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Subject[RFC/RFT][PATCH -mm 3/4] swsusp: separate swap-writing and reading code
Date
This patch moves the in-kernel swap-swap-writing and reading code to
a separate file.


Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

kernel/power/Makefile | 2
kernel/power/swap.c | 641 ++++++++++++++++++++++++++++++++++++++++++++++++++
kernel/power/swsusp.c | 629 -------------------------------------------------
3 files changed, 644 insertions(+), 628 deletions(-)
Index: linux-2.6.15-rc5-mm3/kernel/power/Makefile
===================================================================
--- linux-2.6.15-rc5-mm3.orig/kernel/power/Makefile 2005-12-27 22:33:08.000000000 +0100
+++ linux-2.6.15-rc5-mm3/kernel/power/Makefile 2005-12-27 23:39:20.000000000 +0100
@@ -5,7 +5,7 @@ endif

obj-y := main.o process.o console.o
obj-$(CONFIG_PM_LEGACY) += pm.o
-obj-$(CONFIG_SOFTWARE_SUSPEND) += swsusp.o disk.o snapshot.o user.o
+obj-$(CONFIG_SOFTWARE_SUSPEND) += swsusp.o disk.o snapshot.o user.o swap.o

obj-$(CONFIG_SUSPEND_SMP) += smp.o

Index: linux-2.6.15-rc5-mm3/kernel/power/swap.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.15-rc5-mm3/kernel/power/swap.c 2005-12-27 23:44:45.000000000 +0100
@@ -0,0 +1,641 @@
+/*
+ * 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) 2005 Rafael J. Wysocki <rjw@sisk.pl>
+ *
+ * This file is released under the GPLv2.
+ *
+ */
+
+#include <linux/module.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/genhd.h>
+#include <linux/device.h>
+#include <linux/buffer_head.h>
+#include <linux/bio.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
+#include <linux/pm.h>
+
+#include "power.h"
+
+extern int swsusp_get_swap_index(void);
+extern unsigned int swsusp_available_swap(unsigned int swap);
+
+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;
+}
+
+static int swsusp_swap_check(void) /* This is called before saving image */
+{
+ int res = swsusp_get_swap_index();
+
+ if (res >= 0) {
+ root_swap = res;
+ return 0;
+ }
+ return res;
+}
+
+/**
+ * write_page - Write one page to a fresh swap location.
+ * @buf: Address we're writing.
+ * @loc: Place to store the entry we used.
+ */
+
+static int write_page(void *buf, swp_entry_t *loc)
+{
+ swp_entry_t entry;
+ int error = -ENOSPC;
+
+ entry = get_swap_page_of_type(root_swap);
+ if (swp_offset(entry)) {
+ error = rw_swap_page_sync(WRITE, entry, virt_to_page(buf));
+ if (!error)
+ *loc = entry;
+ else
+ swap_free(entry);
+ }
+ return error;
+}
+
+/**
+ * Swap map-handling functions
+ *
+ * The swap map is a data structure used for keeping track of each page
+ * written to the swap. It consists of many swap_map_page structures
+ * that contain each an array of MAP_PAGE_SIZE swap entries.
+ * These structures are linked together with the help of either the
+ * .next (in memory) or the .next_swap (in swap) member.
+ *
+ * The swap map is created during suspend. At that time we need to keep
+ * it in memory, because we have to free all of the allocated swap
+ * entries if an error occurs. The memory needed is preallocated
+ * so that we know in advance if there's enough of it.
+ *
+ * The first swap_map_page structure is filled with the swap entries that
+ * correspond to the first MAP_PAGE_SIZE data pages written to swap and
+ * so on. After the all of the data pages have been written, the order
+ * of the swap_map_page structures in the map is reversed so that they
+ * can be read from swap in the original order. This causes the data
+ * pages to be loaded in exactly the same order in which they have been
+ * saved.
