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Rev | Author | Line No. | Line |
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1412 | serge | 1 | /* |
2 | * 2002-10-18 written by Jim Houston jim.houston@ccur.com |
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3 | * Copyright (C) 2002 by Concurrent Computer Corporation |
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4 | * Distributed under the GNU GPL license version 2. |
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5 | * |
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6 | * Modified by George Anzinger to reuse immediately and to use |
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7 | * find bit instructions. Also removed _irq on spinlocks. |
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8 | * |
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9 | * Modified by Nadia Derbey to make it RCU safe. |
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10 | * |
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11 | * Small id to pointer translation service. |
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12 | * |
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13 | * It uses a radix tree like structure as a sparse array indexed |
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14 | * by the id to obtain the pointer. The bitmap makes allocating |
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15 | * a new id quick. |
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16 | * |
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17 | * You call it to allocate an id (an int) an associate with that id a |
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18 | * pointer or what ever, we treat it as a (void *). You can pass this |
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19 | * id to a user for him to pass back at a later time. You then pass |
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20 | * that id to this code and it returns your pointer. |
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21 | |||
22 | * You can release ids at any time. When all ids are released, most of |
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3391 | Serge | 23 | * the memory is returned (we keep MAX_IDR_FREE) in a local pool so we |
1412 | serge | 24 | * don't need to go to the memory "store" during an id allocate, just |
25 | * so you don't need to be too concerned about locking and conflicts |
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26 | * with the slab allocator. |
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27 | */ |
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28 | |||
29 | #include |
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3391 | Serge | 30 | #include |
1412 | serge | 31 | #include |
32 | #include |
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33 | #include |
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34 | //#include |
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35 | |||
3391 | Serge | 36 | unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size, |
37 | unsigned long offset); |
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1412 | serge | 38 | |
39 | |||
3391 | Serge | 40 | #define MAX_IDR_SHIFT (sizeof(int) * 8 - 1) |
41 | #define MAX_IDR_BIT (1U << MAX_IDR_SHIFT) |
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1412 | serge | 42 | |
3391 | Serge | 43 | /* Leave the possibility of an incomplete final layer */ |
44 | #define MAX_IDR_LEVEL ((MAX_IDR_SHIFT + IDR_BITS - 1) / IDR_BITS) |
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1412 | serge | 45 | |
3391 | Serge | 46 | /* Number of id_layer structs to leave in free list */ |
47 | #define MAX_IDR_FREE (MAX_IDR_LEVEL * 2) |
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1412 | serge | 48 | |
3391 | Serge | 49 | static struct idr_layer *idr_preload_head; |
50 | static int idr_preload_cnt; |
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1412 | serge | 51 | |
52 | |||
3391 | Serge | 53 | /* the maximum ID which can be allocated given idr->layers */ |
54 | static int idr_max(int layers) |
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55 | { |
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56 | int bits = min_t(int, layers * IDR_BITS, MAX_IDR_SHIFT); |
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1412 | serge | 57 | |
3391 | Serge | 58 | return (1 << bits) - 1; |
59 | } |
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1412 | serge | 60 | |
3391 | Serge | 61 | /* |
62 | * Prefix mask for an idr_layer at @layer. For layer 0, the prefix mask is |
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63 | * all bits except for the lower IDR_BITS. For layer 1, 2 * IDR_BITS, and |
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64 | * so on. |
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65 | */ |
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66 | static int idr_layer_prefix_mask(int layer) |
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67 | { |
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68 | return ~idr_max(layer + 1); |
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69 | } |
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1412 | serge | 70 | |
71 | static struct idr_layer *get_from_free_list(struct idr *idp) |
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72 | { |
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73 | struct idr_layer *p; |
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74 | unsigned long flags; |
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75 | |||
3391 | Serge | 76 | spin_lock_irqsave(&idp->lock, flags); |
1412 | serge | 77 | if ((p = idp->id_free)) { |
78 | idp->id_free = p->ary[0]; |
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79 | idp->id_free_cnt--; |
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80 | p->ary[0] = NULL; |
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81 | } |
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3391 | Serge | 82 | spin_unlock_irqrestore(&idp->lock, flags); |
1412 | serge | 83 | return(p); |
84 | } |
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85 | |||
3391 | Serge | 86 | /** |
87 | * idr_layer_alloc - allocate a new idr_layer |
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88 | * @gfp_mask: allocation mask |
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89 | * @layer_idr: optional idr to allocate from |
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90 | * |
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91 | * If @layer_idr is %NULL, directly allocate one using @gfp_mask or fetch |
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92 | * one from the per-cpu preload buffer. If @layer_idr is not %NULL, fetch |
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93 | * an idr_layer from @idr->id_free. |
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94 | * |
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95 | * @layer_idr is to maintain backward compatibility with the old alloc |
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96 | * interface - idr_pre_get() and idr_get_new*() - and will be removed |
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97 | * together with per-pool preload buffer. |
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98 | */ |
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99 | static struct idr_layer *idr_layer_alloc(gfp_t gfp_mask, struct idr *layer_idr) |
