
+		"PM: Using %u thread(s) for compression.\n"
+		"PM: Compressing and saving image data (%u pages)...\n",
+		nr_threads, nr_to_write);
+	m = nr_to_write / 10;
+	if (!m)
+		m = 1;
+	nr_pages = 0;
+	bio = NULL;
+	start = ktime_get();
+	for (;;) {
+		for (thr = 0; thr < nr_threads; thr++) {
+			for (off = 0; off < LZO_UNC_SIZE; off += PAGE_SIZE) {
+				ret = snapshot_read_next(snapshot);
+				if (ret < 0)
+					goto out_finish;
+
+				if (!ret)
+					break;
+
+				memcpy(data[thr].unc + off,
+				       data_of(*snapshot), PAGE_SIZE);
+
+				if (!(nr_pages % m))
+					printk(KERN_INFO
+					       "PM: Image saving progress: "
+					       "%3d%%\n",
+				               nr_pages / m * 10);
+				nr_pages++;
+			}
+			if (!off)
+				break;
+
+			data[thr].unc_len = off;
+
+			atomic_set(&data[thr].ready, 1);
+			wake_up(&data[thr].go);
+		}
+
+		if (!thr)
+			break;
+
+		crc->run_threads = thr;
+		atomic_set(&crc->ready, 1);
+		wake_up(&crc->go);
+
+		for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
+			wait_event(data[thr].done,
+			           atomic_read(&data[thr].stop));
+			atomic_set(&data[thr].stop, 0);
+
+			ret = data[thr].ret;
+
+			if (ret < 0) {
+				printk(KERN_ERR "PM: LZO compression failed\n");
+				goto out_finish;
+			}
+
+			if (unlikely(!data[thr].cmp_len ||
+			             data[thr].cmp_len >
+			             lzo1x_worst_compress(data[thr].unc_len))) {
+				printk(KERN_ERR
+				       "PM: Invalid LZO compressed length\n");
+				ret = -1;
+				goto out_finish;
+			}
+
+			*(size_t *)data[thr].cmp = data[thr].cmp_len;
+
+			/*
+			 * Given we are writing one page at a time to disk, we
+			 * copy that much from the buffer, although the last
+			 * bit will likely be smaller than full page. This is
+			 * OK - we saved the length of the compressed data, so
+			 * any garbage at the end will be discarded when we
+			 * read it.
+			 */
+			for (off = 0;
+			     off < LZO_HEADER + data[thr].cmp_len;
+			     off += PAGE_SIZE) {
+				memcpy(page, data[thr].cmp + off, PAGE_SIZE);
+
+				ret = swap_write_page(handle, page, &bio);
+				if (ret)
+					goto out_finish;
+			}
+		}
+
+		wait_event(crc->done, atomic_read(&crc->stop));
+		atomic_set(&crc->stop, 0);
+	}
+
+out_finish:
+	err2 = hib_wait_on_bio_chain(&bio);
+	stop = ktime_get();
+	if (!ret)
+		ret = err2;
+	if (!ret)
+		printk(KERN_INFO "PM: Image saving done.\n");
+	swsusp_show_speed(start, stop, nr_to_write, "Wrote");
+out_clean:
+	if (crc) {
+		if (crc->thr)
+			kthread_stop(crc->thr);
+		kfree(crc);
+	}
+	if (data) {
+		for (thr = 0; thr < nr_threads; thr++)
+			if (data[thr].thr)
+				kthread_stop(data[thr].thr);
+		vfree(data);
+	}
+	if (page) free_page((unsigned long)page);
+
+	return ret;
+}
+
+/**
+ *	enough_swap - Make sure we have enough swap to save the image.
+ *
+ *	Returns TRUE or FALSE after checking the total amount of swap
+ *	space avaiable from the resume partition.
