1	// SPDX-License-Identifier: GPL-2.0-only
2	/*
3	* linux/kernel/power/swap.c
4	*
5	* This file provides functions for reading the suspend image from
6	* and writing it to a swap partition.
7	*
8	* Copyright (C) 1998,2001-2005 Pavel Machek <pavel@ucw.cz>
9	* Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
10	* Copyright (C) 2010-2012 Bojan Smojver <bojan@rexursive.com>
11	*/
12
13	#define pr_fmt(fmt) "PM: " fmt
14
15	#include <linux/module.h>
16	#include <linux/file.h>
17	#include <linux/delay.h>
18	#include <linux/bitops.h>
19	#include <linux/device.h>
20	#include <linux/bio.h>
21	#include <linux/blkdev.h>
22	#include <linux/swap.h>
23	#include <linux/swapops.h>
24	#include <linux/pm.h>
25	#include <linux/slab.h>
26	#include <linux/lzo.h>
27	#include <linux/vmalloc.h>
28	#include <linux/cpumask.h>
29	#include <linux/atomic.h>
30	#include <linux/kthread.h>
31	#include <linux/crc32.h>
32	#include <linux/ktime.h>
33
34	#include "power.h"
35
36	#define HIBERNATE_SIG "S1SUSPEND"
37
38	u32 swsusp_hardware_signature;
39
40	/*
41	* When reading an {un,}compressed image, we may restore pages in place,
42	* in which case some architectures need these pages cleaning before they
43	* can be executed. We don't know which pages these may be, so clean the lot.
44	*/
45	static bool clean_pages_on_read;
46	static bool clean_pages_on_decompress;
47
48	/*
49	* The swap map is a data structure used for keeping track of each page
50	* written to a swap partition. It consists of many swap_map_page
51	* structures that contain each an array of MAP_PAGE_ENTRIES swap entries.
52	* These structures are stored on the swap and linked together with the
53	* help of the .next_swap member.
54	*
55	* The swap map is created during suspend. The swap map pages are
56	* allocated and populated one at a time, so we only need one memory
57	* page to set up the entire structure.
58	*
59	* During resume we pick up all swap_map_page structures into a list.
60	*/
61
62	#define MAP_PAGE_ENTRIES (PAGE_SIZE / sizeof(sector_t) - 1)
63
64	/*
65	* Number of free pages that are not high.
66	*/
67	static inline unsigned long low_free_pages(void)
68	{
69	return nr_free_pages() - nr_free_highpages();
70	}
71
72	/*
73	* Number of pages required to be kept free while writing the image. Always
74	* half of all available low pages before the writing starts.
75	*/
76	static inline unsigned long reqd_free_pages(void)
77	{
78	return low_free_pages() / 2;
79	}
80
81	struct swap_map_page {
82	sector_t entries[MAP_PAGE_ENTRIES];
83	sector_t next_swap;
84	};
85
86	struct swap_map_page_list {
87	struct swap_map_page *map;
88	struct swap_map_page_list *next;
89	};
90
91	/*
92	* The swap_map_handle structure is used for handling swap in
93	* a file-alike way
94	*/
95
96	struct swap_map_handle {
97	struct swap_map_page *cur;
98	struct swap_map_page_list *maps;
99	sector_t cur_swap;
100	sector_t first_sector;
101	unsigned int k;
102	unsigned long reqd_free_pages;
103	u32 crc32;
104	};
105
106	struct swsusp_header {
107	char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int) -
108	sizeof(u32) - sizeof(u32)];
109	u32 hw_sig;
110	u32 crc32;
111	sector_t image;
112	unsigned int flags; /* Flags to pass to the "boot" kernel */
113	char orig_sig[10];
114	char sig[10];
115	} __packed;
116
117	static struct swsusp_header *swsusp_header;
118
119	/*
120	* The following functions are used for tracing the allocated
121	* swap pages, so that they can be freed in case of an error.
122	*/
123
124	struct swsusp_extent {
125	struct rb_node node;
126	unsigned long start;
127	unsigned long end;
128	};
129
130	static struct rb_root swsusp_extents = RB_ROOT;
131
132	static int swsusp_extents_insert(unsigned long swap_offset)
133	{
134	struct rb_node **new = &(swsusp_extents.rb_node);
135	struct rb_node *parent = NULL;
136	struct swsusp_extent *ext;
137
138	/* Figure out where to put the new node */
139	while (*new) {
140	ext = rb_entry(*new, struct swsusp_extent, node);
141	parent = *new;
142	if (swap_offset < ext->start) {
143	/* Try to merge */
144	if (swap_offset == ext->start - 1) {
145	ext->start--;
146	return 0;
147	}
148	new = &((*new)->rb_left);
149	} else if (swap_offset > ext->end) {
150	/* Try to merge */
151	if (swap_offset == ext->end + 1) {
152	ext->end++;
153	return 0;
154	}
155	new = &((*new)->rb_right);
156	} else {
157	/* It already is in the tree */
158	return -EINVAL;
159	}
160	}
161	/* Add the new node and rebalance the tree. */
162	ext = kzalloc(size: sizeof(struct swsusp_extent), GFP_KERNEL);
163	if (!ext)
164	return -ENOMEM;
165
166	ext->start = swap_offset;
167	ext->end = swap_offset;
168	rb_link_node(node: &ext->node, parent, rb_link: new);
169	rb_insert_color(&ext->node, &swsusp_extents);
170	return 0;
171	}
172
173	/*
174	* alloc_swapdev_block - allocate a swap page and register that it has
175	* been allocated, so that it can be freed in case of an error.
176	*/
177
178	sector_t alloc_swapdev_block(int swap)
179	{
180	unsigned long offset;
181
182	offset = swp_offset(entry: get_swap_page_of_type(swap));
183	if (offset) {
184	if (swsusp_extents_insert(swap_offset: offset))
185	swap_free(swp_entry(type: swap, offset));
186	else
187	return swapdev_block(swap, offset);
188	}
189	return 0;
190	}
191
192	/*
193	* free_all_swap_pages - free swap pages allocated for saving image data.
194	* It also frees the extents used to register which swap entries had been
195	* allocated.
