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
  38u32 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 */
  45static bool clean_pages_on_read;
  46static 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 */
  67static 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 */
  76static inline unsigned long reqd_free_pages(void)
  77{
  78	return low_free_pages() / 2;
  79}
  80
  81struct swap_map_page {
  82	sector_t entries[MAP_PAGE_ENTRIES];
  83	sector_t next_swap;
  84};
  85
  86struct 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
  96struct 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
 106struct 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
 117static 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
 124struct swsusp_extent {
 125	struct rb_node node;
 126	unsigned long start;
 127	unsigned long end;
 128};
 129
 130static struct rb_root swsusp_extents = RB_ROOT;
 131
 132static 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(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(&ext->node, parent, 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
 178sector_t alloc_swapdev_block(int swap)
 179{
 180	unsigned long offset;
 181
 182	offset = swp_offset(get_swap_page_of_type(swap));
 183	if (offset) {
 184		if (swsusp_extents_insert(offset))
 185			swap_free(swp_entry(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
 198void 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(swap, offset));
 210
 211		kfree(ext);
 212	}
 213}
 214
 215int swsusp_swap_in_use(void)
 216{
 217	return (swsusp_extents.rb_node != NULL);
 218}
 219
 220/*
 221 * General things
 222 */
 223
 224static unsigned short root_swap = 0xffff;
 225static struct bdev_handle *hib_resume_bdev_handle;
 226
 227struct 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
 234static void hib_init_batch(struct hib_bio_batch *hb)
 235{
 236	atomic_set(&hb->count, 0);
 237	init_waitqueue_head(&hb->wait);
 238	hb->error = BLK_STS_OK;
 239	blk_start_plug(&hb->plug);
 240}
 241
 242static void hib_finish_batch(struct hib_bio_batch *hb)
 243{
 244	blk_finish_plug(&hb->plug);
 245}
 246
 247static 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((unsigned long)page_address(page),
 262				   (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(&hb->count))
 267		wake_up(&hb->wait);
 268
 269	bio_put(bio);
 270}
 271
 272static 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(hib_resume_bdev_handle->bdev, 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, 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(&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
 303static 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(hb->error);
 311}
 312
 313/*
 314 * Saving part
 315 */
 
 316static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags)
 317{
 318	int error;
 319
 320	hib_submit_io(REQ_OP_READ, swsusp_resume_block, swsusp_header, NULL);
 
 321	if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
 322	    !memcmp("SWAPSPACE2",swsusp_header->sig, 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(REQ_OP_WRITE | REQ_SYNC,
 334				      swsusp_resume_block, 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 */
 348static int swsusp_swap_check(void)
 349{
 350	int res;
 351
 352	if (swsusp_resume_device)
 353		res = swap_type_of(swsusp_resume_device, swsusp_resume_block);
 354	else
 355		res = find_first_swap(&swsusp_resume_device);
 356	if (res < 0)
 357		return res;
 358	root_swap = res;
 359
 360	hib_resume_bdev_handle = bdev_open_by_dev(swsusp_resume_device,
 361			BLK_OPEN_WRITE, NULL, NULL);
 362	if (IS_ERR(hib_resume_bdev_handle))
 363		return PTR_ERR(hib_resume_bdev_handle);
 364
 365	res = set_blocksize(hib_resume_bdev_handle->bdev, PAGE_SIZE);
 366	if (res < 0)
 367		bdev_release(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
 379static 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(src, 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(src, 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(REQ_OP_WRITE | REQ_SYNC, offset, src, hb);
 411}
 412
 413static 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
 420static 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(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;
 444err_rel:
 445	release_swap_writer(handle);
 446err_close:
 447	swsusp_close();
 448	return ret;
 449}
 450
 451static int swap_write_page(struct swap_map_handle *handle, void *buf,
 452		struct hib_bio_batch *hb)
 453{
 454	int error;
 455	sector_t offset;
 456
 457	if (!handle->cur)
 458		return -EINVAL;
 459	offset = alloc_swapdev_block(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(root_swap);
 466		if (!offset)
 467			return -ENOSPC;
 468		handle->cur->next_swap = offset;
 469		error = write_page(handle->cur, handle->cur_swap, hb);
 470		if (error)
 471			goto out;
 472		clear_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
 491static int flush_swap_writer(struct swap_map_handle *handle)
 492{
 493	if (handle->cur && handle->cur_swap)
 494		return write_page(handle->cur, handle->cur_swap, NULL);
 495	else
 496		return -EINVAL;
 497}
 498
 499static 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(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
 541static 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);
 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(snapshot);
 564		if (ret <= 0)
 565			break;
 566		ret = swap_write_page(handle, data_of(*snapshot), &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);
 575	hib_finish_batch(&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 */
 588struct 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 */
 603static 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_acquire(&d->ready) ||
 610		                  kthread_should_stop());
 611		if (kthread_should_stop()) {
 612			d->thr = NULL;
 613			atomic_set_release(&d->stop, 1);
 614			wake_up(&d->done);
 615			break;
 616		}
 617		atomic_set(&d->ready, 0);
 618
 619		for (i = 0; i < d->run_threads; i++)
 620			*d->crc32 = crc32_le(*d->crc32,
 621			                     d->unc[i], *d->unc_len[i]);
 622		atomic_set_release(&d->stop, 1);
 623		wake_up(&d->done);
 624	}
 625	return 0;
 626}
 627/*
 628 * Structure used for LZO data compression.