+ */
+
+static int enough_swap(unsigned int nr_pages, unsigned int flags)
+{
+	unsigned int free_swap = count_swap_pages(root_swap, 1);
+	unsigned int required;
+
+	pr_debug("PM: Free swap pages: %u\n", free_swap);
+
+	required = PAGES_FOR_IO + nr_pages;
+	return free_swap > required;
+}
+
+/**
+ *	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;
+	unsigned long pages;
+	int error;
+
+	pages = snapshot_get_image_size();
+	error = get_swap_writer(&handle);
+	if (error) {
+		printk(KERN_ERR "PM: Cannot get swap writer\n");
+		return error;
+	}
+	if (flags & SF_NOCOMPRESS_MODE) {
+		if (!enough_swap(pages, flags)) {
+			printk(KERN_ERR "PM: Not enough free swap\n");
+			error = -ENOSPC;
+			goto out_finish;
+		}
+	}
+	memset(&snapshot, 0, sizeof(struct snapshot_handle));
+	error = snapshot_read_next(&snapshot);
+	if (error < PAGE_SIZE) {
+		if (error >= 0)
+			error = -EFAULT;
+
+		goto out_finish;
+	}
+	header = (struct swsusp_info *)data_of(snapshot);
+	error = swap_write_page(&handle, header, NULL);
+	if (!error) {
+		error = (flags & SF_NOCOMPRESS_MODE) ?
+			save_image(&handle, &snapshot, pages - 1) :
+			save_image_lzo(&handle, &snapshot, pages - 1);
+	}
+out_finish:
+	error = swap_writer_finish(&handle, flags, error);
+	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)
+{
+	struct swap_map_page_list *tmp;
+
+	while (handle->maps) {
+		if (handle->maps->map)
+			free_page((unsigned long)handle->maps->map);
+		tmp = handle->maps;
+		handle->maps = handle->maps->next;
+		kfree(tmp);
+	}
+	handle->cur = NULL;
+}
+
+static int get_swap_reader(struct swap_map_handle *handle,
+		unsigned int *flags_p)
+{
+	int error;
+	struct swap_map_page_list *tmp, *last;
+	sector_t offset;
+
+	*flags_p = swsusp_header->flags;
+
+	if (!swsusp_header->image) /* how can this happen? */
+		return -EINVAL;
+
+	handle->cur = NULL;
+	last = handle->maps = NULL;
+	offset = swsusp_header->image;
+	while (offset) {
+		tmp = kmalloc(sizeof(*handle->maps), GFP_KERNEL);
+		if (!tmp) {
+			release_swap_reader(handle);
+			return -ENOMEM;
+		}
+		memset(tmp, 0, sizeof(*tmp));
+		if (!handle->maps)
+			handle->maps = tmp;
+		if (last)
+			last->next = tmp;
+		last = tmp;
+
+		tmp->map = (struct swap_map_page *)
+		           __get_free_page(__GFP_WAIT | __GFP_HIGH);
+		if (!tmp->map) {
+			release_swap_reader(handle);
+			return -ENOMEM;
+		}
+
+		error = hib_bio_read_page(offset, tmp->map, NULL);
+		if (error) {
+			release_swap_reader(handle);
+			return error;
+		}
+		offset = tmp->map->next_swap;
+	}
+	handle->k = 0;
+	handle->cur = handle->maps->map;
+	return 0;
+}
+
+static int swap_read_page(struct swap_map_handle *handle, void *buf,
+				struct bio **bio_chain)
+{
+	sector_t offset;
+	int error;
+	struct swap_map_page_list *tmp;
+
+	if (!handle->cur)
+		return -EINVAL;
+	offset = handle->cur->entries[handle->k];
+	if (!offset)
+		return -EFAULT;
+	error = hib_bio_read_page(offset, buf, bio_chain);
+	if (error)
+		return error;
+	if (++handle->k >= MAP_PAGE_ENTRIES) {
+		handle->k = 0;
+		free_page((unsigned long)handle->maps->map);
+		tmp = handle->maps;
+		handle->maps = handle->maps->next;
+		kfree(tmp);
+		if (!handle->maps)
+			release_swap_reader(handle);
+		else
+			handle->cur = handle->maps->map;
+	}
+	return error;
+}
+
+static int swap_reader_finish(struct swap_map_handle *handle)
+{
+	release_swap_reader(handle);