196	*/
197
198	void free_all_swap_pages(int swap)
199	{
200	struct rb_node *node;
201
202	while ((node = swsusp_extents.rb_node)) {
203	struct swsusp_extent *ext;
204	unsigned long offset;
205
206	ext = rb_entry(node, struct swsusp_extent, node);
207	rb_erase(node, &swsusp_extents);
208	for (offset = ext->start; offset <= ext->end; offset++)
209	swap_free(swp_entry(type: swap, offset));
210
211	kfree(objp: ext);
212	}
213	}
214
215	int swsusp_swap_in_use(void)
216	{
217	return (swsusp_extents.rb_node != NULL);
218	}
219
220	/*
221	* General things
222	*/
223
224	static unsigned short root_swap = 0xffff;
225	static struct bdev_handle *hib_resume_bdev_handle;
226
227	struct hib_bio_batch {
228	atomic_t count;
229	wait_queue_head_t wait;
230	blk_status_t error;
231	struct blk_plug plug;
232	};
233
234	static void hib_init_batch(struct hib_bio_batch *hb)
235	{
236	atomic_set(v: &hb->count, i: 0);
237	init_waitqueue_head(&hb->wait);
238	hb->error = BLK_STS_OK;
239	blk_start_plug(&hb->plug);
240	}
241
242	static void hib_finish_batch(struct hib_bio_batch *hb)
243	{
244	blk_finish_plug(&hb->plug);
245	}
246
247	static void hib_end_io(struct bio *bio)
248	{
249	struct hib_bio_batch *hb = bio->bi_private;
250	struct page *page = bio_first_page_all(bio);
251
252	if (bio->bi_status) {
253	pr_alert("Read-error on swap-device (%u:%u:%Lu)\n",
254	MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)),
255	(unsigned long long)bio->bi_iter.bi_sector);
256	}
257
258	if (bio_data_dir(bio) == WRITE)
259	put_page(page);
260	else if (clean_pages_on_read)
261	flush_icache_range(start: (unsigned long)page_address(page),
262	end: (unsigned long)page_address(page) + PAGE_SIZE);
263
264	if (bio->bi_status && !hb->error)
265	hb->error = bio->bi_status;
266	if (atomic_dec_and_test(v: &hb->count))
267	wake_up(&hb->wait);
268
269	bio_put(bio);
270	}
271
272	static int hib_submit_io(blk_opf_t opf, pgoff_t page_off, void *addr,
273	struct hib_bio_batch *hb)
274	{
275	struct page *page = virt_to_page(addr);
276	struct bio *bio;
277	int error = 0;
278
279	bio = bio_alloc(bdev: hib_resume_bdev_handle->bdev, nr_vecs: 1, opf,
280	GFP_NOIO | __GFP_HIGH);
281	bio->bi_iter.bi_sector = page_off * (PAGE_SIZE >> 9);
282
283	if (bio_add_page(bio, page, PAGE_SIZE, off: 0) < PAGE_SIZE) {
284	pr_err("Adding page to bio failed at %llu\n",
285	(unsigned long long)bio->bi_iter.bi_sector);
286	bio_put(bio);
287	return -EFAULT;
288	}
289
290	if (hb) {
291	bio->bi_end_io = hib_end_io;
292	bio->bi_private = hb;
293	atomic_inc(v: &hb->count);
294	submit_bio(bio);
295	} else {
296	error = submit_bio_wait(bio);
297	bio_put(bio);
298	}
299
300	return error;
301	}
302
303	static int hib_wait_io(struct hib_bio_batch *hb)
304	{
305	/*
306	* We are relying on the behavior of blk_plug that a thread with
307	* a plug will flush the plug list before sleeping.
308	*/
309	wait_event(hb->wait, atomic_read(&hb->count) == 0);
310	return blk_status_to_errno(status: hb->error);
311	}
312
313	/*
314	* Saving part
315	*/
316	static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags)
317	{
318	int error;
319
320	hib_submit_io(opf: REQ_OP_READ, page_off: swsusp_resume_block, addr: swsusp_header, NULL);
321	if (!memcmp(p: "SWAP-SPACE",q: swsusp_header->sig, size: 10) ||
322	!memcmp(p: "SWAPSPACE2",q: swsusp_header->sig, size: 10)) {
323	memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
324	memcpy(swsusp_header->sig, HIBERNATE_SIG, 10);
325	swsusp_header->image = handle->first_sector;
326	if (swsusp_hardware_signature) {
327	swsusp_header->hw_sig = swsusp_hardware_signature;
328	flags |= SF_HW_SIG;
329	}
330	swsusp_header->flags = flags;
331	if (flags & SF_CRC32_MODE)
332	swsusp_header->crc32 = handle->crc32;
333	error = hib_submit_io(opf: REQ_OP_WRITE | REQ_SYNC,
334	page_off: swsusp_resume_block, addr: swsusp_header, NULL);
335	} else {
336	pr_err("Swap header not found!\n");
337	error = -ENODEV;
338	}
339	return error;
340	}
341
342	/**
343	* swsusp_swap_check - check if the resume device is a swap device
344	* and get its index (if so)
345	*
346	* This is called before saving image
347	*/
348	static int swsusp_swap_check(void)
349	{
350	int res;
351
352	if (swsusp_resume_device)
353	res = swap_type_of(device: swsusp_resume_device, offset: swsusp_resume_block);
354	else
355	res = find_first_swap(device: &swsusp_resume_device);
356	if (res < 0)
357	return res;
358	root_swap = res;
359
360	hib_resume_bdev_handle = bdev_open_by_dev(dev: swsusp_resume_device,
361	BLK_OPEN_WRITE, NULL, NULL);
362	if (IS_ERR(ptr: hib_resume_bdev_handle))
363	return PTR_ERR(ptr: hib_resume_bdev_handle);
364
365	res = set_blocksize(bdev: hib_resume_bdev_handle->bdev, PAGE_SIZE);
366	if (res < 0)
367	bdev_release(handle: hib_resume_bdev_handle);
368
369	return res;
370	}
371
372	/**
373	* write_page - Write one page to given swap location.
374	* @buf: Address we're writing.
375	* @offset: Offset of the swap page we're writing to.