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100 | { |
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101 | struct idr_layer *new; |
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102 | |||
103 | /* this is the old path, bypass to get_from_free_list() */ |
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104 | if (layer_idr) |
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105 | return get_from_free_list(layer_idr); |
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106 | |||
107 | /* try to allocate directly from kmem_cache */ |
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108 | new = kzalloc(sizeof(struct idr_layer), gfp_mask); |
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109 | if (new) |
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110 | return new; |
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111 | |||
112 | |||
113 | new = idr_preload_head; |
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114 | if (new) { |
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115 | idr_preload_head = new->ary[0]; |
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116 | idr_preload_cnt--; |
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117 | new->ary[0] = NULL; |
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118 | } |
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119 | preempt_enable(); |
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120 | return new; |
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121 | } |
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122 | |||
1412 | serge | 123 | static void idr_layer_rcu_free(struct rcu_head *head) |
124 | { |
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125 | struct idr_layer *layer; |
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126 | |||
127 | layer = container_of(head, struct idr_layer, rcu_head); |
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128 | kfree(layer); |
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129 | } |
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130 | |||
3391 | Serge | 131 | static inline void free_layer(struct idr *idr, struct idr_layer *p) |
1412 | serge | 132 | { |
3391 | Serge | 133 | if (idr->hint && idr->hint == p) |
134 | RCU_INIT_POINTER(idr->hint, NULL); |
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135 | idr_layer_rcu_free(&p->rcu_head); |
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1412 | serge | 136 | } |
137 | |||
138 | /* only called when idp->lock is held */ |
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139 | static void __move_to_free_list(struct idr *idp, struct idr_layer *p) |
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140 | { |
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141 | p->ary[0] = idp->id_free; |
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142 | idp->id_free = p; |
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143 | idp->id_free_cnt++; |
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144 | } |
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145 | |||
146 | static void move_to_free_list(struct idr *idp, struct idr_layer *p) |
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147 | { |
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148 | unsigned long flags; |
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149 | |||
150 | /* |
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151 | * Depends on the return element being zeroed. |
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152 | */ |
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3391 | Serge | 153 | spin_lock_irqsave(&idp->lock, flags); |
1412 | serge | 154 | __move_to_free_list(idp, p); |
3391 | Serge | 155 | spin_unlock_irqrestore(&idp->lock, flags); |
1412 | serge | 156 | } |
157 | |||
158 | static void idr_mark_full(struct idr_layer **pa, int id) |
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159 | { |
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160 | struct idr_layer *p = pa[0]; |
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161 | int l = 0; |
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162 | |||
3391 | Serge | 163 | __set_bit(id & IDR_MASK, p->bitmap); |
1412 | serge | 164 | /* |
165 | * If this layer is full mark the bit in the layer above to |
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166 | * show that this part of the radix tree is full. This may |
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167 | * complete the layer above and require walking up the radix |
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168 | * tree. |
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169 | */ |
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3391 | Serge | 170 | while (bitmap_full(p->bitmap, IDR_SIZE)) { |
1412 | serge | 171 | if (!(p = pa[++l])) |
172 | break; |
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173 | id = id >> IDR_BITS; |
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3391 | Serge | 174 | __set_bit((id & IDR_MASK), p->bitmap); |
1412 | serge | 175 | } |
176 | } |
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177 | |||
178 | /** |
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2966 | Serge | 179 | * idr_pre_get - reserve resources for idr allocation |
1412 | serge | 180 | * @idp: idr handle |
181 | * @gfp_mask: memory allocation flags |
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182 | * |
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2966 | Serge | 183 | * This function should be called prior to calling the idr_get_new* functions. |
184 | * It preallocates enough memory to satisfy the worst possible allocation. The |
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185 | * caller should pass in GFP_KERNEL if possible. This of course requires that |
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186 | * no spinning locks be held. |
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1412 | serge | 187 | * |
2966 | Serge | 188 | * If the system is REALLY out of memory this function returns %0, |
189 | * otherwise %1. |
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1412 | serge | 190 | */ |
2966 | Serge | 191 | int idr_pre_get(struct idr *idp, gfp_t gfp_mask) |
1412 | serge | 192 | { |
3391 | Serge | 193 | while (idp->id_free_cnt < MAX_IDR_FREE) { |
1412 | serge | 194 | struct idr_layer *new; |
195 | new = kzalloc(sizeof(struct idr_layer), gfp_mask); |
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196 | if (new == NULL) |
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197 | return (0); |
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198 | move_to_free_list(idp, new); |
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199 | } |
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200 | return 1; |
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201 | } |
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3391 | Serge | 202 | EXPORT_SYMBOL(idr_pre_get); |
1412 | serge | 203 | |
3391 | Serge | 204 | /** |
205 | * sub_alloc - try to allocate an id without growing the tree depth |
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206 | * @idp: idr handle |
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207 | * @starting_id: id to start search at |
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208 | * @id: pointer to the allocated handle |
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209 | * @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer |
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210 | * @gfp_mask: allocation mask for idr_layer_alloc() |
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211 | * @layer_idr: optional idr passed to idr_layer_alloc() |
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212 | * |
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213 | * Allocate an id in range [@starting_id, INT_MAX] from @idp without |
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214 | * growing its depth. Returns |
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215 | * |
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216 | * the allocated id >= 0 if successful, |
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217 | * -EAGAIN if the tree needs to grow for allocation to succeed, |
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218 | * -ENOSPC if the id space is exhausted, |
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219 | * -ENOMEM if more idr_layers need to be allocated. |
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220 | */ |
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221 | static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa, |
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222 | gfp_t gfp_mask, struct idr *layer_idr) |
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1412 | serge | 223 | { |
224 | int n, m, sh; |
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225 | struct idr_layer *p, *new; |
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226 | int l, id, oid; |
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227 | |||
228 | id = *starting_id; |
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229 | restart: |
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230 | p = idp->top; |
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231 | l = idp->layers; |
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232 | pa[l--] = NULL; |
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233 | while (1) { |
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234 | /* |
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235 | * We run around this while until we reach the leaf node... |
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236 | */ |
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237 | n = (id >> (IDR_BITS*l)) & IDR_MASK; |
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3391 | Serge | 238 | m = find_next_zero_bit(p->bitmap, IDR_SIZE, n); |
1412 | serge | 239 | if (m == IDR_SIZE) { |
240 | /* no space available go back to previous layer. */ |
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241 | l++; |
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242 | oid = id; |
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243 | id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; |
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244 | |||
245 | /* if already at the top layer, we need to grow */ |
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3391 | Serge | 246 | if (id >= 1 << (idp->layers * IDR_BITS)) { |
1412 | serge | 247 | *starting_id = id; |
3391 | Serge | 248 | return -EAGAIN; |
1412 | serge | 249 | } |
3391 | Serge | 250 | p = pa[l]; |
251 | BUG_ON(!p); |
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1412 | serge | 252 | |
253 | /* If we need to go up one layer, continue the |
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254 | * loop; otherwise, restart from the top. |
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255 | */ |
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256 | sh = IDR_BITS * (l + 1); |
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257 | if (oid >> sh == id >> sh) |
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258 | continue; |
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259 | else |
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260 | goto restart; |
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261 | } |
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262 | if (m != n) { |
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263 | sh = IDR_BITS*l; |
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264 | id = ((id >> sh) ^ n ^ m) << sh; |
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265 | } |
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3391 | Serge | 266 | if ((id >= MAX_IDR_BIT) || (id < 0)) |
267 | return -ENOSPC; |
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1412 | serge | 268 | if (l == 0) |
269 | break; |
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270 | /* |
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271 | * Create the layer below if it is missing. |
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272 | */ |
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273 | if (!p->ary[m]) { |
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3391 | Serge | 274 | new = idr_layer_alloc(gfp_mask, layer_idr); |
1412 | serge | 275 | if (!new) |
3391 | Serge | 276 | return -ENOMEM; |
1412 | serge | 277 | new->layer = l-1; |
3391 | Serge | 278 | new->prefix = id & idr_layer_prefix_mask(new->layer); |
1412 | serge | 279 | rcu_assign_pointer(p->ary[m], new); |
280 | p->count++; |
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281 | } |
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282 | pa[l--] = p; |
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283 | p = p->ary[m]; |
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284 | } |
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285 | |||
286 | pa[l] = p; |
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287 | return id; |
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288 | } |
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289 | |||
290 | static int idr_get_empty_slot(struct idr *idp, int starting_id, |
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3391 | Serge | 291 | struct idr_layer **pa, gfp_t gfp_mask, |
292 | struct idr *layer_idr) |
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1412 | serge | 293 | { |
294 | struct idr_layer *p, *new; |
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295 | int layers, v, id; |
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296 | unsigned long flags; |
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297 | |||
298 | id = starting_id; |
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299 | build_up: |
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300 | p = idp->top; |
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301 | layers = idp->layers; |
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302 | if (unlikely(!p)) { |
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3391 | Serge | 303 | if (!(p = idr_layer_alloc(gfp_mask, layer_idr))) |
304 | return -ENOMEM; |
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1412 | serge | 305 | p->layer = 0; |
306 | layers = 1; |
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307 | } |
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308 | /* |
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309 | * Add a new layer to the top of the tree if the requested |
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310 | * id is larger than the currently allocated space. |
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311 | */ |
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3391 | Serge | 312 | while (id > idr_max(layers)) { |
1412 | serge | 313 | layers++; |
