Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 | /*
* linux/kernel/power/snapshot.c
*
* This file provide system snapshot/restore functionality.
*
* Copyright (C) 1998-2005 Pavel Machek <pavel@suse.cz>
*
* This file is released under the GPLv2, and is based on swsusp.c.
*
*/
#include <linux/version.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/suspend.h>
#include <linux/smp_lock.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/kernel.h>
#include <linux/pm.h>
#include <linux/device.h>
#include <linux/bootmem.h>
#include <linux/syscalls.h>
#include <linux/console.h>
#include <linux/highmem.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/io.h>
#include "power.h"
struct pbe *pagedir_nosave;
static unsigned int nr_copy_pages;
static unsigned int nr_meta_pages;
static unsigned long *buffer;
#ifdef CONFIG_HIGHMEM
unsigned int count_highmem_pages(void)
{
struct zone *zone;
unsigned long zone_pfn;
unsigned int n = 0;
for_each_zone (zone)
if (is_highmem(zone)) {
mark_free_pages(zone);
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; zone_pfn++) {
struct page *page;
unsigned long pfn = zone_pfn + zone->zone_start_pfn;
if (!pfn_valid(pfn))
continue;
page = pfn_to_page(pfn);
if (PageReserved(page))
continue;
if (PageNosaveFree(page))
continue;
n++;
}
}
return n;
}
struct highmem_page {
char *data;
struct page *page;
struct highmem_page *next;
};
static struct highmem_page *highmem_copy;
static int save_highmem_zone(struct zone *zone)
{
unsigned long zone_pfn;
mark_free_pages(zone);
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
struct page *page;
struct highmem_page *save;
void *kaddr;
unsigned long pfn = zone_pfn + zone->zone_start_pfn;
if (!(pfn%10000))
printk(".");
if (!pfn_valid(pfn))
continue;
page = pfn_to_page(pfn);
/*
* This condition results from rvmalloc() sans vmalloc_32()
* and architectural memory reservations. This should be
* corrected eventually when the cases giving rise to this
* are better understood.
*/
if (PageReserved(page))
continue;
BUG_ON(PageNosave(page));
if (PageNosaveFree(page))
continue;
save = kmalloc(sizeof(struct highmem_page), GFP_ATOMIC);
if (!save)
return -ENOMEM;
save->next = highmem_copy;
save->page = page;
save->data = (void *) get_zeroed_page(GFP_ATOMIC);
if (!save->data) {
kfree(save);
return -ENOMEM;
}
kaddr = kmap_atomic(page, KM_USER0);
memcpy(save->data, kaddr, PAGE_SIZE);
kunmap_atomic(kaddr, KM_USER0);
highmem_copy = save;
}
return 0;
}
int save_highmem(void)
{
struct zone *zone;
int res = 0;
pr_debug("swsusp: Saving Highmem");
drain_local_pages();
for_each_zone (zone) {
if (is_highmem(zone))
res = save_highmem_zone(zone);
if (res)
return res;
}
printk("\n");
return 0;
}
int restore_highmem(void)
{
printk("swsusp: Restoring Highmem\n");
while (highmem_copy) {
struct highmem_page *save = highmem_copy;
void *kaddr;
highmem_copy = save->next;
kaddr = kmap_atomic(save->page, KM_USER0);
memcpy(kaddr, save->data, PAGE_SIZE);
kunmap_atomic(kaddr, KM_USER0);
free_page((long) save->data);
kfree(save);
}
return 0;
}
#else
static inline unsigned int count_highmem_pages(void) {return 0;}
static inline int save_highmem(void) {return 0;}
static inline int restore_highmem(void) {return 0;}
#endif
static int pfn_is_nosave(unsigned long pfn)
{
unsigned long nosave_begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
unsigned long nosave_end_pfn = PAGE_ALIGN(__pa(&__nosave_end)) >> PAGE_SHIFT;
return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
}
/**
* saveable - Determine whether a page should be cloned or not.
