kernel/power/swsusp.c

   1 /*
   2  * linux/kernel/power/swsusp.c
   3  *
   4  * This file provides code to write suspend image to swap and read it back.
   5  *
   6  * Copyright (C) 1998-2001 Gabor Kuti <seasons@fornax.hu>
   7  * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@suse.cz>
   8  *
   9  * This file is released under the GPLv2.
  10  *
  11  * I'd like to thank the following people for their work:
  12  *
  13  * Pavel Machek <pavel@ucw.cz>:
  14  * Modifications, defectiveness pointing, being with me at the very beginning,
  15  * suspend to swap space, stop all tasks. Port to 2.4.18-ac and 2.5.17.
  16  *
  17  * Steve Doddi <dirk@loth.demon.co.uk>:
  18  * Support the possibility of hardware state restoring.
  19  *
  20  * Raph <grey.havens@earthling.net>:
  21  * Support for preserving states of network devices and virtual console
  22  * (including X and svgatextmode)
  23  *
  24  * Kurt Garloff <garloff@suse.de>:
  25  * Straightened the critical function in order to prevent compilers from
  26  * playing tricks with local variables.
  27  *
  28  * Andreas Mohr <a.mohr@mailto.de>
  29  *
  30  * Alex Badea <vampire@go.ro>:
  31  * Fixed runaway init
  32  *
  33  * Rafael J. Wysocki <rjw@sisk.pl>
  34  * Reworked the freeing of memory and the handling of swap
  35  *
  36  * More state savers are welcome. Especially for the scsi layer...
  37  *
  38  * For TODOs,FIXMEs also look in Documentation/power/swsusp.txt
  39  */
  40
  41 #include <linux/mm.h>
  42 #include <linux/suspend.h>
  43 #include <linux/spinlock.h>
  44 #include <linux/kernel.h>
  45 #include <linux/major.h>
  46 #include <linux/swap.h>
  47 #include <linux/pm.h>
  48 #include <linux/swapops.h>
  49 #include <linux/bootmem.h>
  50 #include <linux/syscalls.h>
  51 #include <linux/highmem.h>
  52 #include <linux/time.h>
  53 #include <linux/rbtree.h>
  54 #include <linux/io.h>
  55
  56 #include "power.h"
  57
  58 int in_suspend __nosavedata = 0;
  59
  60 /**
  61  *      The following functions are used for tracing the allocated
  62  *      swap pages, so that they can be freed in case of an error.
  63  */
  64
  65 struct swsusp_extent {
  66         struct rb_node node;
  67         unsigned long start;
  68         unsigned long end;
  69 };
  70
  71 static struct rb_root swsusp_extents = RB_ROOT;
  72
  73 static int swsusp_extents_insert(unsigned long swap_offset)
  74 {
  75         struct rb_node **new = &(swsusp_extents.rb_node);
  76         struct rb_node *parent = NULL;
  77         struct swsusp_extent *ext;
  78
  79         /* Figure out where to put the new node */
  80         while (*new) {
  81                 ext = container_of(*new, struct swsusp_extent, node);
  82                 parent = *new;
  83                 if (swap_offset < ext->start) {
  84                         /* Try to merge */
  85                         if (swap_offset == ext->start - 1) {
  86                                 ext->start--;
  87                                 return 0;
  88                         }
  89                         new = &((*new)->rb_left);
  90                 } else if (swap_offset > ext->end) {
  91                         /* Try to merge */
  92                         if (swap_offset == ext->end + 1) {
  93                                 ext->end++;
  94                                 return 0;
  95                         }
  96                         new = &((*new)->rb_right);
  97                 } else {
  98                         /* It already is in the tree */
  99                         return -EINVAL;
 100                 }
 101         }
 102         /* Add the new node and rebalance the tree. */
 103         ext = kzalloc(sizeof(struct swsusp_extent), GFP_KERNEL);
 104         if (!ext)
 105                 return -ENOMEM;
 106
 107         ext->start = swap_offset;
 108         ext->end = swap_offset;
 109         rb_link_node(&ext->node, parent, new);
 110         rb_insert_color(&ext->node, &swsusp_extents);
 111         return 0;
 112 }
 113
 114 /**
 115  *      alloc_swapdev_block - allocate a swap page and register that it has
 116  *      been allocated, so that it can be freed in case of an error.
 117  */
 118
 119 sector_t alloc_swapdev_block(int swap)
 120 {
 121         unsigned long offset;
 122
 123         offset = swp_offset(get_swap_page_of_type(swap));
 124         if (offset) {
 125                 if (swsusp_extents_insert(offset))
 126                         swap_free(swp_entry(swap, offset));
 127                 else
 128                         return swapdev_block(swap, offset);
 129         }
 130         return 0;
 131 }
 132
 133 /**
 134  *      free_all_swap_pages - free swap pages allocated for saving image data.
 135  *      It also frees the extents used to register which swap entres had been
 136  *      allocated.
 137  */
 138
 139 void free_all_swap_pages(int swap)
 140 {
 141         struct rb_node *node;
 142
 143         while ((node = swsusp_extents.rb_node)) {
 144                 struct swsusp_extent *ext;
 145                 unsigned long offset;
 146
 147                 ext = container_of(node, struct swsusp_extent, node);
 148                 rb_erase(node, &swsusp_extents);
 149                 for (offset = ext->start; offset <= ext->end; offset++)
 150                         swap_free(swp_entry(swap, offset));
 151
 152                 kfree(ext);
 153         }
 154 }
 155
 156 int swsusp_swap_in_use(void)
 157 {
 158         return (swsusp_extents.rb_node != NULL);
 159 }
 160
 161 /**
 162  *      swsusp_show_speed - print the time elapsed between two events represented by
 163  *      @start and @stop
 164  *
 165  *      @nr_pages -     number of pages processed between @start and @stop
 166  *      @msg -          introductory message to print
 167  */
 168
 169 void swsusp_show_speed(struct timeval *start, struct timeval *stop,
 170                         unsigned nr_pages, char *msg)
 171 {
 172         s64 elapsed_centisecs64;
 173         int centisecs;
 174         int k;
 175         int kps;
 176
 177         elapsed_centisecs64 = timeval_to_ns(stop) - timeval_to_ns(start);
 178         do_div(elapsed_centisecs64, NSEC_PER_SEC / 100);
 179         centisecs = elapsed_centisecs64;
 180         if (centisecs == 0)
 181                 centisecs = 1;  /* avoid div-by-zero */
 182         k = nr_pages * (PAGE_SIZE / 1024);
 183         kps = (k * 100) / centisecs;
 184         printk(KERN_INFO "PM: %s %d kbytes in %d.%02d seconds (%d.%02d MB/s)\n",
 185                         msg, k,
 186                         centisecs / 100, centisecs % 100,
 187                         kps / 1000, (kps % 1000) / 10);
 188 }