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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 | */ |
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22 | |||
5270 | serge | 23 | #ifndef TEST // to test in user space... |
24 | #include |
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6934 | serge | 25 | #include |
3391 | Serge | 26 | #include |
5270 | serge | 27 | #endif |
28 | #include |
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1412 | serge | 29 | #include |
30 | #include |
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5270 | serge | 31 | #include |
1412 | serge | 32 | |
4103 | Serge | 33 | |
1412 | serge | 34 | |
35 | |||
3391 | Serge | 36 | #define MAX_IDR_SHIFT (sizeof(int) * 8 - 1) |
37 | #define MAX_IDR_BIT (1U << MAX_IDR_SHIFT) |
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1412 | serge | 38 | |
3391 | Serge | 39 | /* Leave the possibility of an incomplete final layer */ |
40 | #define MAX_IDR_LEVEL ((MAX_IDR_SHIFT + IDR_BITS - 1) / IDR_BITS) |
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1412 | serge | 41 | |
3391 | Serge | 42 | /* Number of id_layer structs to leave in free list */ |
43 | #define MAX_IDR_FREE (MAX_IDR_LEVEL * 2) |
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1412 | serge | 44 | |
3391 | Serge | 45 | static struct idr_layer *idr_preload_head; |
46 | static int idr_preload_cnt; |
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1412 | serge | 47 | |
4103 | Serge | 48 | static DEFINE_SPINLOCK(simple_ida_lock); |
1412 | serge | 49 | |
3391 | Serge | 50 | /* the maximum ID which can be allocated given idr->layers */ |
51 | static int idr_max(int layers) |
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52 | { |
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53 | int bits = min_t(int, layers * IDR_BITS, MAX_IDR_SHIFT); |
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1412 | serge | 54 | |
3391 | Serge | 55 | return (1 << bits) - 1; |
56 | } |
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1412 | serge | 57 | |
3391 | Serge | 58 | /* |
59 | * Prefix mask for an idr_layer at @layer. For layer 0, the prefix mask is |
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60 | * all bits except for the lower IDR_BITS. For layer 1, 2 * IDR_BITS, and |
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61 | * so on. |
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62 | */ |
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63 | static int idr_layer_prefix_mask(int layer) |
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64 | { |
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65 | return ~idr_max(layer + 1); |
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66 | } |
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1412 | serge | 67 | |
68 | static struct idr_layer *get_from_free_list(struct idr *idp) |
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69 | { |
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70 | struct idr_layer *p; |
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71 | unsigned long flags; |
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72 | |||
3391 | Serge | 73 | spin_lock_irqsave(&idp->lock, flags); |
1412 | serge | 74 | if ((p = idp->id_free)) { |
75 | idp->id_free = p->ary[0]; |
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76 | idp->id_free_cnt--; |
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77 | p->ary[0] = NULL; |
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78 | } |
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3391 | Serge | 79 | spin_unlock_irqrestore(&idp->lock, flags); |
1412 | serge | 80 | return(p); |
81 | } |
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82 | |||
3391 | Serge | 83 | /** |
84 | * idr_layer_alloc - allocate a new idr_layer |
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85 | * @gfp_mask: allocation mask |
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86 | * @layer_idr: optional idr to allocate from |
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87 | * |
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88 | * If @layer_idr is %NULL, directly allocate one using @gfp_mask or fetch |
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89 | * one from the per-cpu preload buffer. If @layer_idr is not %NULL, fetch |
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90 | * an idr_layer from @idr->id_free. |
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91 | * |
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92 | * @layer_idr is to maintain backward compatibility with the old alloc |
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93 | * interface - idr_pre_get() and idr_get_new*() - and will be removed |
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94 | * together with per-pool preload buffer. |
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95 | */ |
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96 | static struct idr_layer *idr_layer_alloc(gfp_t gfp_mask, struct idr *layer_idr) |
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97 | { |
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98 | struct idr_layer *new; |
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99 | |||
100 | /* this is the old path, bypass to get_from_free_list() */ |
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101 | if (layer_idr) |
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102 | return get_from_free_list(layer_idr); |
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103 | |||
104 | /* try to allocate directly from kmem_cache */ |
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105 | new = kzalloc(sizeof(struct idr_layer), gfp_mask); |
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106 | if (new) |
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107 | return new; |
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108 | |||
109 | |||
110 | new = idr_preload_head; |
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111 | if (new) { |
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112 | idr_preload_head = new->ary[0]; |
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113 | idr_preload_cnt--; |
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114 | new->ary[0] = NULL; |
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115 | } |
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116 | preempt_enable(); |
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117 | return new; |
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118 | } |
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119 | |||
1412 | serge | 120 | static void idr_layer_rcu_free(struct rcu_head *head) |
121 | { |
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122 | struct idr_layer *layer; |
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123 | |||
124 | layer = container_of(head, struct idr_layer, rcu_head); |
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125 | kfree(layer); |
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126 | } |
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127 | |||
3391 | Serge | 128 | static inline void free_layer(struct idr *idr, struct idr_layer *p) |
1412 | serge | 129 | { |
5056 | serge | 130 | if (idr->hint == p) |
3391 | Serge | 131 | RCU_INIT_POINTER(idr->hint, NULL); |
5270 | serge | 132 | call_rcu(&p->rcu_head, idr_layer_rcu_free); |
1412 | serge | 133 | } |
134 | |||
135 | /* only called when idp->lock is held */ |
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136 | static void __move_to_free_list(struct idr *idp, struct idr_layer *p) |
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137 | { |
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138 | p->ary[0] = idp->id_free; |
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139 | idp->id_free = p; |
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140 | idp->id_free_cnt++; |
