xref: /openbmc/linux/kernel/power/swap.c (revision aac5987a)
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@ucw.cz>
8  * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
9  * Copyright (C) 2010-2012 Bojan Smojver <bojan@rexursive.com>
10  *
11  * This file is released under the GPLv2.
12  *
13  */
14 
15 #include <linux/module.h>
16 #include <linux/file.h>
17 #include <linux/delay.h>
18 #include <linux/bitops.h>
19 #include <linux/genhd.h>
20 #include <linux/device.h>
21 #include <linux/bio.h>
22 #include <linux/blkdev.h>
23 #include <linux/swap.h>
24 #include <linux/swapops.h>
25 #include <linux/pm.h>
26 #include <linux/slab.h>
27 #include <linux/lzo.h>
28 #include <linux/vmalloc.h>
29 #include <linux/cpumask.h>
30 #include <linux/atomic.h>
31 #include <linux/kthread.h>
32 #include <linux/crc32.h>
33 #include <linux/ktime.h>
34 
35 #include "power.h"
36 
37 #define HIBERNATE_SIG	"S1SUSPEND"
38 
39 /*
40  * When reading an {un,}compressed image, we may restore pages in place,
41  * in which case some architectures need these pages cleaning before they
42  * can be executed. We don't know which pages these may be, so clean the lot.
43  */
44 static bool clean_pages_on_read;
45 static bool clean_pages_on_decompress;
46 
47 /*
48  *	The swap map is a data structure used for keeping track of each page
49  *	written to a swap partition.  It consists of many swap_map_page
50  *	structures that contain each an array of MAP_PAGE_ENTRIES swap entries.
51  *	These structures are stored on the swap and linked together with the
52  *	help of the .next_swap member.
53  *
54  *	The swap map is created during suspend.  The swap map pages are
55  *	allocated and populated one at a time, so we only need one memory
56  *	page to set up the entire structure.
57  *
58  *	During resume we pick up all swap_map_page structures into a list.
59  */
60 
61 #define MAP_PAGE_ENTRIES	(PAGE_SIZE / sizeof(sector_t) - 1)
62 
63 /*
64  * Number of free pages that are not high.
65  */
66 static inline unsigned long low_free_pages(void)
67 {
68 	return nr_free_pages() - nr_free_highpages();
69 }
70 
71 /*
72  * Number of pages required to be kept free while writing the image. Always
73  * half of all available low pages before the writing starts.
74  */
75 static inline unsigned long reqd_free_pages(void)
76 {
77 	return low_free_pages() / 2;
78 }
79 
80 struct swap_map_page {
81 	sector_t entries[MAP_PAGE_ENTRIES];
82 	sector_t next_swap;
83 };
84 
85 struct swap_map_page_list {
86 	struct swap_map_page *map;
87 	struct swap_map_page_list *next;
88 };
89 
90 /**
91  *	The swap_map_handle structure is used for handling swap in
92  *	a file-alike way
93  */
94 
95 struct swap_map_handle {
96 	struct swap_map_page *cur;
97 	struct swap_map_page_list *maps;
98 	sector_t cur_swap;
99 	sector_t first_sector;
100 	unsigned int k;
101 	unsigned long reqd_free_pages;
102 	u32 crc32;
103 };
104 
105 struct swsusp_header {
106 	char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int) -
107 	              sizeof(u32)];
108 	u32	crc32;
109 	sector_t image;
110 	unsigned int flags;	/* Flags to pass to the "boot" kernel */
111 	char	orig_sig[10];
112 	char	sig[10];
113 } __packed;
114 
115 static struct swsusp_header *swsusp_header;
116 
117 /**
118  *	The following functions are used for tracing the allocated
119  *	swap pages, so that they can be freed in case of an error.
120  */
121 
122 struct swsusp_extent {
123 	struct rb_node node;
124 	unsigned long start;
125 	unsigned long end;
126 };
127 
128 static struct rb_root swsusp_extents = RB_ROOT;
129 
130 static int swsusp_extents_insert(unsigned long swap_offset)
131 {
132 	struct rb_node **new = &(swsusp_extents.rb_node);
133 	struct rb_node *parent = NULL;
134 	struct swsusp_extent *ext;
135 
136 	/* Figure out where to put the new node */
137 	while (*new) {
138 		ext = rb_entry(*new, struct swsusp_extent, node);
139 		parent = *new;
140 		if (swap_offset < ext->start) {
141 			/* Try to merge */
142 			if (swap_offset == ext->start - 1) {
143 				ext->start--;
144 				return 0;
145 			}
146 			new = &((*new)->rb_left);
147 		} else if (swap_offset > ext->end) {
148 			/* Try to merge */
149 			if (swap_offset == ext->end + 1) {
150 				ext->end++;
151 				return 0;
152 			}
153 			new = &((*new)->rb_right);
154 		} else {
155 			/* It already is in the tree */
156 			return -EINVAL;
157 		}
158 	}
159 	/* Add the new node and rebalance the tree. */
160 	ext = kzalloc(sizeof(struct swsusp_extent), GFP_KERNEL);
161 	if (!ext)
162 		return -ENOMEM;
163 
164 	ext->start = swap_offset;
165 	ext->end = swap_offset;
166 	rb_link_node(&ext->node, parent, new);
167 	rb_insert_color(&ext->node, &swsusp_extents);
168 	return 0;
169 }
170 
171 /**
172  *	alloc_swapdev_block - allocate a swap page and register that it has
173  *	been allocated, so that it can be freed in case of an error.
174  */
175 
176 sector_t alloc_swapdev_block(int swap)
177 {
178 	unsigned long offset;
179 
180 	offset = swp_offset(get_swap_page_of_type(swap));
181 	if (offset) {
182 		if (swsusp_extents_insert(offset))
183 			swap_free(swp_entry(swap, offset));
184 		else
185 			return swapdev_block(swap, offset);
186 	}
187 	return 0;
188 }
189 
190 /**
191  *	free_all_swap_pages - free swap pages allocated for saving image data.
192  *	It also frees the extents used to register which swap entries had been
193  *	allocated.