376	* @hb: bio completion batch
377	*/
378
379	static int write_page(void *buf, sector_t offset, struct hib_bio_batch *hb)
380	{
381	void *src;
382	int ret;
383
384	if (!offset)
385	return -ENOSPC;
386
387	if (hb) {
388	src = (void *)__get_free_page(GFP_NOIO | __GFP_NOWARN |
389	__GFP_NORETRY);
390	if (src) {
391	copy_page(to: src, from: buf);
392	} else {
393	ret = hib_wait_io(hb); /* Free pages */
394	if (ret)
395	return ret;
396	src = (void *)__get_free_page(GFP_NOIO |
397	__GFP_NOWARN |
398	__GFP_NORETRY);
399	if (src) {
400	copy_page(to: src, from: buf);
401	} else {
402	WARN_ON_ONCE(1);
403	hb = NULL; /* Go synchronous */
404	src = buf;
405	}
406	}
407	} else {
408	src = buf;
409	}
410	return hib_submit_io(opf: REQ_OP_WRITE | REQ_SYNC, page_off: offset, addr: src, hb);
411	}
412
413	static void release_swap_writer(struct swap_map_handle *handle)
414	{
415	if (handle->cur)
416	free_page((unsigned long)handle->cur);
417	handle->cur = NULL;
418	}
419
420	static int get_swap_writer(struct swap_map_handle *handle)
421	{
422	int ret;
423
424	ret = swsusp_swap_check();
425	if (ret) {
426	if (ret != -ENOSPC)
427	pr_err("Cannot find swap device, try swapon -a\n");
428	return ret;
429	}
430	handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
431	if (!handle->cur) {
432	ret = -ENOMEM;
433	goto err_close;
434	}
435	handle->cur_swap = alloc_swapdev_block(swap: root_swap);
436	if (!handle->cur_swap) {
437	ret = -ENOSPC;
438	goto err_rel;
439	}
440	handle->k = 0;
441	handle->reqd_free_pages = reqd_free_pages();
442	handle->first_sector = handle->cur_swap;
443	return 0;
444	err_rel:
445	release_swap_writer(handle);
446	err_close:
447	swsusp_close();
448	return ret;
449	}
450
451	static int swap_write_page(struct swap_map_handle *handle, void *buf,
452	struct hib_bio_batch *hb)
453	{
454	int error = 0;
455	sector_t offset;
456
457	if (!handle->cur)
458	return -EINVAL;
459	offset = alloc_swapdev_block(swap: root_swap);
460	error = write_page(buf, offset, hb);
461	if (error)
462	return error;
463	handle->cur->entries[handle->k++] = offset;
464	if (handle->k >= MAP_PAGE_ENTRIES) {
465	offset = alloc_swapdev_block(swap: root_swap);
466	if (!offset)
467	return -ENOSPC;
468	handle->cur->next_swap = offset;
469	error = write_page(buf: handle->cur, offset: handle->cur_swap, hb);
470	if (error)
471	goto out;
472	clear_page(page: handle->cur);
473	handle->cur_swap = offset;
474	handle->k = 0;
475
476	if (hb && low_free_pages() <= handle->reqd_free_pages) {
477	error = hib_wait_io(hb);
478	if (error)
479	goto out;
480	/*
481	* Recalculate the number of required free pages, to
482	* make sure we never take more than half.
483	*/
484	handle->reqd_free_pages = reqd_free_pages();
485	}
486	}
487	out:
488	return error;
489	}
490
491	static int flush_swap_writer(struct swap_map_handle *handle)
492	{
493	if (handle->cur && handle->cur_swap)
494	return write_page(buf: handle->cur, offset: handle->cur_swap, NULL);
495	else
496	return -EINVAL;
497	}
498
499	static int swap_writer_finish(struct swap_map_handle *handle,
500	unsigned int flags, int error)
501	{
502	if (!error) {
503	pr_info("S");
504	error = mark_swapfiles(handle, flags);
505	pr_cont("|\n");
506	flush_swap_writer(handle);
507	}
508
509	if (error)
510	free_all_swap_pages(swap: root_swap);
511	release_swap_writer(handle);
512	swsusp_close();
513
514	return error;
515	}
516
517	/* We need to remember how much compressed data we need to read. */
518	#define LZO_HEADER sizeof(size_t)
519
520	/* Number of pages/bytes we'll compress at one time. */
521	#define LZO_UNC_PAGES 32
522	#define LZO_UNC_SIZE (LZO_UNC_PAGES * PAGE_SIZE)
523
524	/* Number of pages/bytes we need for compressed data (worst case). */
525	#define LZO_CMP_PAGES DIV_ROUND_UP(lzo1x_worst_compress(LZO_UNC_SIZE) + \
526	LZO_HEADER, PAGE_SIZE)
527	#define LZO_CMP_SIZE (LZO_CMP_PAGES * PAGE_SIZE)
528
529	/* Maximum number of threads for compression/decompression. */
530	#define LZO_THREADS 3
531
532	/* Minimum/maximum number of pages for read buffering. */
533	#define LZO_MIN_RD_PAGES 1024
534	#define LZO_MAX_RD_PAGES 8192
535
536
537	/**
538	* save_image - save the suspend image data
539	*/
540
541	static int save_image(struct swap_map_handle *handle,
542	struct snapshot_handle *snapshot,
543	unsigned int nr_to_write)
544	{
545	unsigned int m;
546	int ret;
547	int nr_pages;
548	int err2;
549	struct hib_bio_batch hb;
550	ktime_t start;
551	ktime_t stop;
552
553	hib_init_batch(hb: &hb);
554
555	pr_info("Saving image data pages (%u pages)...\n",
556	nr_to_write);
557	m = nr_to_write / 10;
558	if (!m)
559	m = 1;
560	nr_pages = 0;
561	start = ktime_get();
562	while (1) {
563	ret = snapshot_read_next(handle: snapshot);
564	if (ret <= 0)
565	break;
566	ret = swap_write_page(handle, data_of(*snapshot), hb: &hb);
567	if (ret)
568	break;
569	if (!(nr_pages % m))
570	pr_info("Image saving progress: %3d%%\n",
571	nr_pages / m * 10);
572	nr_pages++;
573	}
574	err2 = hib_wait_io(hb: &hb);
575	hib_finish_batch(hb: &hb);
576	stop = ktime_get();
577	if (!ret)
578	ret = err2;
579	if (!ret)
580	pr_info("Image saving done\n");
581	swsusp_show_speed(start, stop, nr_to_write, "Wrote");
582	return ret;
583	}
584
585	/*
586	* Structure used for CRC32.
587	*/
588	struct crc_data {
589	struct task_struct *thr; /* thread */
590	atomic_t ready; /* ready to start flag */
591	atomic_t stop; /* ready to stop flag */
592	unsigned run_threads; /* nr current threads */
593	wait_queue_head_t go; /* start crc update */
594	wait_queue_head_t done; /* crc update done */
595	u32 *crc32; /* points to handle's crc32 */
596	size_t *unc_len[LZO_THREADS]; /* uncompressed lengths */
597	unsigned char *unc[LZO_THREADS]; /* uncompressed data */
598	};
599
600	/*
601	* CRC32 update function that runs in its own thread.
602	*/
603	static int crc32_threadfn(void *data)
604	{
605	struct crc_data *d = data;
606	unsigned i;
607
608	while (1) {
609	wait_event(d->go, atomic_read(&d->ready) ||
610	kthread_should_stop());
611	if (kthread_should_stop()) {
612	d->thr = NULL;
613	atomic_set(v: &d->stop, i: 1);
614	wake_up(&d->done);
615	break;
616	}
617	atomic_set(v: &d->ready, i: 0);
618
619	for (i = 0; i < d->run_threads; i++)
620	*d->crc32 = crc32_le(crc: *d->crc32,
621	p: d->unc[i], len: *d->unc_len[i]);
622	atomic_set(v: &d->stop, i: 1);
623	wake_up(&d->done);
624	}
625	return 0;
626	}
627	/*
628	* Structure used for LZO data compression.