* @pfn: The page
*
* We save a page if it's Reserved, and not in the range of pages
* statically defined as 'unsaveable', or if it isn't reserved, and
* isn't part of a free chunk of pages.
*/
static int saveable(struct zone *zone, unsigned long *zone_pfn)
{
unsigned long pfn = *zone_pfn + zone->zone_start_pfn;
struct page *page;
if (!pfn_valid(pfn))
return 0;
page = pfn_to_page(pfn);
BUG_ON(PageReserved(page) && PageNosave(page));
if (PageNosave(page))
return 0;
if (PageReserved(page) && pfn_is_nosave(pfn))
return 0;
if (PageNosaveFree(page))
return 0;
return 1;
}
unsigned int count_data_pages(void)
{
struct zone *zone;
unsigned long zone_pfn;
unsigned int n = 0;
for_each_zone (zone) {
if (is_highmem(zone))
continue;
mark_free_pages(zone);
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
n += saveable(zone, &zone_pfn);
}
return n;
}
static void copy_data_pages(struct pbe *pblist)
{
struct zone *zone;
unsigned long zone_pfn;
struct pbe *pbe, *p;
pbe = pblist;
for_each_zone (zone) {
if (is_highmem(zone))
continue;
mark_free_pages(zone);
/* This is necessary for swsusp_free() */
for_each_pb_page (p, pblist)
SetPageNosaveFree(virt_to_page(p));
for_each_pbe (p, pblist)
SetPageNosaveFree(virt_to_page(p->address));
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
if (saveable(zone, &zone_pfn)) {
struct page *page;
long *src, *dst;
int n;
page = pfn_to_page(zone_pfn + zone->zone_start_pfn);
BUG_ON(!pbe);
pbe->orig_address = (unsigned long)page_address(page);
/* copy_page and memcpy are not usable for copying task structs. */
dst = (long *)pbe->address;
src = (long *)pbe->orig_address;
for (n = PAGE_SIZE / sizeof(long); n; n--)
*dst++ = *src++;
pbe = pbe->next;
}
}
}
BUG_ON(pbe);
}
/**
* free_pagedir - free pages allocated with alloc_pagedir()
*/
static void free_pagedir(struct pbe *pblist, int clear_nosave_free)
{
struct pbe *pbe;
while (pblist) {
pbe = (pblist + PB_PAGE_SKIP)->next;
ClearPageNosave(virt_to_page(pblist));
if (clear_nosave_free)
ClearPageNosaveFree(virt_to_page(pblist));
free_page((unsigned long)pblist);
pblist = pbe;
}
}
/**
* fill_pb_page - Create a list of PBEs on a given memory page
*/
static inline void fill_pb_page(struct pbe *pbpage)
{
struct pbe *p;
p = pbpage;
pbpage += PB_PAGE_SKIP;
do
p->next = p + 1;
while (++p < pbpage);
}
/**
* create_pbe_list - Create a list of PBEs on top of a given chain
* of memory pages allocated with alloc_pagedir()
*/
static inline void create_pbe_list(struct pbe *pblist, unsigned int nr_pages)
{
struct pbe *pbpage, *p;
unsigned int num = PBES_PER_PAGE;
for_each_pb_page (pbpage, pblist) {
if (num >= nr_pages)
break;
fill_pb_page(pbpage);
num += PBES_PER_PAGE;
}
if (pbpage) {
for (num -= PBES_PER_PAGE - 1, p = pbpage; num < nr_pages; p++, num++)
p->next = p + 1;
p->next = NULL;
}
}
static unsigned int unsafe_pages;
/**
* @safe_needed - on resume, for storing the PBE list and the image,
* we can only use memory pages that do not conflict with the pages
* used before suspend.