+
+	return 0;
+}
+
+/**
+ *	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 ret = 0;
+	ktime_t start;
+	ktime_t stop;
+	struct bio *bio;
+	int err2;
+	unsigned nr_pages;
+
+	printk(KERN_INFO "PM: Loading image data pages (%u pages)...\n",
+		nr_to_read);
+	m = nr_to_read / 10;
+	if (!m)
+		m = 1;
+	nr_pages = 0;
+	bio = NULL;
+	start = ktime_get();
+	for ( ; ; ) {
+		ret = snapshot_write_next(snapshot);
+		if (ret <= 0)
+			break;
+		ret = swap_read_page(handle, data_of(*snapshot), &bio);
+		if (ret)
+			break;
+		if (snapshot->sync_read)
+			ret = hib_wait_on_bio_chain(&bio);
+		if (ret)
+			break;
+		if (!(nr_pages % m))
+			printk(KERN_INFO "PM: Image loading progress: %3d%%\n",
+			       nr_pages / m * 10);
+		nr_pages++;
+	}
+	err2 = hib_wait_on_bio_chain(&bio);
+	stop = ktime_get();
+	if (!ret)
+		ret = err2;
+	if (!ret) {
+		printk(KERN_INFO "PM: Image loading done.\n");
+		snapshot_write_finalize(snapshot);
+		if (!snapshot_image_loaded(snapshot))
+			ret = -ENODATA;
+	}
+	swsusp_show_speed(start, stop, nr_to_read, "Read");
+	return ret;
+}
+
+/**
+ * Structure used for LZO data decompression.
+ */
+struct dec_data {
+	struct task_struct *thr;                  /* thread */
+	atomic_t ready;                           /* ready to start flag */
+	atomic_t stop;                            /* ready to stop flag */
+	int ret;                                  /* return code */
+	wait_queue_head_t go;                     /* start decompression */
+	wait_queue_head_t done;                   /* decompression done */
+	size_t unc_len;                           /* uncompressed length */
+	size_t cmp_len;                           /* compressed length */
+	unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
+	unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
+};
+
+/**
+ * Deompression function that runs in its own thread.
+ */
+static int lzo_decompress_threadfn(void *data)
+{
+	struct dec_data *d = data;
+
+	while (1) {
+		wait_event(d->go, atomic_read(&d->ready) ||
+		                  kthread_should_stop());
+		if (kthread_should_stop()) {
+			d->thr = NULL;
+			d->ret = -1;
+			atomic_set(&d->stop, 1);
+			wake_up(&d->done);
+			break;
+		}
+		atomic_set(&d->ready, 0);
+
+		d->unc_len = LZO_UNC_SIZE;
+		d->ret = lzo1x_decompress_safe(d->cmp + LZO_HEADER, d->cmp_len,
+		                               d->unc, &d->unc_len);
+		atomic_set(&d->stop, 1);
+		wake_up(&d->done);
+	}
+	return 0;
+}
+
+/**
+ * load_image_lzo - Load compressed image data and decompress them with LZO.
+ * @handle: Swap map handle to use for loading data.
+ * @snapshot: Image to copy uncompressed data into.
+ * @nr_to_read: Number of pages to load.
+ */
+static int load_image_lzo(struct swap_map_handle *handle,
+                          struct snapshot_handle *snapshot,
+                          unsigned int nr_to_read)
+{
+	unsigned int m;
+	int ret = 0;
+	int eof = 0;
+	struct bio *bio;
+	ktime_t start;
+	ktime_t stop;
+	unsigned nr_pages;
+	size_t off;
+	unsigned i, thr, run_threads, nr_threads;
+	unsigned ring = 0, pg = 0, ring_size = 0,
+	         have = 0, want, need, asked = 0;
+	unsigned long read_pages = 0;
+	unsigned char **page = NULL;
+	struct dec_data *data = NULL;
+	struct crc_data *crc = NULL;
+
+	/*
+	 * We'll limit the number of threads for decompression to limit memory
+	 * footprint.