629	*/
630	struct cmp_data {
631	struct task_struct *thr; /* thread */
632	atomic_t ready; /* ready to start flag */
633	atomic_t stop; /* ready to stop flag */
634	int ret; /* return code */
635	wait_queue_head_t go; /* start compression */
636	wait_queue_head_t done; /* compression done */
637	size_t unc_len; /* uncompressed length */
638	size_t cmp_len; /* compressed length */
639	unsigned char unc[LZO_UNC_SIZE]; /* uncompressed buffer */
640	unsigned char cmp[LZO_CMP_SIZE]; /* compressed buffer */
641	unsigned char wrk[LZO1X_1_MEM_COMPRESS]; /* compression workspace */
642	};
643
644	/*
645	* Compression function that runs in its own thread.
646	*/
647	static int lzo_compress_threadfn(void *data)
648	{
649	struct cmp_data *d = data;
650
651	while (1) {
652	wait_event(d->go, atomic_read(&d->ready) ||
653	kthread_should_stop());
654	if (kthread_should_stop()) {
655	d->thr = NULL;
656	d->ret = -1;
657	atomic_set(v: &d->stop, i: 1);
658	wake_up(&d->done);
659	break;
660	}
661	atomic_set(v: &d->ready, i: 0);
662
663	d->ret = lzo1x_1_compress(src: d->unc, src_len: d->unc_len,
664	dst: d->cmp + LZO_HEADER, dst_len: &d->cmp_len,
665	wrkmem: d->wrk);
666	atomic_set(v: &d->stop, i: 1);
667	wake_up(&d->done);
668	}
669	return 0;
670	}
671
672	/**
673	* save_image_lzo - Save the suspend image data compressed with LZO.
674	* @handle: Swap map handle to use for saving the image.
675	* @snapshot: Image to read data from.
676	* @nr_to_write: Number of pages to save.
677	*/
678	static int save_image_lzo(struct swap_map_handle *handle,
679	struct snapshot_handle *snapshot,
680	unsigned int nr_to_write)
681	{
682	unsigned int m;
683	int ret = 0;
684	int nr_pages;
685	int err2;
686	struct hib_bio_batch hb;
687	ktime_t start;
688	ktime_t stop;
689	size_t off;
690	unsigned thr, run_threads, nr_threads;
691	unsigned char *page = NULL;
692	struct cmp_data *data = NULL;
693	struct crc_data *crc = NULL;
694
695	hib_init_batch(hb: &hb);
696
697	/*
698	* We'll limit the number of threads for compression to limit memory
699	* footprint.
700	*/
701	nr_threads = num_online_cpus() - 1;
702	nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
703
704	page = (void *)__get_free_page(GFP_NOIO | __GFP_HIGH);
705	if (!page) {
706	pr_err("Failed to allocate LZO page\n");
707	ret = -ENOMEM;
708	goto out_clean;
709	}
710
711	data = vzalloc(array_size(nr_threads, sizeof(*data)));
712	if (!data) {
713	pr_err("Failed to allocate LZO data\n");
714	ret = -ENOMEM;
715	goto out_clean;
716	}
717
718	crc = kzalloc(size: sizeof(*crc), GFP_KERNEL);
719	if (!crc) {
720	pr_err("Failed to allocate crc\n");
721	ret = -ENOMEM;
722	goto out_clean;
723	}
724
725	/*
726	* Start the compression threads.
727	*/
728	for (thr = 0; thr < nr_threads; thr++) {
729	init_waitqueue_head(&data[thr].go);
730	init_waitqueue_head(&data[thr].done);
731
732	data[thr].thr = kthread_run(lzo_compress_threadfn,
733	&data[thr],
734	"image_compress/%u", thr);
735	if (IS_ERR(ptr: data[thr].thr)) {
736	data[thr].thr = NULL;
737	pr_err("Cannot start compression threads\n");
738	ret = -ENOMEM;
739	goto out_clean;
740	}
741	}
742
743	/*
744	* Start the CRC32 thread.
745	*/
746	init_waitqueue_head(&crc->go);
747	init_waitqueue_head(&crc->done);
748
749	handle->crc32 = 0;
750	crc->crc32 = &handle->crc32;
751	for (thr = 0; thr < nr_threads; thr++) {
752	crc->unc[thr] = data[thr].unc;
753	crc->unc_len[thr] = &data[thr].unc_len;
754	}
755
756	crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
757	if (IS_ERR(ptr: crc->thr)) {
758	crc->thr = NULL;
759	pr_err("Cannot start CRC32 thread\n");
760	ret = -ENOMEM;
761	goto out_clean;
762	}
763
764	/*
765	* Adjust the number of required free pages after all allocations have
766	* been done. We don't want to run out of pages when writing.
767	*/
768	handle->reqd_free_pages = reqd_free_pages();
769
770	pr_info("Using %u thread(s) for compression\n", nr_threads);
771	pr_info("Compressing and saving image data (%u pages)...\n",
772	nr_to_write);
773	m = nr_to_write / 10;
774	if (!m)
775	m = 1;
776	nr_pages = 0;
777	start = ktime_get();
778	for (;;) {
779	for (thr = 0; thr < nr_threads; thr++) {
780	for (off = 0; off < LZO_UNC_SIZE; off += PAGE_SIZE) {
781	ret = snapshot_read_next(handle: snapshot);
782	if (ret < 0)
783	goto out_finish;
784
785	if (!ret)
786	break;
787
788	memcpy(data[thr].unc + off,
789	data_of(*snapshot), PAGE_SIZE);
790
791	if (!(nr_pages % m))
792	pr_info("Image saving progress: %3d%%\n",
793	nr_pages / m * 10);
794	nr_pages++;
795	}
796	if (!off)
797	break;
798
799	data[thr].unc_len = off;
800
801	atomic_set(v: &data[thr].ready, i: 1);
802	wake_up(&data[thr].go);
803	}
804
805	if (!thr)
806	break;
807
808	crc->run_threads = thr;
809	atomic_set(v: &crc->ready, i: 1);
810	wake_up(&crc->go);
811
812	for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
813	wait_event(data[thr].done,
814	atomic_read(&data[thr].stop));
815	atomic_set(v: &data[thr].stop, i: 0);
816
817	ret = data[thr].ret;
818
819	if (ret < 0) {
820	pr_err("LZO compression failed\n");
821	goto out_finish;
822	}
823
824	if (unlikely(!data[thr].cmp_len ||
825	data[thr].cmp_len >
826	lzo1x_worst_compress(data[thr].unc_len))) {
827	pr_err("Invalid LZO compressed length\n");
828	ret = -1;
829	goto out_finish;
830	}
831
832	*(size_t *)data[thr].cmp = data[thr].cmp_len;
833
834	/*
835	* Given we are writing one page at a time to disk, we
836	* copy that much from the buffer, although the last
837	* bit will likely be smaller than full page. This is
838	* OK - we saved the length of the compressed data, so
839	* any garbage at the end will be discarded when we
840	* read it.
