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[PATCH] swsusp: low level interface 

Introduce the low level interface that can be used for handling the
snapshot of the system memory by the in-kernel swap-writing/reading code of
swsusp and the userland interface code (to be introduced shortly).

Also change the way in which swsusp records the allocated swap pages and,
consequently, simplifies the in-kernel swap-writing/reading code (this is
necessary for the userland interface too).  To this end, it introduces two
helper functions in mm/swapfile.c, so that the swsusp code does not refer
directly to the swap internals.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Rafael J. Wysocki 2006-03-23 02:59:59 -08:00 committed by Linus Torvalds
parent 2b322ce210
commit f577eb30af
6 changed files with 680 additions and 515 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
include/linux/swap.h
View File

@ -234,14 +234,15 @@ extern struct page * read_swap_cache_async(swp_entry_t, struct vm_area_struct *v
/* linux/mm/swapfile.c */
extern long total_swap_pages;
extern unsigned int nr_swapfiles;
extern struct swap_info_struct swap_info[];
extern void si_swapinfo(struct sysinfo *);
extern swp_entry_t get_swap_page(void);
extern swp_entry_t get_swap_page_of_type(int type);
extern swp_entry_t get_swap_page_of_type(int);
extern int swap_duplicate(swp_entry_t);
extern int valid_swaphandles(swp_entry_t, unsigned long *);
extern void swap_free(swp_entry_t);
extern void free_swap_and_cache(swp_entry_t);
extern int swap_type_of(dev_t);
extern unsigned int count_swap_pages(int, int);
extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
extern struct swap_info_struct *get_swap_info_struct(unsigned);
extern int can_share_swap_page(struct page *);

12
kernel/power/disk.c
View File

@ -26,9 +26,9 @@ extern suspend_disk_method_t pm_disk_mode;
extern int swsusp_shrink_memory(void);
extern int swsusp_suspend(void);
extern int swsusp_write(struct pbe *pblist, unsigned int nr_pages);
extern int swsusp_write(void);
extern int swsusp_check(void);
extern int swsusp_read(struct pbe **pblist_ptr);
extern int swsusp_read(void);
extern void swsusp_close(void);
extern int swsusp_resume(void);
@ -70,10 +70,6 @@ static void power_down(suspend_disk_method_t mode)
while(1);
}
static int in_suspend __nosavedata = 0;
static inline void platform_finish(void)
{
if (pm_disk_mode == PM_DISK_PLATFORM) {
@ -145,7 +141,7 @@ int pm_suspend_disk(void)
if (in_suspend) {
device_resume();
pr_debug("PM: writing image.\n");
error = swsusp_write(pagedir_nosave, nr_copy_pages);
error = swsusp_write();
if (!error)
power_down(pm_disk_mode);
else {
@ -216,7 +212,7 @@ static int software_resume(void)
pr_debug("PM: Reading swsusp image.\n");
if ((error = swsusp_read(&pagedir_nosave))) {
if ((error = swsusp_read())) {
swsusp_free();
goto Thaw;
}

26
kernel/power/power.h
View File

@ -37,21 +37,31 @@ extern struct subsystem power_subsys;
/* References to section boundaries */
extern const void __nosave_begin, __nosave_end;
extern unsigned int nr_copy_pages;
extern struct pbe *pagedir_nosave;
/* Preferred image size in bytes (default 500 MB) */
extern unsigned long image_size;
extern int in_suspend;
extern asmlinkage int swsusp_arch_suspend(void);
extern asmlinkage int swsusp_arch_resume(void);
extern unsigned int count_data_pages(void);
extern void free_pagedir(struct pbe *pblist);
extern void release_eaten_pages(void);
extern struct pbe *alloc_pagedir(unsigned nr_pages, gfp_t gfp_mask, int safe_needed);
extern void swsusp_free(void);
extern int alloc_data_pages(struct pbe *pblist, gfp_t gfp_mask, int safe_needed);
extern unsigned int snapshot_nr_pages(void);
extern struct pbe *snapshot_pblist(void);
extern void snapshot_pblist_set(struct pbe *pblist);
struct snapshot_handle {
loff_t offset;
unsigned int page;
