-
-/**
- * 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 void mark_unsafe_pages(struct pbe *pblist)
-{
- struct zone *zone;
- unsigned long zone_pfn;
- struct pbe *p;
-
- if (!pblist) /* a sanity check */
- return;
-
- /* 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)
- SetPageNosaveFree(virt_to_page(p->orig_address));
-
-}
-
-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;
- }
-}
-
-/*
- * Using bio to read from swap.
- * This code requires a bit more work than just using buffer heads
- * but, it is the recommended way for 2.5/2.6.
- * The following are to signal the beginning and end of I/O. Bios
- * finish asynchronously, while we want them to happen synchronously.
- * A simple atomic_t, and a wait loop take care of this problem.
- */
-
-static atomic_t io_done = ATOMIC_INIT(0);
-
-static int end_io(struct bio *bio, unsigned int num, int err)
-{
- if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
- panic("I/O error reading memory image");
- atomic_set(&io_done, 0);
- return 0;
-}
-
-static struct block_device *resume_bdev;
-
-/**
- * submit - submit BIO request.
- * @rw: READ or WRITE.
- * @off physical offset of page.
- * @page: page we're reading or writing.
- *
- * Straight from the textbook - allocate and initialize the bio.
- * If we're writing, make sure the page is marked as dirty.
- * Then submit it and wait.
- */
-
-static int submit(int rw, pgoff_t page_off, void *page)
-{
- int error = 0;
- struct bio *bio;
-
- bio = bio_alloc(GFP_ATOMIC, 1);
- if (!bio)
- return -ENOMEM;
- bio->bi_sector = page_off * (PAGE_SIZE >> 9);
- bio->bi_bdev = resume_bdev;
- bio->bi_end_io = end_io;
-
- if (bio_add_page(bio, virt_to_page(page), PAGE_SIZE, 0) < PAGE_SIZE) {
- printk("swsusp: ERROR: adding page to bio at %ld\n",page_off);
- error = -EFAULT;
- goto Done;
- }
-
-
- atomic_set(&io_done, 1);
- submit_bio(rw | (1 << BIO_RW_SYNC), bio);
- while (atomic_read(&io_done))
- yield();
- if (rw == READ)
- bio_set_pages_dirty(bio);
- Done:
- bio_put(bio);
- return error;
-}
-
-static int bio_read_page(pgoff_t page_off, void *page)
-{
- return submit(READ, page_off, page);
-}
-
-static int bio_write_page(pgoff_t page_off, void *page)
-{
- return submit(WRITE, page_off, page);
-}
-
-/**
- * The following functions allow us to read data using a swap map
- * in a file-alike way
- */
-
-static inline void release_swap_map_reader(struct swap_map_handle *handle)
-{
- if (handle->cur)
- free_page((unsigned long)handle->cur);
- handle->cur = NULL;
-}
-
-static inline int get_swap_map_reader(struct swap_map_handle *handle,
- swp_entry_t start)
-{
- int error;
-
- if (!swp_offset(start))
- return -EINVAL;
- handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC);
- if (!handle->cur)
- return -ENOMEM;
- error = bio_read_page(swp_offset(start), handle->cur);
- if (error) {
- release_swap_map_reader(handle);
- return error;
- }
- handle->k = 0;
- return 0;
-}
-
-static inline int swap_map_read_page(struct swap_map_handle *handle, void *buf)
-{
- unsigned long offset;
- int error;
-
- if (!handle->cur)
- return -EINVAL;
- offset = swp_offset(handle->cur->entries[handle->k]);
- if (!offset)
- return -EINVAL;
- error = bio_read_page(offset, buf);
- if (error)
- return error;
- if (++handle->k >= MAP_PAGE_SIZE) {
- handle->k = 0;
- offset = swp_offset(handle->cur->next_swap);
- if (!offset)
- release_swap_map_reader(handle);
- else
- error = bio_read_page(offset, handle->cur);
- }
- return error;
-}
-
-static int check_header(void)
-{
- char *reason = NULL;
-
- dump_info();
- if (swsusp_info.version_code != LINUX_VERSION_CODE)
- reason = "kernel version";
- if (swsusp_info.num_physpages != num_physpages)
- reason = "memory size";
- if (strcmp(swsusp_info.uts.sysname,system_utsname.sysname))
- reason = "system type";
- if (strcmp(swsusp_info.uts.release,system_utsname.release))
- reason = "kernel release";
- if (strcmp(swsusp_info.uts.version,system_utsname.version))
- reason = "version";
- if (strcmp(swsusp_info.uts.machine,system_utsname.machine))