841	*/
842	for (off = 0;
843	off < LZO_HEADER + data[thr].cmp_len;
844	off += PAGE_SIZE) {
845	memcpy(page, data[thr].cmp + off, PAGE_SIZE);
846
847	ret = swap_write_page(handle, buf: page, hb: &hb);
848	if (ret)
849	goto out_finish;
850	}
851	}
852
853	wait_event(crc->done, atomic_read(&crc->stop));
854	atomic_set(v: &crc->stop, i: 0);
855	}
856
857	out_finish:
858	err2 = hib_wait_io(hb: &hb);
859	stop = ktime_get();
860	if (!ret)
861	ret = err2;
862	if (!ret)
863	pr_info("Image saving done\n");
864	swsusp_show_speed(start, stop, nr_to_write, "Wrote");
865	out_clean:
866	hib_finish_batch(hb: &hb);
867	if (crc) {
868	if (crc->thr)
869	kthread_stop(k: crc->thr);
870	kfree(objp: crc);
871	}
872	if (data) {
873	for (thr = 0; thr < nr_threads; thr++)
874	if (data[thr].thr)
875	kthread_stop(k: data[thr].thr);
876	vfree(addr: data);
877	}
878	if (page) free_page((unsigned long)page);
879
880	return ret;
881	}
882
883	/**
884	* enough_swap - Make sure we have enough swap to save the image.
885	*
886	* Returns TRUE or FALSE after checking the total amount of swap
887	* space available from the resume partition.
888	*/
889
890	static int enough_swap(unsigned int nr_pages)
891	{
892	unsigned int free_swap = count_swap_pages(root_swap, 1);
893	unsigned int required;
894
895	pr_debug("Free swap pages: %u\n", free_swap);
896
897	required = PAGES_FOR_IO + nr_pages;
898	return free_swap > required;
899	}
900
901	/**
902	* swsusp_write - Write entire image and metadata.
903	* @flags: flags to pass to the "boot" kernel in the image header
904	*
905	* It is important _NOT_ to umount filesystems at this point. We want
906	* them synced (in case something goes wrong) but we DO not want to mark
907	* filesystem clean: it is not. (And it does not matter, if we resume
908	* correctly, we'll mark system clean, anyway.)
909	*/
910
911	int swsusp_write(unsigned int flags)
912	{
913	struct swap_map_handle handle;
914	struct snapshot_handle snapshot;
915	struct swsusp_info *header;
916	unsigned long pages;
917	int error;
918
919	pages = snapshot_get_image_size();
920	error = get_swap_writer(handle: &handle);
921	if (error) {
922	pr_err("Cannot get swap writer\n");
923	return error;
924	}
925	if (flags & SF_NOCOMPRESS_MODE) {
926	if (!enough_swap(nr_pages: pages)) {
927	pr_err("Not enough free swap\n");
928	error = -ENOSPC;
929	goto out_finish;
930	}
931	}
932	memset(&snapshot, 0, sizeof(struct snapshot_handle));
933	error = snapshot_read_next(handle: &snapshot);
934	if (error < (int)PAGE_SIZE) {
935	if (error >= 0)
936	error = -EFAULT;
937
938	goto out_finish;
939	}
940	header = (struct swsusp_info *)data_of(snapshot);
941	error = swap_write_page(handle: &handle, buf: header, NULL);
942	if (!error) {
943	error = (flags & SF_NOCOMPRESS_MODE) ?
944	save_image(handle: &handle, snapshot: &snapshot, nr_to_write: pages - 1) :
945	save_image_lzo(handle: &handle, snapshot: &snapshot, nr_to_write: pages - 1);
946	}
947	out_finish:
948	error = swap_writer_finish(handle: &handle, flags, error);
949	return error;
950	}
951
952	/*
953	* The following functions allow us to read data using a swap map
954	* in a file-like way.
955	*/
956
957	static void release_swap_reader(struct swap_map_handle *handle)
958	{
959	struct swap_map_page_list *tmp;
960
961	while (handle->maps) {
962	if (handle->maps->map)
963	free_page((unsigned long)handle->maps->map);
964	tmp = handle->maps;
965	handle->maps = handle->maps->next;
966	kfree(objp: tmp);
967	}
968	handle->cur = NULL;
969	}
970
971	static int get_swap_reader(struct swap_map_handle *handle,
972	unsigned int *flags_p)
973	{
974	int error;
975	struct swap_map_page_list *tmp, *last;
976	sector_t offset;
977
978	*flags_p = swsusp_header->flags;
979
980	if (!swsusp_header->image) /* how can this happen? */
981	return -EINVAL;
982
983	handle->cur = NULL;
984	last = handle->maps = NULL;
985	offset = swsusp_header->image;
986	while (offset) {
987	tmp = kzalloc(size: sizeof(*handle->maps), GFP_KERNEL);
988	if (!tmp) {
989	release_swap_reader(handle);
990	return -ENOMEM;
991	}
992	if (!handle->maps)
993	handle->maps = tmp;
994	if (last)
995	last->next = tmp;
996	last = tmp;
997
998	tmp->map = (struct swap_map_page *)
999	__get_free_page(GFP_NOIO | __GFP_HIGH);
1000	if (!tmp->map) {
1001	release_swap_reader(handle);
1002	return -ENOMEM;
1003	}
1004
1005	error = hib_submit_io(opf: REQ_OP_READ, page_off: offset, addr: tmp->map, NULL);
1006	if (error) {
1007	release_swap_reader(handle);
1008	return error;
1009	}
1010	offset = tmp->map->next_swap;
1011	}
1012	handle->k = 0;
1013	handle->cur = handle->maps->map;
1014	return 0;
1015	}
1016
1017	static int swap_read_page(struct swap_map_handle *handle, void *buf,
1018	struct hib_bio_batch *hb)
1019	{
1020	sector_t offset;
1021	int error;
1022	struct swap_map_page_list *tmp;
1023
1024	if (!handle->cur)
1025	return -EINVAL;
1026	offset = handle->cur->entries[handle->k];
1027	if (!offset)
1028	return -EFAULT;
1029	error = hib_submit_io(opf: REQ_OP_READ, page_off: offset, addr: buf, hb);
1030	if (error)
1031	return error;
1032	if (++handle->k >= MAP_PAGE_ENTRIES) {
1033	handle->k = 0;
1034	free_page((unsigned long)handle->maps->map);
1035	tmp = handle->maps;
1036	handle->maps = handle->maps->next;
1037	kfree(objp: tmp);
1038	if (!handle->maps)
1039	release_swap_reader(handle);
1040	else