unsigned int page_offset;
unsigned int prev;
struct pbe *pbe;
void *buffer;
unsigned int buf_offset;
};
#define data_of(handle) ((handle).buffer + (handle).buf_offset)
extern int snapshot_read_next(struct snapshot_handle *handle, size_t count);
extern int snapshot_write_next(struct snapshot_handle *handle, size_t count);
int snapshot_image_loaded(struct snapshot_handle *handle);

326
kernel/power/snapshot.c
View File

@ -10,6 +10,7 @@
*/
#include <linux/version.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/suspend.h>
@ -34,7 +35,8 @@
#include "power.h"
struct pbe *pagedir_nosave;
unsigned int nr_copy_pages;
static unsigned int nr_copy_pages;
static unsigned int nr_meta_pages;
#ifdef CONFIG_HIGHMEM
unsigned int count_highmem_pages(void)
@ -235,7 +237,7 @@ static void copy_data_pages(struct pbe *pblist)
* free_pagedir - free pages allocated with alloc_pagedir()
*/
void free_pagedir(struct pbe *pblist)
static void free_pagedir(struct pbe *pblist)
{
struct pbe *pbe;
@ -301,7 +303,7 @@ struct eaten_page {
static struct eaten_page *eaten_pages = NULL;
void release_eaten_pages(void)
static void release_eaten_pages(void)
{
struct eaten_page *p, *q;
@ -376,7 +378,6 @@ struct pbe *alloc_pagedir(unsigned int nr_pages, gfp_t gfp_mask, int safe_needed
if (!nr_pages)
return NULL;
pr_debug("alloc_pagedir(): nr_pages = %d\n", nr_pages);
pblist = alloc_image_page(gfp_mask, safe_needed);
/* FIXME: rewrite this ugly loop */
for (pbe = pblist, num = PBES_PER_PAGE; pbe && num < nr_pages;
@ -414,6 +415,9 @@ void swsusp_free(void)
}
}
}
nr_copy_pages = 0;
nr_meta_pages = 0;
pagedir_nosave = NULL;
}
@ -437,7 +441,7 @@ static int enough_free_mem(unsigned int nr_pages)
(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
}
int alloc_data_pages(struct pbe *pblist, gfp_t gfp_mask, int safe_needed)
static int alloc_data_pages(struct pbe *pblist, gfp_t gfp_mask, int safe_needed)
{
struct pbe *p;
@ -504,7 +508,319 @@ asmlinkage int swsusp_save(void)
*/
nr_copy_pages = nr_pages;
nr_meta_pages = (nr_pages * sizeof(long) + PAGE_SIZE - 1) >> PAGE_SHIFT;
printk("swsusp: critical section/: done (%d pages copied)\n", nr_pages);
return 0;
}
static void init_header(struct swsusp_info *info)
{
memset(info, 0, sizeof(struct swsusp_info));
info->version_code = LINUX_VERSION_CODE;
info->num_physpages = num_physpages;
memcpy(&info->uts, &system_utsname, sizeof(system_utsname));
info->cpus = num_online_cpus();
info->image_pages = nr_copy_pages;
info->pages = nr_copy_pages + nr_meta_pages + 1;
}
/**
* pack_orig_addresses - the .orig_address fields of the PBEs from the
* list starting at @pbe are stored in the array @buf[] (1 page)
*/
static inline struct pbe *pack_orig_addresses(unsigned long *buf, struct pbe *pbe)
{
int j;
for (j = 0; j < PAGE_SIZE / sizeof(long) && pbe; j++) {
buf[j] = pbe->orig_address;
pbe = pbe->next;
}
if (!pbe)
for (; j < PAGE_SIZE / sizeof(long); j++)
buf[j] = 0;
return pbe;
}
/**
* snapshot_read_next - used for reading the system memory snapshot.
*
* On the first call to it @handle should point to a zeroed
* snapshot_handle structure. The structure gets updated and a pointer
* to it should be passed to this function every next time.
*
* The @count parameter should contain the number of bytes the caller
* wants to read from the snapshot. It must not be zero.
*
* On success the function returns a positive number. Then, the caller
* is allowed to read up to the returned number of bytes from the memory
* location computed by the data_of() macro. The number returned
* may be smaller than @count, but this only happens if the read would
* cross a page boundary otherwise.
*
* The function returns 0 to indicate the end of data stream condition,
* and a negative number is returned on error. In such cases the
* structure pointed to by @handle is not updated and should not be used
* any more.