*
* The unsafe pages are marked with the PG_nosave_free flag
* and we count them using unsafe_pages
*/
static inline void *alloc_image_page(gfp_t gfp_mask, int safe_needed)
{
void *res;
res = (void *)get_zeroed_page(gfp_mask);
if (safe_needed)
while (res && PageNosaveFree(virt_to_page(res))) {
/* The page is unsafe, mark it for swsusp_free() */
SetPageNosave(virt_to_page(res));
unsafe_pages++;
res = (void *)get_zeroed_page(gfp_mask);
}
if (res) {
SetPageNosave(virt_to_page(res));
SetPageNosaveFree(virt_to_page(res));
}
return res;
}
unsigned long get_safe_page(gfp_t gfp_mask)
{
return (unsigned long)alloc_image_page(gfp_mask, 1);
}
/**
* alloc_pagedir - Allocate the page directory.
*
* First, determine exactly how many pages we need and
* allocate them.
*
* We arrange the pages in a chain: each page is an array of PBES_PER_PAGE
* struct pbe elements (pbes) and the last element in the page points
* to the next page.
*
* On each page we set up a list of struct_pbe elements.
*/
static struct pbe *alloc_pagedir(unsigned int nr_pages, gfp_t gfp_mask,
int safe_needed)
{
unsigned int num;
struct pbe *pblist, *pbe;
if (!nr_pages)
return NULL;
pblist = alloc_image_page(gfp_mask, safe_needed);
/* FIXME: rewrite this ugly loop */
for (pbe = pblist, num = PBES_PER_PAGE; pbe && num < nr_pages;
pbe = pbe->next, num += PBES_PER_PAGE) {
pbe += PB_PAGE_SKIP;
pbe->next = alloc_image_page(gfp_mask, safe_needed);
}
if (!pbe) { /* get_zeroed_page() failed */
free_pagedir(pblist, 1);
pblist = NULL;
} else
create_pbe_list(pblist, nr_pages);
return pblist;
}
/**
* Free pages we allocated for suspend. Suspend pages are alocated
* before atomic copy, so we need to free them after resume.
*/
void swsusp_free(void)
{
struct zone *zone;
unsigned long zone_pfn;
for_each_zone(zone) {
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
if (pfn_valid(zone_pfn + zone->zone_start_pfn)) {
struct page *page;
page = pfn_to_page(zone_pfn + zone->zone_start_pfn);
if (PageNosave(page) && PageNosaveFree(page)) {
ClearPageNosave(page);
ClearPageNosaveFree(page);
free_page((long) page_address(page));
}
}
}
nr_copy_pages = 0;
nr_meta_pages = 0;
pagedir_nosave = NULL;
buffer = NULL;
}
/**
* enough_free_mem - Make sure we enough free memory to snapshot.
*
* Returns TRUE or FALSE after checking the number of available
* free pages.
*/
static int enough_free_mem(unsigned int nr_pages)
{
struct zone *zone;
unsigned int n = 0;
for_each_zone (zone)
if (!is_highmem(zone))
n += zone->free_pages;
pr_debug("swsusp: available memory: %u pages\n", n);
return n > (nr_pages + PAGES_FOR_IO +
(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
}
static int alloc_data_pages(struct pbe *pblist, gfp_t gfp_mask, int safe_needed)
{
struct pbe *p;
for_each_pbe (p, pblist) {
p->address = (unsigned long)alloc_image_page(gfp_mask, safe_needed);
if (!p->address)
return -ENOMEM;
}
return 0;
}
static struct pbe *swsusp_alloc(unsigned int nr_pages)
{
struct pbe *pblist;
if (!(pblist = alloc_pagedir(nr_pages, GFP_ATOMIC | __GFP_COLD, 0))) {
printk(KERN_ERR "suspend: Allocating pagedir failed.\n");
return NULL;
}
if (alloc_data_pages(pblist, GFP_ATOMIC | __GFP_COLD, 0)) {
printk(KERN_ERR "suspend: Allocating image pages failed.\n");
swsusp_free();
return NULL;
}
return pblist;
}
asmlinkage int swsusp_save(void)
{
unsigned int nr_pages;
pr_debug("swsusp: critical section: \n");
drain_local_pages();
nr_pages = count_data_pages();
printk("swsusp: Need to copy %u pages\n", nr_pages);
pr_debug("swsusp: pages needed: %u + %lu + %u, free: %u\n",
nr_pages,
(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE,
PAGES_FOR_IO, nr_free_pages());
if (!enough_free_mem(nr_pages)) {
printk(KERN_ERR "swsusp: Not enough free memory\n");
return -ENOMEM;
}
pagedir_nosave = swsusp_alloc(nr_pages);
if (!pagedir_nosave)
return -ENOMEM;
/* During allocating of suspend pagedir, new cold pages may appear.