1041	handle->cur = handle->maps->map;
1042	}
1043	return error;
1044	}
1045
1046	static int swap_reader_finish(struct swap_map_handle *handle)
1047	{
1048	release_swap_reader(handle);
1049
1050	return 0;
1051	}
1052
1053	/**
1054	* load_image - load the image using the swap map handle
1055	* @handle and the snapshot handle @snapshot
1056	* (assume there are @nr_pages pages to load)
1057	*/
1058
1059	static int load_image(struct swap_map_handle *handle,
1060	struct snapshot_handle *snapshot,
1061	unsigned int nr_to_read)
1062	{
1063	unsigned int m;
1064	int ret = 0;
1065	ktime_t start;
1066	ktime_t stop;
1067	struct hib_bio_batch hb;
1068	int err2;
1069	unsigned nr_pages;
1070
1071	hib_init_batch(hb: &hb);
1072
1073	clean_pages_on_read = true;
1074	pr_info("Loading image data pages (%u pages)...\n", nr_to_read);
1075	m = nr_to_read / 10;
1076	if (!m)
1077	m = 1;
1078	nr_pages = 0;
1079	start = ktime_get();
1080	for ( ; ; ) {
1081	ret = snapshot_write_next(handle: snapshot);
1082	if (ret <= 0)
1083	break;
1084	ret = swap_read_page(handle, data_of(*snapshot), hb: &hb);
1085	if (ret)
1086	break;
1087	if (snapshot->sync_read)
1088	ret = hib_wait_io(hb: &hb);
1089	if (ret)
1090	break;
1091	if (!(nr_pages % m))
1092	pr_info("Image loading progress: %3d%%\n",
1093	nr_pages / m * 10);
1094	nr_pages++;
1095	}
1096	err2 = hib_wait_io(hb: &hb);
1097	hib_finish_batch(hb: &hb);
1098	stop = ktime_get();
1099	if (!ret)
1100	ret = err2;
1101	if (!ret) {
1102	pr_info("Image loading done\n");
1103	snapshot_write_finalize(handle: snapshot);
1104	if (!snapshot_image_loaded(handle: snapshot))
1105	ret = -ENODATA;
1106	}
1107	swsusp_show_speed(start, stop, nr_to_read, "Read");
1108	return ret;
1109	}
1110
1111	/*
1112	* Structure used for LZO data decompression.
1113	*/
1114	struct dec_data {
1115	struct task_struct *thr; /* thread */
1116	atomic_t ready; /* ready to start flag */
1117	atomic_t stop; /* ready to stop flag */
1118	int ret; /* return code */
1119	wait_queue_head_t go; /* start decompression */
1120	wait_queue_head_t done; /* decompression done */
1121	size_t unc_len; /* uncompressed length */
1122	size_t cmp_len; /* compressed length */
1123	unsigned char unc[LZO_UNC_SIZE]; /* uncompressed buffer */
1124	unsigned char cmp[LZO_CMP_SIZE]; /* compressed buffer */
1125	};
1126
1127	/*
1128	* Decompression function that runs in its own thread.
1129	*/
1130	static int lzo_decompress_threadfn(void *data)
1131	{
1132	struct dec_data *d = data;
1133
1134	while (1) {
1135	wait_event(d->go, atomic_read(&d->ready) ||
1136	kthread_should_stop());
1137	if (kthread_should_stop()) {
1138	d->thr = NULL;
1139	d->ret = -1;
1140	atomic_set(v: &d->stop, i: 1);
1141	wake_up(&d->done);
1142	break;
1143	}
1144	atomic_set(v: &d->ready, i: 0);
1145
1146	d->unc_len = LZO_UNC_SIZE;
1147	d->ret = lzo1x_decompress_safe(src: d->cmp + LZO_HEADER, src_len: d->cmp_len,
1148	dst: d->unc, dst_len: &d->unc_len);
1149	if (clean_pages_on_decompress)
1150	flush_icache_range(start: (unsigned long)d->unc,
1151	end: (unsigned long)d->unc + d->unc_len);
1152
1153	atomic_set(v: &d->stop, i: 1);
1154	wake_up(&d->done);
1155	}
1156	return 0;
1157	}
1158
1159	/**
1160	* load_image_lzo - Load compressed image data and decompress them with LZO.
1161	* @handle: Swap map handle to use for loading data.
1162	* @snapshot: Image to copy uncompressed data into.
1163	* @nr_to_read: Number of pages to load.
1164	*/
1165	static int load_image_lzo(struct swap_map_handle *handle,
1166	struct snapshot_handle *snapshot,
1167	unsigned int nr_to_read)
1168	{
1169	unsigned int m;
1170	int ret = 0;
1171	int eof = 0;
1172	struct hib_bio_batch hb;
1173	ktime_t start;
1174	ktime_t stop;
1175	unsigned nr_pages;
1176	size_t off;
1177	unsigned i, thr, run_threads, nr_threads;
1178	unsigned ring = 0, pg = 0, ring_size = 0,
1179	have = 0, want, need, asked = 0;
1180	unsigned long read_pages = 0;
1181	unsigned char **page = NULL;
1182	struct dec_data *data = NULL;
1183	struct crc_data *crc = NULL;
1184
1185	hib_init_batch(hb: &hb);
1186
1187	/*
1188	* We'll limit the number of threads for decompression to limit memory
1189	* footprint.
1190	*/
1191	nr_threads = num_online_cpus() - 1;
1192	nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
1193
1194	page = vmalloc(array_size(LZO_MAX_RD_PAGES, sizeof(*page)));
1195	if (!page) {
1196	pr_err("Failed to allocate LZO page\n");
1197	ret = -ENOMEM;
1198	goto out_clean;
1199	}
1200
1201	data = vzalloc(array_size(nr_threads, sizeof(*data)));
1202	if (!data) {
1203	pr_err("Failed to allocate LZO data\n");
1204	ret = -ENOMEM;
1205	goto out_clean;
1206	}
1207
1208	crc = kzalloc(size: sizeof(*crc), GFP_KERNEL);
1209	if (!crc) {
1210	pr_err("Failed to allocate crc\n");
1211	ret = -ENOMEM;
1212	goto out_clean;
1213	}
1214
1215	clean_pages_on_decompress = true;
1216
1217	/*
1218	* Start the decompression threads.
1219	*/
1220	for (thr = 0; thr < nr_threads; thr++) {
1221	init_waitqueue_head(&data[thr].go);
1222	init_waitqueue_head(&data[thr].done);
1223
1224	data[thr].thr = kthread_run(lzo_decompress_threadfn,
1225	&data[thr],
1226	"image_decompress/%u", thr);
1227	if (IS_ERR(ptr: data[thr].thr)) {
1228	data[thr].thr = NULL;
1229	pr_err("Cannot start decompression threads\n");
1230	ret = -ENOMEM;
1231	goto out_clean;
1232	}
1233	}
1234
1235	/*
1236	* Start the CRC32 thread.