*/
int snapshot_read_next(struct snapshot_handle *handle, size_t count)
{
static unsigned long *buffer;
if (handle->page > nr_meta_pages + nr_copy_pages)
return 0;
if (!buffer) {
/* This makes the buffer be freed by swsusp_free() */
buffer = alloc_image_page(GFP_ATOMIC, 0);
if (!buffer)
return -ENOMEM;
}
if (!handle->offset) {
init_header((struct swsusp_info *)buffer);
handle->buffer = buffer;
handle->pbe = pagedir_nosave;
}
if (handle->prev < handle->page) {
if (handle->page <= nr_meta_pages) {
handle->pbe = pack_orig_addresses(buffer, handle->pbe);
if (!handle->pbe)
handle->pbe = pagedir_nosave;
} else {
handle->buffer = (void *)handle->pbe->address;
handle->pbe = handle->pbe->next;
}
handle->prev = handle->page;
}
handle->buf_offset = handle->page_offset;
if (handle->page_offset + count >= PAGE_SIZE) {
count = PAGE_SIZE - handle->page_offset;
handle->page_offset = 0;
handle->page++;
} else {
handle->page_offset += count;
}
handle->offset += count;
return count;
}
/**
* mark_unsafe_pages - mark the pages that cannot be used for storing
* the image during resume, because they conflict with the pages that
* had been used before suspend
*/
static int mark_unsafe_pages(struct pbe *pblist)
{
struct zone *zone;
unsigned long zone_pfn;
struct pbe *p;
if (!pblist) /* a sanity check */
return -EINVAL;
/* Clear page flags */
for_each_zone (zone) {
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
if (pfn_valid(zone_pfn + zone->zone_start_pfn))
ClearPageNosaveFree(pfn_to_page(zone_pfn +
zone->zone_start_pfn));
}
/* Mark orig addresses */
for_each_pbe (p, pblist) {
if (virt_addr_valid(p->orig_address))
SetPageNosaveFree(virt_to_page(p->orig_address));
else
return -EFAULT;
}
return 0;
}
static void copy_page_backup_list(struct pbe *dst, struct pbe *src)
{
/* We assume both lists contain the same number of elements */
while (src) {
dst->orig_address = src->orig_address;
dst = dst->next;
src = src->next;
}
}
static int check_header(struct swsusp_info *info)
{
char *reason = NULL;
if (info->version_code != LINUX_VERSION_CODE)
reason = "kernel version";
if (info->num_physpages != num_physpages)
reason = "memory size";
if (strcmp(info->uts.sysname,system_utsname.sysname))
reason = "system type";
if (strcmp(info->uts.release,system_utsname.release))
reason = "kernel release";
if (strcmp(info->uts.version,system_utsname.version))
reason = "version";
if (strcmp(info->uts.machine,system_utsname.machine))
reason = "machine";
if (reason) {
printk(KERN_ERR "swsusp: Resume mismatch: %s\n", reason);
return -EPERM;
}
return 0;
}
/**
* load header - check the image header and copy data from it
*/
static int load_header(struct snapshot_handle *handle,
struct swsusp_info *info)
{
int error;
struct pbe *pblist;
error = check_header(info);
if (!error) {
pblist = alloc_pagedir(info->image_pages, GFP_ATOMIC, 0);
if (!pblist)
return -ENOMEM;
pagedir_nosave = pblist;
handle->pbe = pblist;
nr_copy_pages = info->image_pages;
nr_meta_pages = info->pages - info->image_pages - 1;
}
return error;
}
/**
* unpack_orig_addresses - copy the elements of @buf[] (1 page) to
* the PBEs in the list starting at @pbe
*/
static inline struct pbe *unpack_orig_addresses(unsigned long *buf,
struct pbe *pbe)
{
int j;
for (j = 0; j < PAGE_SIZE / sizeof(long) && pbe; j++) {
pbe->orig_address = buf[j];
pbe = pbe->next;
}
return pbe;
}
/**
* create_image - use metadata contained in the PBE list
* pointed to by pagedir_nosave to mark the pages that will
* be overwritten in the process of restoring the system
* memory state from the image and allocate memory for
* the image avoiding these pages
*/
static int create_image(struct snapshot_handle *handle)
{
int error = 0;
struct pbe *p, *pblist;
p = pagedir_nosave;
error = mark_unsafe_pages(p);
if (!error) {
pblist = alloc_pagedir(nr_copy_pages, GFP_ATOMIC, 1);
if (pblist)
copy_page_backup_list(pblist, p);
free_pagedir(p);
if (!pblist)
error = -ENOMEM;
}
if (!error)
error = alloc_data_pages(pblist, GFP_ATOMIC, 1);
if (!error) {
release_eaten_pages();
pagedir_nosave = pblist;
} else {
pagedir_nosave = NULL;
handle->pbe = NULL;
nr_copy_pages = 0;
nr_meta_pages = 0;
}
return error;
}
/**
* snapshot_write_next - used for writing the system memory snapshot.
*
* On the first call to it @handle should point to a zeroed
* snapshot_handle structure. The structure gets updated and a pointer
* to it should be passed to this function every next time.
*
* The @count parameter should contain the number of bytes the caller
* wants to write to the image. It must not be zero.
*
* On success the function returns a positive number. Then, the caller
* is allowed to write up to the returned number of bytes to the memory
* location computed by the data_of() macro. The number returned
* may be smaller than @count, but this only happens if the write would
* cross a page boundary otherwise.
