2 * linux/kernel/power/swap.c
4 * This file provides functions for reading the suspend image from
5 * and writing it to a swap partition.
7 * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@suse.cz>
8 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
10 * This file is released under the GPLv2.
14 #include <linux/module.h>
15 #include <linux/smp_lock.h>
16 #include <linux/file.h>
17 #include <linux/utsname.h>
18 #include <linux/version.h>
19 #include <linux/delay.h>
20 #include <linux/bitops.h>
21 #include <linux/genhd.h>
22 #include <linux/device.h>
23 #include <linux/buffer_head.h>
24 #include <linux/bio.h>
25 #include <linux/blkdev.h>
26 #include <linux/swap.h>
27 #include <linux/swapops.h>
32 extern char resume_file[];
34 #define SWSUSP_SIG "S1SUSPEND"
36 struct swsusp_header {
37 char reserved[PAGE_SIZE - 20 - sizeof(sector_t)];
41 } __attribute__((packed));
43 static struct swsusp_header *swsusp_header;
49 static unsigned short root_swap = 0xffff;
50 static struct block_device *resume_bdev;
53 * submit - submit BIO request.
55 * @off physical offset of page.
56 * @page: page we're reading or writing.
57 * @bio_chain: list of pending biod (for async reading)
59 * Straight from the textbook - allocate and initialize the bio.
60 * If we're reading, make sure the page is marked as dirty.
61 * Then submit it and, if @bio_chain == NULL, wait.
63 static int submit(int rw, pgoff_t page_off, struct page *page,
64 struct bio **bio_chain)
68 bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
71 bio->bi_sector = page_off * (PAGE_SIZE >> 9);
72 bio->bi_bdev = resume_bdev;
73 bio->bi_end_io = end_swap_bio_read;
75 if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
76 printk("swsusp: ERROR: adding page to bio at %ld\n", page_off);
84 if (bio_chain == NULL) {
85 submit_bio(rw | (1 << BIO_RW_SYNC), bio);
86 wait_on_page_locked(page);
88 bio_set_pages_dirty(bio);
92 get_page(page); /* These pages are freed later */
93 bio->bi_private = *bio_chain;
95 submit_bio(rw | (1 << BIO_RW_SYNC), bio);
100 static int bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
102 return submit(READ, page_off, virt_to_page(addr), bio_chain);
105 static int bio_write_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
107 return submit(WRITE, page_off, virt_to_page(addr), bio_chain);
110 static int wait_on_bio_chain(struct bio **bio_chain)
113 struct bio *next_bio;
116 if (bio_chain == NULL)
125 next_bio = bio->bi_private;
126 page = bio->bi_io_vec[0].bv_page;
127 wait_on_page_locked(page);
128 if (!PageUptodate(page) || PageError(page))
142 static int mark_swapfiles(sector_t start)
146 bio_read_page(swsusp_resume_block, swsusp_header, NULL);
147 if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
148 !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
149 memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
150 memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
151 swsusp_header->image = start;
152 error = bio_write_page(swsusp_resume_block,
153 swsusp_header, NULL);
155 printk(KERN_ERR "swsusp: Swap header not found!\n");
162 * swsusp_swap_check - check if the resume device is a swap device
163 * and get its index (if so)
166 static int swsusp_swap_check(void) /* This is called before saving image */
170 res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
176 res = blkdev_get(resume_bdev, FMODE_WRITE, O_RDWR);
180 res = set_blocksize(resume_bdev, PAGE_SIZE);
182 blkdev_put(resume_bdev);
188 * write_page - Write one page to given swap location.
189 * @buf: Address we're writing.
190 * @offset: Offset of the swap page we're writing to.
191 * @bio_chain: Link the next write BIO here
194 static int write_page(void *buf, sector_t offset, struct bio **bio_chain)
202 src = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
204 memcpy(src, buf, PAGE_SIZE);
207 bio_chain = NULL; /* Go synchronous */
213 return bio_write_page(offset, src, bio_chain);
217 * The swap map is a data structure used for keeping track of each page
218 * written to a swap partition. It consists of many swap_map_page
219 * structures that contain each an array of MAP_PAGE_SIZE swap entries.
220 * These structures are stored on the swap and linked together with the
221 * help of the .next_swap member.
223 * The swap map is created during suspend. The swap map pages are
224 * allocated and populated one at a time, so we only need one memory
225 * page to set up the entire structure.