314 | if (!p->count) { |
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315 | /* special case: if the tree is currently empty, |
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316 | * then we grow the tree by moving the top node |
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317 | * upwards. |
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318 | */ |
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319 | p->layer++; |
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3391 | Serge | 320 | WARN_ON_ONCE(p->prefix); |
1412 | serge | 321 | continue; |
322 | } |
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3391 | Serge | 323 | if (!(new = idr_layer_alloc(gfp_mask, layer_idr))) { |
1412 | serge | 324 | /* |
325 | * The allocation failed. If we built part of |
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326 | * the structure tear it down. |
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327 | */ |
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3391 | Serge | 328 | spin_lock_irqsave(&idp->lock, flags); |
1412 | serge | 329 | for (new = p; p && p != idp->top; new = p) { |
330 | p = p->ary[0]; |
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331 | new->ary[0] = NULL; |
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3391 | Serge | 332 | new->count = 0; |
333 | bitmap_clear(new->bitmap, 0, IDR_SIZE); |
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1412 | serge | 334 | __move_to_free_list(idp, new); |
335 | } |
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3391 | Serge | 336 | spin_unlock_irqrestore(&idp->lock, flags); |
337 | return -ENOMEM; |
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1412 | serge | 338 | } |
339 | new->ary[0] = p; |
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340 | new->count = 1; |
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341 | new->layer = layers-1; |
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3391 | Serge | 342 | new->prefix = id & idr_layer_prefix_mask(new->layer); |
343 | if (bitmap_full(p->bitmap, IDR_SIZE)) |
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344 | __set_bit(0, new->bitmap); |
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1412 | serge | 345 | p = new; |
346 | } |
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347 | rcu_assign_pointer(idp->top, p); |
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348 | idp->layers = layers; |
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3391 | Serge | 349 | v = sub_alloc(idp, &id, pa, gfp_mask, layer_idr); |
350 | if (v == -EAGAIN) |
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1412 | serge | 351 | goto build_up; |
352 | return(v); |
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353 | } |
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354 | |||
3391 | Serge | 355 | /* |
356 | * @id and @pa are from a successful allocation from idr_get_empty_slot(). |
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357 | * Install the user pointer @ptr and mark the slot full. |
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358 | */ |
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359 | static void idr_fill_slot(struct idr *idr, void *ptr, int id, |
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360 | struct idr_layer **pa) |
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1412 | serge | 361 | { |
3391 | Serge | 362 | /* update hint used for lookup, cleared from free_layer() */ |
363 | rcu_assign_pointer(idr->hint, pa[0]); |
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1412 | serge | 364 | |
3391 | Serge | 365 | rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], (struct idr_layer *)ptr); |
1412 | serge | 366 | pa[0]->count++; |
367 | idr_mark_full(pa, id); |
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368 | } |
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369 | |||
370 | /** |
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371 | * idr_get_new_above - allocate new idr entry above or equal to a start id |
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372 | * @idp: idr handle |
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2966 | Serge | 373 | * @ptr: pointer you want associated with the id |
374 | * @starting_id: id to start search at |
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1412 | serge | 375 | * @id: pointer to the allocated handle |
376 | * |
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377 | * This is the allocate id function. It should be called with any |
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378 | * required locks. |
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379 | * |
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2966 | Serge | 380 | * If allocation from IDR's private freelist fails, idr_get_new_above() will |
381 | * return %-EAGAIN. The caller should retry the idr_pre_get() call to refill |
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382 | * IDR's preallocation and then retry the idr_get_new_above() call. |
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1412 | serge | 383 | * |
2966 | Serge | 384 | * If the idr is full idr_get_new_above() will return %-ENOSPC. |
385 | * |
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386 | * @id returns a value in the range @starting_id ... %0x7fffffff |
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1412 | serge | 387 | */ |
388 | int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) |
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389 | { |
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3391 | Serge | 390 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
1412 | serge | 391 | int rv; |
2966 | Serge | 392 | |
3391 | Serge | 393 | rv = idr_get_empty_slot(idp, starting_id, pa, 0, idp); |
1412 | serge | 394 | if (rv < 0) |
3391 | Serge | 395 | return rv == -ENOMEM ? -EAGAIN : rv; |
396 | |||
397 | idr_fill_slot(idp, ptr, rv, pa); |
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1412 | serge | 398 | *id = rv; |
399 | return 0; |
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400 | } |
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3391 | Serge | 401 | EXPORT_SYMBOL(idr_get_new_above); |
1412 | serge | 402 | |
403 | /** |
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3391 | Serge | 404 | * idr_preload - preload for idr_alloc() |
405 | * @gfp_mask: allocation mask to use for preloading |
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1412 | serge | 406 | * |
3391 | Serge | 407 | * Preload per-cpu layer buffer for idr_alloc(). Can only be used from |
408 | * process context and each idr_preload() invocation should be matched with |
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409 | * idr_preload_end(). Note that preemption is disabled while preloaded. |
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1412 | serge | 410 | * |
3391 | Serge | 411 | * The first idr_alloc() in the preloaded section can be treated as if it |
412 | * were invoked with @gfp_mask used for preloading. This allows using more |
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413 | * permissive allocation masks for idrs protected by spinlocks. |
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1412 | serge | 414 | * |
3391 | Serge | 415 | * For example, if idr_alloc() below fails, the failure can be treated as |
416 | * if idr_alloc() were called with GFP_KERNEL rather than GFP_NOWAIT. |
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417 | * |