+ *
+ * During resume we only need to use one swap_map_page structure
+ * at a time, which means that we only need to use two memory pages for
+ * reading the image - one for reading the swap_map_page structures
+ * and the second for reading the data pages from swap.
+ */
+
+#define MAP_PAGE_SIZE ((PAGE_SIZE - sizeof(swp_entry_t) - sizeof(void *)) \
+ / sizeof(swp_entry_t))
+
+struct swap_map_page {
+ swp_entry_t entries[MAP_PAGE_SIZE];
+ swp_entry_t next_swap;
+ struct swap_map_page *next;
+};
+
+static inline void free_swap_map(struct swap_map_page *swap_map)
+{
+ struct swap_map_page *swp;
+
+ while (swap_map) {
+ swp = swap_map->next;
+ free_page((unsigned long)swap_map);
+ swap_map = swp;
+ }
+}
+
+static struct swap_map_page *alloc_swap_map(unsigned int nr_pages)
+{
+ struct swap_map_page *swap_map, *swp;
+ unsigned n = 0;
+
+ if (!nr_pages)
+ return NULL;
+
+ pr_debug("alloc_swap_map(): nr_pages = %d\n", nr_pages);
+ swap_map = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC);
+ swp = swap_map;
+ for (n = MAP_PAGE_SIZE; n < nr_pages; n += MAP_PAGE_SIZE) {
+ swp->next = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC);
+ swp = swp->next;
+ if (!swp) {
+ free_swap_map(swap_map);
+ return NULL;
+ }
+ }
+ return swap_map;
+}
+
+/**
+ * reverse_swap_map - reverse the order of pages in the swap map
+ * @swap_map
+ */
+
+static inline struct swap_map_page *reverse_swap_map(struct swap_map_page *swap_map)
+{
+ struct swap_map_page *prev, *next;
+
+ prev = NULL;
+ while (swap_map) {
+ next = swap_map->next;
+ swap_map->next = prev;
+ prev = swap_map;
+ swap_map = next;
+ }
+ return prev;
+}
+
+/**
+ * free_swap_map_entries - free the swap entries allocated to store
+ * the swap map @swap_map (this is only called in case of an error)
+ */
+static inline void free_swap_map_entries(struct swap_map_page *swap_map)
+{
+ while (swap_map) {
+ if (swap_map->next_swap.val)
+ swap_free(swap_map->next_swap);
+ swap_map = swap_map->next;
+ }
+}
+
+/**
+ * save_swap_map - save the swap map used for tracing the data pages
+ * stored in the swap
+ */
+
+static int save_swap_map(struct swap_map_page *swap_map, swp_entry_t *start)
+{
+ swp_entry_t entry = (swp_entry_t){0};
+ int error;
+
+ while (swap_map) {
+ swap_map->next_swap = entry;
+ if ((error = write_page(swap_map, &entry)))
+ return error;
+ swap_map = swap_map->next;
+ }
+ *start = entry;
+ return 0;
+}
+
+/**
+ * free_image_entries - free the swap entries allocated to store
+ * the image data pages (this is only called in case of an error)
+ */
+
+static inline void free_image_entries(struct swap_map_page *swp)
+{
+ unsigned k;
+
+ while (swp) {
+ for (k = 0; k < MAP_PAGE_SIZE; k++)
+ if (swp->entries[k].val)
+ swap_free(swp->entries[k]);
+ swp = swp->next;
+ }
+}
+
+/**
+ * The swap_map_handle structure is used for handling the swap map in
+ * a file-alike way
+ */
+
+struct swap_map_handle {
+ struct swap_map_page *cur;
+ unsigned int k;
+};
+
+static inline void init_swap_map_handle(struct swap_map_handle *handle,
+ struct swap_map_page *map)
+{
+ handle->cur = map;
+ handle->k = 0;
+}
+
+static inline int swap_map_write_page(struct swap_map_handle *handle, void *buf)
+{
+ int error;
+
+ error = write_page(buf, handle->cur->entries + handle->k);
+ if (error)
+ return error;
+ if (++handle->k >= MAP_PAGE_SIZE) {
+ handle->cur = handle->cur->next;
+ handle->k = 0;
+ }
+ return 0;
+}
+
+/**
