[PATCH] swsusp: separate swap-writing/reading code

Move the swap-writing/reading code of swsusp to a separate file.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 6 insertions, 562 deletions

diff --git a/kernel/power/swsusp.c b/kernel/power/swsusp.c
index 457084f50010..c4016cbbd3e0 100644
--- a/kernel/power/swsusp.c
+++ b/kernel/power/swsusp.c
@@ -31,41 +31,24 @@
  * Fixed runaway init
  *
  * Rafael J. Wysocki <rjw@sisk.pl>
- * Added the swap map data structure and reworked the handling of swap
+ * Reworked the freeing of memory and the handling of swap
  *
  * More state savers are welcome. Especially for the scsi layer...
  *
  * For TODOs,FIXMEs also look in Documentation/power/swsusp.txt
  */
 
-#include <linux/module.h>
 #include <linux/mm.h>
 #include <linux/suspend.h>
-#include <linux/smp_lock.h>
-#include <linux/file.h>
-#include <linux/utsname.h>
-#include <linux/version.h>
-#include <linux/delay.h>
-#include <linux/bitops.h>
 #include <linux/spinlock.h>
-#include <linux/genhd.h>
 #include <linux/kernel.h>
 #include <linux/major.h>
 #include <linux/swap.h>
 #include <linux/pm.h>
-#include <linux/device.h>
-#include <linux/buffer_head.h>
 #include <linux/swapops.h>
 #include <linux/bootmem.h>
 #include <linux/syscalls.h>
 #include <linux/highmem.h>
-#include <linux/bio.h>
-
-#include <asm/uaccess.h>
-#include <asm/mmu_context.h>
-#include <asm/pgtable.h>
-#include <asm/tlbflush.h>
-#include <asm/io.h>
 
 #include "power.h"
 
@@ -89,91 +72,15 @@ static int restore_highmem(void) { return 0; }
 static unsigned int count_highmem_pages(void) { return 0; }
 #endif
 
-extern char resume_file[];
-
-#define SWSUSP_SIG      "S1SUSPEND"
-
-static struct swsusp_header {
-        char reserved[PAGE_SIZE - 20 - sizeof(swp_entry_t)];
-        swp_entry_t image;
-        char    orig_sig[10];
-        char    sig[10];
-} __attribute__((packed, aligned(PAGE_SIZE))) swsusp_header;
-
-/*
- * Saving part...
- */
-
-static unsigned short root_swap = 0xffff;
-
-static int mark_swapfiles(swp_entry_t start)
-{
-        int error;
-
-        rw_swap_page_sync(READ,
-                          swp_entry(root_swap, 0),
-                          virt_to_page((unsigned long)&swsusp_header));
-        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;
-                error = rw_swap_page_sync(WRITE,
-                                          swp_entry(root_swap, 0),
-                                          virt_to_page((unsigned long)
-                                                       &swsusp_header));
-        } else {
-                pr_debug("swsusp: Partition is not swap space.\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 = swap_type_of(swsusp_resume_device);
-
-        if (res >= 0) {
-                root_swap = res;
-                return 0;
-        }
-        return res;
-}
-
-/**
- *      The bitmap is used for tracing allocated swap pages
- *
- *      The entire bitmap consists of a number of bitmap_page
- *      structures linked with the help of the .next member.
- *      Thus each page can be allocated individually, so we only
- *      need to make 0-order memory allocations to create
- *      the bitmap.
- */
-
-#define BITMAP_PAGE_SIZE        (PAGE_SIZE - sizeof(void *))
-#define BITMAP_PAGE_CHUNKS      (BITMAP_PAGE_SIZE / sizeof(long))
-#define BITS_PER_CHUNK          (sizeof(long) * 8)
-#define BITMAP_PAGE_BITS        (BITMAP_PAGE_CHUNKS * BITS_PER_CHUNK)
-
-struct bitmap_page {
-        unsigned long           chunks[BITMAP_PAGE_CHUNKS];
-        struct bitmap_page      *next;
-};
-
 /**
  *      The following functions are used for tracing the allocated
  *      swap pages, so that they can be freed in case of an error.
  *
  *      The functions operate on a linked bitmap structure defined
- *      above
+ *      in power.h
  */
 