194  */
195 
196 void free_all_swap_pages(int swap)
197 {
198 	struct rb_node *node;
199 
200 	while ((node = swsusp_extents.rb_node)) {
201 		struct swsusp_extent *ext;
202 		unsigned long offset;
203 
204 		ext = rb_entry(node, struct swsusp_extent, node);
205 		rb_erase(node, &swsusp_extents);
206 		for (offset = ext->start; offset <= ext->end; offset++)
207 			swap_free(swp_entry(swap, offset));
208 
209 		kfree(ext);
210 	}
211 }
212 
213 int swsusp_swap_in_use(void)
214 {
215 	return (swsusp_extents.rb_node != NULL);
216 }
217 
218 /*
219  * General things
220  */
221 
222 static unsigned short root_swap = 0xffff;
223 static struct block_device *hib_resume_bdev;
224 
225 struct hib_bio_batch {
226 	atomic_t		count;
227 	wait_queue_head_t	wait;
228 	int			error;
229 };
230 
231 static void hib_init_batch(struct hib_bio_batch *hb)
232 {
233 	atomic_set(&hb->count, 0);
234 	init_waitqueue_head(&hb->wait);
235 	hb->error = 0;
236 }
237 
238 static void hib_end_io(struct bio *bio)
239 {
240 	struct hib_bio_batch *hb = bio->bi_private;
241 	struct page *page = bio->bi_io_vec[0].bv_page;
242 
243 	if (bio->bi_error) {
244 		printk(KERN_ALERT "Read-error on swap-device (%u:%u:%Lu)\n",
245 				imajor(bio->bi_bdev->bd_inode),
246 				iminor(bio->bi_bdev->bd_inode),
247 				(unsigned long long)bio->bi_iter.bi_sector);
248 	}
249 
250 	if (bio_data_dir(bio) == WRITE)
251 		put_page(page);
252 	else if (clean_pages_on_read)
253 		flush_icache_range((unsigned long)page_address(page),
254 				   (unsigned long)page_address(page) + PAGE_SIZE);
255 
256 	if (bio->bi_error && !hb->error)
257 		hb->error = bio->bi_error;
258 	if (atomic_dec_and_test(&hb->count))
259 		wake_up(&hb->wait);
260 
261 	bio_put(bio);
262 }
263 
264 static int hib_submit_io(int op, int op_flags, pgoff_t page_off, void *addr,
265 		struct hib_bio_batch *hb)
266 {
267 	struct page *page = virt_to_page(addr);
268 	struct bio *bio;
269 	int error = 0;
270 
271 	bio = bio_alloc(__GFP_RECLAIM | __GFP_HIGH, 1);
272 	bio->bi_iter.bi_sector = page_off * (PAGE_SIZE >> 9);
273 	bio->bi_bdev = hib_resume_bdev;
274 	bio_set_op_attrs(bio, op, op_flags);
275 
276 	if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
277 		printk(KERN_ERR "PM: Adding page to bio failed at %llu\n",
278 			(unsigned long long)bio->bi_iter.bi_sector);
279 		bio_put(bio);
280 		return -EFAULT;
281 	}
282 
283 	if (hb) {
284 		bio->bi_end_io = hib_end_io;
285 		bio->bi_private = hb;
286 		atomic_inc(&hb->count);
287 		submit_bio(bio);
288 	} else {
289 		error = submit_bio_wait(bio);
290 		bio_put(bio);
291 	}
292 
293 	return error;
294 }
295 
296 static int hib_wait_io(struct hib_bio_batch *hb)
297 {
298 	wait_event(hb->wait, atomic_read(&hb->count) == 0);
299 	return hb->error;
300 }
301 
302 /*
303  * Saving part
304  */
305 
306 static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags)
307 {
308 	int error;
309 
310 	hib_submit_io(REQ_OP_READ, 0, swsusp_resume_block,
311 		      swsusp_header, NULL);
312 	if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
313 	    !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
314 		memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
315 		memcpy(swsusp_header->sig, HIBERNATE_SIG, 10);
316 		swsusp_header->image = handle->first_sector;
317 		swsusp_header->flags = flags;
318 		if (flags & SF_CRC32_MODE)
319 			swsusp_header->crc32 = handle->crc32;
320 		error = hib_submit_io(REQ_OP_WRITE, REQ_SYNC,
321 				      swsusp_resume_block, swsusp_header, NULL);
322 	} else {
323 		printk(KERN_ERR "PM: Swap header not found!\n");
324 		error = -ENODEV;
325 	}
326 	return error;
327 }
328 
329 /**
330  *	swsusp_swap_check - check if the resume device is a swap device
331  *	and get its index (if so)
332  *
333  *	This is called before saving image
334  */
335 static int swsusp_swap_check(void)
336 {
337 	int res;
338 
339 	res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
340 			&hib_resume_bdev);
341 	if (res < 0)
342 		return res;
343 
344 	root_swap = res;
345 	res = blkdev_get(hib_resume_bdev, FMODE_WRITE, NULL);
346 	if (res)
347 		return res;
348 
349 	res = set_blocksize(hib_resume_bdev, PAGE_SIZE);
350 	if (res < 0)
351 		blkdev_put(hib_resume_bdev, FMODE_WRITE);
352 
353 	/*
354 	 * Update the resume device to the one actually used,
355 	 * so the test_resume mode can use it in case it is
356 	 * invoked from hibernate() to test the snapshot.
357 	 */
358 	swsusp_resume_device = hib_resume_bdev->bd_dev;
359 	return res;
360 }
361 
362 /**
363  *	write_page - Write one page to given swap location.
364  *	@buf:		Address we're writing.
365  *	@offset:	Offset of the swap page we're writing to.
366  *	@hb:		bio completion batch
367  */
368 
369 static int write_page(void *buf, sector_t offset, struct hib_bio_batch *hb)
370 {
371 	void *src;
372 	int ret;
373 
374 	if (!offset)
375 		return -ENOSPC;
376 
377 	if (hb) {
378 		src = (void *)__get_free_page(__GFP_RECLAIM | __GFP_NOWARN |
379 		                              __GFP_NORETRY);
380 		if (src) {
381 			copy_page(src, buf);
382 		} else {
383 			ret = hib_wait_io(hb); /* Free pages */
384 			if (ret)
385 				return ret;
386 			src = (void *)__get_free_page(__GFP_RECLAIM |
387 			                              __GFP_NOWARN |
388 			                              __GFP_NORETRY);
389 			if (src) {
390 				copy_page(src, buf);
391 			} else {
392 				WARN_ON_ONCE(1);
393 				hb = NULL;	/* Go synchronous */
394 				src = buf;
395 			}
396 		}
397 	} else {
398 		src = buf;
399 	}
400 	return hib_submit_io(REQ_OP_WRITE, REQ_SYNC, offset, src, hb);
401 }
402 
403 static void release_swap_writer(struct swap_map_handle *handle)
404 {
405 	if (handle->cur)
406 		free_page((unsigned long)handle->cur);
407 	handle->cur = NULL;
408 }
409 
410 static int get_swap_writer(struct swap_map_handle *handle)
411 {
412 	int ret;
413 
414 	ret = swsusp_swap_check();
415 	if (ret) {
416 		if (ret != -ENOSPC)
417 			printk(KERN_ERR "PM: Cannot find swap device, try "
418 					"swapon -a.\n");
419 		return ret;
420 	}
421 	handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
422 	if (!handle->cur) {
423 		ret = -ENOMEM;
424 		goto err_close;
425 	}
426 	handle->cur_swap = alloc_swapdev_block(root_swap);
427 	if (!handle->cur_swap) {
428 		ret = -ENOSPC;
429 		goto err_rel;
430 	}
431 	handle->k = 0;
432 	handle->reqd_free_pages = reqd_free_pages();
433 	handle->first_sector = handle->cur_swap;
434 	return 0;
435 err_rel:
436 	release_swap_writer(handle);
437 err_close:
438 	swsusp_close(FMODE_WRITE);
439 	return ret;
440 }
441 
442 static int swap_write_page(struct swap_map_handle *handle, void *buf,
443 		struct hib_bio_batch *hb)
444 {
445 	int error = 0;
446 	sector_t offset;
447 
448 	if (!handle->cur)
449 		return -EINVAL;
450 	offset = alloc_swapdev_block(root_swap);
451 	error = write_page(buf, offset, hb);
452 	if (error)
453 		return error;
454 	handle->cur->entries[handle->k++] = offset;
455 	if (handle->k >= MAP_PAGE_ENTRIES) {
456 		offset = alloc_swapdev_block(root_swap);
457 		if (!offset)
458 			return -ENOSPC;
459 		handle->cur->next_swap = offset;
460 		error = write_page(handle->cur, handle->cur_swap, hb);
461 		if (error)
462 			goto out;
463 		clear_page(handle->cur);
464 		handle->cur_swap = offset;
465 		handle->k = 0;
466 
467 		if (hb && low_free_pages() <= handle->reqd_free_pages) {
468 			error = hib_wait_io(hb);
469 			if (error)
470 				goto out;
471 			/*
472 			 * Recalculate the number of required free pages, to
473 			 * make sure we never take more than half.