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418 | * idr_preload(GFP_KERNEL); |
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419 | * spin_lock(lock); |
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420 | * |
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421 | * id = idr_alloc(idr, ptr, start, end, GFP_NOWAIT); |
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422 | * |
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423 | * spin_unlock(lock); |
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424 | * idr_preload_end(); |
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425 | * if (id < 0) |
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426 | * error; |
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1412 | serge | 427 | */ |
3391 | Serge | 428 | void idr_preload(gfp_t gfp_mask) |
1412 | serge | 429 | { |
430 | |||
431 | /* |
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3391 | Serge | 432 | * idr_alloc() is likely to succeed w/o full idr_layer buffer and |
433 | * return value from idr_alloc() needs to be checked for failure |
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434 | * anyway. Silently give up if allocation fails. The caller can |
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435 | * treat failures from idr_alloc() as if idr_alloc() were called |
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436 | * with @gfp_mask which should be enough. |
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1412 | serge | 437 | */ |
3391 | Serge | 438 | while (idr_preload_cnt < MAX_IDR_FREE) { |
439 | struct idr_layer *new; |
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440 | |||
441 | new = kzalloc(sizeof(struct idr_layer), gfp_mask); |
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442 | if (!new) |
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443 | break; |
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444 | |||
445 | /* link the new one to per-cpu preload list */ |
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446 | new->ary[0] = idr_preload_head; |
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447 | idr_preload_head = new; |
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448 | idr_preload_cnt++; |
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449 | } |
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1412 | serge | 450 | } |
3391 | Serge | 451 | EXPORT_SYMBOL(idr_preload); |
1412 | serge | 452 | |
3391 | Serge | 453 | /** |
454 | * idr_alloc - allocate new idr entry |
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455 | * @idr: the (initialized) idr |
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456 | * @ptr: pointer to be associated with the new id |
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457 | * @start: the minimum id (inclusive) |
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458 | * @end: the maximum id (exclusive, <= 0 for max) |
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459 | * @gfp_mask: memory allocation flags |
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460 | * |
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461 | * Allocate an id in [start, end) and associate it with @ptr. If no ID is |
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462 | * available in the specified range, returns -ENOSPC. On memory allocation |
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463 | * failure, returns -ENOMEM. |
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464 | * |
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465 | * Note that @end is treated as max when <= 0. This is to always allow |
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466 | * using @start + N as @end as long as N is inside integer range. |
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467 | * |
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468 | * The user is responsible for exclusively synchronizing all operations |
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469 | * which may modify @idr. However, read-only accesses such as idr_find() |
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470 | * or iteration can be performed under RCU read lock provided the user |
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471 | * destroys @ptr in RCU-safe way after removal from idr. |
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472 | */ |
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473 | int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask) |
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474 | { |
||
475 | int max = end > 0 ? end - 1 : INT_MAX; /* inclusive upper limit */ |
||
476 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
||
477 | int id; |
||
478 | |||
479 | /* sanity checks */ |
||
480 | if (WARN_ON_ONCE(start < 0)) |
||
481 | return -EINVAL; |
||
482 | if (unlikely(max < start)) |
||
483 | return -ENOSPC; |
||
484 | |||
485 | /* allocate id */ |
||
486 | id = idr_get_empty_slot(idr, start, pa, gfp_mask, NULL); |
||
487 | if (unlikely(id < 0)) |
||
488 | return id; |
||
489 | if (unlikely(id > max)) |
||
490 | return -ENOSPC; |
||
491 | |||
492 | idr_fill_slot(idr, ptr, id, pa); |
||
493 | return id; |
||
494 | } |
||
495 | EXPORT_SYMBOL_GPL(idr_alloc); |
||
496 | |||
1412 | serge | 497 | static void idr_remove_warning(int id) |
498 | { |
||
499 | printk(KERN_WARNING |
||
500 | "idr_remove called for id=%d which is not allocated.\n", id); |
||
501 | // dump_stack(); |
||
502 | } |
||
503 | |||
504 | static void sub_remove(struct idr *idp, int shift, int id) |
||
505 | { |
||
506 | struct idr_layer *p = idp->top; |
||
3391 | Serge | 507 | struct idr_layer **pa[MAX_IDR_LEVEL + 1]; |
1412 | serge | 508 | struct idr_layer ***paa = &pa[0]; |
509 | struct idr_layer *to_free; |
||
510 | int n; |
||
511 | |||
512 | *paa = NULL; |
||
513 | *++paa = &idp->top; |
||
514 | |||
515 | while ((shift > 0) && p) { |
||
516 | n = (id >> shift) & IDR_MASK; |
||
3391 | Serge | 517 | __clear_bit(n, p->bitmap); |
1412 | serge | 518 | *++paa = &p->ary[n]; |
519 | p = p->ary[n]; |
||
520 | shift -= IDR_BITS; |
||
521 | } |
||
522 | n = id & IDR_MASK; |
||
3391 | Serge | 523 | if (likely(p != NULL && test_bit(n, p->bitmap))) { |
524 | __clear_bit(n, p->bitmap); |
||
1412 | serge | 525 | rcu_assign_pointer(p->ary[n], NULL); |
526 | to_free = NULL; |
||
527 | while(*paa && ! --((**paa)->count)){ |
||
528 | if (to_free) |
||
3391 | Serge | 529 | free_layer(idp, to_free); |
1412 | serge | 530 | to_free = **paa; |
531 | **paa-- = NULL; |
||
532 | } |
||
533 | if (!*paa) |
||
534 | idp->layers = 0; |
||
535 | if (to_free) |
||
3391 | Serge | 536 | free_layer(idp, to_free); |
1412 | serge | 537 | } else |
538 | idr_remove_warning(id); |
||
539 | } |
||
540 | |||
541 | /** |
||
2966 | Serge | 542 | * idr_remove - remove the given id and free its slot |
1412 | serge | 543 | * @idp: idr handle |
544 | * @id: unique key |
||
545 | */ |
||
546 | void idr_remove(struct idr *idp, int id) |
||
547 | { |
||
548 | struct idr_layer *p; |
||
549 | struct idr_layer *to_free; |
||
550 | |||
3391 | Serge | 551 | /* see comment in idr_find_slowpath() */ |
552 | if (WARN_ON_ONCE(id < 0)) |
||
553 | return; |
||
1412 | serge | 554 | |
555 | sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); |
||
556 | if (idp->top && idp->top->count == 1 && (idp->layers > 1) && |
||
557 | idp->top->ary[0]) { |
||
558 | /* |
||
559 | * Single child at leftmost slot: we can shrink the tree. |
||
