/* * linux/kernel/power/swap.c * * This file provides functions for reading the suspend image from * and writing it to a swap partition. * * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@ucw.cz> * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl> * * This file is released under the GPLv2. * */ #include <linux/module.h> #include <linux/file.h> #include <linux/delay.h> #include <linux/bitops.h> #include <linux/genhd.h> #include <linux/device.h> #include <linux/buffer_head.h> #include <linux/bio.h> #include <linux/blkdev.h> #include <linux/swap.h> #include <linux/swapops.h> #include <linux/pm.h> #include <linux/slab.h> #include "power.h" #define SWSUSP_SIG "S1SUSPEND" /* * The swap map is a data structure used for keeping track of each page * written to a swap partition. It consists of many swap_map_page * structures that contain each an array of MAP_PAGE_ENTRIES swap entries. * These structures are stored on the swap and linked together with the * help of the .next_swap member. * * The swap map is created during suspend. The swap map pages are * allocated and populated one at a time, so we only need one memory * page to set up the entire structure. * * During resume we also only need to use one swap_map_page structure * at a time. */ #define MAP_PAGE_ENTRIES (PAGE_SIZE / sizeof(sector_t) - 1) struct swap_map_page { sector_t entries[MAP_PAGE_ENTRIES]; sector_t next_swap; }; /** * The swap_map_handle structure is used for handling swap in * a file-alike way */ struct swap_map_handle { struct swap_map_page *cur; sector_t cur_swap; sector_t first_sector; unsigned int k; }; struct swsusp_header { char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int)]; sector_t image; unsigned int flags; /* Flags to pass to the "boot" kernel */ char orig_sig[10]; char sig[10]; } __attribute__((packed)); static struct swsusp_header *swsusp_header; /** * The following functions are used for tracing the allocated * swap pages, so that they can be freed in case of an error. */ struct swsusp_extent { struct rb_node node; unsigned long start; unsigned long end; }; static struct rb_root swsusp_extents = RB_ROOT; static int swsusp_extents_insert(unsigned long swap_offset) { struct rb_node **new = &(swsusp_extents.rb_node); struct rb_node *parent = NULL; struct swsusp_extent *ext; /* Figure out where to put the new node */ while (*new) { ext = container_of(*new, struct swsusp_extent, node); parent = *new; if (swap_offset < ext->start) { /* Try to merge */ if (swap_offset == ext->start - 1) { ext->start--; return 0; } new = &((*new)->rb_left); } else if (swap_offset > ext->end) { /* Try to merge */ if (swap_offset == ext->end + 1) { ext->end++; return 0; } new = &((*new)->rb_right); } else { /* It already is in the tree */ return -EINVAL; } } /* Add the new node and rebalance the tree. */ ext = kzalloc(sizeof(struct swsusp_extent), GFP_KERNEL); if (!ext) return -ENOMEM; ext->start = swap_offset; ext->end = swap_offset; rb_link_node(&ext->node, parent, new); rb_insert_color(&ext->node, &swsusp_extents); return 0; } /** * alloc_swapdev_block - allocate a swap page and register that it has * been allocated, so that it can be freed in case of an error. */ sector_t alloc_swapdev_block(int swap) { unsigned long offset; offset = swp_offset(get_swap_page_of_type(swap)); if (offset) { if (swsusp_extents_insert(offset)) swap_free(swp_entry(swap, offset)); else return swapdev_block(swap, offset); } return 0; } /** * free_all_swap_pages - free swap pages allocated for saving image data. * It also frees the extents used to register which swap entries had been * allocated. */ void free_all_swap_pages(int swap) { struct rb_node *node; while ((node = swsusp_extents.rb_node)) { struct swsusp_extent *ext; unsigned long offset; ext = container_of(node, struct swsusp_extent, node); rb_erase(node, &swsusp_extents); for (offset = ext->start; offset <= ext->end; offset++) swap_free(swp_entry(swap, offset)); kfree(ext); } } int swsusp_swap_in_use(void) { return (swsusp_extents.rb_node != NULL); } /* * General things */ static unsigned short root_swap = 0xffff; struct block_device *hib_resume_bdev; /* * Saving part */ static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags) { int error; hib_bio_read_page(swsusp_resume_block, swsusp_header, NULL); if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) || !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) { memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10); memcpy(swsusp_header->sig,SWSUSP_SIG, 10); swsusp_header->image = handle->first_sector; swsusp_header->flags = flags; error = hib_bio_write_page(swsusp_resume_block, swsusp_header, NULL); } else { printk(KERN_ERR "PM: Swap header not found!\n"); error = -ENODEV; } return error; } /** * swsusp_swap_check - check if the resume device is a swap device * and get its index (if so) * * This is called before saving image */ static int swsusp_swap_check(void) { int res; res = swap_type_of(swsusp_resume_device, swsusp_resume_block, &hib_resume_bdev); if (res < 0) return res; root_swap = res; res = blkdev_get(hib_resume_bdev, FMODE_WRITE); if (res) return res; res = set_blocksize(hib_resume_bdev, PAGE_SIZE); if (res < 0) blkdev_put(hib_resume_bdev, FMODE_WRITE); return res; } /** * write_page - Write one page to given swap location. * @buf: Address we're writing. * @offset: Offset of the swap page we're writing to. * @bio_chain: Link the next write BIO here */ static int write_page(void *buf, sector_t offset, struct bio **bio_chain) { void *src; if (!offset) return -ENOSPC; if (bio_chain) { src = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH); if (src) { memcpy(src, buf, PAGE_SIZE); } else { WARN_ON_ONCE(1); bio_chain = NULL; /* Go synchronous */ src = buf; } } else { src = buf; } return hib_bio_write_page(offset, src, bio_chain); } static void release_swap_writer(struct swap_map_handle *handle) { if (handle->cur) free_page((unsigned long)handle->cur); handle->cur = NULL; } static int get_swap_writer(struct swap_map_handle *handle) { int ret; ret = swsusp_swap_check(); if (ret) { if (ret != -ENOSPC) printk(KERN_ERR "PM: Cannot find swap device, try " "swapon -a.\n"); return ret; } handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL); if (!handle->cur) { ret = -ENOMEM; goto err_close; } handle->cur_swap = alloc_swapdev_block(root_swap); if (!handle->cur_swap) { ret = -ENOSPC; goto err_rel; } handle->k = 0; handle->first_sector = handle->cur_swap; return 0; err_rel: release_swap_writer(handle); err_close: swsusp_close(FMODE_WRITE); return ret; } static int swap_write_page(struct swap_map_handle *handle, void *buf, struct bio **bio_chain) { int error = 0; sector_t offset; if (!handle->cur) return -EINVAL; offset = alloc_swapdev_block(root_swap); error = write_page(buf, offset, bio_chain); if (error) return error; handle->cur->entries[handle->k++] = offset; if (handle->k >= MAP_PAGE_ENTRIES) { error = hib_wait_on_bio_chain(bio_chain); if (error) goto out; offset = alloc_swapdev_block(root_swap); if (!offset) return -ENOSPC; handle->cur->next_swap = offset; error = write_page(handle->cur, handle->cur_swap, NULL); if (error) goto out; memset(handle->cur, 0, PAGE_SIZE); handle->cur_swap = offset; handle->k = 0; } out: return error; } static int flush_swap_writer(struct swap_map_handle *handle) { if (handle->cur && handle->cur_swap) return write_page(handle->cur, handle->cur_swap, NULL); else return -EINVAL; } static int swap_writer_finish(struct