474 			 */
475 			handle->reqd_free_pages = reqd_free_pages();
476 		}
477 	}
478  out:
479 	return error;
480 }
481 
482 static int flush_swap_writer(struct swap_map_handle *handle)
483 {
484 	if (handle->cur && handle->cur_swap)
485 		return write_page(handle->cur, handle->cur_swap, NULL);
486 	else
487 		return -EINVAL;
488 }
489 
490 static int swap_writer_finish(struct swap_map_handle *handle,
491 		unsigned int flags, int error)
492 {
493 	if (!error) {
494 		flush_swap_writer(handle);
495 		printk(KERN_INFO "PM: S");
496 		error = mark_swapfiles(handle, flags);
497 		printk("|\n");
498 	}
499 
500 	if (error)
501 		free_all_swap_pages(root_swap);
502 	release_swap_writer(handle);
503 	swsusp_close(FMODE_WRITE);
504 
505 	return error;
506 }
507 
508 /* We need to remember how much compressed data we need to read. */
509 #define LZO_HEADER	sizeof(size_t)
510 
511 /* Number of pages/bytes we'll compress at one time. */
512 #define LZO_UNC_PAGES	32
513 #define LZO_UNC_SIZE	(LZO_UNC_PAGES * PAGE_SIZE)
514 
515 /* Number of pages/bytes we need for compressed data (worst case). */
516 #define LZO_CMP_PAGES	DIV_ROUND_UP(lzo1x_worst_compress(LZO_UNC_SIZE) + \
517 			             LZO_HEADER, PAGE_SIZE)
518 #define LZO_CMP_SIZE	(LZO_CMP_PAGES * PAGE_SIZE)
519 
520 /* Maximum number of threads for compression/decompression. */
521 #define LZO_THREADS	3
522 
523 /* Minimum/maximum number of pages for read buffering. */
524 #define LZO_MIN_RD_PAGES	1024
525 #define LZO_MAX_RD_PAGES	8192
526 
527 
528 /**
529  *	save_image - save the suspend image data
530  */
531 
532 static int save_image(struct swap_map_handle *handle,
533                       struct snapshot_handle *snapshot,
534                       unsigned int nr_to_write)
535 {
536 	unsigned int m;
537 	int ret;
538 	int nr_pages;
539 	int err2;
540 	struct hib_bio_batch hb;
541 	ktime_t start;
542 	ktime_t stop;
543 
544 	hib_init_batch(&hb);
545 
546 	printk(KERN_INFO "PM: Saving image data pages (%u pages)...\n",
547 		nr_to_write);
548 	m = nr_to_write / 10;
549 	if (!m)
550 		m = 1;
551 	nr_pages = 0;
552 	start = ktime_get();
553 	while (1) {
554 		ret = snapshot_read_next(snapshot);
555 		if (ret <= 0)
556 			break;
557 		ret = swap_write_page(handle, data_of(*snapshot), &hb);
558 		if (ret)
559 			break;
560 		if (!(nr_pages % m))
561 			printk(KERN_INFO "PM: Image saving progress: %3d%%\n",
562 			       nr_pages / m * 10);
563 		nr_pages++;
564 	}
565 	err2 = hib_wait_io(&hb);
566 	stop = ktime_get();
567 	if (!ret)
568 		ret = err2;
569 	if (!ret)
570 		printk(KERN_INFO "PM: Image saving done.\n");
571 	swsusp_show_speed(start, stop, nr_to_write, "Wrote");
572 	return ret;
573 }
574 
575 /**
576  * Structure used for CRC32.
577  */
578 struct crc_data {
579 	struct task_struct *thr;                  /* thread */
580 	atomic_t ready;                           /* ready to start flag */
581 	atomic_t stop;                            /* ready to stop flag */
582 	unsigned run_threads;                     /* nr current threads */
583 	wait_queue_head_t go;                     /* start crc update */
584 	wait_queue_head_t done;                   /* crc update done */
585 	u32 *crc32;                               /* points to handle's crc32 */
586 	size_t *unc_len[LZO_THREADS];             /* uncompressed lengths */
587 	unsigned char *unc[LZO_THREADS];          /* uncompressed data */
588 };
589 
590 /**
591  * CRC32 update function that runs in its own thread.
592  */
593 static int crc32_threadfn(void *data)
594 {
595 	struct crc_data *d = data;
596 	unsigned i;
597 
598 	while (1) {
599 		wait_event(d->go, atomic_read(&d->ready) ||
600 		                  kthread_should_stop());
601 		if (kthread_should_stop()) {
602 			d->thr = NULL;
603 			atomic_set(&d->stop, 1);
604 			wake_up(&d->done);
605 			break;
606 		}
607 		atomic_set(&d->ready, 0);
608 
609 		for (i = 0; i < d->run_threads; i++)
610 			*d->crc32 = crc32_le(*d->crc32,
611 			                     d->unc[i], *d->unc_len[i]);
612 		atomic_set(&d->stop, 1);
613 		wake_up(&d->done);
614 	}
615 	return 0;
616 }
617 /**
618  * Structure used for LZO data compression.
619  */
620 struct cmp_data {
621 	struct task_struct *thr;                  /* thread */
622 	atomic_t ready;                           /* ready to start flag */
623 	atomic_t stop;                            /* ready to stop flag */
624 	int ret;                                  /* return code */
625 	wait_queue_head_t go;                     /* start compression */
626 	wait_queue_head_t done;                   /* compression done */
627 	size_t unc_len;                           /* uncompressed length */
628 	size_t cmp_len;                           /* compressed length */
629 	unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
630 	unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
631 	unsigned char wrk[LZO1X_1_MEM_COMPRESS];  /* compression workspace */
632 };
633 
634 /**
635  * Compression function that runs in its own thread.
