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 static struct swsusp_header {
37 char reserved[PAGE_SIZE - 20 - sizeof(swp_entry_t)];
41 } __attribute__((packed, aligned(PAGE_SIZE))) swsusp_header;
47 static unsigned short root_swap = 0xffff;
48 static struct block_device *resume_bdev;
51 * submit - submit BIO request.
53 * @off physical offset of page.
54 * @page: page we're reading or writing.
55 * @bio_chain: list of pending biod (for async reading)
57 * Straight from the textbook - allocate and initialize the bio.
58 * If we're reading, make sure the page is marked as dirty.
59 * Then submit it and, if @bio_chain == NULL, wait.
61 static int submit(int rw, pgoff_t page_off, struct page *page,
62 struct bio **bio_chain)
66 bio = bio_alloc(GFP_ATOMIC, 1);
69 bio->bi_sector = page_off * (PAGE_SIZE >> 9);
70 bio->bi_bdev = resume_bdev;
71 bio->bi_end_io = end_swap_bio_read;
73 if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
74 printk("swsusp: ERROR: adding page to bio at %ld\n", page_off);
82 if (bio_chain == NULL) {
83 submit_bio(rw | (1 << BIO_RW_SYNC), bio);
84 wait_on_page_locked(page);
86 bio_set_pages_dirty(bio);
90 get_page(page); /* These pages are freed later */
91 bio->bi_private = *bio_chain;
93 submit_bio(rw | (1 << BIO_RW_SYNC), bio);
98 static int bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
100 return submit(READ, page_off, virt_to_page(addr), bio_chain);
103 static int bio_write_page(pgoff_t page_off, void *addr)
105 return submit(WRITE, page_off, virt_to_page(addr), NULL);
108 static int wait_on_bio_chain(struct bio **bio_chain)
111 struct bio *next_bio;
114 if (bio_chain == NULL)
123 next_bio = bio->bi_private;
124 page = bio->bi_io_vec[0].bv_page;
125 wait_on_page_locked(page);
126 if (!PageUptodate(page) || PageError(page))
136 static void show_speed(struct timeval *start, struct timeval *stop,
137 unsigned nr_pages, char *msg)
139 s64 elapsed_centisecs64;
144 elapsed_centisecs64 = timeval_to_ns(stop) - timeval_to_ns(start);
145 do_div(elapsed_centisecs64, NSEC_PER_SEC / 100);
146 centisecs = elapsed_centisecs64;
148 centisecs = 1; /* avoid div-by-zero */
149 k = nr_pages * (PAGE_SIZE / 1024);
150 kps = (k * 100) / centisecs;
151 printk("%s %d kbytes in %d.%02d seconds (%d.%02d MB/s)\n", msg, k,
152 centisecs / 100, centisecs % 100,
153 kps / 1000, (kps % 1000) / 10);
160 static int mark_swapfiles(swp_entry_t start)
164 rw_swap_page_sync(READ, swp_entry(root_swap, 0),
165 virt_to_page((unsigned long)&swsusp_header), NULL);
166 if (!memcmp("SWAP-SPACE",swsusp_header.sig, 10) ||
167 !memcmp("SWAPSPACE2",swsusp_header.sig, 10)) {
168 memcpy(swsusp_header.orig_sig,swsusp_header.sig, 10);
169 memcpy(swsusp_header.sig,SWSUSP_SIG, 10);
170 swsusp_header.image = start;
171 error = rw_swap_page_sync(WRITE, swp_entry(root_swap, 0),
172 virt_to_page((unsigned long)&swsusp_header),
175 pr_debug("swsusp: Partition is not swap space.\n");
182 * swsusp_swap_check - check if the resume device is a swap device
183 * and get its index (if so)
186 static int swsusp_swap_check(void) /* This is called before saving image */
188 int res = swap_type_of(swsusp_resume_device, 0);
198 * write_page - Write one page to given swap location.
199 * @buf: Address we're writing.
200 * @offset: Offset of the swap page we're writing to.
201 * @bio_chain: Link the next write BIO here
204 static int write_page(void *buf, unsigned long offset, struct bio **bio_chain)
210 struct page *page = virt_to_page(buf);
214 * Whether or not we successfully allocated a copy page,
215 * we take a ref on the page here. It gets undone in
216 * wait_on_bio_chain().