*
* The function returns 0 to indicate the "end of file" condition,
* and a negative number is returned on error. In such cases the
* structure pointed to by @handle is not updated and should not be used
* any more.
*/
int snapshot_write_next(struct snapshot_handle *handle, size_t count)
{
static unsigned long *buffer;
int error = 0;
if (handle->prev && handle->page > nr_meta_pages + nr_copy_pages)
return 0;
if (!buffer) {
/* This makes the buffer be freed by swsusp_free() */
buffer = alloc_image_page(GFP_ATOMIC, 0);
if (!buffer)
return -ENOMEM;
}
if (!handle->offset)
handle->buffer = buffer;
if (handle->prev < handle->page) {
if (!handle->prev) {
error = load_header(handle, (struct swsusp_info *)buffer);
if (error)
return error;
} else if (handle->prev <= nr_meta_pages) {
handle->pbe = unpack_orig_addresses(buffer, handle->pbe);
if (!handle->pbe) {
error = create_image(handle);
if (error)
return error;
handle->pbe = pagedir_nosave;
handle->buffer = (void *)handle->pbe->address;
}
} else {
handle->pbe = handle->pbe->next;
handle->buffer = (void *)handle->pbe->address;
}
handle->prev = handle->page;
}
handle->buf_offset = handle->page_offset;
if (handle->page_offset + count >= PAGE_SIZE) {
count = PAGE_SIZE - handle->page_offset;
handle->page_offset = 0;
handle->page++;
} else {
handle->page_offset += count;
}
handle->offset += count;
return count;
}
int snapshot_image_loaded(struct snapshot_handle *handle)
{
return !(!handle->pbe || handle->pbe->next || !nr_copy_pages ||
handle->page <= nr_meta_pages + nr_copy_pages);
}

771
kernel/power/swsusp.c
View File

@ -77,6 +77,8 @@
*/
unsigned long image_size = 500 * 1024 * 1024;
int in_suspend __nosavedata = 0;
#ifdef CONFIG_HIGHMEM
unsigned int count_highmem_pages(void);
int save_highmem(void);
@ -98,8 +100,6 @@ static struct swsusp_header {
char sig[10];
} __attribute__((packed, aligned(PAGE_SIZE))) swsusp_header;
static struct swsusp_info swsusp_info;
/*
* Saving part...
*/
@ -129,255 +129,261 @@ static int mark_swapfiles(swp_entry_t start)
return error;
}
/*
* Check whether the swap device is the specified resume
* device, irrespective of whether they are specified by
* identical names.
*
* (Thus, device inode aliasing is allowed. You can say /dev/hda4
* instead of /dev/ide/host0/bus0/target0/lun0/part4 [if using devfs]
* and they'll be considered the same device. This is *necessary* for
* devfs, since the resume code can only recognize the form /dev/hda4,
* but the suspend code would see the long name.)
/**
* swsusp_swap_check - check if the resume device is a swap device
* and get its index (if so)
*/
static inline int is_resume_device(const struct swap_info_struct *swap_info)
{
struct file *file = swap_info->swap_file;
struct inode *inode = file->f_dentry->d_inode;
return S_ISBLK(inode->i_mode) &&
swsusp_resume_device == MKDEV(imajor(inode), iminor(inode));
}
static int swsusp_swap_check(void) /* This is called before saving image */
{
int i;
int res = swap_type_of(swsusp_resume_device);
if (!swsusp_resume_device)
return -ENODEV;
spin_lock(&swap_lock);
for (i = 0; i < MAX_SWAPFILES; i++) {
if (!(swap_info[i].flags & SWP_WRITEOK))
continue;
if (is_resume_device(swap_info + i)) {
spin_unlock(&swap_lock);
root_swap = i;
return 0;
}
if (res >= 0) {
root_swap = res;
return 0;
}
spin_unlock(&swap_lock);
return -ENODEV;
return res;
}
/**
* write_page - Write one page to a fresh swap location.
* @addr: Address we're writing.
* @loc: Place to store the entry we used.
* The bitmap is used for tracing allocated swap pages
*
* Allocate a new swap entry and 'sync' it. Note we discard -EIO
* errors. That is an artifact left over from swsusp. It did not
* check the return of rw_swap_page_sync() at all, since most pages
* written back to swap would return -EIO.
* This is a partial improvement, since we will at least return other
* errors, though we need to eventually fix the damn code.
* 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.