636  */
637 static int lzo_compress_threadfn(void *data)
638 {
639 	struct cmp_data *d = data;
640 
641 	while (1) {
642 		wait_event(d->go, atomic_read(&d->ready) ||
643 		                  kthread_should_stop());
644 		if (kthread_should_stop()) {
645 			d->thr = NULL;
646 			d->ret = -1;
647 			atomic_set(&d->stop, 1);
648 			wake_up(&d->done);
649 			break;
650 		}
651 		atomic_set(&d->ready, 0);
652 
653 		d->ret = lzo1x_1_compress(d->unc, d->unc_len,
654 		                          d->cmp + LZO_HEADER, &d->cmp_len,
655 		                          d->wrk);
656 		atomic_set(&d->stop, 1);
657 		wake_up(&d->done);
658 	}
659 	return 0;
660 }
661 
662 /**
663  * save_image_lzo - Save the suspend image data compressed with LZO.
664  * @handle: Swap map handle to use for saving the image.
665  * @snapshot: Image to read data from.
666  * @nr_to_write: Number of pages to save.
667  */
668 static int save_image_lzo(struct swap_map_handle *handle,
669                           struct snapshot_handle *snapshot,
670                           unsigned int nr_to_write)
671 {
672 	unsigned int m;
673 	int ret = 0;
674 	int nr_pages;
675 	int err2;
676 	struct hib_bio_batch hb;
677 	ktime_t start;
678 	ktime_t stop;
679 	size_t off;
680 	unsigned thr, run_threads, nr_threads;
681 	unsigned char *page = NULL;
682 	struct cmp_data *data = NULL;
683 	struct crc_data *crc = NULL;
684 
685 	hib_init_batch(&hb);
686 
687 	/*
688 	 * We'll limit the number of threads for compression to limit memory
689 	 * footprint.
690 	 */
691 	nr_threads = num_online_cpus() - 1;
692 	nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
693 
694 	page = (void *)__get_free_page(__GFP_RECLAIM | __GFP_HIGH);
695 	if (!page) {
696 		printk(KERN_ERR "PM: Failed to allocate LZO page\n");
697 		ret = -ENOMEM;
698 		goto out_clean;
699 	}
700 
701 	data = vmalloc(sizeof(*data) * nr_threads);
702 	if (!data) {
703 		printk(KERN_ERR "PM: Failed to allocate LZO data\n");
704 		ret = -ENOMEM;
705 		goto out_clean;
706 	}
707 	for (thr = 0; thr < nr_threads; thr++)
708 		memset(&data[thr], 0, offsetof(struct cmp_data, go));
709 
710 	crc = kmalloc(sizeof(*crc), GFP_KERNEL);
711 	if (!crc) {
712 		printk(KERN_ERR "PM: Failed to allocate crc\n");
713 		ret = -ENOMEM;
714 		goto out_clean;
715 	}
716 	memset(crc, 0, offsetof(struct crc_data, go));
717 
718 	/*
719 	 * Start the compression threads.
720 	 */
721 	for (thr = 0; thr < nr_threads; thr++) {
722 		init_waitqueue_head(&data[thr].go);
723 		init_waitqueue_head(&data[thr].done);
724 
725 		data[thr].thr = kthread_run(lzo_compress_threadfn,
726 		                            &data[thr],
727 		                            "image_compress/%u", thr);
728 		if (IS_ERR(data[thr].thr)) {
729 			data[thr].thr = NULL;
730 			printk(KERN_ERR
731 			       "PM: Cannot start compression threads\n");
732 			ret = -ENOMEM;
733 			goto out_clean;
734 		}
735 	}
736 
737 	/*
738 	 * Start the CRC32 thread.
739 	 */
740 	init_waitqueue_head(&crc->go);
741 	init_waitqueue_head(&crc->done);
742 
743 	handle->crc32 = 0;
744 	crc->crc32 = &handle->crc32;
745 	for (thr = 0; thr < nr_threads; thr++) {
746 		crc->unc[thr] = data[thr].unc;
747 		crc->unc_len[thr] = &data[thr].unc_len;
748 	}
749 
750 	crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
751 	if (IS_ERR(crc->thr)) {
752 		crc->thr = NULL;
753 		printk(KERN_ERR "PM: Cannot start CRC32 thread\n");
754 		ret = -ENOMEM;
755 		goto out_clean;
756 	}
757 
758 	/*
759 	 * Adjust the number of required free pages after all allocations have
760 	 * been done. We don't want to run out of pages when writing.
761 	 */
762 	handle->reqd_free_pages = reqd_free_pages();
763 
764 	printk(KERN_INFO
765 		"PM: Using %u thread(s) for compression.\n"
766 		"PM: Compressing and saving image data (%u pages)...\n",
767 		nr_threads, nr_to_write);
768 	m = nr_to_write / 10;
769 	if (!m)
770 		m = 1;
771 	nr_pages = 0;
772 	start = ktime_get();
773 	for (;;) {
774 		for (thr = 0; thr < nr_threads; thr++) {
775 			for (off = 0; off < LZO_UNC_SIZE; off += PAGE_SIZE) {
776 				ret = snapshot_read_next(snapshot);
777 				if (ret < 0)
778 					goto out_finish;
779 
780 				if (!ret)
781 					break;
782 
783 				memcpy(data[thr].unc + off,
784 				       data_of(*snapshot), PAGE_SIZE);
785 
786 				if (!(nr_pages % m))
787 					printk(KERN_INFO
788 					       "PM: Image saving progress: "
789 					       "%3d%%\n",
790 				               nr_pages / m * 10);
791 				nr_pages++;
792 			}
793 			if (!off)
794 				break;
795 
796 			data[thr].unc_len = off;
797 
798 			atomic_set(&data[thr].ready, 1);
799 			wake_up(&data[thr].go);
800 		}
801 
802 		if (!thr)
803 			break;
804 
805 		crc->run_threads = thr;
806 		atomic_set(&crc->ready, 1);
807 		wake_up(&crc->go);
808 
809 		for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
810 			wait_event(data[thr].done,
811 			           atomic_read(&data[thr].stop));
812 			atomic_set(&data[thr].stop, 0);
813 
814 			ret = data[thr].ret;
815 
816 			if (ret < 0) {
817 				printk(KERN_ERR "PM: LZO compression failed\n");
818 				goto out_finish;
819 			}
820 
821 			if (unlikely(!data[thr].cmp_len ||
822 			             data[thr].cmp_len >
823 			             lzo1x_worst_compress(data[thr].unc_len))) {
824 				printk(KERN_ERR
825 				       "PM: Invalid LZO compressed length\n");
826 				ret = -1;
827 				goto out_finish;
828 			}
829 
830 			*(size_t *)data[thr].cmp = data[thr].cmp_len;
831 
832 			/*
833 			 * Given we are writing one page at a time to disk, we
834 			 * copy that much from the buffer, although the last
835 			 * bit will likely be smaller than full page. This is
836 			 * OK - we saved the length of the compressed data, so
837 			 * any garbage at the end will be discarded when we
838 			 * read it.