-static void free_bitmap(struct bitmap_page *bitmap)
+void free_bitmap(struct bitmap_page *bitmap)
 {
         struct bitmap_page *bp;
 
@@ -184,7 +91,7 @@ static void free_bitmap(struct bitmap_page *bitmap)
         }
 }
 
-static struct bitmap_page *alloc_bitmap(unsigned int nr_bits)
+struct bitmap_page *alloc_bitmap(unsigned int nr_bits)
 {
         struct bitmap_page *bitmap, *bp;
         unsigned int n;
@@ -227,7 +134,7 @@ static int bitmap_set(struct bitmap_page *bitmap, unsigned long bit)
         return 0;
 }
 
-static unsigned long alloc_swap_page(int swap, struct bitmap_page *bitmap)
+unsigned long alloc_swap_page(int swap, struct bitmap_page *bitmap)
 {
         unsigned long offset;
 
@@ -241,7 +148,7 @@ static unsigned long alloc_swap_page(int swap, struct bitmap_page *bitmap)
         return offset;
 }
 
-static void free_all_swap_pages(int swap, struct bitmap_page *bitmap)
+void free_all_swap_pages(int swap, struct bitmap_page *bitmap)
 {
         unsigned int bit, n;
         unsigned long test;
@@ -259,220 +166,6 @@ static void free_all_swap_pages(int swap, struct bitmap_page *bitmap)
 }
 