+ * 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_map_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 = swsusp_available_swap(root_swap);
+
+ 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_page *swap_map;
+ struct swap_map_handle handle;
+ struct snapshot_handle snapshot;
+ struct swsusp_info *header;
+ unsigned int nr_pages;
+ swp_entry_t 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);
+ nr_pages = header->image_pages;
+ if (!enough_swap(nr_pages)) {
+ printk(KERN_ERR "swsusp: Not enough free swap\n");
+ return -ENOSPC;
+ }
+ swap_map = alloc_swap_map(header->pages);
+ if (!swap_map)
+ return -ENOMEM;
+ init_swap_map_handle(&handle, swap_map);
+
+ error = swap_map_write_page(&handle, header);
+ if (!error)
+ error = save_image(&handle, &snapshot, nr_pages);
+ if (error)
+ goto Free_image_entries;
+
+ swap_map = reverse_swap_map(swap_map);
+ error = save_swap_map(swap_map, &start);
+ if (error)
+ goto Free_map_entries;
+
+ printk( "S" );
+ error = mark_swapfiles(start);
+ printk( "|\n" );
+ if (error)
+ goto Free_map_entries;
+
+Free_swap_map:
+ free_swap_map(swap_map);
+ return error;
+
+Free_map_entries:
+ free_swap_map_entries(swap_map);
+Free_image_entries:
+ free_image_entries(swap_map);
+ goto Free_swap_map;
+}
+
+/*
+ * 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_get(bio);
+ 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;
+ }
+
+ if (rw == WRITE)
+ bio_set_pages_dirty(bio);
+
+ atomic_set(&io_done, 1);
+ submit_bio(rw | (1 << BIO_RW_SYNC), bio);
+ while (atomic_read(&io_done))
+ yield();
+
+ 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 -EFAULT;
+ 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;
+}
+
+/**
+ * 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_map_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_ready(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_map_reader(&handle, swsusp_header.image);
+ if (!error)
+ error = swap_map_read_page(&handle, header);
+ if (!error) {
+ nr_pages = header->image_pages;
+ error = load_image(&handle, &snapshot, nr_pages);
+ }
+ 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);
+}
Index: linux-2.6.15-rc5-mm3/kernel/power/swsusp.c
===================================================================
--- linux-2.6.15-rc5-mm3.orig/kernel/power/swsusp.c 2005-12-27 21:53:03.000000000 +0100
+++ linux-2.6.15-rc5-mm3/kernel/power/swsusp.c 2005-12-27 23:42:40.000000000 +0100
@@ -38,34 +38,17 @@
* 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"

@@ -89,47 +72,7 @@ static int restore_highmem(void) { retur
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;
-}
-
-/*
+/**
* Check whether the swap device is the specified resume
* device, irrespective of whether they are specified by
* identical names.
@@ -140,6 +83,7 @@ static int mark_swapfiles(swp_entry_t st
* devfs, since the resume code can only recognize the form /dev/hda4,
* but the suspend code would see the long name.)
*/
+
static inline int is_resume_device(const struct swap_info_struct *swap_info)
{
struct file *file = swap_info->swap_file;
@@ -168,242 +112,6 @@ int swsusp_get_swap_index(void)
return -ENODEV;
}

-static int swsusp_swap_check(void) /* This is called before saving image */
-{
- int res = swsusp_get_swap_index();
-
- if (res >= 0) {
- root_swap = res;
- return 0;
- }
- return res;
-}
-
-/**
- * write_page - Write one page to a fresh swap location.
- * @buf: Address we're writing.