218 struct page *page_copy;
219 page_copy = alloc_page(GFP_ATOMIC);
220 if (page_copy == NULL) {
222 bio_chain = NULL; /* Go synchronous */
225 memcpy(page_address(page_copy),
226 page_address(page), PAGE_SIZE);
230 entry = swp_entry(root_swap, offset);
231 error = rw_swap_page_sync(WRITE, entry, page, bio_chain);
237 * The swap map is a data structure used for keeping track of each page
238 * written to a swap partition. It consists of many swap_map_page
239 * structures that contain each an array of MAP_PAGE_SIZE swap entries.
240 * These structures are stored on the swap and linked together with the
241 * help of the .next_swap member.
243 * The swap map is created during suspend. The swap map pages are
244 * allocated and populated one at a time, so we only need one memory
245 * page to set up the entire structure.
247 * During resume we also only need to use one swap_map_page structure
251 #define MAP_PAGE_ENTRIES (PAGE_SIZE / sizeof(long) - 1)
253 struct swap_map_page {
254 unsigned long entries[MAP_PAGE_ENTRIES];
255 unsigned long next_swap;
259 * The swap_map_handle structure is used for handling swap in
263 struct swap_map_handle {
264 struct swap_map_page *cur;
265 unsigned long cur_swap;
266 struct bitmap_page *bitmap;
270 static void release_swap_writer(struct swap_map_handle *handle)
273 free_page((unsigned long)handle->cur);
276 free_bitmap(handle->bitmap);
277 handle->bitmap = NULL;
280 static int get_swap_writer(struct swap_map_handle *handle)
282 handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
285 handle->bitmap = alloc_bitmap(count_swap_pages(root_swap, 0));
286 if (!handle->bitmap) {
287 release_swap_writer(handle);
290 handle->cur_swap = alloc_swap_page(root_swap, handle->bitmap);
291 if (!handle->cur_swap) {
292 release_swap_writer(handle);
299 static int swap_write_page(struct swap_map_handle *handle, void *buf,
300 struct bio **bio_chain)
303 unsigned long offset;
307 offset = alloc_swap_page(root_swap, handle->bitmap);
308 error = write_page(buf, offset, bio_chain);
311 handle->cur->entries[handle->k++] = offset;
312 if (handle->k >= MAP_PAGE_ENTRIES) {
313 error = wait_on_bio_chain(bio_chain);
316 offset = alloc_swap_page(root_swap, handle->bitmap);
319 handle->cur->next_swap = offset;
320 error = write_page(handle->cur, handle->cur_swap, NULL);
323 memset(handle->cur, 0, PAGE_SIZE);
324 handle->cur_swap = offset;
331 static int flush_swap_writer(struct swap_map_handle *handle)
333 if (handle->cur && handle->cur_swap)
334 return write_page(handle->cur, handle->cur_swap, NULL);
340 * save_image - save the suspend image data
343 static int save_image(struct swap_map_handle *handle,
344 struct snapshot_handle *snapshot,
345 unsigned int nr_to_write)
353 struct timeval start;
356 printk("Saving image data pages (%u pages) ... ", nr_to_write);
357 m = nr_to_write / 100;
362 do_gettimeofday(&start);
364 ret = snapshot_read_next(snapshot, PAGE_SIZE);
366 error = swap_write_page(handle, data_of(*snapshot),
371 printk("\b\b\b\b%3d%%", nr_pages / m);
375 err2 = wait_on_bio_chain(&bio);
376 do_gettimeofday(&stop);
380 printk("\b\b\b\bdone\n");
381 show_speed(&start, &stop, nr_to_write, "Wrote");
386 * enough_swap - Make sure we have enough swap to save the image.
388 * Returns TRUE or FALSE after checking the total amount of swap
389 * space avaiable from the resume partition.
392 static int enough_swap(unsigned int nr_pages)
394 unsigned int free_swap = count_swap_pages(root_swap, 1);
396 pr_debug("swsusp: free swap pages: %u\n", free_swap);
397 return free_swap > nr_pages + PAGES_FOR_IO;
401 * swsusp_write - Write entire image and metadata.
403 * It is important _NOT_ to umount filesystems at this point. We want
404 * them synced (in case something goes wrong) but we DO not want to mark
405 * filesystem clean: it is not. (And it does not matter, if we resume
406 * correctly, we'll mark system clean, anyway.)