*/
static int write_page(unsigned long addr, swp_entry_t *loc)
#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
*/
static void free_bitmap(struct bitmap_page *bitmap)
{
struct bitmap_page *bp;
while (bitmap) {
bp = bitmap->next;
free_page((unsigned long)bitmap);
bitmap = bp;
}
}
static struct bitmap_page *alloc_bitmap(unsigned int nr_bits)
{
struct bitmap_page *bitmap, *bp;
unsigned int n;
if (!nr_bits)
return NULL;
bitmap = (struct bitmap_page *)get_zeroed_page(GFP_KERNEL);
bp = bitmap;
for (n = BITMAP_PAGE_BITS; n < nr_bits; n += BITMAP_PAGE_BITS) {
bp->next = (struct bitmap_page *)get_zeroed_page(GFP_KERNEL);
bp = bp->next;
if (!bp) {
free_bitmap(bitmap);
return NULL;
}
}
return bitmap;
}
static int bitmap_set(struct bitmap_page *bitmap, unsigned long bit)
{
unsigned int n;
n = BITMAP_PAGE_BITS;
while (bitmap && n <= bit) {
n += BITMAP_PAGE_BITS;
bitmap = bitmap->next;
}
if (!bitmap)
return -EINVAL;
n -= BITMAP_PAGE_BITS;
bit -= n;
n = 0;
while (bit >= BITS_PER_CHUNK) {
bit -= BITS_PER_CHUNK;
n++;
}
bitmap->chunks[n] |= (1UL << bit);
return 0;
}
static unsigned long alloc_swap_page(int swap, struct bitmap_page *bitmap)
{
unsigned long offset;
offset = swp_offset(get_swap_page_of_type(swap));
if (offset) {
if (bitmap_set(bitmap, offset)) {
swap_free(swp_entry(swap, offset));
offset = 0;
}
}
return offset;
}
static void free_all_swap_pages(int swap, struct bitmap_page *bitmap)
{
unsigned int bit, n;
unsigned long test;
bit = 0;
while (bitmap) {
for (n = 0; n < BITMAP_PAGE_CHUNKS; n++)
for (test = 1UL; test; test <<= 1) {
if (bitmap->chunks[n] & test)
swap_free(swp_entry(swap, bit));
bit++;
}
bitmap = bitmap->next;
}
}
/**
* 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;
entry = get_swap_page_of_type(root_swap);
if (swp_offset(entry)) {
error = rw_swap_page_sync(WRITE, entry, virt_to_page(addr));
if (!error || error == -EIO)
*loc = entry;
if (offset) {
entry = swp_entry(root_swap, offset);
error = rw_swap_page_sync(WRITE, entry, virt_to_page(buf));
}
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.
* 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. 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 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.
*
* 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.
* During resume we also only need to use one swap_map_page structure
* at a time.
*/
#define MAP_PAGE_SIZE ((PAGE_SIZE - sizeof(swp_entry_t) - sizeof(void *)) \
/ sizeof(swp_entry_t))
#define MAP_PAGE_ENTRIES (PAGE_SIZE / sizeof(long) - 1)
struct swap_map_page {
swp_entry_t entries[MAP_PAGE_SIZE];
swp_entry_t next_swap;
struct swap_map_page *next;
unsigned long entries[MAP_PAGE_ENTRIES];
unsigned long next_swap;
};
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((unsigned long)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
* 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 inline void init_swap_map_handle(struct swap_map_handle *handle,
struct swap_map_page *map)
static void release_swap_writer(struct swap_map_handle *handle)
{
handle->cur = map;
handle->k = 0;
if (handle->cur)
free_page((unsigned long)handle->cur);
handle->cur = NULL;
if (handle->bitmap)
free_bitmap(handle->bitmap);
handle->bitmap = NULL;
}
static inline int swap_map_write_page(struct swap_map_handle *handle,
unsigned long addr)
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;
error = write_page(addr, handle->cur->entries + handle->k);
if (!handle->cur)
return -EINVAL;
offset = alloc_swap_page(root_swap, handle->bitmap);
error = write_page(buf, offset);
if (error)
return error;
if (++handle->k >= MAP_PAGE_SIZE) {