 629 */
 630struct 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 */
 647static int lzo_compress_threadfn(void *data)
 648{
 649	struct cmp_data *d = data;
 650
 651	while (1) {
 652		wait_event(d->go, atomic_read_acquire(&d->ready) ||
 653		                  kthread_should_stop());
 654		if (kthread_should_stop()) {
 655			d->thr = NULL;
 656			d->ret = -1;
 657			atomic_set_release(&d->stop, 1);
 658			wake_up(&d->done);
 659			break;
 660		}
 661		atomic_set(&d->ready, 0);
 662
 663		d->ret = lzo1x_1_compress(d->unc, d->unc_len,
 664		                          d->cmp + LZO_HEADER, &d->cmp_len,
 665		                          d->wrk);
 666		atomic_set_release(&d->stop, 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 */
 678static 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);
 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(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(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(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(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_release(&data[thr].ready, 1);
 802			wake_up(&data[thr].go);
 803		}
 804
 805		if (!thr)
 806			break;
 807
 808		crc->run_threads = thr;
 809		atomic_set_release(&crc->ready, 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_acquire(&data[thr].stop));
 815			atomic_set(&data[thr].stop, 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, page, &hb);
 848				if (ret)
 849					goto out_finish;
 850			}
 851		}
 852
 853		wait_event(crc->done, atomic_read_acquire(&crc->stop));
 854		atomic_set(&crc->stop, 0);
 855	}
 856
 857out_finish:
 858	err2 = hib_wait_io(&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");
 865out_clean:
 866	hib_finish_batch(&hb);
 867	if (crc) {
 868		if (crc->thr)
 869			kthread_stop(crc->thr);
 870		kfree(crc);
 871	}
 872	if (data) {
 873		for (thr = 0; thr < nr_threads; thr++)
 874			if (data[thr].thr)
 875				kthread_stop(data[thr].thr);
 876		vfree(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
 890static 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
 911int 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);
 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(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(&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, header, NULL);
 942	if (!error) {
 943		error = (flags & SF_NOCOMPRESS_MODE) ?