839 			 */
840 			for (off = 0;
841 			     off < LZO_HEADER + data[thr].cmp_len;
842 			     off += PAGE_SIZE) {
843 				memcpy(page, data[thr].cmp + off, PAGE_SIZE);
844 
845 				ret = swap_write_page(handle, page, &hb);
846 				if (ret)
847 					goto out_finish;
848 			}
849 		}
850 
851 		wait_event(crc->done, atomic_read(&crc->stop));
852 		atomic_set(&crc->stop, 0);
853 	}
854 
855 out_finish:
856 	err2 = hib_wait_io(&hb);
857 	stop = ktime_get();
858 	if (!ret)
859 		ret = err2;
860 	if (!ret)
861 		printk(KERN_INFO "PM: Image saving done.\n");
862 	swsusp_show_speed(start, stop, nr_to_write, "Wrote");
863 out_clean:
864 	if (crc) {
865 		if (crc->thr)
866 			kthread_stop(crc->thr);
867 		kfree(crc);
868 	}
869 	if (data) {
870 		for (thr = 0; thr < nr_threads; thr++)
871 			if (data[thr].thr)
872 				kthread_stop(data[thr].thr);
873 		vfree(data);
874 	}
875 	if (page) free_page((unsigned long)page);
876 
877 	return ret;
878 }
879 
880 /**
881  *	enough_swap - Make sure we have enough swap to save the image.
882  *
883  *	Returns TRUE or FALSE after checking the total amount of swap
884  *	space avaiable from the resume partition.
885  */
886 
887 static int enough_swap(unsigned int nr_pages, unsigned int flags)
888 {
889 	unsigned int free_swap = count_swap_pages(root_swap, 1);
890 	unsigned int required;
891 
892 	pr_debug("PM: Free swap pages: %u\n", free_swap);
893 
894 	required = PAGES_FOR_IO + nr_pages;
895 	return free_swap > required;
896 }
897 
898 /**
899  *	swsusp_write - Write entire image and metadata.
900  *	@flags: flags to pass to the "boot" kernel in the image header
901  *
902  *	It is important _NOT_ to umount filesystems at this point. We want
903  *	them synced (in case something goes wrong) but we DO not want to mark
904  *	filesystem clean: it is not. (And it does not matter, if we resume
905  *	correctly, we'll mark system clean, anyway.)
906  */
907 
908 int swsusp_write(unsigned int flags)
909 {
910 	struct swap_map_handle handle;
911 	struct snapshot_handle snapshot;
912 	struct swsusp_info *header;
913 	unsigned long pages;
914 	int error;
915 
916 	pages = snapshot_get_image_size();
917 	error = get_swap_writer(&handle);
918 	if (error) {
919 		printk(KERN_ERR "PM: Cannot get swap writer\n");
920 		return error;
921 	}
922 	if (flags & SF_NOCOMPRESS_MODE) {
923 		if (!enough_swap(pages, flags)) {
924 			printk(KERN_ERR "PM: Not enough free swap\n");
925 			error = -ENOSPC;
926 			goto out_finish;
927 		}
928 	}
929 	memset(&snapshot, 0, sizeof(struct snapshot_handle));
930 	error = snapshot_read_next(&snapshot);
931 	if (error < PAGE_SIZE) {
932 		if (error >= 0)
933 			error = -EFAULT;
934 
935 		goto out_finish;
936 	}
937 	header = (struct swsusp_info *)data_of(snapshot);
938 	error = swap_write_page(&handle, header, NULL);
939 	if (!error) {
940 		error = (flags & SF_NOCOMPRESS_MODE) ?
941 			save_image(&handle, &snapshot, pages - 1) :
942 			save_image_lzo(&handle, &snapshot, pages - 1);
943 	}
944 out_finish:
945 	error = swap_writer_finish(&handle, flags, error);
946 	return error;
947 }
948 
949 /**
950  *	The following functions allow us to read data using a swap map
951  *	in a file-alike way
952  */
953 
954 static void release_swap_reader(struct swap_map_handle *handle)
955 {
956 	struct swap_map_page_list *tmp;
957 
958 	while (handle->maps) {
959 		if (handle->maps->map)
960 			free_page((unsigned long)handle->maps->map);
961 		tmp = handle->maps;
962 		handle->maps = handle->maps->next;
963 		kfree(tmp);
964 	}
965 	handle->cur = NULL;
966 }
967 
968 static int get_swap_reader(struct swap_map_handle *handle,
969 		unsigned int *flags_p)
970 {
971 	int error;
972 	struct swap_map_page_list *tmp, *last;
973 	sector_t offset;
974 
975 	*flags_p = swsusp_header->flags;
976 
977 	if (!swsusp_header->image) /* how can this happen? */
978 		return -EINVAL;
979 
980 	handle->cur = NULL;
981 	last = handle->maps = NULL;
982 	offset = swsusp_header->image;
983 	while (offset) {
984 		tmp = kmalloc(sizeof(*handle->maps), GFP_KERNEL);
985 		if (!tmp) {
986 			release_swap_reader(handle);
987 			return -ENOMEM;
988 		}
989 		memset(tmp, 0, sizeof(*tmp));
990 		if (!handle->maps)
991 			handle->maps = tmp;
992 		if (last)
993 			last->next = tmp;
994 		last = tmp;
995 
996 		tmp->map = (struct swap_map_page *)
997 			   __get_free_page(__GFP_RECLAIM | __GFP_HIGH);
998 		if (!tmp->map) {
999 			release_swap_reader(handle);
1000 			return -ENOMEM;
1001 		}
1002 
1003 		error = hib_submit_io(REQ_OP_READ, 0, offset, tmp->map, NULL);
1004 		if (error) {
1005 			release_swap_reader(handle);
1006 			return error;
1007 		}
1008 		offset = tmp->map->next_swap;
1009 	}
1010 	handle->k = 0;
1011 	handle->cur = handle->maps->map;
1012 	return 0;
1013 }
1014 
1015 static int swap_read_page(struct swap_map_handle *handle, void *buf,
1016 		struct hib_bio_batch *hb)
1017 {
1018 	sector_t offset;
1019 	int error;
1020 	struct swap_map_page_list *tmp;
1021 
1022 	if (!handle->cur)
1023 		return -EINVAL;
1024 	offset = handle->cur->entries[handle->k];
1025 	if (!offset)
1026 		return -EFAULT;
1027 	error = hib_submit_io(REQ_OP_READ, 0, offset, buf, hb);
1028 	if (error)
1029 		return error;
1030 	if (++handle->k >= MAP_PAGE_ENTRIES) {
1031 		handle->k = 0;
1032 		free_page((unsigned long)handle->maps->map);
1033 		tmp = handle->maps;
1034 		handle->maps = handle->maps->next;
1035 		kfree(tmp);
1036 		if (!handle->maps)
1037 			release_swap_reader(handle);
1038 		else
1039 			handle->cur = handle->maps->map;
1040 	}
1041 	return error;
1042 }
1043 
1044 static int swap_reader_finish(struct swap_map_handle *handle)
1045 {
1046 	release_swap_reader(handle);
1047 
1048 	return 0;
1049 }
1050 
1051 /**
1052  *	load_image - load the image using the swap map handle