+	 */
+	nr_threads = num_online_cpus() - 1;
+	nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
+
+	page = vmalloc(sizeof(*page) * LZO_MAX_RD_PAGES);
+	if (!page) {
+		printk(KERN_ERR "PM: Failed to allocate LZO page\n");
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+
+	data = vmalloc(sizeof(*data) * nr_threads);
+	if (!data) {
+		printk(KERN_ERR "PM: Failed to allocate LZO data\n");
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+	for (thr = 0; thr < nr_threads; thr++)
+		memset(&data[thr], 0, offsetof(struct dec_data, go));
+
+	crc = kmalloc(sizeof(*crc), GFP_KERNEL);
+	if (!crc) {
+		printk(KERN_ERR "PM: Failed to allocate crc\n");
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+	memset(crc, 0, offsetof(struct crc_data, go));
+
+	/*
+	 * Start the decompression threads.
+	 */
+	for (thr = 0; thr < nr_threads; thr++) {
+		init_waitqueue_head(&data[thr].go);
+		init_waitqueue_head(&data[thr].done);
+
+		data[thr].thr = kthread_run(lzo_decompress_threadfn,
+		                            &data[thr],
+		                            "image_decompress/%u", thr);
+		if (IS_ERR(data[thr].thr)) {
+			data[thr].thr = NULL;
+			printk(KERN_ERR
+			       "PM: Cannot start decompression threads\n");
+			ret = -ENOMEM;
+			goto out_clean;
+		}
+	}
+
+	/*
+	 * Start the CRC32 thread.
+	 */
+	init_waitqueue_head(&crc->go);
+	init_waitqueue_head(&crc->done);
+
+	handle->crc32 = 0;
+	crc->crc32 = &handle->crc32;
+	for (thr = 0; thr < nr_threads; thr++) {
+		crc->unc[thr] = data[thr].unc;
+		crc->unc_len[thr] = &data[thr].unc_len;
+	}
+
+	crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
+	if (IS_ERR(crc->thr)) {
+		crc->thr = NULL;
+		printk(KERN_ERR "PM: Cannot start CRC32 thread\n");
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+
+	/*
+	 * Set the number of pages for read buffering.
+	 * This is complete guesswork, because we'll only know the real
+	 * picture once prepare_image() is called, which is much later on
+	 * during the image load phase. We'll assume the worst case and
+	 * say that none of the image pages are from high memory.
+	 */
+	if (low_free_pages() > snapshot_get_image_size())
+		read_pages = (low_free_pages() - snapshot_get_image_size()) / 2;
+	read_pages = clamp_val(read_pages, LZO_MIN_RD_PAGES, LZO_MAX_RD_PAGES);
+
+	for (i = 0; i < read_pages; i++) {
+		page[i] = (void *)__get_free_page(i < LZO_CMP_PAGES ?
+		                                  __GFP_WAIT | __GFP_HIGH :
+		                                  __GFP_WAIT | __GFP_NOWARN |
+		                                  __GFP_NORETRY);
+
+		if (!page[i]) {
+			if (i < LZO_CMP_PAGES) {
+				ring_size = i;
+				printk(KERN_ERR
+				       "PM: Failed to allocate LZO pages\n");
+				ret = -ENOMEM;
+				goto out_clean;
+			} else {
+				break;
+			}
+		}
+	}
+	want = ring_size = i;
+
+	printk(KERN_INFO
+		"PM: Using %u thread(s) for decompression.\n"
+		"PM: Loading and decompressing image data (%u pages)...\n",
+		nr_threads, nr_to_read);
+	m = nr_to_read / 10;
+	if (!m)
+		m = 1;
+	nr_pages = 0;
+	bio = NULL;
+	start = ktime_get();
+
+	ret = snapshot_write_next(snapshot);
+	if (ret <= 0)
+		goto out_finish;
+
+	for(;;) {
+		for (i = 0; !eof && i < want; i++) {
+			ret = swap_read_page(handle, page[ring], &bio);
+			if (ret) {
+				/*
+				 * On real read error, finish. On end of data,
+				 * set EOF flag and just exit the read loop.
+				 */
+				if (handle->cur &&
+				    handle->cur->entries[handle->k]) {
+					goto out_finish;
+				} else {
+					eof = 1;
+					break;
+				}
+			}
+			if (++ring >= ring_size)
+				ring = 0;
+		}
+		asked += i;
+		want -= i;
+
+		/*
+		 * We are out of data, wait for some more.
