[PATCH] swsusp: struct snapshot_handle cleanup
[linux-2.6.git] / kernel / power / power.h
1 #include <linux/suspend.h>
2 #include <linux/utsname.h>
3
4 struct swsusp_info {
5         struct new_utsname      uts;
6         u32                     version_code;
7         unsigned long           num_physpages;
8         int                     cpus;
9         unsigned long           image_pages;
10         unsigned long           pages;
11         unsigned long           size;
12 } __attribute__((aligned(PAGE_SIZE)));
13
14
15
16 #ifdef CONFIG_SOFTWARE_SUSPEND
17 extern int pm_suspend_disk(void);
18
19 #else
20 static inline int pm_suspend_disk(void)
21 {
22         return -EPERM;
23 }
24 #endif
25 extern struct semaphore pm_sem;
26 #define power_attr(_name) \
27 static struct subsys_attribute _name##_attr = { \
28         .attr   = {                             \
29                 .name = __stringify(_name),     \
30                 .mode = 0644,                   \
31         },                                      \
32         .show   = _name##_show,                 \
33         .store  = _name##_store,                \
34 }
35
36 extern struct subsystem power_subsys;
37
38 /* References to section boundaries */
39 extern const void __nosave_begin, __nosave_end;
40
41 extern struct pbe *pagedir_nosave;
42
43 /* Preferred image size in bytes (default 500 MB) */
44 extern unsigned long image_size;
45 extern int in_suspend;
46 extern dev_t swsusp_resume_device;
47
48 extern asmlinkage int swsusp_arch_suspend(void);
49 extern asmlinkage int swsusp_arch_resume(void);
50
51 extern unsigned int count_data_pages(void);
52
53 /**
54  *      Auxiliary structure used for reading the snapshot image data and
55  *      metadata from and writing them to the list of page backup entries
56  *      (PBEs) which is the main data structure of swsusp.
57  *
58  *      Using struct snapshot_handle we can transfer the image, including its
59  *      metadata, as a continuous sequence of bytes with the help of
60  *      snapshot_read_next() and snapshot_write_next().
61  *
62  *      The code that writes the image to a storage or transfers it to
63  *      the user land is required to use snapshot_read_next() for this
64  *      purpose and it should not make any assumptions regarding the internal
65  *      structure of the image.  Similarly, the code that reads the image from
66  *      a storage or transfers it from the user land is required to use
67  *      snapshot_write_next().
68  *
69  *      This may allow us to change the internal structure of the image
70  *      in the future with considerably less effort.
71  */
72
73 struct snapshot_handle {
74         loff_t          offset; /* number of the last byte ready for reading
75                                  * or writing in the sequence
76                                  */
77         unsigned int    cur;    /* number of the block of PAGE_SIZE bytes the
78                                  * next operation will refer to (ie. current)
79                                  */
80         unsigned int    cur_offset;     /* offset with respect to the current
81                                          * block (for the next operation)
82                                          */
83         unsigned int    prev;   /* number of the block of PAGE_SIZE bytes that
84                                  * was the current one previously
85                                  */
86         struct pbe      *pbe;   /* PBE that corresponds to 'buffer' */
87         struct pbe      *last_pbe;      /* When the image is restored (eg. read
88                                          * from disk) we can store some image
89                                          * data directly in the page frames
90                                          * in which they were before suspend.
91                                          * In such a case the PBEs that
92                                          * correspond to them will be unused.
93                                          * This is the last PBE, so far, that
94                                          * does not correspond to such data.
95                                          */
96         void            *buffer;        /* address of the block to read from
97                                          * or write to
98                                          */
99         unsigned int    buf_offset;     /* location to read from or write to,
100                                          * given as a displacement from 'buffer'
101                                          */
102         int             sync_read;      /* Set to one to notify the caller of
103                                          * snapshot_write_next() that it may
104                                          * need to call wait_on_bio_chain()
105                                          */
106 };
107
108 /* This macro returns the address from/to which the caller of
109  * snapshot_read_next()/snapshot_write_next() is allowed to
110  * read/write data after the function returns
111  */
112 #define data_of(handle) ((handle).buffer + (handle).buf_offset)
113
114 extern int snapshot_read_next(struct snapshot_handle *handle, size_t count);
115 extern int snapshot_write_next(struct snapshot_handle *handle, size_t count);
116 int snapshot_image_loaded(struct snapshot_handle *handle);
117
118 #define SNAPSHOT_IOC_MAGIC      '3'
119 #define SNAPSHOT_FREEZE                 _IO(SNAPSHOT_IOC_MAGIC, 1)
120 #define SNAPSHOT_UNFREEZE               _IO(SNAPSHOT_IOC_MAGIC, 2)
121 #define SNAPSHOT_ATOMIC_SNAPSHOT        _IOW(SNAPSHOT_IOC_MAGIC, 3, void *)
122 #define SNAPSHOT_ATOMIC_RESTORE         _IO(SNAPSHOT_IOC_MAGIC, 4)
123 #define SNAPSHOT_FREE                   _IO(SNAPSHOT_IOC_MAGIC, 5)
124 #define SNAPSHOT_SET_IMAGE_SIZE         _IOW(SNAPSHOT_IOC_MAGIC, 6, unsigned long)
125 #define SNAPSHOT_AVAIL_SWAP             _IOR(SNAPSHOT_IOC_MAGIC, 7, void *)
126 #define SNAPSHOT_GET_SWAP_PAGE          _IOR(SNAPSHOT_IOC_MAGIC, 8, void *)
127 #define SNAPSHOT_FREE_SWAP_PAGES        _IO(SNAPSHOT_IOC_MAGIC, 9)
128 #define SNAPSHOT_SET_SWAP_FILE          _IOW(SNAPSHOT_IOC_MAGIC, 10, unsigned int)
129 #define SNAPSHOT_S2RAM                  _IO(SNAPSHOT_IOC_MAGIC, 11)
130 #define SNAPSHOT_IOC_MAXNR      11
131
132 /**
133  *      The bitmap is used for tracing allocated swap pages
134  *
135  *      The entire bitmap consists of a number of bitmap_page
136  *      structures linked with the help of the .next member.
137  *      Thus each page can be allocated individually, so we only
138  *      need to make 0-order memory allocations to create
139  *      the bitmap.
140  */
141
142 #define BITMAP_PAGE_SIZE        (PAGE_SIZE - sizeof(void *))
143 #define BITMAP_PAGE_CHUNKS      (BITMAP_PAGE_SIZE / sizeof(long))
144 #define BITS_PER_CHUNK          (sizeof(long) * 8)
145 #define BITMAP_PAGE_BITS        (BITMAP_PAGE_CHUNKS * BITS_PER_CHUNK)
146
147 struct bitmap_page {
148         unsigned long           chunks[BITMAP_PAGE_CHUNKS];
149         struct bitmap_page      *next;
150 };
151
152 extern void free_bitmap(struct bitmap_page *bitmap);
153 extern struct bitmap_page *alloc_bitmap(unsigned int nr_bits);
154 extern unsigned long alloc_swap_page(int swap, struct bitmap_page *bitmap);
155 extern void free_all_swap_pages(int swap, struct bitmap_page *bitmap);
156
157 extern int swsusp_check(void);
158 extern int swsusp_shrink_memory(void);
159 extern void swsusp_free(void);
160 extern int swsusp_suspend(void);
161 extern int swsusp_resume(void);
162 extern int swsusp_read(void);
163 extern int swsusp_write(void);
164 extern void swsusp_close(void);
165 extern int suspend_enter(suspend_state_t state);