560 | * This level is not needed anymore since when layers are |
||
561 | * inserted, they are inserted at the top of the existing |
||
562 | * tree. |
||
563 | */ |
||
564 | to_free = idp->top; |
||
565 | p = idp->top->ary[0]; |
||
566 | rcu_assign_pointer(idp->top, p); |
||
567 | --idp->layers; |
||
3391 | Serge | 568 | to_free->count = 0; |
569 | bitmap_clear(to_free->bitmap, 0, IDR_SIZE); |
||
570 | free_layer(idp, to_free); |
||
1412 | serge | 571 | } |
3391 | Serge | 572 | while (idp->id_free_cnt >= MAX_IDR_FREE) { |
1412 | serge | 573 | p = get_from_free_list(idp); |
574 | /* |
||
575 | * Note: we don't call the rcu callback here, since the only |
||
576 | * layers that fall into the freelist are those that have been |
||
577 | * preallocated. |
||
578 | */ |
||
579 | kfree(p); |
||
580 | } |
||
581 | return; |
||
582 | } |
||
3391 | Serge | 583 | EXPORT_SYMBOL(idr_remove); |
1412 | serge | 584 | |
3391 | Serge | 585 | void __idr_remove_all(struct idr *idp) |
1412 | serge | 586 | { |
587 | int n, id, max; |
||
2966 | Serge | 588 | int bt_mask; |
1412 | serge | 589 | struct idr_layer *p; |
3391 | Serge | 590 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
1412 | serge | 591 | struct idr_layer **paa = &pa[0]; |
592 | |||
593 | n = idp->layers * IDR_BITS; |
||
594 | p = idp->top; |
||
595 | rcu_assign_pointer(idp->top, NULL); |
||
3391 | Serge | 596 | max = idr_max(idp->layers); |
1412 | serge | 597 | |
598 | id = 0; |
||
3391 | Serge | 599 | while (id >= 0 && id <= max) { |
1412 | serge | 600 | while (n > IDR_BITS && p) { |
601 | n -= IDR_BITS; |
||
602 | *paa++ = p; |
||
603 | p = p->ary[(id >> n) & IDR_MASK]; |
||
604 | } |
||
605 | |||
2966 | Serge | 606 | bt_mask = id; |
1412 | serge | 607 | id += 1 << n; |
2966 | Serge | 608 | /* Get the highest bit that the above add changed from 0->1. */ |
609 | while (n < fls(id ^ bt_mask)) { |
||
1412 | serge | 610 | if (p) |
3391 | Serge | 611 | free_layer(idp, p); |
1412 | serge | 612 | n += IDR_BITS; |
613 | p = *--paa; |
||
614 | } |
||
615 | } |
||
616 | idp->layers = 0; |
||
617 | } |
||
3391 | Serge | 618 | EXPORT_SYMBOL(__idr_remove_all); |
1412 | serge | 619 | |
620 | /** |
||
621 | * idr_destroy - release all cached layers within an idr tree |
||
2966 | Serge | 622 | * @idp: idr handle |
3391 | Serge | 623 | * |
624 | * Free all id mappings and all idp_layers. After this function, @idp is |
||
625 | * completely unused and can be freed / recycled. The caller is |
||
626 | * responsible for ensuring that no one else accesses @idp during or after |
||
627 | * idr_destroy(). |
||
628 | * |
||
629 | * A typical clean-up sequence for objects stored in an idr tree will use |
||
630 | * idr_for_each() to free all objects, if necessay, then idr_destroy() to |
||
631 | * free up the id mappings and cached idr_layers. |
||
1412 | serge | 632 | */ |
633 | void idr_destroy(struct idr *idp) |
||
634 | { |
||
3391 | Serge | 635 | __idr_remove_all(idp); |
636 | |||
1412 | serge | 637 | while (idp->id_free_cnt) { |
638 | struct idr_layer *p = get_from_free_list(idp); |
||
639 | kfree(p); |
||
640 | } |
||
641 | } |
||
3391 | Serge | 642 | EXPORT_SYMBOL(idr_destroy); |
1412 | serge | 643 | |
3391 | Serge | 644 | void *idr_find_slowpath(struct idr *idp, int id) |
1412 | serge | 645 | { |
646 | int n; |
||
647 | struct idr_layer *p; |
||
648 | |||
3391 | Serge | 649 | /* |
650 | * If @id is negative, idr_find() used to ignore the sign bit and |
||
651 | * performed lookup with the rest of bits, which is weird and can |
||
652 | * lead to very obscure bugs. We're now returning NULL for all |
||
653 | * negative IDs but just in case somebody was depending on the sign |
||
654 | * bit being ignored, let's trigger WARN_ON_ONCE() so that they can |
||
655 | * be detected and fixed. WARN_ON_ONCE() can later be removed. |
||
656 | */ |
||
657 | if (WARN_ON_ONCE(id < 0)) |
||
658 | return NULL; |
||
659 | |||
660 | p = rcu_dereference_raw(idp->top); |
||
1412 | serge | 661 | if (!p) |
662 | return NULL; |
||
663 | n = (p->layer+1) * IDR_BITS; |
||
664 | |||
3391 | Serge | 665 | if (id > idr_max(p->layer + 1)) |
1412 | serge | 666 | return NULL; |
667 | BUG_ON(n == 0); |
||
668 | |||
669 | while (n > 0 && p) { |
||
670 | n -= IDR_BITS; |
||
671 | BUG_ON(n != p->layer*IDR_BITS); |
||
3391 | Serge | 672 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
1412 | serge | 673 | } |
674 | return((void *)p); |
||
675 | } |
||
3391 | Serge | 676 | EXPORT_SYMBOL(idr_find_slowpath); |
1412 | serge | 677 | |
678 | #if 0 |
||
679 | /** |
||
680 | * idr_for_each - iterate through all stored pointers |
||
681 | * @idp: idr handle |
||
682 | * @fn: function to be called for each pointer |
||
683 | * @data: data passed back to callback function |
||
684 | * |
||
685 | * Iterate over the pointers registered with the given idr. The |
||
686 | * callback function will be called for each pointer currently |
||
687 | * registered, passing the id, the pointer and the data pointer passed |
||
688 | * to this function. It is not safe to modify the idr tree while in |
||
689 | * the callback, so functions such as idr_get_new and idr_remove are |
||
690 | * not allowed. |
||
691 | * |
||
692 | * We check the return of @fn each time. If it returns anything other |
||
2966 | Serge | 693 | * than %0, we break out and return that value. |
1412 | serge | 694 | * |
695 | * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). |
||
696 | */ |
||
697 | int idr_for_each(struct idr *idp, |
||
698 | int (*fn)(int id, void *p, void *data), void *data) |
||
699 | { |
||
700 | int n, id, max, error = 0; |
||
701 | struct idr_layer *p; |
||
3391 | Serge | 702 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
1412 | serge | 703 | struct idr_layer **paa = &pa[0]; |
704 | |||
705 | n = idp->layers * IDR_BITS; |
||
3391 | Serge | 706 | p = rcu_dereference_raw(idp->top); |
707 | max = idr_max(idp->layers); |
||
1412 | serge | 708 | |
709 | id = 0; |
||
3391 | Serge | 710 | while (id >= 0 && id <= max) { |
1412 | serge | 711 | while (n > 0 && p) { |
712 | n -= IDR_BITS; |
||
713 | *paa++ = p; |
||
3391 | Serge | 714 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
1412 | serge | 715 | } |
716 | |||
717 | if (p) { |
||
718 | error = fn(id, (void *)p, data); |
||
719 | if (error) |
||
720 | break; |
||
721 | } |
||
722 | |||
723 | id += 1 << n; |
||
724 | while (n < fls(id)) { |
||
725 | n += IDR_BITS; |
||
726 | p = *--paa; |
||
727 | } |
||
728 | } |
||
729 | |||
730 | return error; |
||
731 | } |
||
732 | EXPORT_SYMBOL(idr_for_each); |
||
733 | |||
734 | /** |
||
735 | * idr_get_next - lookup next object of id to given id. |
||
736 | * @idp: idr handle |
||
2966 | Serge | 737 | * @nextidp: pointer to lookup key |
1412 | serge | 738 | * |
739 | * Returns pointer to registered object with id, which is next number to |
||
2966 | Serge | 740 | * given id. After being looked up, *@nextidp will be updated for the next |
741 | * iteration. |
||
3391 | Serge | 742 | * |
743 | * This function can be called under rcu_read_lock(), given that the leaf |
||
744 | * pointers lifetimes are correctly managed. |
||
1412 | serge | 745 | */ |
746 | void *idr_get_next(struct idr *idp, int *nextidp) |
||
747 | { |
||
3391 | Serge | 748 | struct idr_layer *p, *pa[MAX_IDR_LEVEL + 1]; |
1412 | serge | 749 | struct idr_layer **paa = &pa[0]; |
750 | int id = *nextidp; |
||
751 | int n, max; |
||
752 | |||
753 | /* find first ent */ |
||
3391 | Serge | 754 | p = rcu_dereference_raw(idp->top); |
1412 | serge | 755 | if (!p) |