swap_map_handle *handle, unsigned int flags, int error) { if (!error) { flush_swap_writer(handle); printk(KERN_INFO "PM: S"); error = mark_swapfiles(handle, flags); printk("|\n"); } if (error) free_all_swap_pages(root_swap); release_swap_writer(handle); swsusp_close(FMODE_WRITE); return error; } /** * save_image - save the suspend image data */ static int save_image(struct swap_map_handle *handle, struct snapshot_handle *snapshot, unsigned int nr_to_write) { unsigned int m; int ret; int nr_pages; int err2; struct bio *bio; struct timeval start; struct timeval stop; printk(KERN_INFO "PM: Saving image data pages (%u pages) ... ", nr_to_write); m = nr_to_write / 100; if (!m) m = 1; nr_pages = 0; bio = NULL; do_gettimeofday(&start); while (1) { ret = snapshot_read_next(snapshot); if (ret <= 0) break; ret = swap_write_page(handle, data_of(*snapshot), &bio); if (ret) break; if (!(nr_pages % m)) printk(KERN_CONT "\b\b\b\b%3d%%", nr_pages / m); nr_pages++; } err2 = hib_wait_on_bio_chain(&bio); do_gettimeofday(&stop); if (!ret) ret = err2; if (!ret) printk(KERN_CONT "\b\b\b\bdone\n"); else printk(KERN_CONT "\n"); swsusp_show_speed(&start, &stop, nr_to_write, "Wrote"); return ret; } /** * enough_swap - Make sure we have enough swap to save the image. * * Returns TRUE or FALSE after checking the total amount of swap * space avaiable from the resume partition. */ static int enough_swap(unsigned int nr_pages) { unsigned int free_swap = count_swap_pages(root_swap, 1); pr_debug("PM: Free swap pages: %u\n", free_swap); return free_swap > nr_pages + PAGES_FOR_IO; } /** * swsusp_write - Write entire image and metadata. * @flags: flags to pass to the "boot" kernel in the image header * * It is important _NOT_ to umount filesystems at this point. We want * them synced (in case something goes wrong) but we DO not want to mark * filesystem clean: it is not. (And it does not matter, if we resume * correctly, we'll mark system clean, anyway.) */ int swsusp_write(unsigned int flags) { struct swap_map_handle handle; struct snapshot_handle snapshot; struct swsusp_info *header; unsigned long pages; int error; pages = snapshot_get_image_size(); error = get_swap_writer(&handle); if (error) { printk(KERN_ERR "PM: Cannot get swap writer\n"); return error; } if (!enough_swap(pages)) { printk(KERN_ERR "PM: Not enough free swap\n"); error = -ENOSPC; goto out_finish; } memset(&snapshot, 0, sizeof(struct snapshot_handle)); error = snapshot_read_next(&snapshot); if (error < PAGE_SIZE) { if (error >= 0) error = -EFAULT; goto out_finish; } header = (struct swsusp_info *)data_of(snapshot); error = swap_write_page(&handle, header, NULL); if (!error) error = save_image(&handle, &snapshot, pages - 1); out_finish: error = swap_writer_finish(&handle, flags, error); return error; } /** * The following functions allow us to read data using a swap map * in a file-alike way */ static void release_swap_reader(struct swap_map_handle *handle) { if (handle->cur) free_page((unsigned long)handle->cur); handle->cur = NULL; } static int get_swap_reader(struct swap_map_handle *handle, unsigned int *flags_p) { int error; *flags_p = swsusp_header->flags; if (!swsusp_header->image) /* how can this happen? */ return -EINVAL; handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT | __GFP_HIGH); if (!handle->cur) return -ENOMEM; error = hib_bio_read_page(swsusp_header->image, handle->cur, NULL); if (error) { release_swap_reader(handle); return error; } handle->k = 0; return 0; } static int swap_read_page(struct swap_map_handle *handle, void *buf, struct bio **bio_chain) { sector_t offset; int error; if (!handle->cur) return -EINVAL; offset = handle->cur->entries[handle->k]; if (!offset) return -EFAULT; error = hib_bio_read_page(offset, buf, bio_chain); if (error) return error; if (++handle->k >= MAP_PAGE_ENTRIES) { error = hib_wait_on_bio_chain(bio_chain); handle->k = 0; offset = handle->cur->next_swap; if (!offset) release_swap_reader(handle); else if (!error) error = hib_bio_read_page(offset, handle->cur, NULL); } return error; } static int swap_reader_finish(struct swap_map_handle *handle) { release_swap_reader(handle); return 0; } /** * load_image - load the image using the swap map handle * @handle and the snapshot handle @snapshot * (assume there are @nr_pages pages to load) */ static int load_image(struct swap_map_handle *handle, struct snapshot_handle *snapshot, unsigned int nr_to_read) { unsigned int m; int error = 0; struct timeval start; struct timeval stop; struct bio *bio; int err2; unsigned nr_pages; printk(KERN_INFO "PM: Loading image data pages (%u pages) ... ", nr_to_read); m = nr_to_read / 100; if (!m) m = 1; nr_pages = 0; bio = NULL; do_gettimeofday(&start); for ( ; ; ) { error = snapshot_write_next(snapshot); if (error <= 0) break; error = swap_read_page(handle, data_of(*snapshot), &bio); if (error) break; if (snapshot->sync_read) error = hib_wait_on_bio_chain(&bio); if (error) break; if (!(nr_pages % m)) printk("\b\b\b\b%3d%%", nr_pages / m); nr_pages++; } err2 = hib_wait_on_bio_chain(&bio); do_gettimeofday(&stop); if (!error) error = err2; if (!error) { printk("\b\b\b\bdone\n"); snapshot_write_finalize(snapshot); if (!snapshot_image_loaded(snapshot)) error = -ENODATA; } else printk("\n"); swsusp_show_speed(&start, &stop, nr_to_read, "Read"); return error; } /** * swsusp_read - read the hibernation image. * @flags_p: flags passed by the "frozen" kernel in the image header should * be written into this memeory location */ int swsusp_read(unsigned int *flags_p) { int error; struct swap_map_handle handle; struct snapshot_handle snapshot; struct swsusp_info *header; memset(&snapshot, 0, sizeof(struct snapshot_handle)); error = snapshot_write_next(&snapshot); if (error < PAGE_SIZE) return error < 0 ? error : -EFAULT; header = (struct swsusp_info *)data_of(snapshot); error = get_swap_reader(&handle, flags_p); if (error) goto end; if (!error) error = swap_read_page(&handle, header, NULL); if (!error) error = load_image(&handle, &snapshot, header->pages - 1); swap_reader_finish(&handle); end: if (!error) pr_debug("PM: Image successfully loaded\n"); else pr_debug("PM: Error %d resuming\n", error); return error; } /** * swsusp_check - Check for swsusp signature in the resume device */ int swsusp_check(void) { int error; hib_resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ); if (!IS_ERR(hib_resume_bdev)) { set_blocksize(hib_resume_bdev, PAGE_SIZE); memset(swsusp_header, 0, PAGE_SIZE); error = hib_bio_read_page(swsusp_resume_block, swsusp_header, NULL); if (error) goto put; if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) { memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10); /* Reset swap signature now */ error = hib_bio_write_page(swsusp_resume_block, swsusp_header, NULL); } else { error = -EINVAL; } put: if (error) blkdev_put(hib_resume_bdev, FMODE_READ); else pr_debug("PM: Signature found, resuming\n"); } else { error = PTR_ERR(hib_resume_bdev); } if (error) pr_debug("PM: Error %d checking image file\n", error); return error; } /** * swsusp_close - close swap device. */ void swsusp_close(fmode_t mode) { if (IS_ERR(hib_resume_bdev)) { pr_debug("PM: Image device not initialised\n"); return; } blkdev_put(hib_resume_bdev, mode); } static int swsusp_header_init(void) { swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL); if (!swsusp_header) panic("Could not allocate memory for swsusp_header\n"); return 0; } core_initcall(swsusp_header_init);