- reason = "machine";
- if (reason) {
- printk(KERN_ERR "swsusp: Resume mismatch: %s\n", reason);
- return -EPERM;
- }
- return 0;
-}
-
-/**
- * load_image_data - load the image data using the swap map handle
- * @handle and store them using the page backup list @pblist
- * (assume there are @nr_pages pages to load)
- */
-
-static int load_image_data(struct pbe *pblist,
- struct swap_map_handle *handle,
- unsigned int nr_pages)
-{
- int error;
- unsigned int m;
- struct pbe *p;
-
- if (!pblist)
- return -EINVAL;
- printk("Loading image data pages (%u pages) ... ", nr_pages);
- m = nr_pages / 100;
- if (!m)
- m = 1;
- nr_pages = 0;
- p = pblist;
- while (p) {
- error = swap_map_read_page(handle, (void *)p->address);
- if (error)
- break;
- p = p->next;
- if (!(nr_pages % m))
- printk("\b\b\b\b%3d%%", nr_pages / m);
- nr_pages++;
- }
- if (!error)
- printk("\b\b\b\bdone\n");
- 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;
-}
-
-/**
- * load_image_metadata - load the image metadata using the swap map
- * handle @handle and put them into the PBEs in the list @pblist
- */
-
-static int load_image_metadata(struct pbe *pblist, struct swap_map_handle *handle)
-{
- struct pbe *p;
- unsigned long *buf;
- unsigned int n = 0;
- int error = 0;
-
- printk("Loading image metadata ... ");
- buf = (unsigned long *)get_zeroed_page(GFP_ATOMIC);
- if (!buf)
- return -ENOMEM;
- p = pblist;
- while (p) {
- error = swap_map_read_page(handle, buf);
- if (error)
- break;
- p = unpack_orig_addresses(buf, p);
- n++;
- }
- free_page((unsigned long)buf);
- if (!error)
- printk("done (%u pages loaded)\n", n);
- return error;
-}
-
-int swsusp_read(struct pbe **pblist_ptr)
-{
- int error;
- struct pbe *p, *pblist;
- struct swap_map_handle handle;
- unsigned int nr_pages;
-
- if (IS_ERR(resume_bdev)) {
- pr_debug("swsusp: block device not initialised\n");
- return PTR_ERR(resume_bdev);
- }
-
- error = get_swap_map_reader(&handle, swsusp_header.image);
- if (!error)
- error = swap_map_read_page(&handle, &swsusp_info);
- if (!error)
- error = check_header();
- if (error)
- return error;
- nr_pages = swsusp_info.image_pages;
- p = alloc_pagedir(nr_pages, GFP_ATOMIC, 0);
- if (!p)
- return -ENOMEM;
- error = load_image_metadata(p, &handle);
- if (!error) {
- mark_unsafe_pages(p);
- pblist = alloc_pagedir(nr_pages, GFP_ATOMIC, 1);
- if (pblist)
- copy_page_backup_list(pblist, p);
- free_pagedir(p);
- if (!pblist)
- error = -ENOMEM;
-
- /* Allocate memory for the image and read the data from swap */
- if (!error)
- error = alloc_data_pages(pblist, GFP_ATOMIC, 1);
- if (!error) {
- release_eaten_pages();
- error = load_image_data(pblist, &handle, nr_pages);
- }
- if (!error)
- *pblist_ptr = pblist;
- }
- release_swap_map_reader(&handle);
-
- blkdev_put(resume_bdev);
-
- if (!error)
- pr_debug("swsusp: Reading resume file was successful\n");
- else
- pr_debug("swsusp: Error %d resuming\n", error);
- return error;
-}
-
-/**
- * swsusp_check - Check for swsusp signature in the resume device
- */
-
-int swsusp_check(void)
-{
- int error;
-
- resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
- if (!IS_ERR(resume_bdev)) {
- set_blocksize(resume_bdev, PAGE_SIZE);
- memset(&swsusp_header, 0, sizeof(swsusp_header));
- if ((error = bio_read_page(0, &swsusp_header)))
- return error;
- if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) {
- memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10);
- /* Reset swap signature now */
- error = bio_write_page(0, &swsusp_header);
- } else {
- return -EINVAL;
- }
- if (error)
- blkdev_put(resume_bdev);
- else
- pr_debug("swsusp: Signature found, resuming\n");
- } else {
- error = PTR_ERR(resume_bdev);
- }
-
- if (error)
- pr_debug("swsusp: Error %d check for resume file\n", error);
-
- return error;
-}
-
-/**
- * swsusp_close - close swap device.
- */
-
-void swsusp_close(void)
-{
- if (IS_ERR(resume_bdev)) {
- pr_debug("swsusp: block device not initialised\n");
- return;
- }
-
- blkdev_put(resume_bdev);
-}