handle->cur = handle->cur->next;
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_data - save the data pages pointed to by the PBEs
* from the list @pblist using the swap map handle @handle
* (assume there are @nr_pages data pages to save)
* save_image - save the suspend image data
*/
static int save_image_data(struct pbe *pblist,
struct swap_map_handle *handle,
unsigned int nr_pages)
static int save_image(struct swap_map_handle *handle,
struct snapshot_handle *snapshot,
unsigned int nr_pages)
{
unsigned int m;
struct pbe *p;
int ret;
int error = 0;
printk("Saving image data pages (%u pages) ... ", nr_pages);
@ -385,98 +391,22 @@ static int save_image_data(struct pbe *pblist,
if (!m)
m = 1;
nr_pages = 0;
for_each_pbe (p, pblist) {
error = swap_map_write_page(handle, p->address);
if (error)
break;
if (!(nr_pages % m))
printk("\b\b\b\b%3d%%", nr_pages / m);
nr_pages++;
}
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;
}
static void dump_info(void)
{
pr_debug(" swsusp: Version: %u\n",swsusp_info.version_code);
pr_debug(" swsusp: Num Pages: %ld\n",swsusp_info.num_physpages);
pr_debug(" swsusp: UTS Sys: %s\n",swsusp_info.uts.sysname);
pr_debug(" swsusp: UTS Node: %s\n",swsusp_info.uts.nodename);
pr_debug(" swsusp: UTS Release: %s\n",swsusp_info.uts.release);
pr_debug(" swsusp: UTS Version: %s\n",swsusp_info.uts.version);
pr_debug(" swsusp: UTS Machine: %s\n",swsusp_info.uts.machine);
pr_debug(" swsusp: UTS Domain: %s\n",swsusp_info.uts.domainname);
pr_debug(" swsusp: CPUs: %d\n",swsusp_info.cpus);
pr_debug(" swsusp: Image: %ld Pages\n",swsusp_info.image_pages);
pr_debug(" swsusp: Total: %ld Pages\n", swsusp_info.pages);
}
static void init_header(unsigned int nr_pages)
{
memset(&swsusp_info, 0, sizeof(swsusp_info));
swsusp_info.version_code = LINUX_VERSION_CODE;
swsusp_info.num_physpages = num_physpages;
memcpy(&swsusp_info.uts, &system_utsname, sizeof(system_utsname));
swsusp_info.cpus = num_online_cpus();
swsusp_info.image_pages = nr_pages;
swsusp_info.pages = nr_pages +
((nr_pages * sizeof(long) + PAGE_SIZE - 1) >> PAGE_SHIFT) + 1;
}
/**
* pack_orig_addresses - the .orig_address fields of the PBEs from the
* list starting at @pbe are stored in the array @buf[] (1 page)
*/
static inline struct pbe *pack_orig_addresses(unsigned long *buf,
struct pbe *pbe)
{
int j;
for (j = 0; j < PAGE_SIZE / sizeof(long) && pbe; j++) {
buf[j] = pbe->orig_address;
pbe = pbe->next;
}
if (!pbe)
for (; j < PAGE_SIZE / sizeof(long); j++)
buf[j] = 0;
return pbe;
}
/**
* save_image_metadata - save the .orig_address fields of the PBEs
* from the list @pblist using the swap map handle @handle
*/
static int save_image_metadata(struct pbe *pblist,
struct swap_map_handle *handle)
{
unsigned long *buf;
unsigned int n = 0;
struct pbe *p;
int error = 0;
printk("Saving image metadata ... ");
buf = (unsigned long *)get_zeroed_page(GFP_ATOMIC);
if (!buf)
return -ENOMEM;
p = pblist;
while (p) {
p = pack_orig_addresses(buf, p);
error = swap_map_write_page(handle, (unsigned long)buf);
if (error)
break;
n++;
}
free_page((unsigned long)buf);
if (!error)
printk("done (%u pages saved)\n", n);
return error;
}
/**
* enough_swap - Make sure we have enough swap to save the image.
*
@ -486,8 +416,7 @@ static int save_image_metadata(struct pbe *pblist,
static int enough_swap(unsigned int nr_pages)
{
unsigned int free_swap = swap_info[root_swap].pages -
swap_info[root_swap].inuse_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 +
@ -503,57 +432,44 @@ static int enough_swap(unsigned int nr_pages)
* correctly, we'll mark system clean, anyway.)