+		 */
+		if (!have) {
+			if (!asked)
+				break;
+
+			ret = hib_wait_on_bio_chain(&bio);
+			if (ret)
+				goto out_finish;
+			have += asked;
+			asked = 0;
+			if (eof)
+				eof = 2;
+		}
+
+		if (crc->run_threads) {
+			wait_event(crc->done, atomic_read(&crc->stop));
+			atomic_set(&crc->stop, 0);
+			crc->run_threads = 0;
+		}
+
+		for (thr = 0; have && thr < nr_threads; thr++) {
+			data[thr].cmp_len = *(size_t *)page[pg];
+			if (unlikely(!data[thr].cmp_len ||
+			             data[thr].cmp_len >
+			             lzo1x_worst_compress(LZO_UNC_SIZE))) {
+				printk(KERN_ERR
+				       "PM: Invalid LZO compressed length\n");
+				ret = -1;
+				goto out_finish;
+			}
+
+			need = DIV_ROUND_UP(data[thr].cmp_len + LZO_HEADER,
+			                    PAGE_SIZE);
+			if (need > have) {
+				if (eof > 1) {
+					ret = -1;
+					goto out_finish;
+				}
+				break;
+			}
+
+			for (off = 0;
+			     off < LZO_HEADER + data[thr].cmp_len;
+			     off += PAGE_SIZE) {
+				memcpy(data[thr].cmp + off,
+				       page[pg], PAGE_SIZE);
+				have--;
+				want++;
+				if (++pg >= ring_size)
+					pg = 0;
+			}
+
+			atomic_set(&data[thr].ready, 1);
+			wake_up(&data[thr].go);
+		}
+
+		/*
+		 * Wait for more data while we are decompressing.
+		 */
+		if (have < LZO_CMP_PAGES && asked) {
+			ret = hib_wait_on_bio_chain(&bio);
+			if (ret)
+				goto out_finish;
+			have += asked;
+			asked = 0;
+			if (eof)
+				eof = 2;
+		}
+
+		for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
+			wait_event(data[thr].done,
+			           atomic_read(&data[thr].stop));
+			atomic_set(&data[thr].stop, 0);
+
+			ret = data[thr].ret;
+
+			if (ret < 0) {
+				printk(KERN_ERR
+				       "PM: LZO decompression failed\n");
+				goto out_finish;
+			}
+
+			if (unlikely(!data[thr].unc_len ||
+			             data[thr].unc_len > LZO_UNC_SIZE ||
+			             data[thr].unc_len & (PAGE_SIZE - 1))) {
+				printk(KERN_ERR
+				       "PM: Invalid LZO uncompressed length\n");
+				ret = -1;
+				goto out_finish;
+			}
+
+			for (off = 0;
+			     off < data[thr].unc_len; off += PAGE_SIZE) {
+				memcpy(data_of(*snapshot),
+				       data[thr].unc + off, PAGE_SIZE);
+
+				if (!(nr_pages % m))
+					printk(KERN_INFO
+					       "PM: Image loading progress: "
+					       "%3d%%\n",
+					       nr_pages / m * 10);
+				nr_pages++;
+
+				ret = snapshot_write_next(snapshot);
+				if (ret <= 0) {
+					crc->run_threads = thr + 1;
+					atomic_set(&crc->ready, 1);
+					wake_up(&crc->go);
+					goto out_finish;
+				}
+			}
+		}
+
+		crc->run_threads = thr;
+		atomic_set(&crc->ready, 1);
+		wake_up(&crc->go);
+	}
+
+out_finish:
+	if (crc->run_threads) {
+		wait_event(crc->done, atomic_read(&crc->stop));
+		atomic_set(&crc->stop, 0);
+	}
+	stop = ktime_get();
+	if (!ret) {
+		printk(KERN_INFO "PM: Image loading done.\n");
+		snapshot_write_finalize(snapshot);
+		if (!snapshot_image_loaded(snapshot))
+			ret = -ENODATA;
+		if (!ret) {
+			if (swsusp_header->flags & SF_CRC32_MODE) {
+				if(handle->crc32 != swsusp_header->crc32) {
+					printk(KERN_ERR
+					       "PM: Invalid image CRC32!\n");
+					ret = -ENODATA;
+				}
+			}
+		}
+	}
+	swsusp_show_speed(start, stop, nr_to_read, "Read");
+out_clean:
+	for (i = 0; i < ring_size; i++)
+		free_page((unsigned long)page[i]);
+	if (crc) {
+		if (crc->thr)
+			kthread_stop(crc->thr);
+		kfree(crc);
+	}
+	if (data) {
+		for (thr = 0; thr < nr_threads; thr++)
+			if (data[thr].thr)
+				kthread_stop(data[thr].thr);
+		vfree(data);
+	}
+	vfree(page);
+
+	return ret;
+}
+
+/**
+ *	swsusp_read - read the hibernation image.