- * @loc: Place to store the entry we used.
- */
-
-static int write_page(void *buf, swp_entry_t *loc)
-{
- swp_entry_t entry;
- int error = -ENOSPC;
-
- entry = get_swap_page_of_type(root_swap);
- if (swp_offset(entry)) {
- error = rw_swap_page_sync(WRITE, entry, virt_to_page(buf));
- if (!error)
- *loc = entry;
- else
- swap_free(entry);
- }
- return error;
-}
-
-/**
- * Swap map-handling functions
- *
- * The swap map is a data structure used for keeping track of each page
- * written to the swap. It consists of many swap_map_page structures
- * that contain each an array of MAP_PAGE_SIZE swap entries.
- * These structures are linked together with the help of either the
- * .next (in memory) or the .next_swap (in swap) member.
- *
- * The swap map is created during suspend. At that time we need to keep
- * it in memory, because we have to free all of the allocated swap
- * entries if an error occurs. The memory needed is preallocated
- * so that we know in advance if there's enough of it.
- *
- * The first swap_map_page structure is filled with the swap entries that
- * correspond to the first MAP_PAGE_SIZE data pages written to swap and
- * so on. After the all of the data pages have been written, the order
- * of the swap_map_page structures in the map is reversed so that they
- * can be read from swap in the original order. This causes the data
- * pages to be loaded in exactly the same order in which they have been
- * saved.
- *
- * During resume we only need to use one swap_map_page structure
- * at a time, which means that we only need to use two memory pages for
- * reading the image - one for reading the swap_map_page structures
- * and the second for reading the data pages from swap.
- */
-
-#define MAP_PAGE_SIZE ((PAGE_SIZE - sizeof(swp_entry_t) - sizeof(void *)) \
- / sizeof(swp_entry_t))
-
-struct swap_map_page {
- swp_entry_t entries[MAP_PAGE_SIZE];
- swp_entry_t next_swap;
- struct swap_map_page *next;
-};
-
-static inline void free_swap_map(struct swap_map_page *swap_map)
-{
- struct swap_map_page *swp;
-
- while (swap_map) {
- swp = swap_map->next;
- free_page((unsigned long)swap_map);
- swap_map = swp;
- }
-}
-
-static struct swap_map_page *alloc_swap_map(unsigned int nr_pages)
-{
- struct swap_map_page *swap_map, *swp;
- unsigned n = 0;
-
- if (!nr_pages)
- return NULL;
-
- pr_debug("alloc_swap_map(): nr_pages = %d\n", nr_pages);
- swap_map = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC);
- swp = swap_map;
- for (n = MAP_PAGE_SIZE; n < nr_pages; n += MAP_PAGE_SIZE) {
- swp->next = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC);
- swp = swp->next;
- if (!swp) {
- free_swap_map(swap_map);
- return NULL;
- }
- }
- return swap_map;
-}
-
-/**
- * reverse_swap_map - reverse the order of pages in the swap map
- * @swap_map
- */
-
-static inline struct swap_map_page *reverse_swap_map(struct swap_map_page *swap_map)
-{
- struct swap_map_page *prev, *next;
-
- prev = NULL;
- while (swap_map) {
- next = swap_map->next;
- swap_map->next = prev;
- prev = swap_map;
- swap_map = next;
- }
- return prev;
-}
-
-/**
- * free_swap_map_entries - free the swap entries allocated to store
- * the swap map @swap_map (this is only called in case of an error)
- */
-static inline void free_swap_map_entries(struct swap_map_page *swap_map)
-{
- while (swap_map) {
- if (swap_map->next_swap.val)
- swap_free(swap_map->next_swap);
- swap_map = swap_map->next;
- }
-}
-
-/**
- * save_swap_map - save the swap map used for tracing the data pages
- * stored in the swap
- */
-
-static int save_swap_map(struct swap_map_page *swap_map, swp_entry_t *start)
-{
- swp_entry_t entry = (swp_entry_t){0};
- int error;
-
- while (swap_map) {