*/
int swsusp_write(struct pbe *pblist, unsigned int nr_pages)
int swsusp_write(void)
{
struct swap_map_page *swap_map;
struct swap_map_handle handle;
swp_entry_t start;
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;
}
if (!enough_swap(nr_pages)) {
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;
}
init_header(nr_pages);
swap_map = alloc_swap_map(swsusp_info.pages);
if (!swap_map)
return -ENOMEM;
init_swap_map_handle(&handle, swap_map);
error = swap_map_write_page(&handle, (unsigned long)&swsusp_info);
error = get_swap_writer(&handle);
if (!error) {
start = handle.cur_swap;
error = swap_write_page(&handle, header);
}
if (!error)
error = save_image_metadata(pblist, &handle);
if (!error)
error = save_image_data(pblist, &handle, nr_pages);
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)
goto Free_image_entries;
swap_map = reverse_swap_map(swap_map);
error = save_swap_map(swap_map, &start);
if (error)
goto Free_map_entries;
dump_info();
printk( "S" );
error = mark_swapfiles(start);
printk( "|\n" );
if (error)
goto Free_map_entries;
Free_swap_map:
free_swap_map(swap_map);
free_all_swap_pages(root_swap, handle.bitmap);
release_swap_writer(&handle);
return error;
Free_map_entries:
free_swap_map_entries(swap_map);
Free_image_entries:
free_image_entries(swap_map);
goto Free_swap_map;
}
/**
@ -663,45 +579,6 @@ int swsusp_resume(void)
return error;
}
/**
* mark_unsafe_pages - mark the pages that cannot be used for storing
* the image during resume, because they conflict with the pages that
* had been used before suspend
*/
static void mark_unsafe_pages(struct pbe *pblist)
{
struct zone *zone;
unsigned long zone_pfn;
struct pbe *p;
if (!pblist) /* a sanity check */
return;
/* Clear page flags */
for_each_zone (zone) {
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
if (pfn_valid(zone_pfn + zone->zone_start_pfn))
ClearPageNosaveFree(pfn_to_page(zone_pfn +
zone->zone_start_pfn));
}
/* Mark orig addresses */
for_each_pbe (p, pblist)
SetPageNosaveFree(virt_to_page(p->orig_address));
}
static void copy_page_backup_list(struct pbe *dst, struct pbe *src)
{
/* We assume both lists contain the same number of elements */
while (src) {
dst->orig_address = src->orig_address;
dst = dst->next;
src = src->next;
}
}
/*
* Using bio to read from swap.
* This code requires a bit more work than just using buffer heads
@ -779,14 +656,14 @@ static int bio_write_page(pgoff_t page_off, void *page)
* in a file-alike way
*/
static inline void release_swap_map_reader(struct swap_map_handle *handle)
static void release_swap_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,
static int get_swap_reader(struct swap_map_handle *handle,
swp_entry_t start)
{
int error;
@ -798,149 +675,80 @@ static inline int get_swap_map_reader(struct swap_map_handle *handle,
return -ENOMEM;
error = bio_read_page(swp_offset(start), handle->cur);
if (error) {
release_swap_map_reader(handle);
release_swap_reader(handle);
return error;
}
handle->k = 0;
return 0;
}
static inline int swap_map_read_page(struct swap_map_handle *handle, void *buf)
static int swap_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]);
offset = handle->cur->entries[handle->k];
if (!offset)
return -EINVAL;
return -EFAULT;
error = bio_read_page(offset, buf);
if (error)
return error;
if (++handle->k >= MAP_PAGE_SIZE) {
if (++handle->k >= MAP_PAGE_ENTRIES) {
handle->k = 0;
offset = swp_offset(handle->cur->next_swap);
offset = handle->cur->next_swap;
if (!offset)
release_swap_map_reader(handle);
release_swap_reader(handle);
else
error = bio_read_page(offset, handle->cur);
}
return error;
}
static int check_header(void)
{
char *reason = NULL;
dump_info();
if (swsusp_info.version_code != LINUX_VERSION_CODE)
reason = "kernel version";
if (swsusp_info.num_physpages != num_physpages)
reason = "memory size";
if (strcmp(swsusp_info.uts.sysname,system_utsname.sysname))
reason = "system type";
if (strcmp(swsusp_info.uts.release,system_utsname.release))
reason = "kernel release";
if (strcmp(swsusp_info.uts.version,system_utsname.version))
reason = "version";
if (strcmp(swsusp_info.uts.machine,system_utsname.machine))
reason = "machine";
if (reason) {
printk(KERN_ERR "swsusp: Resume mismatch: %s\n", reason);
return -EPERM;
}
return 0;
}
/**
* load_image_data - load the image data using the swap map handle
* @handle and store them using the page backup list @pblist
* 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_data(struct pbe *pblist,