* Kill them.
*/
drain_local_pages();
copy_data_pages(pagedir_nosave);
/*
* End of critical section. From now on, we can write to memory,
* but we should not touch disk. This specially means we must _not_
* touch swap space! Except we must write out our image of course.
*/
nr_copy_pages = nr_pages;
nr_meta_pages = (nr_pages * sizeof(long) + PAGE_SIZE - 1) >> PAGE_SHIFT;
printk("swsusp: critical section/: done (%d pages copied)\n", nr_pages);
return 0;
}
static void init_header(struct swsusp_info *info)
{
memset(info, 0, sizeof(struct swsusp_info));
info->version_code = LINUX_VERSION_CODE;
info->num_physpages = num_physpages;
memcpy(&info->uts, &system_utsname, sizeof(system_utsname));
info->cpus = num_online_cpus();
info->image_pages = nr_copy_pages;
info->pages = nr_copy_pages + nr_meta_pages + 1;
info->size = info->pages;
info->size <<= PAGE_SHIFT;
}
/**
* pack_orig_addresses - the .orig_address fields of the PBEs from the
* list starting at @pbe are stored in the array @buf[] (1 page)
*/
static inline struct pbe *pack_orig_addresses(unsigned long *buf, struct pbe *pbe)
{
int j;
for (j = 0; j < PAGE_SIZE / sizeof(long) && pbe; j++) {
buf[j] = pbe->orig_address;
pbe = pbe->next;
}
if (!pbe)
for (; j < PAGE_SIZE / sizeof(long); j++)
buf[j] = 0;
return pbe;
}
/**
* snapshot_read_next - used for reading the system memory snapshot.
*
* On the first call to it @handle should point to a zeroed
* snapshot_handle structure. The structure gets updated and a pointer
* to it should be passed to this function every next time.
*
* The @count parameter should contain the number of bytes the caller
* wants to read from the snapshot. It must not be zero.
*
* On success the function returns a positive number. Then, the caller
* is allowed to read up to the returned number of bytes from the memory
* location computed by the data_of() macro. The number returned
* may be smaller than @count, but this only happens if the read would
* cross a page boundary otherwise.
*
* The function returns 0 to indicate the end of data stream condition,
* and a negative number is returned on error. In such cases the
* structure pointed to by @handle is not updated and should not be used
* any more.
