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authorRafael J. Wysocki <rjw@sisk.pl>2006-03-23 03:00:03 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-23 07:38:07 -0800
commit6e1819d615f24ce0726a7d0bd3dd0152d7b21654 (patch)
treeabc68747446e8241a1a7103882b9f6b6e24fa274 /kernel/power
parent543cc27d09643640cbc34189c03a40beb8227aef (diff)
[PATCH] swsusp: userland interface
This patch introduces a user space interface for swsusp. The interface is based on a special character device, called the snapshot device, that allows user space processes to perform suspend and resume-related operations with the help of some ioctls and the read()/write() functions.  Additionally it allows these processes to allocate free swap pages from a selected swap partition, called the resume partition, so that they know which sectors of the resume partition are available to them. The interface uses the same low-level system memory snapshot-handling functions that are used by the built-it swap-writing/reading code of swsusp. The interface documentation is included in the patch. The patch assumes that the major and minor numbers of the snapshot device will be 10 (ie. misc device) and 231, the registration of which has already been requested. 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>
Diffstat (limited to 'kernel/power')
-rw-r--r--kernel/power/Makefile2
-rw-r--r--kernel/power/power.h14
-rw-r--r--kernel/power/snapshot.c9
-rw-r--r--kernel/power/user.c301
4 files changed, 321 insertions, 5 deletions
diff --git a/kernel/power/Makefile b/kernel/power/Makefile
index bb91a0615303..8d0af3d37a4b 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -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 swap.o
+obj-$(CONFIG_SOFTWARE_SUSPEND) += swsusp.o disk.o snapshot.o swap.o user.o
obj-$(CONFIG_SUSPEND_SMP) += smp.o
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 5d1abffbb9ce..42c431c8bdde 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -8,6 +8,7 @@ struct swsusp_info {
int cpus;
unsigned long image_pages;
unsigned long pages;
+ unsigned long size;
} __attribute__((aligned(PAGE_SIZE)));
@@ -65,6 +66,19 @@ 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);
+#define SNAPSHOT_IOC_MAGIC '3'
+#define SNAPSHOT_FREEZE _IO(SNAPSHOT_IOC_MAGIC, 1)
+#define SNAPSHOT_UNFREEZE _IO(SNAPSHOT_IOC_MAGIC, 2)
+#define SNAPSHOT_ATOMIC_SNAPSHOT _IOW(SNAPSHOT_IOC_MAGIC, 3, void *)
+#define SNAPSHOT_ATOMIC_RESTORE _IO(SNAPSHOT_IOC_MAGIC, 4)
+#define SNAPSHOT_FREE _IO(SNAPSHOT_IOC_MAGIC, 5)
+#define SNAPSHOT_SET_IMAGE_SIZE _IOW(SNAPSHOT_IOC_MAGIC, 6, unsigned long)
+#define SNAPSHOT_AVAIL_SWAP _IOR(SNAPSHOT_IOC_MAGIC, 7, void *)
+#define SNAPSHOT_GET_SWAP_PAGE _IOR(SNAPSHOT_IOC_MAGIC, 8, void *)
+#define SNAPSHOT_FREE_SWAP_PAGES _IO(SNAPSHOT_IOC_MAGIC, 9)
+#define SNAPSHOT_SET_SWAP_FILE _IOW(SNAPSHOT_IOC_MAGIC, 10, unsigned int)
+#define SNAPSHOT_IOC_MAXNR 10
+
/**
* The bitmap is used for tracing allocated swap pages
*
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index cc349437fb72..0036955357e0 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -37,6 +37,7 @@
struct pbe *pagedir_nosave;
static unsigned int nr_copy_pages;
static unsigned int nr_meta_pages;
+static unsigned long *buffer;
#ifdef CONFIG_HIGHMEM
unsigned int count_highmem_pages(void)
@@ -389,7 +390,7 @@ struct pbe *alloc_pagedir(unsigned int nr_pages, gfp_t gfp_mask, int safe_needed
free_pagedir(pblist);
pblist = NULL;
} else
- create_pbe_list(pblist, nr_pages);
+ create_pbe_list(pblist, nr_pages);
return pblist;
}
@@ -418,6 +419,7 @@ void swsusp_free(void)
nr_copy_pages = 0;
nr_meta_pages = 0;
pagedir_nosave = NULL;
+ buffer = NULL;
}
@@ -523,6 +525,8 @@ static void init_header(struct swsusp_info *info)
info->cpus = num_online_cpus();
info->image_pages = nr_copy_pages;
info->pages = nr_copy_pages + nr_meta_pages + 1;
+ info->size = info->pages;
+ info->size <<= PAGE_SHIFT;
}
/**
@@ -568,8 +572,6 @@ static inline struct pbe *pack_orig_addresses(unsigned long *buf, struct pbe *pb
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) {
@@ -774,7 +776,6 @@ static int create_image(struct snapshot_handle *handle)
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)
diff --git a/kernel/power/user.c b/kernel/power/user.c
new file mode 100644
index 000000000000..8cabc405ca10
--- /dev/null
+++ b/kernel/power/user.c
@@ -0,0 +1,301 @@
+/*
+ * linux/kernel/power/user.c
+ *
+ * This file provides the user space interface for software suspend/resume.