1237	*/
1238	init_waitqueue_head(&crc->go);
1239	init_waitqueue_head(&crc->done);
1240
1241	handle->crc32 = 0;
1242	crc->crc32 = &handle->crc32;
1243	for (thr = 0; thr < nr_threads; thr++) {
1244	crc->unc[thr] = data[thr].unc;
1245	crc->unc_len[thr] = &data[thr].unc_len;
1246	}
1247
1248	crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
1249	if (IS_ERR(ptr: crc->thr)) {
1250	crc->thr = NULL;
1251	pr_err("Cannot start CRC32 thread\n");
1252	ret = -ENOMEM;
1253	goto out_clean;
1254	}
1255
1256	/*
1257	* Set the number of pages for read buffering.
1258	* This is complete guesswork, because we'll only know the real
1259	* picture once prepare_image() is called, which is much later on
1260	* during the image load phase. We'll assume the worst case and
1261	* say that none of the image pages are from high memory.
1262	*/
1263	if (low_free_pages() > snapshot_get_image_size())
1264	read_pages = (low_free_pages() - snapshot_get_image_size()) / 2;
1265	read_pages = clamp_val(read_pages, LZO_MIN_RD_PAGES, LZO_MAX_RD_PAGES);
1266
1267	for (i = 0; i < read_pages; i++) {
1268	page[i] = (void *)__get_free_page(i < LZO_CMP_PAGES ?
1269	GFP_NOIO | __GFP_HIGH :
1270	GFP_NOIO | __GFP_NOWARN |
1271	__GFP_NORETRY);
1272
1273	if (!page[i]) {
1274	if (i < LZO_CMP_PAGES) {
1275	ring_size = i;
1276	pr_err("Failed to allocate LZO pages\n");
1277	ret = -ENOMEM;
1278	goto out_clean;
1279	} else {
1280	break;
1281	}
1282	}
1283	}
1284	want = ring_size = i;
1285
1286	pr_info("Using %u thread(s) for decompression\n", nr_threads);
1287	pr_info("Loading and decompressing image data (%u pages)...\n",
1288	nr_to_read);
1289	m = nr_to_read / 10;
1290	if (!m)
1291	m = 1;
1292	nr_pages = 0;
1293	start = ktime_get();
1294
1295	ret = snapshot_write_next(handle: snapshot);
1296	if (ret <= 0)
1297	goto out_finish;
1298
1299	for(;;) {
1300	for (i = 0; !eof && i < want; i++) {
1301	ret = swap_read_page(handle, buf: page[ring], hb: &hb);
1302	if (ret) {
1303	/*
1304	* On real read error, finish. On end of data,
1305	* set EOF flag and just exit the read loop.
1306	*/
1307	if (handle->cur &&
1308	handle->cur->entries[handle->k]) {
1309	goto out_finish;
1310	} else {
1311	eof = 1;
1312	break;
1313	}
1314	}
1315	if (++ring >= ring_size)
1316	ring = 0;
1317	}
1318	asked += i;
1319	want -= i;
1320
1321	/*
1322	* We are out of data, wait for some more.
1323	*/
1324	if (!have) {
1325	if (!asked)
1326	break;
1327
1328	ret = hib_wait_io(hb: &hb);
1329	if (ret)
1330	goto out_finish;
1331	have += asked;
1332	asked = 0;
1333	if (eof)
1334	eof = 2;
1335	}
1336
1337	if (crc->run_threads) {
1338	wait_event(crc->done, atomic_read(&crc->stop));
1339	atomic_set(v: &crc->stop, i: 0);
1340	crc->run_threads = 0;
1341	}
1342
1343	for (thr = 0; have && thr < nr_threads; thr++) {
1344	data[thr].cmp_len = *(size_t *)page[pg];
1345	if (unlikely(!data[thr].cmp_len ||
1346	data[thr].cmp_len >
1347	lzo1x_worst_compress(LZO_UNC_SIZE))) {
1348	pr_err("Invalid LZO compressed length\n");
1349	ret = -1;
1350	goto out_finish;
1351	}
1352
1353	need = DIV_ROUND_UP(data[thr].cmp_len + LZO_HEADER,
1354	PAGE_SIZE);
1355	if (need > have) {
1356	if (eof > 1) {
1357	ret = -1;
1358	goto out_finish;
1359	}
1360	break;
1361	}
1362
1363	for (off = 0;
1364	off < LZO_HEADER + data[thr].cmp_len;
1365	off += PAGE_SIZE) {
1366	memcpy(data[thr].cmp + off,
1367	page[pg], PAGE_SIZE);
1368	have--;
1369	want++;
1370	if (++pg >= ring_size)
1371	pg = 0;
1372	}
1373
1374	atomic_set(v: &data[thr].ready, i: 1);
1375	wake_up(&data[thr].go);
1376	}
1377
1378	/*
1379	* Wait for more data while we are decompressing.
1380	*/
1381	if (have < LZO_CMP_PAGES && asked) {
1382	ret = hib_wait_io(hb: &hb);
1383	if (ret)
1384	goto out_finish;
1385	have += asked;
1386	asked = 0;
1387	if (eof)
1388	eof = 2;
1389	}
1390
1391	for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
1392	wait_event(data[thr].done,
1393	atomic_read(&data[thr].stop));
1394	atomic_set(v: &data[thr].stop, i: 0);
1395
1396	ret = data[thr].ret;
1397
1398	if (ret < 0) {
1399	pr_err("LZO decompression failed\n");
1400	goto out_finish;
1401	}
1402
1403	if (unlikely(!data[thr].unc_len ||
1404	data[thr].unc_len > LZO_UNC_SIZE ||
1405	data[thr].unc_len & (PAGE_SIZE - 1))) {
1406	pr_err("Invalid LZO uncompressed length\n");
1407	ret = -1;
1408	goto out_finish;
1409	}
1410
1411	for (off = 0;
1412	off < data[thr].unc_len; off += PAGE_SIZE) {
1413	memcpy(data_of(*snapshot),
1414	data[thr].unc + off, PAGE_SIZE);
1415
1416	if (!(nr_pages % m))
1417	pr_info("Image loading progress: %3d%%\n",
1418	nr_pages / m * 10);
1419	nr_pages++;
1420
1421	ret = snapshot_write_next(handle: snapshot);
1422	if (ret <= 0) {
1423	crc->run_threads = thr + 1;
1424	atomic_set(v: &crc->ready, i: 1);
1425	wake_up(&crc->go);
1426	goto out_finish;
1427	}
1428	}
1429	}
1430
1431	crc->run_threads = thr;
1432	atomic_set(v: &crc->ready, i: 1);
1433	wake_up(&crc->go);
1434	}
1435
1436	out_finish:
1437	if (crc->run_threads) {
1438	wait_event(crc->done, atomic_read(&crc->stop));
1439	atomic_set(v: &crc->stop, i: 0);
1440	}
1441	stop = ktime_get();
1442	if (!ret) {
1443	pr_info("Image loading done\n");
1444	snapshot_write_finalize(handle: snapshot);
1445	if (!snapshot_image_loaded(handle: snapshot))
1446	ret = -ENODATA;
1447	if (!ret) {
1448	if (swsusp_header->flags & SF_CRC32_MODE) {
1449	if(handle->crc32 != swsusp_header->crc32) {
1450	pr_err("Invalid image CRC32!\n");
1451	ret = -ENODATA;
1452	}
1453	}
1454	}
1455	}
1456	swsusp_show_speed(start, stop, nr_to_read, "Read");
1457	out_clean:
1458	hib_finish_batch(hb: &hb);
1459	for (i = 0; i < ring_size; i++)
1460	free_page((unsigned long)page[i]);
1461	if (crc) {
1462	if (crc->thr)
1463	kthread_stop(k: crc->thr);
1464	kfree(objp: crc);
1465	}
1466	if (data) {
1467	for (thr = 0; thr < nr_threads; thr++)
1468	if (data[thr].thr)
1469	kthread_stop(k: data[thr].thr);
1470	vfree(addr: data);
1471	}
1472	vfree(addr: page);
1473
1474	return ret;
1475	}
1476
1477	/**
1478	* swsusp_read - read the hibernation image.
