[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 457084f5001..c4016cbbd3e 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);
-}