*/
int snapshot_read_next(struct snapshot_handle *handle, size_t count)
{
if (handle->page > nr_meta_pages + nr_copy_pages)
return 0;
if (!buffer) {
/* This makes the buffer be freed by swsusp_free() */
buffer = alloc_image_page(GFP_ATOMIC, 0);
if (!buffer)
return -ENOMEM;
}
if (!handle->offset) {
init_header((struct swsusp_info *)buffer);
handle->buffer = buffer;
handle->pbe = pagedir_nosave;
}
if (handle->prev < handle->page) {
if (handle->page <= nr_meta_pages) {
handle->pbe = pack_orig_addresses(buffer, handle->pbe);
if (!handle->pbe)
handle->pbe = pagedir_nosave;
} else {
handle->buffer = (void *)handle->pbe->address;
handle->pbe = handle->pbe->next;
}
handle->prev = handle->page;
}
handle->buf_offset = handle->page_offset;
if (handle->page_offset + count >= PAGE_SIZE) {
count = PAGE_SIZE - handle->page_offset;
handle->page_offset = 0;
handle->page++;
} else {
handle->page_offset += count;
}
handle->offset += count;
return count;
}
/**
* mark_unsafe_pages - mark the pages that cannot be used for storing
* the image during resume, because they conflict with the pages that
* had been used before suspend
*/
static int mark_unsafe_pages(struct pbe *pblist)
{
struct zone *zone;
unsigned long zone_pfn;
struct pbe *p;
if (!pblist) /* a sanity check */
return -EINVAL;
/* Clear page flags */
for_each_zone (zone) {
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
if (pfn_valid(zone_pfn + zone->zone_start_pfn))
ClearPageNosaveFree(pfn_to_page(zone_pfn +
zone->zone_start_pfn));
}
/* Mark orig addresses */
for_each_pbe (p, pblist) {
if (virt_addr_valid(p->orig_address))
SetPageNosaveFree(virt_to_page(p->orig_address));
else
return -EFAULT;
}
unsafe_pages = 0;
return 0;
}
static void copy_page_backup_list(struct pbe *dst, struct pbe *src)
{
/* We assume both lists contain the same number of elements */
while (src) {
dst->orig_address = src->orig_address;
dst = dst->next;
src = src->next;
}
}
static int check_header(struct swsusp_info *info)
{
char *reason = NULL;
if (info->version_code != LINUX_VERSION_CODE)
reason = "kernel version";
if (info->num_physpages != num_physpages)
reason = "memory size";
if (strcmp(info->uts.sysname,system_utsname.sysname))
reason = "system type";
if (strcmp(info->uts.release,system_utsname.release))
reason = "kernel release";
if (strcmp(info->uts.version,system_utsname.version))
reason = "version";
if (strcmp(info->uts.machine,system_utsname.machine))
reason = "machine";
if (reason) {
printk(KERN_ERR "swsusp: Resume mismatch: %s\n", reason);
return -EPERM;
}
return 0;
}
/**
* load header - check the image header and copy data from it
*/
static int load_header(struct snapshot_handle *handle,
struct swsusp_info *info)
{
int error;
struct pbe *pblist;
error = check_header(info);
if (!error) {
pblist = alloc_pagedir(info->image_pages, GFP_ATOMIC, 0);
if (!pblist)
return -ENOMEM;
pagedir_nosave = pblist;
handle->pbe = pblist;
nr_copy_pages = info->image_pages;
nr_meta_pages = info->pages - info->image_pages - 1;
}
return error;
}
/**
* unpack_orig_addresses - copy the elements of @buf[] (1 page) to
* the PBEs in the list starting at @pbe
*/
static inline struct pbe *unpack_orig_addresses(unsigned long *buf,
struct pbe *pbe)
{
int j;
for (j = 0; j < PAGE_SIZE / sizeof(long) && pbe; j++) {
pbe->orig_address = buf[j];
pbe = pbe->next;
}
return pbe;
}
/**
* prepare_image - use metadata contained in the PBE list
* pointed to by pagedir_nosave to mark the pages that will
* be overwritten in the process of restoring the system
* memory state from the image ("unsafe" pages) and allocate
* memory for the image
*
* The idea is to allocate the PBE list first and then
* allocate as many pages as it's needed for the image data,
* but not to assign these pages to the PBEs initially.