 /**
- *      write_page - Write one page to given swap location.
- *      @buf:           Address we're writing.
- *      @offset:        Offset of the swap page we're writing to.
- */
-
-static int write_page(void *buf, unsigned long offset)
-{
-        swp_entry_t entry;
-        int error = -ENOSPC;
-
-        if (offset) {
-                entry = swp_entry(root_swap, offset);
-                error = rw_swap_page_sync(WRITE, entry, virt_to_page(buf));
-        }
-        return error;
-}
-
-/*
- *      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(long) - 1)
-
-struct swap_map_page {
-        unsigned long           entries[MAP_PAGE_ENTRIES];
-        unsigned long           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;
-        unsigned long cur_swap;
-        struct bitmap_page *bitmap;
-        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;
-        if (handle->bitmap)
-                free_bitmap(handle->bitmap);
-        handle->bitmap = 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->bitmap = alloc_bitmap(count_swap_pages(root_swap, 0));
-        if (!handle->bitmap) {
-                release_swap_writer(handle);
-                return -ENOMEM;
-        }
-        handle->cur_swap = alloc_swap_page(root_swap, handle->bitmap);
-        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)
-{
-        int error;
-        unsigned long offset;
-
-        if (!handle->cur)
-                return -EINVAL;
-        offset = alloc_swap_page(root_swap, handle->bitmap);
-        error = write_page(buf, offset);
-        if (error)
-                return error;
-        handle->cur->entries[handle->k++] = offset;
-        if (handle->k >= MAP_PAGE_ENTRIES) {
-                offset = alloc_swap_page(root_swap, handle->bitmap);
-                if (!offset)
-                        return -ENOSPC;
-                handle->cur->next_swap = offset;
-                error = write_page(handle->cur, handle->cur_swap);
-                if (error)
-                        return error;
-                memset(handle->cur, 0, PAGE_SIZE);
-                handle->cur_swap = offset;
-                handle->k = 0;
-        }
-        return 0;
-}
-
-static int flush_swap_writer(struct swap_map_handle *handle)
-{
-        if (handle->cur && handle->cur_swap)
-                return write_page(handle->cur, handle->cur_swap);
-        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_pages)
-{
-        unsigned int m;
-        int ret;
-        int error = 0;
-
-        printk("Saving image data pages (%u pages) ...     ", nr_pages);
-        m = nr_pages / 100;
-        if (!m)
-                m = 1;
-        nr_pages = 0;
-        do {
-                ret = snapshot_read_next(snapshot, PAGE_SIZE);
-                if (ret > 0) {
-                        error = swap_write_page(handle, data_of(*snapshot));
-                        if (error)
-                                break;
-                        if (!(nr_pages % m))
-                                printk("\b\b\b\b%3d%%", nr_pages / m);
-                        nr_pages++;
-                }
-        } while (ret > 0);
-        if (!error)
-                printk("\b\b\b\bdone\n");
-        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("swsusp: free swap pages: %u\n", free_swap);
-        return free_swap > (nr_pages + PAGES_FOR_IO +
-                (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
-}
-
-/**
- *      swsusp_write - Write entire image and metadata.
- *
- *      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(void)
-{
-        struct swap_map_handle handle;
-        struct snapshot_handle snapshot;
-        struct swsusp_info *header;
-        unsigned long start;
-        int error;
-
-        if ((error = swsusp_swap_check())) {
-                printk(KERN_ERR "swsusp: 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)
-                return error < 0 ? error : -EFAULT;
-        header = (struct swsusp_info *)data_of(snapshot);
-        if (!enough_swap(header->pages)) {
-                printk(KERN_ERR "swsusp: Not enough free swap\n");
-                return -ENOSPC;
-        }
-        error = get_swap_writer(&handle);
-        if (!error) {
-                start = handle.cur_swap;
-                error = swap_write_page(&handle, header);
-        }
-        if (!error)
-                error = save_image(&handle, &snapshot, header->pages - 1);
-        if (!error) {
-                flush_swap_writer(&handle);
-                printk("S");
-                error = mark_swapfiles(swp_entry(root_swap, start));
-                printk("|\n");
-        }
-        if (error)
-                free_all_swap_pages(root_swap, handle.bitmap);
-        release_swap_writer(&handle);
-        return error;
-}
-
-/**
  *      swsusp_shrink_memory -  Try to free as much memory as needed
  *
  *      ... but do not OOM-kill anyone
@@ -578,252 +271,3 @@ int swsusp_resume(void)
         local_irq_enable();
         return error;
 }
-
-/*
- *      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 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,
-                                      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_reader(handle);
-                return error;
-        }
-        handle->k = 0;
-        return 0;
-}
-
-static int swap_read_page(struct swap_map_handle *handle, void *buf)
-{
-        unsigned long offset;
-        int error;
-
-        if (!handle->cur)
-                return -EINVAL;
-        offset = handle->cur->entries[handle->k];
-        if (!offset)
-                return -EFAULT;
-        error = bio_read_page(offset, buf);
-        if (error)
-                return error;
-        if (++handle->k >= MAP_PAGE_ENTRIES) {
-                handle->k = 0;
-                offset = handle->cur->next_swap;
-                if (!offset)
-                        release_swap_reader(handle);
-                else
-                        error = bio_read_page(offset, handle->cur);
-        }
-        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_pages)
-{
-        unsigned int m;
-        int ret;
-        int error = 0;
-
-        printk("Loading image data pages (%u pages) ...     ", nr_pages);
-        m = nr_pages / 100;
-        if (!m)
-                m = 1;
-        nr_pages = 0;
-        do {
-                ret = snapshot_write_next(snapshot, PAGE_SIZE);
-                if (ret > 0) {
-                        error = swap_read_page(handle, data_of(*snapshot));
-                        if (error)
-                                break;
-                        if (!(nr_pages % m))
-                                printk("\b\b\b\b%3d%%", nr_pages / m);
-                        nr_pages++;
-                }
-        } while (ret > 0);
-        if (!error)
-                printk("\b\b\b\bdone\n");
-        if (!snapshot_image_loaded(snapshot))
-                error = -ENODATA;
-        return error;
-}
-
-int swsusp_read(void)
-{
-        int error;
-        struct swap_map_handle handle;
-        struct snapshot_handle snapshot;
-        struct swsusp_info *header;
-        unsigned int nr_pages;
-
-        if (IS_ERR(resume_bdev)) {
-                pr_debug("swsusp: block 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);
-        if (!error) {
-                nr_pages = header->image_pages;
-                error = load_image(&handle, &snapshot, nr_pages);
-        }
-        release_swap_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);
-}