227 * During resume we also only need to use one swap_map_page structure
231 #define MAP_PAGE_ENTRIES (PAGE_SIZE / sizeof(sector_t) - 1)
233 struct swap_map_page {
234 sector_t entries[MAP_PAGE_ENTRIES];
239 * The swap_map_handle structure is used for handling swap in
243 struct swap_map_handle {
244 struct swap_map_page *cur;
246 struct bitmap_page *bitmap;
250 static void release_swap_writer(struct swap_map_handle *handle)
253 free_page((unsigned long)handle->cur);
256 free_bitmap(handle->bitmap);
257 handle->bitmap = NULL;
260 static int get_swap_writer(struct swap_map_handle *handle)
262 handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
265 handle->bitmap = alloc_bitmap(count_swap_pages(root_swap, 0));
266 if (!handle->bitmap) {
267 release_swap_writer(handle);
270 handle->cur_swap = alloc_swapdev_block(root_swap, handle->bitmap);
271 if (!handle->cur_swap) {
272 release_swap_writer(handle);
279 static int swap_write_page(struct swap_map_handle *handle, void *buf,
280 struct bio **bio_chain)
287 offset = alloc_swapdev_block(root_swap, handle->bitmap);
288 error = write_page(buf, offset, bio_chain);
291 handle->cur->entries[handle->k++] = offset;
292 if (handle->k >= MAP_PAGE_ENTRIES) {
293 error = wait_on_bio_chain(bio_chain);
296 offset = alloc_swapdev_block(root_swap, handle->bitmap);
299 handle->cur->next_swap = offset;
300 error = write_page(handle->cur, handle->cur_swap, NULL);
303 memset(handle->cur, 0, PAGE_SIZE);
304 handle->cur_swap = offset;
311 static int flush_swap_writer(struct swap_map_handle *handle)
313 if (handle->cur && handle->cur_swap)
314 return write_page(handle->cur, handle->cur_swap, NULL);
320 * save_image - save the suspend image data
323 static int save_image(struct swap_map_handle *handle,
324 struct snapshot_handle *snapshot,
325 unsigned int nr_to_write)
333 struct timeval start;
336 printk("Saving image data pages (%u pages) ... ", nr_to_write);
337 m = nr_to_write / 100;
342 do_gettimeofday(&start);
344 ret = snapshot_read_next(snapshot, PAGE_SIZE);
346 error = swap_write_page(handle, data_of(*snapshot),
351 printk("\b\b\b\b%3d%%", nr_pages / m);
355 err2 = wait_on_bio_chain(&bio);
356 do_gettimeofday(&stop);
360 printk("\b\b\b\bdone\n");
361 swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
366 * enough_swap - Make sure we have enough swap to save the image.
368 * Returns TRUE or FALSE after checking the total amount of swap
369 * space avaiable from the resume partition.
372 static int enough_swap(unsigned int nr_pages)
374 unsigned int free_swap = count_swap_pages(root_swap, 1);
376 pr_debug("swsusp: free swap pages: %u\n", free_swap);
377 return free_swap > nr_pages + PAGES_FOR_IO;
381 * swsusp_write - Write entire image and metadata.
383 * It is important _NOT_ to umount filesystems at this point. We want
384 * them synced (in case something goes wrong) but we DO not want to mark
385 * filesystem clean: it is not. (And it does not matter, if we resume
386 * correctly, we'll mark system clean, anyway.)
