diff options
Diffstat (limited to 'kernel/power/swap.c')
| -rw-r--r-- | kernel/power/swap.c | 647 |
1 files changed, 647 insertions, 0 deletions
diff --git a/kernel/power/swap.c b/kernel/power/swap.c new file mode 100644 index 0000000..6da1435 --- /dev/null +++ b/kernel/power/swap.c @@ -0,0 +1,647 @@ +/* + * 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) +{ + 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(rw | (1 << BIO_RW_SYNC), 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(rw | (1 << BIO_RW_SYNC), 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); |