409 int swsusp_write(void)
411 struct swap_map_handle handle;
412 struct snapshot_handle snapshot;
413 struct swsusp_info *header;
416 if ((error = swsusp_swap_check())) {
417 printk(KERN_ERR "swsusp: Cannot find swap device, try "
421 memset(&snapshot, 0, sizeof(struct snapshot_handle));
422 error = snapshot_read_next(&snapshot, PAGE_SIZE);
423 if (error < PAGE_SIZE)
424 return error < 0 ? error : -EFAULT;
425 header = (struct swsusp_info *)data_of(snapshot);
426 if (!enough_swap(header->pages)) {
427 printk(KERN_ERR "swsusp: Not enough free swap\n");
430 error = get_swap_writer(&handle);
432 unsigned long start = handle.cur_swap;
433 error = swap_write_page(&handle, header, NULL);
435 error = save_image(&handle, &snapshot,
438 flush_swap_writer(&handle);
440 error = mark_swapfiles(swp_entry(root_swap, start));
445 free_all_swap_pages(root_swap, handle.bitmap);
446 release_swap_writer(&handle);
451 * The following functions allow us to read data using a swap map
452 * in a file-alike way
455 static void release_swap_reader(struct swap_map_handle *handle)
458 free_page((unsigned long)handle->cur);
462 static int get_swap_reader(struct swap_map_handle *handle,
467 if (!swp_offset(start))
469 handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC);
472 error = bio_read_page(swp_offset(start), handle->cur, NULL);
474 release_swap_reader(handle);
481 static int swap_read_page(struct swap_map_handle *handle, void *buf,
482 struct bio **bio_chain)
484 unsigned long offset;
489 offset = handle->cur->entries[handle->k];
492 error = bio_read_page(offset, buf, bio_chain);
495 if (++handle->k >= MAP_PAGE_ENTRIES) {
496 error = wait_on_bio_chain(bio_chain);
498 offset = handle->cur->next_swap;
500 release_swap_reader(handle);
502 error = bio_read_page(offset, handle->cur, NULL);
508 * load_image - load the image using the swap map handle
509 * @handle and the snapshot handle @snapshot
510 * (assume there are @nr_pages pages to load)
513 static int load_image(struct swap_map_handle *handle,
514 struct snapshot_handle *snapshot,
515 unsigned int nr_to_read)
519 struct timeval start;
525 printk("Loading image data pages (%u pages) ... ", nr_to_read);
526 m = nr_to_read / 100;
531 do_gettimeofday(&start);
533 error = snapshot_write_next(snapshot, PAGE_SIZE);
536 error = swap_read_page(handle, data_of(*snapshot), &bio);
539 if (snapshot->sync_read)
540 error = wait_on_bio_chain(&bio);
544 printk("\b\b\b\b%3d%%", nr_pages / m);
547 err2 = wait_on_bio_chain(&bio);
548 do_gettimeofday(&stop);
552 printk("\b\b\b\bdone\n");
553 snapshot_free_unused_memory(snapshot);
554 if (!snapshot_image_loaded(snapshot))
557 show_speed(&start, &stop, nr_to_read, "Read");
561 int swsusp_read(void)
564 struct swap_map_handle handle;
565 struct snapshot_handle snapshot;
566 struct swsusp_info *header;
568 if (IS_ERR(resume_bdev)) {
569 pr_debug("swsusp: block device not initialised\n");
570 return PTR_ERR(resume_bdev);
573 memset(&snapshot, 0, sizeof(struct snapshot_handle));
574 error = snapshot_write_next(&snapshot, PAGE_SIZE);
575 if (error < PAGE_SIZE)
576 return error < 0 ? error : -EFAULT;
577 header = (struct swsusp_info *)data_of(snapshot);
578 error = get_swap_reader(&handle, swsusp_header.image);
580 error = swap_read_page(&handle, header, NULL);
582 error = load_image(&handle, &snapshot, header->pages - 1);
583 release_swap_reader(&handle);
585 blkdev_put(resume_bdev);
588 pr_debug("swsusp: Reading resume file was successful\n");
590 pr_debug("swsusp: Error %d resuming\n", error);
595 * swsusp_check - Check for swsusp signature in the resume device
598 int swsusp_check(void)
602 resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
603 if (!IS_ERR(resume_bdev)) {
604 set_blocksize(resume_bdev, PAGE_SIZE);
605 memset(&swsusp_header, 0, sizeof(swsusp_header));
606 if ((error = bio_read_page(0, &swsusp_header, NULL)))
608 if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) {
609 memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10);
610 /* Reset swap signature now */
611 error = bio_write_page(0, &swsusp_header);
616 blkdev_put(resume_bdev);
618 pr_debug("swsusp: Signature found, resuming\n");
620 error = PTR_ERR(resume_bdev);
624 pr_debug("swsusp: Error %d check for resume file\n", error);
630 * swsusp_close - close swap device.
633 void swsusp_close(void)
635 if (IS_ERR(resume_bdev)) {
636 pr_debug("swsusp: block device not initialised\n");
640 blkdev_put(resume_bdev);