+ *
+ * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
+ *
+ * This file is released under the GPLv2.
+ *
+ */
+
+#include <linux/suspend.h>
+#include <linux/syscalls.h>
+#include <linux/string.h>
+#include <linux/device.h>
+#include <linux/miscdevice.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
+#include <linux/pm.h>
+#include <linux/fs.h>
+
+#include <asm/uaccess.h>
+
+#include "power.h"
+
+#define SNAPSHOT_MINOR 231
+
+static struct snapshot_data {
+ struct snapshot_handle handle;
+ int swap;
+ struct bitmap_page *bitmap;
+ int mode;
+ char frozen;
+ char ready;
+} snapshot_state;
+
+static atomic_t device_available = ATOMIC_INIT(1);
+
+static int snapshot_open(struct inode *inode, struct file *filp)
+{
+ struct snapshot_data *data;
+
+ if (!atomic_add_unless(&device_available, -1, 0))
+ return -EBUSY;
+
+ if ((filp->f_flags & O_ACCMODE) == O_RDWR)
+ return -ENOSYS;
+
+ nonseekable_open(inode, filp);
+ data = &snapshot_state;
+ filp->private_data = data;
+ memset(&data->handle, 0, sizeof(struct snapshot_handle));
+ if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
+ data->swap = swsusp_resume_device ? swap_type_of(swsusp_resume_device) : -1;
+ data->mode = O_RDONLY;
+ } else {
+ data->swap = -1;
+ data->mode = O_WRONLY;
+ }
+ data->bitmap = NULL;
+ data->frozen = 0;
+ data->ready = 0;
+
+ return 0;
+}
+
+static int snapshot_release(struct inode *inode, struct file *filp)
+{
+ struct snapshot_data *data;
+
+ swsusp_free();
+ data = filp->private_data;
+ free_all_swap_pages(data->swap, data->bitmap);
+ free_bitmap(data->bitmap);
+ if (data->frozen) {
+ down(&pm_sem);
+ thaw_processes();
+ enable_nonboot_cpus();
+ up(&pm_sem);
+ }
+ atomic_inc(&device_available);
+ return 0;
+}
+
+static ssize_t snapshot_read(struct file *filp, char __user *buf,
+ size_t count, loff_t *offp)
+{
+ struct snapshot_data *data;
+ ssize_t res;
+
+ data = filp->private_data;
+ res = snapshot_read_next(&data->handle, count);
+ if (res > 0) {
+ if (copy_to_user(buf, data_of(data->handle), res))
+ res = -EFAULT;
+ else
+ *offp = data->handle.offset;
+ }
+ return res;
+}
+
+static ssize_t snapshot_write(struct file *filp, const char __user *buf,
+ size_t count, loff_t *offp)
+{
+ struct snapshot_data *data;
+ ssize_t res;
+
+ data = filp->private_data;
+ res = snapshot_write_next(&data->handle, count);
+ if (res > 0) {
+ if (copy_from_user(data_of(data->handle), buf, res))
+ res = -EFAULT;
+ else
+ *offp = data->handle.offset;
+ }
+ return res;
+}
+
+static int snapshot_ioctl(struct inode *inode, struct file *filp,
+ unsigned int cmd, unsigned long arg)
+{
+ int error = 0;
+ struct snapshot_data *data;
+ loff_t offset, avail;
+
+ if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
+ return -ENOTTY;
+ if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
+ return -ENOTTY;
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ data = filp->private_data;
+
+ switch (cmd) {
+
+ case SNAPSHOT_FREEZE:
+ if (data->frozen)
+ break;
+ sys_sync();
+ down(&pm_sem);
+ pm_prepare_console();
+ disable_nonboot_cpus();
+ if (freeze_processes()) {
+ thaw_processes();