 944			save_image(&handle, &snapshot, pages - 1) :
 945			save_image_lzo(&handle, &snapshot, pages - 1);
 946	}
 947out_finish:
 948	error = swap_writer_finish(&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
 957static 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(tmp);
 967	}
 968	handle->cur = NULL;
 969}
 970
 971static 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(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(REQ_OP_READ, offset, 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
1017static 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(REQ_OP_READ, offset, 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(tmp);
1038		if (!handle->maps)
1039			release_swap_reader(handle);
1040		else
1041			handle->cur = handle->maps->map;
1042	}
1043	return error;
1044}
1045
1046static 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
1059static 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);
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(snapshot);
1082		if (ret <= 0)
1083			break;
1084		ret = swap_read_page(handle, data_of(*snapshot), &hb);
1085		if (ret)
1086			break;
1087		if (snapshot->sync_read)
1088			ret = hib_wait_io(&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);
1097	hib_finish_batch(&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(snapshot);
1104		if (!snapshot_image_loaded(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 */
1114struct 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 */
1130static int lzo_decompress_threadfn(void *data)
1131{
1132	struct dec_data *d = data;
1133
1134	while (1) {
1135		wait_event(d->go, atomic_read_acquire(&d->ready) ||
1136		                  kthread_should_stop());
1137		if (kthread_should_stop()) {
1138			d->thr = NULL;
1139			d->ret = -1;
1140			atomic_set_release(&d->stop, 1);
1141			wake_up(&d->done);
1142			break;
1143		}
1144		atomic_set(&d->ready, 0);
1145
1146		d->unc_len = LZO_UNC_SIZE;
1147		d->ret = lzo1x_decompress_safe(d->cmp + LZO_HEADER, d->cmp_len,
1148		                               d->unc, &d->unc_len);
1149		if (clean_pages_on_decompress)
1150			flush_icache_range((unsigned long)d->unc,
1151					   (unsigned long)d->unc + d->unc_len);
1152
1153		atomic_set_release(&d->stop, 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 */
1165static 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);
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(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(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(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(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, page[ring], &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);
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_acquire(&crc->stop));
1339			atomic_set(&crc->stop, 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_release(&data[thr].ready, 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);
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_acquire(&data[thr].stop));
1394			atomic_set(&data[thr].stop, 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(snapshot);
1422				if (ret <= 0) {
1423					crc->run_threads = thr + 1;
1424					atomic_set_release(&crc->ready, 1);
1425					wake_up(&crc->go);
1426					goto out_finish;
1427				}
1428			}
1429		}
1430
1431		crc->run_threads = thr;
1432		atomic_set_release(&crc->ready, 1);
1433		wake_up(&crc->go);
1434	}
1435
1436out_finish:
1437	if (crc->run_threads) {
1438		wait_event(crc->done, atomic_read_acquire(&crc->stop));
1439		atomic_set(&crc->stop, 0);
1440	}
1441	stop = ktime_get();
1442	if (!ret) {
1443		pr_info("Image loading done\n");
1444		snapshot_write_finalize(snapshot);
1445		if (!snapshot_image_loaded(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");
1457out_clean:
1458	hib_finish_batch(&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(crc->thr);
1464		kfree(crc);
1465	}
1466	if (data) {
1467		for (thr = 0; thr < nr_threads; thr++)
1468			if (data[thr].thr)
1469				kthread_stop(data[thr].thr);
1470		vfree(data);
1471	}
1472	vfree(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
1483int 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(&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, flags_p);
1496	if (error)
1497		goto end;
1498	if (!error)
1499		error = swap_read_page(&handle, header, NULL);
1500	if (!error) {
1501		error = (*flags_p & SF_NOCOMPRESS_MODE) ?
1502			load_image(&handle, &snapshot, header->pages - 1) :
1503			load_image_lzo(&handle, &snapshot, header->pages - 1);
1504	}
1505	swap_reader_finish(&handle);
1506end:
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
1514static 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
1521int 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(swsusp_resume_device,
1527				BLK_OPEN_READ, holder, NULL);
1528	if (!IS_ERR(hib_resume_bdev_handle)) {
1529		set_blocksize(hib_resume_bdev_handle->bdev, PAGE_SIZE);
1530		clear_page(swsusp_header);
1531		error = hib_submit_io(REQ_OP_READ, swsusp_resume_block,
 
1532					swsusp_header, NULL);
1533		if (error)
1534			goto put;
1535
1536		if (!memcmp(HIBERNATE_SIG, swsusp_header->sig, 10)) {
1537			memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
1538			/* Reset swap signature now */
1539			error = hib_submit_io(REQ_OP_WRITE | REQ_SYNC,
1540						swsusp_resume_block,
1541						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
1552put:
1553		if (error)
1554			bdev_release(hib_resume_bdev_handle);
1555		else
1556			pr_debug("Image signature found, resuming\n");
1557	} else {
1558		error = PTR_ERR(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 */
1570
1571void swsusp_close(void)
1572{
1573	if (IS_ERR(hib_resume_bdev_handle)) {
1574		pr_debug("Image device not initialised\n");
1575		return;
1576	}
1577
1578	bdev_release(hib_resume_bdev_handle);
1579}
1580
1581/**
1582 *      swsusp_unmark - Unmark swsusp signature in the resume device
1583 */
1584
1585#ifdef CONFIG_SUSPEND
1586int swsusp_unmark(void)
1587{
1588	int error;
1589
1590	hib_submit_io(REQ_OP_READ, 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		pr_err("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
1611static int __init 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
1619core_initcall(swsusp_header_init);