kernel/power/tuxonice_extent.c

   1 /*
   2  * kernel/power/tuxonice_extent.c
   3  *
   4  * Copyright (C) 2003-2010 Nigel Cunningham (nigel at tuxonice net)
   5  *
   6  * Distributed under GPLv2.
   7  *
   8  * These functions encapsulate the manipulation of storage metadata.
   9  */
  10
  11 #include <linux/suspend.h>
  12 #include "tuxonice_modules.h"
  13 #include "tuxonice_extent.h"
  14 #include "tuxonice_alloc.h"
  15 #include "tuxonice_ui.h"
  16 #include "tuxonice.h"
  17
  18 /**
  19  * toi_get_extent - return a free extent
  20  *
  21  * May fail, returning NULL instead.
  22  **/
  23 static struct hibernate_extent *toi_get_extent(void)
  24 {
  25         return (struct hibernate_extent *)toi_kzalloc(2,
  26                                                       sizeof(struct hibernate_extent),
  27                                                       TOI_ATOMIC_GFP);
  28 }
  29
  30 /**
  31  * toi_put_extent_chain - free a whole chain of extents
  32  * @chain:      Chain to free.
  33  **/
  34 void toi_put_extent_chain(struct hibernate_extent_chain *chain)
  35 {
  36         struct hibernate_extent *this;
  37
  38         this = chain->first;
  39
  40         while (this) {
  41                 struct hibernate_extent *next = this->next;
  42                 toi_kfree(2, this, sizeof(*this));
  43                 chain->num_extents--;
  44                 this = next;
  45         }
  46
  47         chain->first = NULL;
  48         chain->last_touched = NULL;
  49         chain->current_extent = NULL;
  50         chain->size = 0;
  51 }
  52 EXPORT_SYMBOL_GPL(toi_put_extent_chain);
  53
  54 /**
  55  * toi_add_to_extent_chain - add an extent to an existing chain
  56  * @chain:      Chain to which the extend should be added
  57  * @start:      Start of the extent (first physical block)
  58  * @end:        End of the extent (last physical block)
  59  *
  60  * The chain information is updated if the insertion is successful.
  61  **/
  62 int toi_add_to_extent_chain(struct hibernate_extent_chain *chain,
  63                             unsigned long start, unsigned long end)
  64 {
  65         struct hibernate_extent *new_ext = NULL, *cur_ext = NULL;
  66
  67         toi_message(TOI_IO, TOI_VERBOSE, 0,
  68                     "Adding extent %lu-%lu to chain %p.\n", start, end, chain);
  69
  70         /* Find the right place in the chain */
  71         if (chain->last_touched && chain->last_touched->start < start)
  72                 cur_ext = chain->last_touched;
  73         else if (chain->first && chain->first->start < start)
  74                 cur_ext = chain->first;
  75
  76         if (cur_ext) {
  77                 while (cur_ext->next && cur_ext->next->start < start)
  78                         cur_ext = cur_ext->next;
  79
  80                 if (cur_ext->end == (start - 1)) {
  81                         struct hibernate_extent *next_ext = cur_ext->next;
  82                         cur_ext->end = end;
  83
  84                         /* Merge with the following one? */
  85                         if (next_ext && cur_ext->end + 1 == next_ext->start) {
  86                                 cur_ext->end = next_ext->end;
  87                                 cur_ext->next = next_ext->next;
  88                                 toi_kfree(2, next_ext, sizeof(*next_ext));
  89                                 chain->num_extents--;
  90                         }
  91
  92                         chain->last_touched = cur_ext;
  93                         chain->size += (end - start + 1);
  94
  95                         return 0;
  96                 }
  97         }
  98
  99         new_ext = toi_get_extent();
 100         if (!new_ext) {
 101                 printk(KERN_INFO "Error unable to append a new extent to the " "chain.\n");
 102                 return -ENOMEM;
 103         }
 104
 105         chain->num_extents++;
 106         chain->size += (end - start + 1);
 107         new_ext->start = start;
 108         new_ext->end = end;
 109
 110         chain->last_touched = new_ext;
 111
 112         if (cur_ext) {
 113                 new_ext->next = cur_ext->next;
 114                 cur_ext->next = new_ext;
 115         } else {
 116                 if (chain->first)
 117                         new_ext->next = chain->first;
 118                 chain->first = new_ext;
 119         }
 120
 121         return 0;
 122 }
 123 EXPORT_SYMBOL_GPL(toi_add_to_extent_chain);