* Instead, we just mark them as allocated and create a list
* of "safe" which will be used later
*/
struct safe_page {
struct safe_page *next;
char padding[PAGE_SIZE - sizeof(void *)];
};
static struct safe_page *safe_pages;
static int prepare_image(struct snapshot_handle *handle)
{
int error = 0;
unsigned int nr_pages = nr_copy_pages;
struct pbe *p, *pblist = NULL;
p = pagedir_nosave;
error = mark_unsafe_pages(p);
if (!error) {
pblist = alloc_pagedir(nr_pages, GFP_ATOMIC, 1);
if (pblist)
copy_page_backup_list(pblist, p);
free_pagedir(p, 0);
if (!pblist)
error = -ENOMEM;
}
safe_pages = NULL;
if (!error && nr_pages > unsafe_pages) {
nr_pages -= unsafe_pages;
while (nr_pages--) {
struct safe_page *ptr;
ptr = (struct safe_page *)get_zeroed_page(GFP_ATOMIC);
if (!ptr) {
error = -ENOMEM;
break;
}
if (!PageNosaveFree(virt_to_page(ptr))) {
/* The page is "safe", add it to the list */
ptr->next = safe_pages;
safe_pages = ptr;
}
/* Mark the page as allocated */
SetPageNosave(virt_to_page(ptr));
SetPageNosaveFree(virt_to_page(ptr));
}
}
if (!error) {
pagedir_nosave = pblist;
} else {
handle->pbe = NULL;
swsusp_free();
}
return error;
}
static void *get_buffer(struct snapshot_handle *handle)
{
struct pbe *pbe = handle->pbe, *last = handle->last_pbe;
struct page *page = virt_to_page(pbe->orig_address);
if (PageNosave(page) && PageNosaveFree(page)) {
/*
* We have allocated the "original" page frame and we can
* use it directly to store the read page
*/
pbe->address = 0;
if (last && last->next)
last->next = NULL;
return (void *)pbe->orig_address;
}
/*
* The "original" page frame has not been allocated and we have to
* use a "safe" page frame to store the read page
*/
pbe->address = (unsigned long)safe_pages;
safe_pages = safe_pages->next;
if (last)
last->next = pbe;
handle->last_pbe = pbe;
return (void *)pbe->address;
}
/**
* snapshot_write_next - used for writing the system memory snapshot.
*
* On the first call to it @handle should point to a zeroed
* snapshot_handle structure. The structure gets updated and a pointer
* to it should be passed to this function every next time.
*
* The @count parameter should contain the number of bytes the caller
* wants to write to the image. It must not be zero.
*
* On success the function returns a positive number. Then, the caller
* is allowed to write up to the returned number of bytes to the memory
* location computed by the data_of() macro. The number returned
* may be smaller than @count, but this only happens if the write would
* cross a page boundary otherwise.
*
* The function returns 0 to indicate the "end of file" condition,
* and a negative number is returned on error. In such cases the
* structure pointed to by @handle is not updated and should not be used
* any more.
*/
int snapshot_write_next(struct snapshot_handle *handle, size_t count)
{
int error = 0;
if (handle->prev && handle->page > nr_meta_pages + nr_copy_pages)
return 0;
if (!buffer) {
/* This makes the buffer be freed by swsusp_free() */
buffer = alloc_image_page(GFP_ATOMIC, 0);
if (!buffer)
return -ENOMEM;
}
if (!handle->offset)
handle->buffer = buffer;
if (handle->prev < handle->page) {
if (!handle->prev) {
error = load_header(handle, (struct swsusp_info *)buffer);
if (error)
return error;
} else if (handle->prev <= nr_meta_pages) {
handle->pbe = unpack_orig_addresses(buffer, handle->pbe);
if (!handle->pbe) {
error = prepare_image(handle);
if (error)
return error;
handle->pbe = pagedir_nosave;
handle->last_pbe = NULL;
handle->buffer = get_buffer(handle);
}
} else {
handle->pbe = handle->pbe->next;
handle->buffer = get_buffer(handle);
}
handle->prev = handle->page;
}
handle->buf_offset = handle->page_offset;
if (handle->page_offset + count >= PAGE_SIZE) {
count = PAGE_SIZE - handle->page_offset;
handle->page_offset = 0;
handle->page++;
} else {
handle->page_offset += count;
}
handle->offset += count;
return count;
}
int snapshot_image_loaded(struct snapshot_handle *handle)
{
return !(!handle->pbe || handle->pbe->next || !nr_copy_pages ||
handle->page <= nr_meta_pages + nr_copy_pages);
}
|