389 int swsusp_write(void)
391 struct swap_map_handle handle;
392 struct snapshot_handle snapshot;
393 struct swsusp_info *header;
396 error = swsusp_swap_check();
398 printk(KERN_ERR "swsusp: Cannot find swap device, try "
402 memset(&snapshot, 0, sizeof(struct snapshot_handle));
403 error = snapshot_read_next(&snapshot, PAGE_SIZE);
404 if (error < PAGE_SIZE) {
410 header = (struct swsusp_info *)data_of(snapshot);
411 if (!enough_swap(header->pages)) {
412 printk(KERN_ERR "swsusp: Not enough free swap\n");
416 error = get_swap_writer(&handle);
418 sector_t start = handle.cur_swap;
420 error = swap_write_page(&handle, header, NULL);
422 error = save_image(&handle, &snapshot,
426 flush_swap_writer(&handle);
428 error = mark_swapfiles(start);
433 free_all_swap_pages(root_swap, handle.bitmap);
434 release_swap_writer(&handle);
441 * The following functions allow us to read data using a swap map
442 * in a file-alike way
445 static void release_swap_reader(struct swap_map_handle *handle)
448 free_page((unsigned long)handle->cur);
452 static int get_swap_reader(struct swap_map_handle *handle, sector_t start)
459 handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT | __GFP_HIGH);
463 error = bio_read_page(start, handle->cur, NULL);
465 release_swap_reader(handle);
472 static int swap_read_page(struct swap_map_handle *handle, void *buf,
473 struct bio **bio_chain)
480 offset = handle->cur->entries[handle->k];
483 error = bio_read_page(offset, buf, bio_chain);
486 if (++handle->k >= MAP_PAGE_ENTRIES) {
487 error = wait_on_bio_chain(bio_chain);
489 offset = handle->cur->next_swap;
491 release_swap_reader(handle);
493 error = bio_read_page(offset, handle->cur, NULL);
499 * load_image - load the image using the swap map handle
500 * @handle and the snapshot handle @snapshot
501 * (assume there are @nr_pages pages to load)
504 static int load_image(struct swap_map_handle *handle,
505 struct snapshot_handle *snapshot,
506 unsigned int nr_to_read)
510 struct timeval start;
516 printk("Loading image data pages (%u pages) ... ", nr_to_read);
517 m = nr_to_read / 100;
522 do_gettimeofday(&start);
524 error = snapshot_write_next(snapshot, PAGE_SIZE);
527 error = swap_read_page(handle, data_of(*snapshot), &bio);
530 if (snapshot->sync_read)
531 error = wait_on_bio_chain(&bio);
535 printk("\b\b\b\b%3d%%", nr_pages / m);
538 err2 = wait_on_bio_chain(&bio);
539 do_gettimeofday(&stop);
543 printk("\b\b\b\bdone\n");
544 snapshot_write_finalize(snapshot);
545 if (!snapshot_image_loaded(snapshot))
548 swsusp_show_speed(&start, &stop, nr_to_read, "Read");
552 int swsusp_read(void)
555 struct swap_map_handle handle;
556 struct snapshot_handle snapshot;
557 struct swsusp_info *header;
559 if (IS_ERR(resume_bdev)) {
560 pr_debug("swsusp: block device not initialised\n");
561 return PTR_ERR(resume_bdev);
564 memset(&snapshot, 0, sizeof(struct snapshot_handle));
565 error = snapshot_write_next(&snapshot, PAGE_SIZE);
566 if (error < PAGE_SIZE)
567 return error < 0 ? error : -EFAULT;
568 header = (struct swsusp_info *)data_of(snapshot);
569 error = get_swap_reader(&handle, swsusp_header->image);
571 error = swap_read_page(&handle, header, NULL);
573 error = load_image(&handle, &snapshot, header->pages - 1);
574 release_swap_reader(&handle);
576 blkdev_put(resume_bdev);
579 pr_debug("swsusp: Reading resume file was successful\n");
581 pr_debug("swsusp: Error %d resuming\n", error);
586 * swsusp_check - Check for swsusp signature in the resume device
589 int swsusp_check(void)
593 resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
594 if (!IS_ERR(resume_bdev)) {
595 set_blocksize(resume_bdev, PAGE_SIZE);
596 memset(swsusp_header, 0, sizeof(PAGE_SIZE));
597 error = bio_read_page(swsusp_resume_block,
598 swsusp_header, NULL);
602 if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
603 memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
604 /* Reset swap signature now */
605 error = bio_write_page(swsusp_resume_block,
606 swsusp_header, NULL);
611 blkdev_put(resume_bdev);
613 pr_debug("swsusp: Signature found, resuming\n");
615 error = PTR_ERR(resume_bdev);
619 pr_debug("swsusp: Error %d check for resume file\n", error);
625 * swsusp_close - close swap device.
628 void swsusp_close(void)
630 if (IS_ERR(resume_bdev)) {
631 pr_debug("swsusp: block device not initialised\n");
635 blkdev_put(resume_bdev);
638 static int swsusp_header_init(void)
640 swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
642 panic("Could not allocate memory for swsusp_header\n");
646 core_initcall(swsusp_header_init);