1053  *	@handle and the snapshot handle @snapshot
1054  *	(assume there are @nr_pages pages to load)
1055  */
1056 
1057 static int load_image(struct swap_map_handle *handle,
1058                       struct snapshot_handle *snapshot,
1059                       unsigned int nr_to_read)
1060 {
1061 	unsigned int m;
1062 	int ret = 0;
1063 	ktime_t start;
1064 	ktime_t stop;
1065 	struct hib_bio_batch hb;
1066 	int err2;
1067 	unsigned nr_pages;
1068 
1069 	hib_init_batch(&hb);
1070 
1071 	clean_pages_on_read = true;
1072 	printk(KERN_INFO "PM: Loading image data pages (%u pages)...\n",
1073 		nr_to_read);
1074 	m = nr_to_read / 10;
1075 	if (!m)
1076 		m = 1;
1077 	nr_pages = 0;
1078 	start = ktime_get();
1079 	for ( ; ; ) {
1080 		ret = snapshot_write_next(snapshot);
1081 		if (ret <= 0)
1082 			break;
1083 		ret = swap_read_page(handle, data_of(*snapshot), &hb);
1084 		if (ret)
1085 			break;
1086 		if (snapshot->sync_read)
1087 			ret = hib_wait_io(&hb);
1088 		if (ret)
1089 			break;
1090 		if (!(nr_pages % m))
1091 			printk(KERN_INFO "PM: Image loading progress: %3d%%\n",
1092 			       nr_pages / m * 10);
1093 		nr_pages++;
1094 	}
1095 	err2 = hib_wait_io(&hb);
1096 	stop = ktime_get();
1097 	if (!ret)
1098 		ret = err2;
1099 	if (!ret) {
1100 		printk(KERN_INFO "PM: Image loading done.\n");
1101 		snapshot_write_finalize(snapshot);
1102 		if (!snapshot_image_loaded(snapshot))
1103 			ret = -ENODATA;
1104 	}
1105 	swsusp_show_speed(start, stop, nr_to_read, "Read");
1106 	return ret;
1107 }
1108 
1109 /**
1110  * Structure used for LZO data decompression.
1111  */
1112 struct dec_data {
1113 	struct task_struct *thr;                  /* thread */
1114 	atomic_t ready;                           /* ready to start flag */
1115 	atomic_t stop;                            /* ready to stop flag */
1116 	int ret;                                  /* return code */
1117 	wait_queue_head_t go;                     /* start decompression */
1118 	wait_queue_head_t done;                   /* decompression done */
1119 	size_t unc_len;                           /* uncompressed length */
1120 	size_t cmp_len;                           /* compressed length */
1121 	unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
1122 	unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
1123 };
1124 
1125 /**
1126  * Deompression function that runs in its own thread.
1127  */
1128 static int lzo_decompress_threadfn(void *data)
1129 {
1130 	struct dec_data *d = data;
1131 
1132 	while (1) {
1133 		wait_event(d->go, atomic_read(&d->ready) ||
1134 		                  kthread_should_stop());
1135 		if (kthread_should_stop()) {
1136 			d->thr = NULL;
1137 			d->ret = -1;
1138 			atomic_set(&d->stop, 1);
1139 			wake_up(&d->done);
1140 			break;
1141 		}
1142 		atomic_set(&d->ready, 0);
1143 
1144 		d->unc_len = LZO_UNC_SIZE;
1145 		d->ret = lzo1x_decompress_safe(d->cmp + LZO_HEADER, d->cmp_len,
1146 		                               d->unc, &d->unc_len);
1147 		if (clean_pages_on_decompress)
1148 			flush_icache_range((unsigned long)d->unc,
1149 					   (unsigned long)d->unc + d->unc_len);
1150 
1151 		atomic_set(&d->stop, 1);
1152 		wake_up(&d->done);
1153 	}
1154 	return 0;
1155 }
1156 
1157 /**
1158  * load_image_lzo - Load compressed image data and decompress them with LZO.
1159  * @handle: Swap map handle to use for loading data.
1160  * @snapshot: Image to copy uncompressed data into.
1161  * @nr_to_read: Number of pages to load.
1162  */
1163 static int load_image_lzo(struct swap_map_handle *handle,
1164                           struct snapshot_handle *snapshot,
1165                           unsigned int nr_to_read)
1166 {
1167 	unsigned int m;
1168 	int ret = 0;
1169 	int eof = 0;
1170 	struct hib_bio_batch hb;
1171 	ktime_t start;
1172 	ktime_t stop;
1173 	unsigned nr_pages;
1174 	size_t off;
1175 	unsigned i, thr, run_threads, nr_threads;
1176 	unsigned ring = 0, pg = 0, ring_size = 0,
1177 	         have = 0, want, need, asked = 0;
1178 	unsigned long read_pages = 0;
1179 	unsigned char **page = NULL;
1180 	struct dec_data *data = NULL;
1181 	struct crc_data *crc = NULL;
1182 
1183 	hib_init_batch(&hb);
1184 
1185 	/*
1186 	 * We'll limit the number of threads for decompression to limit memory
1187 	 * footprint.
1188 	 */
1189 	nr_threads = num_online_cpus() - 1;
1190 	nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
1191 
1192 	page = vmalloc(sizeof(*page) * LZO_MAX_RD_PAGES);
1193 	if (!page) {
1194 		printk(KERN_ERR "PM: Failed to allocate LZO page\n");
1195 		ret = -ENOMEM;
1196 		goto out_clean;
1197 	}
1198 
1199 	data = vmalloc(sizeof(*data) * nr_threads);
1200 	if (!data) {
1201 		printk(KERN_ERR "PM: Failed to allocate LZO data\n");
1202 		ret = -ENOMEM;
1203 		goto out_clean;
1204 	}
1205 	for (thr = 0; thr < nr_threads; thr++)
1206 		memset(&data[thr], 0, offsetof(struct dec_data, go));
1207 
1208 	crc = kmalloc(sizeof(*crc), GFP_KERNEL);
1209 	if (!crc) {
1210 		printk(KERN_ERR "PM: Failed to allocate crc\n");
1211 		ret = -ENOMEM;
1212 		goto out_clean;
1213 	}
1214 	memset(crc, 0, offsetof(struct crc_data, go));
1215 
1216 	clean_pages_on_decompress = true;
1217 
1218 	/*
1219 	 * Start the decompression threads.
1220 	 */
1221 	for (thr = 0; thr < nr_threads; thr++) {
1222 		init_waitqueue_head(&data[thr].go);
1223 		init_waitqueue_head(&data[thr].done);
1224 
1225 		data[thr].thr = kthread_run(lzo_decompress_threadfn,
1226 		                            &data[thr],
1227 		                            "image_decompress/%u", thr);
1228 		if (IS_ERR(data[thr].thr)) {
1229 			data[thr].thr = NULL;
1230 			printk(KERN_ERR
1231 			       "PM: Cannot start decompression threads\n");
1232 			ret = -ENOMEM;
1233 			goto out_clean;
1234 		}
1235 	}
1236 
1237 	/*
1238 	 * Start the CRC32 thread.