struct swap_map_handle *handle,
unsigned int nr_pages)
static int load_image(struct swap_map_handle *handle,
struct snapshot_handle *snapshot,
unsigned int nr_pages)
{
int error;
unsigned int m;
struct pbe *p;
int ret;
int error = 0;
if (!pblist)
return -EINVAL;
printk("Loading image data pages (%u pages) ... ", nr_pages);
m = nr_pages / 100;
if (!m)
m = 1;
nr_pages = 0;
p = pblist;
while (p) {
error = swap_map_read_page(handle, (void *)p->address);
if (error)
break;
p = p->next;
if (!(nr_pages % m))
printk("\b\b\b\b%3d%%", nr_pages / m);
nr_pages++;
}
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;
}
/**
* unpack_orig_addresses - copy the elements of @buf[] (1 page) to
* the PBEs in the list starting at @pbe
*/
static inline struct pbe *unpack_orig_addresses(unsigned long *buf,
struct pbe *pbe)
{
int j;
for (j = 0; j < PAGE_SIZE / sizeof(long) && pbe; j++) {
pbe->orig_address = buf[j];
pbe = pbe->next;
}
return pbe;
}
/**
* load_image_metadata - load the image metadata using the swap map
* handle @handle and put them into the PBEs in the list @pblist
*/
static int load_image_metadata(struct pbe *pblist, struct swap_map_handle *handle)
{
struct pbe *p;
unsigned long *buf;
unsigned int n = 0;
int error = 0;
printk("Loading image metadata ... ");
buf = (unsigned long *)get_zeroed_page(GFP_ATOMIC);
if (!buf)
return -ENOMEM;
p = pblist;
while (p) {
error = swap_map_read_page(handle, buf);
if (error)
break;
p = unpack_orig_addresses(buf, p);
n++;
}
free_page((unsigned long)buf);
if (!error)
printk("done (%u pages loaded)\n", n);
return error;
}
int swsusp_read(struct pbe **pblist_ptr)
int swsusp_read(void)
{
int error;
struct pbe *p, *pblist;
struct swap_map_handle handle;
struct snapshot_handle snapshot;
struct swsusp_info *header;
unsigned int nr_pages;
if (IS_ERR(resume_bdev)) {
@ -948,38 +756,19 @@ int swsusp_read(struct pbe **pblist_ptr)
return PTR_ERR(resume_bdev);
}
error = get_swap_map_reader(&handle, swsusp_header.image);
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_map_read_page(&handle, &swsusp_info);
if (!error)
error = check_header();
if (error)
return error;
nr_pages = swsusp_info.image_pages;
p = alloc_pagedir(nr_pages, GFP_ATOMIC, 0);
if (!p)
return -ENOMEM;
error = load_image_metadata(p, &handle);
error = swap_read_page(&handle, header);
if (!error) {
mark_unsafe_pages(p);
pblist = alloc_pagedir(nr_pages, GFP_ATOMIC, 1);
if (pblist)
copy_page_backup_list(pblist, p);
free_pagedir(p);
if (!pblist)
error = -ENOMEM;
/* Allocate memory for the image and read the data from swap */
if (!error)
error = alloc_data_pages(pblist, GFP_ATOMIC, 1);
if (!error) {
release_eaten_pages();
error = load_image_data(pblist, &handle, nr_pages);
}
if (!error)
*pblist_ptr = pblist;
nr_pages = header->image_pages;
error = load_image(&handle, &snapshot, nr_pages);
}
release_swap_map_reader(&handle);
release_swap_reader(&handle);
blkdev_put(resume_bdev);

55
mm/swapfile.c
View File

@ -45,7 +45,7 @@ static const char Unused_offset[] = "Unused swap offset entry ";
struct swap_list_t swap_list = {-1, -1};
struct swap_info_struct swap_info[MAX_SWAPFILES];
static struct swap_info_struct swap_info[MAX_SWAPFILES];
static DEFINE_MUTEX(swapon_mutex);
@ -417,6 +417,59 @@ void free_swap_and_cache(swp_entry_t entry)
}
}
#ifdef CONFIG_SOFTWARE_SUSPEND
/*
* Find the swap type that corresponds to given device (if any)
*
* This is needed for software suspend and is done in such a way that inode
* aliasing is allowed.
*/
int swap_type_of(dev_t device)
{
int i;
if (!device)
return -EINVAL;
spin_lock(&swap_lock);
for (i = 0; i < nr_swapfiles; i++) {
struct inode *inode;
if (!(swap_info[i].flags & SWP_WRITEOK))
continue;
inode = swap_info->swap_file->f_dentry->d_inode;
if (S_ISBLK(inode->i_mode) &&
device == MKDEV(imajor(inode), iminor(inode))) {
spin_unlock(&swap_lock);
return i;
}
}
spin_unlock(&swap_lock);
return -ENODEV;
}
/*
* Return either the total number of swap pages of given type, or the number
* of free pages of that type (depending on @free)
*
* This is needed for software suspend
*/
unsigned int count_swap_pages(int type, int free)
{
unsigned int n = 0;
if (type < nr_swapfiles) {
spin_lock(&swap_lock);
if (swap_info[type].flags & SWP_WRITEOK) {
n = swap_info[type].pages;
if (free)
n -= swap_info[type].inuse_pages;
}
spin_unlock(&swap_lock);
}
return n;
}
#endif
/*
* No need to decide whether this PTE shares the swap entry with others,
* just let do_wp_page work it out if a write is requested later - to