1479	* @flags_p: flags passed by the "frozen" kernel in the image header should
1480	* be written into this memory location
1481	*/
1482
1483	int swsusp_read(unsigned int *flags_p)
1484	{
1485	int error;
1486	struct swap_map_handle handle;
1487	struct snapshot_handle snapshot;
1488	struct swsusp_info *header;
1489
1490	memset(&snapshot, 0, sizeof(struct snapshot_handle));
1491	error = snapshot_write_next(handle: &snapshot);
1492	if (error < (int)PAGE_SIZE)
1493	return error < 0 ? error : -EFAULT;
1494	header = (struct swsusp_info *)data_of(snapshot);
1495	error = get_swap_reader(handle: &handle, flags_p);
1496	if (error)
1497	goto end;
1498	if (!error)
1499	error = swap_read_page(handle: &handle, buf: header, NULL);
1500	if (!error) {
1501	error = (*flags_p & SF_NOCOMPRESS_MODE) ?
1502	load_image(handle: &handle, snapshot: &snapshot, nr_to_read: header->pages - 1) :
1503	load_image_lzo(handle: &handle, snapshot: &snapshot, nr_to_read: header->pages - 1);
1504	}
1505	swap_reader_finish(handle: &handle);
1506	end:
1507	if (!error)
1508	pr_debug("Image successfully loaded\n");
1509	else
1510	pr_debug("Error %d resuming\n", error);
1511	return error;
1512	}
1513
1514	static void *swsusp_holder;
1515
1516	/**
1517	* swsusp_check - Open the resume device and check for the swsusp signature.
1518	* @exclusive: Open the resume device exclusively.
1519	*/
1520
1521	int swsusp_check(bool exclusive)
1522	{
1523	void *holder = exclusive ? &swsusp_holder : NULL;
1524	int error;
1525
1526	hib_resume_bdev_handle = bdev_open_by_dev(dev: swsusp_resume_device,
1527	BLK_OPEN_READ, holder, NULL);
1528	if (!IS_ERR(ptr: hib_resume_bdev_handle)) {
1529	set_blocksize(bdev: hib_resume_bdev_handle->bdev, PAGE_SIZE);
1530	clear_page(page: swsusp_header);
1531	error = hib_submit_io(opf: REQ_OP_READ, page_off: swsusp_resume_block,
1532	addr: swsusp_header, NULL);
1533	if (error)
1534	goto put;
1535
1536	if (!memcmp(HIBERNATE_SIG, q: swsusp_header->sig, size: 10)) {
1537	memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
1538	/* Reset swap signature now */
1539	error = hib_submit_io(opf: REQ_OP_WRITE | REQ_SYNC,
1540	page_off: swsusp_resume_block,
1541	addr: swsusp_header, NULL);
1542	} else {
1543	error = -EINVAL;
1544	}
1545	if (!error && swsusp_header->flags & SF_HW_SIG &&
1546	swsusp_header->hw_sig != swsusp_hardware_signature) {
1547	pr_info("Suspend image hardware signature mismatch (%08x now %08x); aborting resume.\n",
1548	swsusp_header->hw_sig, swsusp_hardware_signature);
1549	error = -EINVAL;
1550	}
1551
1552	put:
1553	if (error)
1554	bdev_release(handle: hib_resume_bdev_handle);
1555	else
1556	pr_debug("Image signature found, resuming\n");
1557	} else {
1558	error = PTR_ERR(ptr: hib_resume_bdev_handle);
1559	}
1560
1561	if (error)
1562	pr_debug("Image not found (code %d)\n", error);
1563
1564	return error;
1565	}
1566
1567	/**
1568	* swsusp_close - close resume device.
1569	* @exclusive: Close the resume device which is exclusively opened.
1570	*/
1571
1572	void swsusp_close(void)
1573	{
1574	if (IS_ERR(ptr: hib_resume_bdev_handle)) {
1575	pr_debug("Image device not initialised\n");
1576	return;
1577	}
1578
1579	bdev_release(handle: hib_resume_bdev_handle);
1580	}
1581
1582	/**
1583	* swsusp_unmark - Unmark swsusp signature in the resume device
1584	*/
1585
1586	#ifdef CONFIG_SUSPEND
1587	int swsusp_unmark(void)
1588	{
1589	int error;
1590
1591	hib_submit_io(opf: REQ_OP_READ, page_off: swsusp_resume_block,
1592	addr: swsusp_header, NULL);
1593	if (!memcmp(HIBERNATE_SIG,q: swsusp_header->sig, size: 10)) {
1594	memcpy(swsusp_header->sig,swsusp_header->orig_sig, 10);
1595	error = hib_submit_io(opf: REQ_OP_WRITE | REQ_SYNC,
1596	page_off: swsusp_resume_block,
1597	addr: swsusp_header, NULL);
1598	} else {
1599	pr_err("Cannot find swsusp signature!\n");
1600	error = -ENODEV;
1601	}
1602
1603	/*
1604	* We just returned from suspend, we don't need the image any more.
1605	*/
1606	free_all_swap_pages(swap: root_swap);
1607
1608	return error;
1609	}
1610	#endif
1611
1612	static int __init swsusp_header_init(void)
1613	{
1614	swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
1615	if (!swsusp_header)
1616	panic(fmt: "Could not allocate memory for swsusp_header\n");
1617	return 0;
1618	}
1619
1620	core_initcall(swsusp_header_init);
1621