756 | return NULL; |
||
3391 | Serge | 757 | n = (p->layer + 1) * IDR_BITS; |
758 | max = idr_max(p->layer + 1); |
||
1412 | serge | 759 | |
3391 | Serge | 760 | while (id >= 0 && id <= max) { |
1412 | serge | 761 | while (n > 0 && p) { |
762 | n -= IDR_BITS; |
||
763 | *paa++ = p; |
||
3391 | Serge | 764 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
1412 | serge | 765 | } |
766 | |||
767 | if (p) { |
||
768 | *nextidp = id; |
||
769 | return p; |
||
770 | } |
||
771 | |||
3391 | Serge | 772 | /* |
773 | * Proceed to the next layer at the current level. Unlike |
||
774 | * idr_for_each(), @id isn't guaranteed to be aligned to |
||
775 | * layer boundary at this point and adding 1 << n may |
||
776 | * incorrectly skip IDs. Make sure we jump to the |
||
777 | * beginning of the next layer using round_up(). |
||
778 | */ |
||
779 | id = round_up(id + 1, 1 << n); |
||
1412 | serge | 780 | while (n < fls(id)) { |
781 | n += IDR_BITS; |
||
782 | p = *--paa; |
||
783 | } |
||
784 | } |
||
785 | return NULL; |
||
786 | } |
||
3391 | Serge | 787 | EXPORT_SYMBOL(idr_get_next); |
1412 | serge | 788 | |
789 | |||
790 | /** |
||
791 | * idr_replace - replace pointer for given id |
||
792 | * @idp: idr handle |
||
793 | * @ptr: pointer you want associated with the id |
||
794 | * @id: lookup key |
||
795 | * |
||
796 | * Replace the pointer registered with an id and return the old value. |
||
2966 | Serge | 797 | * A %-ENOENT return indicates that @id was not found. |
798 | * A %-EINVAL return indicates that @id was not within valid constraints. |
||
1412 | serge | 799 | * |
800 | * The caller must serialize with writers. |
||
801 | */ |
||
802 | void *idr_replace(struct idr *idp, void *ptr, int id) |
||
803 | { |
||
804 | int n; |
||
805 | struct idr_layer *p, *old_p; |
||
806 | |||
3391 | Serge | 807 | /* see comment in idr_find_slowpath() */ |
808 | if (WARN_ON_ONCE(id < 0)) |
||
809 | return ERR_PTR(-EINVAL); |
||
810 | |||
1412 | serge | 811 | p = idp->top; |
812 | if (!p) |
||
813 | return ERR_PTR(-EINVAL); |
||
814 | |||
815 | n = (p->layer+1) * IDR_BITS; |
||
816 | |||
817 | if (id >= (1 << n)) |
||
818 | return ERR_PTR(-EINVAL); |
||
819 | |||
820 | n -= IDR_BITS; |
||
821 | while ((n > 0) && p) { |
||
822 | p = p->ary[(id >> n) & IDR_MASK]; |
||
823 | n -= IDR_BITS; |
||
824 | } |
||
825 | |||
826 | n = id & IDR_MASK; |
||
3391 | Serge | 827 | if (unlikely(p == NULL || !test_bit(n, p->bitmap))) |
1412 | serge | 828 | return ERR_PTR(-ENOENT); |
829 | |||
830 | old_p = p->ary[n]; |
||
831 | rcu_assign_pointer(p->ary[n], ptr); |
||
832 | |||
833 | return old_p; |
||
834 | } |
||
835 | EXPORT_SYMBOL(idr_replace); |
||
836 | |||
837 | |||
838 | #endif |
||
839 | |||
840 | |||
841 | void idr_init_cache(void) |
||
842 | { |
||
843 | //idr_layer_cache = kmem_cache_create("idr_layer_cache", |
||
844 | // sizeof(struct idr_layer), 0, SLAB_PANIC, NULL); |
||
845 | } |
||
846 | |||
847 | /** |
||
848 | * idr_init - initialize idr handle |
||
849 | * @idp: idr handle |
||
850 | * |
||
851 | * This function is use to set up the handle (@idp) that you will pass |
||
852 | * to the rest of the functions. |
||
853 | */ |
||
854 | void idr_init(struct idr *idp) |
||
855 | { |
||
856 | memset(idp, 0, sizeof(struct idr)); |
||
3391 | Serge | 857 | spin_lock_init(&idp->lock); |
1412 | serge | 858 | } |
3391 | Serge | 859 | EXPORT_SYMBOL(idr_init); |
1412 | serge | 860 | |
861 | #if 0 |
||
862 | |||
3391 | Serge | 863 | /** |
864 | * DOC: IDA description |
||
1412 | serge | 865 | * IDA - IDR based ID allocator |
866 | * |
||
2966 | Serge | 867 | * This is id allocator without id -> pointer translation. Memory |
1412 | serge | 868 | * usage is much lower than full blown idr because each id only |
869 | * occupies a bit. ida uses a custom leaf node which contains |
||
870 | * IDA_BITMAP_BITS slots. |
||
871 | * |
||
872 | * 2007-04-25 written by Tejun Heo |
||
873 | */ |
||
874 | |||
875 | static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) |
||
876 | { |
||
877 | unsigned long flags; |
||
878 | |||
879 | if (!ida->free_bitmap) { |
||
880 | spin_lock_irqsave(&ida->idr.lock, flags); |
||
881 | if (!ida->free_bitmap) { |
||
882 | ida->free_bitmap = bitmap; |
||
883 | bitmap = NULL; |
||
884 | } |
||
885 | spin_unlock_irqrestore(&ida->idr.lock, flags); |
||
886 | } |
||
887 | |||
888 | kfree(bitmap); |
||
889 | } |
||
890 | |||
891 | /** |
||
892 | * ida_pre_get - reserve resources for ida allocation |
||
893 | * @ida: ida handle |
||
894 | * @gfp_mask: memory allocation flag |
||
895 | * |
||
896 | * This function should be called prior to locking and calling the |
||
897 | * following function. It preallocates enough memory to satisfy the |
||
898 | * worst possible allocation. |
||
899 | * |
||
2966 | Serge | 900 | * If the system is REALLY out of memory this function returns %0, |
901 | * otherwise %1. |
||
1412 | serge | 902 | */ |
903 | int ida_pre_get(struct ida *ida, gfp_t gfp_mask) |
||
904 | { |
||
905 | /* allocate idr_layers */ |
||
906 | if (!idr_pre_get(&ida->idr, gfp_mask)) |
||
907 | return 0; |
||
908 | |||
909 | /* allocate free_bitmap */ |
||
910 | if (!ida->free_bitmap) { |
||
911 | struct ida_bitmap *bitmap; |
||
912 | |||
3391 | Serge | 913 | bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask); |
1412 | serge | 914 | if (!bitmap) |
915 | return 0; |
||
916 | |||
917 | free_bitmap(ida, bitmap); |
||
918 | } |
||
919 | |||
920 | return 1; |
||
921 | } |
||
922 | EXPORT_SYMBOL(ida_pre_get); |
||
923 | |||
924 | /** |
||
925 | * ida_get_new_above - allocate new ID above or equal to a start id |
||
926 | * @ida: ida handle |
||
2966 | Serge | 927 | * @starting_id: id to start search at |
1412 | serge | 928 | * @p_id: pointer to the allocated handle |
929 | * |
||
2966 | Serge | 930 | * Allocate new ID above or equal to @starting_id. It should be called |
931 | * with any required locks. |
||
1412 | serge | 932 | * |
2966 | Serge | 933 | * If memory is required, it will return %-EAGAIN, you should unlock |
1412 | serge | 934 | * and go back to the ida_pre_get() call. If the ida is full, it will |
2966 | Serge | 935 | * return %-ENOSPC. |
1412 | serge | 936 | * |
2966 | Serge | 937 | * @p_id returns a value in the range @starting_id ... %0x7fffffff. |
1412 | serge | 938 | */ |
939 | int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) |
||
940 | { |
||
3391 | Serge | 941 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
1412 | serge | 942 | struct ida_bitmap *bitmap; |
943 | unsigned long flags; |
||
944 | int idr_id = starting_id / IDA_BITMAP_BITS; |
||
945 | int offset = starting_id % IDA_BITMAP_BITS; |
||
946 | int t, id; |
||
947 | |||
948 | restart: |
||
949 | /* get vacant slot */ |
||
3391 | Serge | 950 | t = idr_get_empty_slot(&ida->idr, idr_id, pa, 0, &ida->idr); |
1412 | serge | 951 | if (t < 0) |
3391 | Serge | 952 | return t == -ENOMEM ? -EAGAIN : t; |
1412 | serge | 953 | |
3391 | Serge | 954 | if (t * IDA_BITMAP_BITS >= MAX_IDR_BIT) |
1412 | serge | 955 | return -ENOSPC; |
956 | |||
957 | if (t != idr_id) |
||
958 | offset = 0; |
||
959 | idr_id = t; |
||
960 | |||
961 | /* if bitmap isn't there, create a new one */ |
||
962 | bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; |
||
963 | if (!bitmap) { |
||
964 | spin_lock_irqsave(&ida->idr.lock, flags); |
||
965 | bitmap = ida->free_bitmap; |
||
966 | ida->free_bitmap = NULL; |
||
967 | spin_unlock_irqrestore(&ida->idr.lock, flags); |
||
968 | |||
969 | if (!bitmap) |
||
970 | return -EAGAIN; |
||
971 | |||