+ enable_nonboot_cpus();
+ pm_restore_console();
+ error = -EBUSY;
+ }
+ up(&pm_sem);
+ if (!error)
+ data->frozen = 1;
+ break;
+
+ case SNAPSHOT_UNFREEZE:
+ if (!data->frozen)
+ break;
+ down(&pm_sem);
+ thaw_processes();
+ enable_nonboot_cpus();
+ pm_restore_console();
+ up(&pm_sem);
+ data->frozen = 0;
+ break;
+
+ case SNAPSHOT_ATOMIC_SNAPSHOT:
+ if (data->mode != O_RDONLY || !data->frozen || data->ready) {
+ error = -EPERM;
+ break;
+ }
+ down(&pm_sem);
+ /* Free memory before shutting down devices. */
+ error = swsusp_shrink_memory();
+ if (!error) {
+ error = device_suspend(PMSG_FREEZE);
+ if (!error) {
+ in_suspend = 1;
+ error = swsusp_suspend();
+ device_resume();
+ }
+ }
+ up(&pm_sem);
+ if (!error)
+ error = put_user(in_suspend, (unsigned int __user *)arg);
+ if (!error)
+ data->ready = 1;
+ break;
+
+ case SNAPSHOT_ATOMIC_RESTORE:
+ if (data->mode != O_WRONLY || !data->frozen ||
+ !snapshot_image_loaded(&data->handle)) {
+ error = -EPERM;
+ break;
+ }
+ down(&pm_sem);
+ pm_prepare_console();
+ error = device_suspend(PMSG_FREEZE);
+ if (!error) {
+ error = swsusp_resume();
+ device_resume();
+ }
+ pm_restore_console();
+ up(&pm_sem);
+ break;
+
+ case SNAPSHOT_FREE:
+ swsusp_free();
+ memset(&data->handle, 0, sizeof(struct snapshot_handle));
+ data->ready = 0;
+ break;
+
+ case SNAPSHOT_SET_IMAGE_SIZE:
+ image_size = arg;
+ break;
+
+ case SNAPSHOT_AVAIL_SWAP:
+ avail = count_swap_pages(data->swap, 1);
+ avail <<= PAGE_SHIFT;
+ error = put_user(avail, (loff_t __user *)arg);
+ break;
+
+ case SNAPSHOT_GET_SWAP_PAGE:
+ if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
+ error = -ENODEV;
+ break;
+ }
+ if (!data->bitmap) {
+ data->bitmap = alloc_bitmap(count_swap_pages(data->swap, 0));
+ if (!data->bitmap) {
+ error = -ENOMEM;
+ break;
+ }
+ }
+ offset = alloc_swap_page(data->swap, data->bitmap);
+ if (offset) {
+ offset <<= PAGE_SHIFT;
+ error = put_user(offset, (loff_t __user *)arg);
+ } else {
+ error = -ENOSPC;
+ }
+ break;
+
+ case SNAPSHOT_FREE_SWAP_PAGES:
+ if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
+ error = -ENODEV;
+ break;
+ }
+ free_all_swap_pages(data->swap, data->bitmap);
+ free_bitmap(data->bitmap);
+ data->bitmap = NULL;
+ break;
+
+ case SNAPSHOT_SET_SWAP_FILE:
+ if (!data->bitmap) {
+ /*
+ * User space encodes device types as two-byte values,
+ * so we need to recode them
+ */
+ if (old_decode_dev(arg)) {
+ data->swap = swap_type_of(old_decode_dev(arg));
+ if (data->swap < 0)
+ error = -ENODEV;
+ } else {
+ data->swap = -1;
+ error = -EINVAL;
+ }
+ } else {
+ error = -EPERM;
+ }
+ break;
+
+ default:
+ error = -ENOTTY;
+
+ }
+
+ return error;
+}
+
+static struct file_operations snapshot_fops = {
+ .open = snapshot_open,
+ .release = snapshot_release,
+ .read = snapshot_read,
+ .write = snapshot_write,
+ .llseek = no_llseek,
+ .ioctl = snapshot_ioctl,
+};
+
+static struct miscdevice snapshot_device = {
+ .minor = SNAPSHOT_MINOR,
+ .name = "snapshot",
+ .fops = &snapshot_fops,
+};
+
+static int __init snapshot_device_init(void)
+{
+ return misc_register(&snapshot_device);
+};
+
+device_initcall(snapshot_device_init);