1239 	 */
1240 	init_waitqueue_head(&crc->go);
1241 	init_waitqueue_head(&crc->done);
1242 
1243 	handle->crc32 = 0;
1244 	crc->crc32 = &handle->crc32;
1245 	for (thr = 0; thr < nr_threads; thr++) {
1246 		crc->unc[thr] = data[thr].unc;
1247 		crc->unc_len[thr] = &data[thr].unc_len;
1248 	}
1249 
1250 	crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
1251 	if (IS_ERR(crc->thr)) {
1252 		crc->thr = NULL;
1253 		printk(KERN_ERR "PM: Cannot start CRC32 thread\n");
1254 		ret = -ENOMEM;
1255 		goto out_clean;
1256 	}
1257 
1258 	/*
1259 	 * Set the number of pages for read buffering.
1260 	 * This is complete guesswork, because we'll only know the real
1261 	 * picture once prepare_image() is called, which is much later on
1262 	 * during the image load phase. We'll assume the worst case and
1263 	 * say that none of the image pages are from high memory.
1264 	 */
1265 	if (low_free_pages() > snapshot_get_image_size())
1266 		read_pages = (low_free_pages() - snapshot_get_image_size()) / 2;
1267 	read_pages = clamp_val(read_pages, LZO_MIN_RD_PAGES, LZO_MAX_RD_PAGES);
1268 
1269 	for (i = 0; i < read_pages; i++) {
1270 		page[i] = (void *)__get_free_page(i < LZO_CMP_PAGES ?
1271 						  __GFP_RECLAIM | __GFP_HIGH :
1272 						  __GFP_RECLAIM | __GFP_NOWARN |
1273 						  __GFP_NORETRY);
1274 
1275 		if (!page[i]) {
1276 			if (i < LZO_CMP_PAGES) {
1277 				ring_size = i;
1278 				printk(KERN_ERR
1279 				       "PM: Failed to allocate LZO pages\n");
1280 				ret = -ENOMEM;
1281 				goto out_clean;
1282 			} else {
1283 				break;
1284 			}
1285 		}
1286 	}
1287 	want = ring_size = i;
1288 
1289 	printk(KERN_INFO
1290 		"PM: Using %u thread(s) for decompression.\n"
1291 		"PM: Loading and decompressing image data (%u pages)...\n",
1292 		nr_threads, nr_to_read);
1293 	m = nr_to_read / 10;
1294 	if (!m)
1295 		m = 1;
1296 	nr_pages = 0;
1297 	start = ktime_get();
1298 
1299 	ret = snapshot_write_next(snapshot);
1300 	if (ret <= 0)
1301 		goto out_finish;
1302 
1303 	for(;;) {
1304 		for (i = 0; !eof && i < want; i++) {
1305 			ret = swap_read_page(handle, page[ring], &hb);
1306 			if (ret) {
1307 				/*
1308 				 * On real read error, finish. On end of data,
1309 				 * set EOF flag and just exit the read loop.
1310 				 */
1311 				if (handle->cur &&
1312 				    handle->cur->entries[handle->k]) {
1313 					goto out_finish;
1314 				} else {
1315 					eof = 1;
1316 					break;
1317 				}
1318 			}
1319 			if (++ring >= ring_size)
1320 				ring = 0;
1321 		}
1322 		asked += i;
1323 		want -= i;
1324 
1325 		/*
1326 		 * We are out of data, wait for some more.
1327 		 */
1328 		if (!have) {
1329 			if (!asked)
1330 				break;
1331 
1332 			ret = hib_wait_io(&hb);
1333 			if (ret)
1334 				goto out_finish;
1335 			have += asked;
1336 			asked = 0;
1337 			if (eof)
1338 				eof = 2;
1339 		}
1340 
1341 		if (crc->run_threads) {
1342 			wait_event(crc->done, atomic_read(&crc->stop));
1343 			atomic_set(&crc->stop, 0);
1344 			crc->run_threads = 0;
1345 		}
1346 
1347 		for (thr = 0; have && thr < nr_threads; thr++) {
1348 			data[thr].cmp_len = *(size_t *)page[pg];
1349 			if (unlikely(!data[thr].cmp_len ||
1350 			             data[thr].cmp_len >
1351 			             lzo1x_worst_compress(LZO_UNC_SIZE))) {
1352 				printk(KERN_ERR
1353 				       "PM: Invalid LZO compressed length\n");
1354 				ret = -1;
1355 				goto out_finish;
1356 			}
1357 
1358 			need = DIV_ROUND_UP(data[thr].cmp_len + LZO_HEADER,
1359 			                    PAGE_SIZE);
1360 			if (need > have) {
1361 				if (eof > 1) {
1362 					ret = -1;
1363 					goto out_finish;
1364 				}
1365 				break;
1366 			}
1367 
1368 			for (off = 0;
1369 			     off < LZO_HEADER + data[thr].cmp_len;
1370 			     off += PAGE_SIZE) {
1371 				memcpy(data[thr].cmp + off,
1372 				       page[pg], PAGE_SIZE);
1373 				have--;
1374 				want++;
1375 				if (++pg >= ring_size)
1376 					pg = 0;
1377 			}
1378 
1379 			atomic_set(&data[thr].ready, 1);
1380 			wake_up(&data[thr].go);
1381 		}
1382 
1383 		/*
1384 		 * Wait for more data while we are decompressing.