- swap_map->next_swap = entry;
- if ((error = write_page(swap_map, &entry)))
- return error;
- swap_map = swap_map->next;
- }
- *start = entry;
- return 0;
-}
-
-/**
- * free_image_entries - free the swap entries allocated to store
- * the image data pages (this is only called in case of an error)
- */
-
-static inline void free_image_entries(struct swap_map_page *swp)
-{
- unsigned k;
-
- while (swp) {
- for (k = 0; k < MAP_PAGE_SIZE; k++)
- if (swp->entries[k].val)
- swap_free(swp->entries[k]);
- swp = swp->next;
- }
-}
-
-/**
- * The swap_map_handle structure is used for handling the swap map in
- * a file-alike way
- */
-
-struct swap_map_handle {
- struct swap_map_page *cur;
- unsigned int k;
-};
-
-static inline void init_swap_map_handle(struct swap_map_handle *handle,
- struct swap_map_page *map)
-{
- handle->cur = map;
- handle->k = 0;
-}
-
-static inline int swap_map_write_page(struct swap_map_handle *handle, void *buf)
-{
- int error;
-
- error = write_page(buf, handle->cur->entries + handle->k);
- if (error)
- return error;
- if (++handle->k >= MAP_PAGE_SIZE) {
- handle->cur = handle->cur->next;
- handle->k = 0;
- }
- return 0;
-}
-
-/**
- * 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_map_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;
-}
-
/**
* swsusp_available_swap - check the total amount of swap
* space avaiable from given swap partition/file
@@ -424,88 +132,6 @@ unsigned int swsusp_available_swap(unsig
}

/**
- * 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 = swsusp_available_swap(root_swap);
-
- 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_page *swap_map;
- struct swap_map_handle handle;
- struct snapshot_handle snapshot;
- struct swsusp_info *header;
- unsigned int nr_pages;
- swp_entry_t 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);
- nr_pages = header->image_pages;
- if (!enough_swap(nr_pages)) {
- printk(KERN_ERR "swsusp: Not enough free swap\n");
- return -ENOSPC;
- }
- swap_map = alloc_swap_map(header->pages);
- if (!swap_map)
- return -ENOMEM;
- init_swap_map_handle(&handle, swap_map);
-
- error = swap_map_write_page(&handle, header);
- if (!error)
- error = save_image(&handle, &snapshot, nr_pages);
- if (error)
- goto Free_image_entries;
-
- swap_map = reverse_swap_map(swap_map);
- error = save_swap_map(swap_map, &start);
- if (error)
- goto Free_map_entries;
-
- printk( "S" );
- error = mark_swapfiles(start);
- printk( "|\n" );
- if (error)
- goto Free_map_entries;
-
-Free_swap_map:
- free_swap_map(swap_map);
- return error;
-
-Free_map_entries:
- free_swap_map_entries(swap_map);
-Free_image_entries:
- free_image_entries(swap_map);
- goto Free_swap_map;
-}
-
-/**
* swsusp_shrink_memory - Try to free as much memory as needed
*
* ... but do not OOM-kill anyone
@@ -611,254 +237,3 @@ 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_get(bio);
- 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;
- }
-
- if (rw == WRITE)
- bio_set_pages_dirty(bio);
-
- atomic_set(&io_done, 1);
- submit_bio(rw | (1 << BIO_RW_SYNC), bio);
- while (atomic_read(&io_done))
- yield();
-
- 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 -EFAULT;
- 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;
-}
-
-/**
- * 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_map_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_ready(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_map_reader(&handle, swsusp_header.image);
- if (!error)
- error = swap_map_read_page(&handle, header);
- if (!error) {
- nr_pages = header->image_pages;
- error = load_image(&handle, &snapshot, nr_pages);
- }
- 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);
-}
-
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