/* * 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@suse.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/utsname.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 "power.h" #define SWSUSP_SIG "S1SUSPEND" 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; /* * General things */ static unsigned short root_swap = 0xffff; 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. * @bio_chain: list of pending biod (for async reading) * * Straight from the textbook - allocate and initialize the bio. * If we're reading, make sure the page is marked as dirty. * Then submit it and, if @bio_chain == NULL, wait. */ static int submit(int rw, pgoff_t page_off, struct page *page, struct bio **bio_chain) { const int bio_rw = rw | (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG); struct bio *bio; bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1); if (!bio) return -ENOMEM; bio->bi_sector = page_off * (PAGE_SIZE >> 9); bio->bi_bdev = resume_bdev; bio->bi_end_io = end_swap_bio_read; if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) { printk(KERN_ERR "PM: Adding page to bio failed at %ld\n", page_off); bio_put(bio); return -EFAULT; } lock_page(page); bio_get(bio); if (bio_chain == NULL) { submit_bio(bio_rw, bio); wait_on_page_locked(page); if (rw == READ) bio_set_pages_dirty(bio); bio_put(bio); } else { if (rw == READ) get_page(page); /* These pages are freed later */ bio->bi_private = *bio_chain; *bio_chain = bio; submit_bio(bio_rw, bio); } return 0; } static int bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain) { return submit(READ, page_off, virt_to_page(addr), bio_chain); } static int bio_write_page(pgoff_t page_off, void *addr, struct bio **bio_chain) { return submit(WRITE, page_off, virt_to_page(addr), bio_chain); } static int wait_on_bio_chain(struct bio **bio_chain) { struct bio *bio; struct bio *next_bio; int ret = 0; if (bio_chain == NULL) return 0; bio = *bio_chain; if (bio == NULL) return 0; while (bio) { struct page *page; next_bio = bio->bi_private; page = bio->bi_io_vec[0].bv_page; wait_on_page_locked(page); if (!PageUptodate(page) || PageError(page)) ret = -EIO; put_page(page); bio_put(bio); bio = next_bio; } *bio_chain = NULL; return ret; } /* * Saving part */ static int mark_swapfiles(sector_t start, unsigned int flags) { int error; 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 = start; swsusp_header->flags = flags; error = 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) */ static int swsusp_swap_check(void) /* This is called before saving image */ { int res; res = swap_type_of(swsusp_resume_device, swsusp_resume_block, &resume_bdev); if (res < 0) return res; root_swap = res; res = blkdev_get(resume_bdev, FMODE_WRITE); if (res) return res; res = set_blocksize(resume_bdev, PAGE_SIZE); if (res < 0) blkdev_put(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 bio_write_page(offset, src, bio_chain); } /* * 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_SIZE 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; unsigned int k; }; 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) { handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL); if (!handle->cur) return -ENOMEM; handle->cur_swap = alloc_swapdev_block(root_swap); if (!handle->cur_swap) { release_swap_writer(handle); return -ENOSPC; } handle->k = 0; return 0; } 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 = 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; } /** * 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 error = 0; 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); do { ret = snapshot_read_next(snapshot, PAGE_SIZE); if (ret > 0) { error = swap_write_page(handle, data_of(*snapshot), &bio); if (error) break; if (!(nr_pages % m)) printk("\b\b\b\b%3d%%", nr_pages / m); nr_pages++; } } while (ret > 0); err2 = wait_on_bio_chain(&bio); do_gettimeofday(&stop); if (!error) error = err2; if (!error) printk("\b\b\b\bdone\n"); swsusp_show_speed(&start, &stop, nr_to_write, "Wrote"); return error; } /** * 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; int error; error = swsusp_swap_check(); if (error) { printk(KERN_ERR "PM: Cannot find swap device, try " "swapon -a.\n"); return error; } memset(&snapshot, 0, sizeof(struct snapshot_handle)); error = snapshot_read_next(&snapshot, PAGE_SIZE); if (error < PAGE_SIZE) { if (error >= 0) error = -EFAULT; goto out; } header = (struct swsusp_info *)data_of(snapshot); if (!enough_swap(header->pages)) { printk(KERN_ERR "PM: Not enough free swap\n"); error = -ENOSPC; goto out; } error = get_swap_writer(&handle); if (!error) { sector_t start = handle.cur_swap; error = swap_write_page(&handle, header, NULL); if (!error) error = save_image(&handle, &snapshot, header->pages - 1); if (!error) { flush_swap_writer(&handle); printk(KERN_INFO "PM: S"); error = mark_swapfiles(start, flags); printk("|\n"); } } if (error) free_all_swap_pages(root_swap); release_swap_writer(&handle); out: swsusp_close(FMODE_WRITE); 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, sector_t start) { int error; if (!start) return -EINVAL; handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT | __GFP_HIGH); if (!handle->cur) return -ENOMEM; error = bio_read_page(start, 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 = bio_read_page(offset, buf, bio_chain); if (error) return error; if (++handle->k >= MAP_PAGE_ENTRIES) { error = wait_on_bio_chain(bio_chain); handle->k = 0; offset = handle->cur->next_swap; if (!offset) release_swap_reader(handle); else if (!error) error = bio_read_page(offset, handle->cur, NULL); } return error; } /** * 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, PAGE_SIZE); if (error <= 0) break; error = swap_read_page(handle, data_of(*snapshot), &bio); if (error) break; if (snapshot->sync_read) error = wait_on_bio_chain(&bio); if (error) break; if (!(nr_pages % m)) printk("\b\b\b\b%3d%%", nr_pages / m); nr_pages++; } err2 = 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; } 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; *flags_p = swsusp_header->flags; if (IS_ERR(resume_bdev)) { pr_debug("PM: Image device not initialised\n"); return PTR_ERR(resume_bdev); } memset(&snapshot, 0, sizeof(struct snapshot_handle)); error = snapshot_write_next(&snapshot, PAGE_SIZE); if (error < PAGE_SIZE) return error < 0 ? error : -EFAULT; header = (struct swsusp_info *)data_of(snapshot); error = get_swap_reader(&handle, swsusp_header->image); if (!error) error = swap_read_page(&handle, header, NULL); if (!error) error = load_image(&handle, &snapshot, header->pages - 1); release_swap_reader(&handle); blkdev_put(resume_bdev, FMODE_READ); 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; 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, PAGE_SIZE); error = bio_read_page(swsusp_resume_block, swsusp_header, NULL); if (error) 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(swsusp_resume_block, swsusp_header, NULL); } else { return -EINVAL; } if (error) blkdev_put(resume_bdev, FMODE_READ); else pr_debug("PM: Signature found, resuming\n"); } else { error = PTR_ERR(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(resume_bdev)) { pr_debug("PM: Image device not initialised\n"); return; } blkdev_put(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);