972 | memset(bitmap, 0, sizeof(struct ida_bitmap)); |
||
973 | rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], |
||
974 | (void *)bitmap); |
||
975 | pa[0]->count++; |
||
976 | } |
||
977 | |||
978 | /* lookup for empty slot */ |
||
979 | t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); |
||
980 | if (t == IDA_BITMAP_BITS) { |
||
981 | /* no empty slot after offset, continue to the next chunk */ |
||
982 | idr_id++; |
||
983 | offset = 0; |
||
984 | goto restart; |
||
985 | } |
||
986 | |||
987 | id = idr_id * IDA_BITMAP_BITS + t; |
||
3391 | Serge | 988 | if (id >= MAX_IDR_BIT) |
1412 | serge | 989 | return -ENOSPC; |
990 | |||
991 | __set_bit(t, bitmap->bitmap); |
||
992 | if (++bitmap->nr_busy == IDA_BITMAP_BITS) |
||
993 | idr_mark_full(pa, idr_id); |
||
994 | |||
995 | *p_id = id; |
||
996 | |||
997 | /* Each leaf node can handle nearly a thousand slots and the |
||
998 | * whole idea of ida is to have small memory foot print. |
||
999 | * Throw away extra resources one by one after each successful |
||
1000 | * allocation. |
||
1001 | */ |
||
1002 | if (ida->idr.id_free_cnt || ida->free_bitmap) { |
||
1003 | struct idr_layer *p = get_from_free_list(&ida->idr); |
||
1004 | if (p) |
||
1005 | kmem_cache_free(idr_layer_cache, p); |
||
1006 | } |
||
1007 | |||
1008 | return 0; |
||
1009 | } |
||
1010 | EXPORT_SYMBOL(ida_get_new_above); |
||
1011 | |||
1012 | /** |
||
1013 | * ida_remove - remove the given ID |
||
1014 | * @ida: ida handle |
||
1015 | * @id: ID to free |
||
1016 | */ |
||
1017 | void ida_remove(struct ida *ida, int id) |
||
1018 | { |
||
1019 | struct idr_layer *p = ida->idr.top; |
||
1020 | int shift = (ida->idr.layers - 1) * IDR_BITS; |
||
1021 | int idr_id = id / IDA_BITMAP_BITS; |
||
1022 | int offset = id % IDA_BITMAP_BITS; |
||
1023 | int n; |
||
1024 | struct ida_bitmap *bitmap; |
||
1025 | |||
1026 | /* clear full bits while looking up the leaf idr_layer */ |
||
1027 | while ((shift > 0) && p) { |
||
1028 | n = (idr_id >> shift) & IDR_MASK; |
||
3391 | Serge | 1029 | __clear_bit(n, p->bitmap); |
1412 | serge | 1030 | p = p->ary[n]; |
1031 | shift -= IDR_BITS; |
||
1032 | } |
||
1033 | |||
1034 | if (p == NULL) |
||
1035 | goto err; |
||
1036 | |||
1037 | n = idr_id & IDR_MASK; |
||
3391 | Serge | 1038 | __clear_bit(n, p->bitmap); |
1412 | serge | 1039 | |
1040 | bitmap = (void *)p->ary[n]; |
||
1041 | if (!test_bit(offset, bitmap->bitmap)) |
||
1042 | goto err; |
||
1043 | |||
1044 | /* update bitmap and remove it if empty */ |
||
1045 | __clear_bit(offset, bitmap->bitmap); |
||
1046 | if (--bitmap->nr_busy == 0) { |
||
3391 | Serge | 1047 | __set_bit(n, p->bitmap); /* to please idr_remove() */ |
1412 | serge | 1048 | idr_remove(&ida->idr, idr_id); |
1049 | free_bitmap(ida, bitmap); |
||
1050 | } |
||
1051 | |||
1052 | return; |
||
1053 | |||
1054 | err: |
||
1055 | printk(KERN_WARNING |
||
1056 | "ida_remove called for id=%d which is not allocated.\n", id); |
||
1057 | } |
||
1058 | EXPORT_SYMBOL(ida_remove); |
||
1059 | |||
1060 | /** |
||
1061 | * ida_destroy - release all cached layers within an ida tree |
||
2966 | Serge | 1062 | * @ida: ida handle |
1412 | serge | 1063 | */ |
1064 | void ida_destroy(struct ida *ida) |
||
1065 | { |
||
1066 | idr_destroy(&ida->idr); |
||
1067 | kfree(ida->free_bitmap); |
||
1068 | } |
||
1069 | EXPORT_SYMBOL(ida_destroy); |
||
1070 | |||
1071 | /** |
||
1072 | * ida_init - initialize ida handle |
||
1073 | * @ida: ida handle |
||
1074 | * |
||
1075 | * This function is use to set up the handle (@ida) that you will pass |
||
1076 | * to the rest of the functions. |
||
1077 | */ |
||
1078 | void ida_init(struct ida *ida) |
||
1079 | { |
||
1080 | memset(ida, 0, sizeof(struct ida)); |
||
1081 | idr_init(&ida->idr); |
||
1082 | |||
1083 | } |
||
1084 | EXPORT_SYMBOL(ida_init); |
||
1085 | |||
1086 | |||
1087 | #endif |
||
3391 | Serge | 1088 | |
1089 | |||
1090 | unsigned long find_first_bit(const unsigned long *addr, unsigned long size) |
||
1091 | { |
||
1092 | const unsigned long *p = addr; |
||
1093 | unsigned long result = 0; |
||
1094 | unsigned long tmp; |
||
1095 | |||
1096 | while (size & ~(BITS_PER_LONG-1)) { |
||
1097 | if ((tmp = *(p++))) |
||
1098 | goto found; |
||
1099 | result += BITS_PER_LONG; |
||
1100 | size -= BITS_PER_LONG; |
||
1101 | } |
||
1102 | if (!size) |
||
1103 | return result; |
||
1104 | |||
1105 | tmp = (*p) & (~0UL >> (BITS_PER_LONG - size)); |
||
1106 | if (tmp == 0UL) /* Are any bits set? */ |
||
1107 | return result + size; /* Nope. */ |
||
1108 | found: |
||
1109 | return result + __ffs(tmp); |
||
1110 | } |
||
1111 | |||
1112 | unsigned long find_next_bit(const unsigned long *addr, unsigned long size, |
||
1113 | unsigned long offset) |
||
1114 | { |
||
1115 | const unsigned long *p = addr + BITOP_WORD(offset); |
||
1116 | unsigned long result = offset & ~(BITS_PER_LONG-1); |
||
1117 | unsigned long tmp; |
||
1118 | |||
1119 | if (offset >= size) |
||
1120 | return size; |
||
1121 | size -= result; |
||
1122 | offset %= BITS_PER_LONG; |
||
1123 | if (offset) { |
||
1124 | tmp = *(p++); |
||
1125 | tmp &= (~0UL << offset); |
||
1126 | if (size < BITS_PER_LONG) |
||
1127 | goto found_first; |
||
1128 | if (tmp) |
||
1129 | goto found_middle; |
||
1130 | size -= BITS_PER_LONG; |
||
1131 | result += BITS_PER_LONG; |
||
1132 | } |
||
1133 | while (size & ~(BITS_PER_LONG-1)) { |
||
1134 | if ((tmp = *(p++))) |
||
1135 | goto found_middle; |
||
1136 | result += BITS_PER_LONG; |
||
1137 | size -= BITS_PER_LONG; |
||
1138 | } |
||
1139 | if (!size) |
||
1140 | return result; |
||
1141 | tmp = *p; |
||
1142 | |||
1143 | found_first: |
||
1144 | tmp &= (~0UL >> (BITS_PER_LONG - size)); |
||
1145 | if (tmp == 0UL) /* Are any bits set? */ |
||
1146 | return result + size; /* Nope. */ |
||
1147 | found_middle: |
||
1148 | return result + __ffs(tmp); |
||
1149 | } |
||
1150 | |||
1151 | unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size, |
||
1152 | unsigned long offset) |
||
1153 | { |
||
1154 | const unsigned long *p = addr + BITOP_WORD(offset); |
||
1155 | unsigned long result = offset & ~(BITS_PER_LONG-1); |
||
1156 | unsigned long tmp; |
||
1157 | |||
1158 | if (offset >= size) |
||
1159 | return size; |
||
1160 | size -= result; |
||
1161 | offset %= BITS_PER_LONG; |
||
1162 | if (offset) { |
||
1163 | tmp = *(p++); |
||
1164 | tmp |= ~0UL >> (BITS_PER_LONG - offset); |
||
1165 | if (size < BITS_PER_LONG) |
||
1166 | goto found_first; |
||
1167 | if (~tmp) |
||
1168 | goto found_middle; |
||
1169 | size -= BITS_PER_LONG; |
||
1170 | result += BITS_PER_LONG; |
||
1171 | } |
||
1172 | while (size & ~(BITS_PER_LONG-1)) { |
||
1173 | if (~(tmp = *(p++))) |
||
1174 | goto found_middle; |
||
1175 | result += BITS_PER_LONG; |
||
1176 | size -= BITS_PER_LONG; |
||
1177 | } |
||
1178 | if (!size) |
||
1179 | return result; |
||
1180 | tmp = *p; |
||
1181 | |||
1182 | found_first: |
||
1183 | tmp |= ~0UL << size; |
||
1184 | if (tmp == ~0UL) /* Are any bits zero? */ |
||
1185 | return result + size; /* Nope. */ |
||
1186 | found_middle: |
||
1187 | return result + ffz(tmp); |
||
1188 | } |
||
1189 | |||
1190 | unsigned int hweight32(unsigned int w) |
||
1191 | { |
||
1192 | unsigned int res = w - ((w >> 1) & 0x55555555); |
||
1193 | res = (res & 0x33333333) + ((res >> 2) & 0x33333333); |
||
1194 | res = (res + (res >> 4)) & 0x0F0F0F0F; |
||
1195 | res = res + (res >> 8); |
||
1196 | return (res + (res >> 16)) & 0x000000FF; |
||
1197 | }><>>>><>>><>>>><>><>=>>><>=>>>><>=>>>>>=>=>>>>>><>><>><>>><>><> |
||
1198 |