1385 		 */
1386 		if (have < LZO_CMP_PAGES && asked) {
1387 			ret = hib_wait_io(&hb);
1388 			if (ret)
1389 				goto out_finish;
1390 			have += asked;
1391 			asked = 0;
1392 			if (eof)
1393 				eof = 2;
1394 		}
1395 
1396 		for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
1397 			wait_event(data[thr].done,
1398 			           atomic_read(&data[thr].stop));
1399 			atomic_set(&data[thr].stop, 0);
1400 
1401 			ret = data[thr].ret;
1402 
1403 			if (ret < 0) {
1404 				printk(KERN_ERR
1405 				       "PM: LZO decompression failed\n");
1406 				goto out_finish;
1407 			}
1408 
1409 			if (unlikely(!data[thr].unc_len ||
1410 			             data[thr].unc_len > LZO_UNC_SIZE ||
1411 			             data[thr].unc_len & (PAGE_SIZE - 1))) {
1412 				printk(KERN_ERR
1413 				       "PM: Invalid LZO uncompressed length\n");
1414 				ret = -1;
1415 				goto out_finish;
1416 			}
1417 
1418 			for (off = 0;
1419 			     off < data[thr].unc_len; off += PAGE_SIZE) {
1420 				memcpy(data_of(*snapshot),
1421 				       data[thr].unc + off, PAGE_SIZE);
1422 
1423 				if (!(nr_pages % m))
1424 					printk(KERN_INFO
1425 					       "PM: Image loading progress: "
1426 					       "%3d%%\n",
1427 					       nr_pages / m * 10);
1428 				nr_pages++;
1429 
1430 				ret = snapshot_write_next(snapshot);
1431 				if (ret <= 0) {
1432 					crc->run_threads = thr + 1;
1433 					atomic_set(&crc->ready, 1);
1434 					wake_up(&crc->go);
1435 					goto out_finish;
1436 				}
1437 			}
1438 		}
1439 
1440 		crc->run_threads = thr;
1441 		atomic_set(&crc->ready, 1);
1442 		wake_up(&crc->go);
1443 	}
1444 
1445 out_finish:
1446 	if (crc->run_threads) {
1447 		wait_event(crc->done, atomic_read(&crc->stop));
1448 		atomic_set(&crc->stop, 0);
1449 	}
1450 	stop = ktime_get();
1451 	if (!ret) {
1452 		printk(KERN_INFO "PM: Image loading done.\n");
1453 		snapshot_write_finalize(snapshot);
1454 		if (!snapshot_image_loaded(snapshot))
1455 			ret = -ENODATA;
1456 		if (!ret) {
1457 			if (swsusp_header->flags & SF_CRC32_MODE) {
1458 				if(handle->crc32 != swsusp_header->crc32) {
1459 					printk(KERN_ERR
1460 					       "PM: Invalid image CRC32!\n");
1461 					ret = -ENODATA;
1462 				}
1463 			}
1464 		}
1465 	}
1466 	swsusp_show_speed(start, stop, nr_to_read, "Read");
1467 out_clean:
1468 	for (i = 0; i < ring_size; i++)
1469 		free_page((unsigned long)page[i]);
1470 	if (crc) {
1471 		if (crc->thr)
1472 			kthread_stop(crc->thr);
1473 		kfree(crc);
1474 	}
1475 	if (data) {
1476 		for (thr = 0; thr < nr_threads; thr++)
1477 			if (data[thr].thr)
1478 				kthread_stop(data[thr].thr);
1479 		vfree(data);
1480 	}
1481 	vfree(page);
1482 
1483 	return ret;
1484 }
1485 
1486 /**
1487  *	swsusp_read - read the hibernation image.
1488  *	@flags_p: flags passed by the "frozen" kernel in the image header should
1489  *		  be written into this memory location
1490  */
1491 
1492 int swsusp_read(unsigned int *flags_p)
1493 {
1494 	int error;
1495 	struct swap_map_handle handle;
1496 	struct snapshot_handle snapshot;
1497 	struct swsusp_info *header;
1498 
1499 	memset(&snapshot, 0, sizeof(struct snapshot_handle));
1500 	error = snapshot_write_next(&snapshot);
1501 	if (error < PAGE_SIZE)
1502 		return error < 0 ? error : -EFAULT;
1503 	header = (struct swsusp_info *)data_of(snapshot);
1504 	error = get_swap_reader(&handle, flags_p);
1505 	if (error)
1506 		goto end;
1507 	if (!error)
1508 		error = swap_read_page(&handle, header, NULL);
1509 	if (!error) {
1510 		error = (*flags_p & SF_NOCOMPRESS_MODE) ?
1511 			load_image(&handle, &snapshot, header->pages - 1) :
1512 			load_image_lzo(&handle, &snapshot, header->pages - 1);
1513 	}
1514 	swap_reader_finish(&handle);
1515 end:
1516 	if (!error)
1517 		pr_debug("PM: Image successfully loaded\n");
1518 	else
1519 		pr_debug("PM: Error %d resuming\n", error);
1520 	return error;
1521 }
1522 
1523 /**
1524  *      swsusp_check - Check for swsusp signature in the resume device
1525  */
1526 
1527 int swsusp_check(void)
1528 {
1529 	int error;
1530 
1531 	hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device,
1532 					    FMODE_READ, NULL);
1533 	if (!IS_ERR(hib_resume_bdev)) {
1534 		set_blocksize(hib_resume_bdev, PAGE_SIZE);
1535 		clear_page(swsusp_header);
1536 		error = hib_submit_io(REQ_OP_READ, 0,
1537 					swsusp_resume_block,
1538 					swsusp_header, NULL);
1539 		if (error)
1540 			goto put;
1541 
1542 		if (!memcmp(HIBERNATE_SIG, swsusp_header->sig, 10)) {
1543 			memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
1544 			/* Reset swap signature now */
1545 			error = hib_submit_io(REQ_OP_WRITE, REQ_SYNC,
1546 						swsusp_resume_block,
1547 						swsusp_header, NULL);
1548 		} else {
1549 			error = -EINVAL;
1550 		}
1551 
1552 put:
1553 		if (error)
1554 			blkdev_put(hib_resume_bdev, FMODE_READ);
1555 		else
1556 			pr_debug("PM: Image signature found, resuming\n");
1557 	} else {
1558 		error = PTR_ERR(hib_resume_bdev);
1559 	}
1560 
1561 	if (error)
1562 		pr_debug("PM: Image not found (code %d)\n", error);
1563 
1564 	return error;
1565 }
1566 
1567 /**
1568  *	swsusp_close - close swap device.
1569  */
1570 
1571 void swsusp_close(fmode_t mode)
1572 {
1573 	if (IS_ERR(hib_resume_bdev)) {
1574 		pr_debug("PM: Image device not initialised\n");
1575 		return;
1576 	}
1577 
1578 	blkdev_put(hib_resume_bdev, mode);
1579 }
1580 
1581 /**
1582  *      swsusp_unmark - Unmark swsusp signature in the resume device
1583  */
1584 
1585 #ifdef CONFIG_SUSPEND
1586 int swsusp_unmark(void)
1587 {
1588 	int error;
1589 
1590 	hib_submit_io(REQ_OP_READ, 0, swsusp_resume_block,
1591 		      swsusp_header, NULL);
1592 	if (!memcmp(HIBERNATE_SIG,swsusp_header->sig, 10)) {
1593 		memcpy(swsusp_header->sig,swsusp_header->orig_sig, 10);
1594 		error = hib_submit_io(REQ_OP_WRITE, REQ_SYNC,
1595 					swsusp_resume_block,
1596 					swsusp_header, NULL);
1597 	} else {
1598 		printk(KERN_ERR "PM: Cannot find swsusp signature!\n");
1599 		error = -ENODEV;
1600 	}
1601 
1602 	/*
1603 	 * We just returned from suspend, we don't need the image any more.
1604 	 */
1605 	free_all_swap_pages(root_swap);
1606 
1607 	return error;
1608 }
1609 #endif
1610 
1611 static int swsusp_header_init(void)
1612 {
1613 	swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
1614 	if (!swsusp_header)
1615 		panic("Could not allocate memory for swsusp_header\n");
1616 	return 0;
1617 }
1618 
1619 core_initcall(swsusp_header_init);
1620