+ *	@flags_p: flags passed by the "frozen" kernel in the image header should
+ *		  be written into this memory location
+ */
+
+int swsusp_read(unsigned int *flags_p)
+{
+	int error;
+	struct swap_map_handle handle;
+	struct snapshot_handle snapshot;
+	struct swsusp_info *header;
+
+	memset(&snapshot, 0, sizeof(struct snapshot_handle));
+	error = snapshot_write_next(&snapshot);
+	if (error < PAGE_SIZE)
+		return error < 0 ? error : -EFAULT;
+	header = (struct swsusp_info *)data_of(snapshot);
+	error = get_swap_reader(&handle, flags_p);
+	if (error)
+		goto end;
+	if (!error)
+		error = swap_read_page(&handle, header, NULL);
+	if (!error) {
+		error = (*flags_p & SF_NOCOMPRESS_MODE) ?
+			load_image(&handle, &snapshot, header->pages - 1) :
+			load_image_lzo(&handle, &snapshot, header->pages - 1);
+	}
+	swap_reader_finish(&handle);
+end:
+	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;
+
+	hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device,
+					    FMODE_READ, NULL);
+	if (!IS_ERR(hib_resume_bdev)) {
+		set_blocksize(hib_resume_bdev, PAGE_SIZE);
+		clear_page(swsusp_header);
+		error = hib_bio_read_page(swsusp_resume_block,
+					swsusp_header, NULL);
+		if (error)
+			goto put;
+
+		if (!memcmp(HIBERNATE_SIG, swsusp_header->sig, 10)) {
+			memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
+			/* Reset swap signature now */
+			error = hib_bio_write_page(swsusp_resume_block,
+						swsusp_header, NULL);
+		} else {
+			error = -EINVAL;
+		}
+
+put:
+		if (error)
+			blkdev_put(hib_resume_bdev, FMODE_READ);
+		else
+			pr_debug("PM: Image signature found, resuming\n");
+	} else {
+		error = PTR_ERR(hib_resume_bdev);
+	}
+
+	if (error)
+		pr_debug("PM: Image not found (code %d)\n", error);
+
+	return error;
+}
+
+/**
+ *	swsusp_close - close swap device.
+ */
+
+void swsusp_close(fmode_t mode)
+{
+	if (IS_ERR(hib_resume_bdev)) {
+		pr_debug("PM: Image device not initialised\n");
+		return;
+	}
+
+	blkdev_put(hib_resume_bdev, mode);
+}
+
+/**
+ *      swsusp_unmark - Unmark swsusp signature in the resume device
+ */
+
+#ifdef CONFIG_SUSPEND
+int swsusp_unmark(void)
+{
+	int error;
+
+	hib_bio_read_page(swsusp_resume_block, swsusp_header, NULL);
+	if (!memcmp(HIBERNATE_SIG,swsusp_header->sig, 10)) {
+		memcpy(swsusp_header->sig,swsusp_header->orig_sig, 10);
+		error = hib_bio_write_page(swsusp_resume_block,
+					swsusp_header, NULL);
+	} else {
+		printk(KERN_ERR "PM: Cannot find swsusp signature!\n");
+		error = -ENODEV;
+	}
+
+	/*
+	 * We just returned from suspend, we don't need the image any more.
+	 */
+	free_all_swap_pages(root_swap);
+
+	return error;
+}
+#endif
+
+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);