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141 | } |
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142 | |||
143 | static void move_to_free_list(struct idr *idp, struct idr_layer *p) |
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144 | { |
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145 | unsigned long flags; |
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146 | |||
147 | /* |
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148 | * Depends on the return element being zeroed. |
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149 | */ |
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3391 | Serge | 150 | spin_lock_irqsave(&idp->lock, flags); |
1412 | serge | 151 | __move_to_free_list(idp, p); |
3391 | Serge | 152 | spin_unlock_irqrestore(&idp->lock, flags); |
1412 | serge | 153 | } |
154 | |||
155 | static void idr_mark_full(struct idr_layer **pa, int id) |
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156 | { |
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157 | struct idr_layer *p = pa[0]; |
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158 | int l = 0; |
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159 | |||
3391 | Serge | 160 | __set_bit(id & IDR_MASK, p->bitmap); |
1412 | serge | 161 | /* |
162 | * If this layer is full mark the bit in the layer above to |
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163 | * show that this part of the radix tree is full. This may |
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164 | * complete the layer above and require walking up the radix |
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165 | * tree. |
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166 | */ |
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3391 | Serge | 167 | while (bitmap_full(p->bitmap, IDR_SIZE)) { |
1412 | serge | 168 | if (!(p = pa[++l])) |
169 | break; |
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170 | id = id >> IDR_BITS; |
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3391 | Serge | 171 | __set_bit((id & IDR_MASK), p->bitmap); |
1412 | serge | 172 | } |
173 | } |
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174 | |||
5056 | serge | 175 | static int __idr_pre_get(struct idr *idp, gfp_t gfp_mask) |
1412 | serge | 176 | { |
3391 | Serge | 177 | while (idp->id_free_cnt < MAX_IDR_FREE) { |
1412 | serge | 178 | struct idr_layer *new; |
179 | new = kzalloc(sizeof(struct idr_layer), gfp_mask); |
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180 | if (new == NULL) |
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181 | return (0); |
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182 | move_to_free_list(idp, new); |
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183 | } |
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184 | return 1; |
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185 | } |
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186 | |||
3391 | Serge | 187 | /** |
188 | * sub_alloc - try to allocate an id without growing the tree depth |
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189 | * @idp: idr handle |
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190 | * @starting_id: id to start search at |
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191 | * @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer |
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192 | * @gfp_mask: allocation mask for idr_layer_alloc() |
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193 | * @layer_idr: optional idr passed to idr_layer_alloc() |
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194 | * |
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195 | * Allocate an id in range [@starting_id, INT_MAX] from @idp without |
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196 | * growing its depth. Returns |
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197 | * |
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198 | * the allocated id >= 0 if successful, |
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199 | * -EAGAIN if the tree needs to grow for allocation to succeed, |
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200 | * -ENOSPC if the id space is exhausted, |
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201 | * -ENOMEM if more idr_layers need to be allocated. |
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202 | */ |
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203 | static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa, |
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204 | gfp_t gfp_mask, struct idr *layer_idr) |
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1412 | serge | 205 | { |
206 | int n, m, sh; |
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207 | struct idr_layer *p, *new; |
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208 | int l, id, oid; |
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209 | |||
210 | id = *starting_id; |
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211 | restart: |
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212 | p = idp->top; |
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213 | l = idp->layers; |
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214 | pa[l--] = NULL; |
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215 | while (1) { |
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216 | /* |
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217 | * We run around this while until we reach the leaf node... |
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218 | */ |
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219 | n = (id >> (IDR_BITS*l)) & IDR_MASK; |
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3391 | Serge | 220 | m = find_next_zero_bit(p->bitmap, IDR_SIZE, n); |
1412 | serge | 221 | if (m == IDR_SIZE) { |
222 | /* no space available go back to previous layer. */ |
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223 | l++; |
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224 | oid = id; |
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225 | id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; |
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226 | |||
227 | /* if already at the top layer, we need to grow */ |
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5056 | serge | 228 | if (id > idr_max(idp->layers)) { |
1412 | serge | 229 | *starting_id = id; |
3391 | Serge | 230 | return -EAGAIN; |
1412 | serge | 231 | } |
3391 | Serge | 232 | p = pa[l]; |
233 | BUG_ON(!p); |
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1412 | serge | 234 | |
235 | /* If we need to go up one layer, continue the |
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236 | * loop; otherwise, restart from the top. |
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237 | */ |
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238 | sh = IDR_BITS * (l + 1); |
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239 | if (oid >> sh == id >> sh) |
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240 | continue; |
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241 | else |
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242 | goto restart; |
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243 | } |
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244 | if (m != n) { |
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245 | sh = IDR_BITS*l; |
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246 | id = ((id >> sh) ^ n ^ m) << sh; |
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247 | } |
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3391 | Serge | 248 | if ((id >= MAX_IDR_BIT) || (id < 0)) |
249 | return -ENOSPC; |
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1412 | serge | 250 | if (l == 0) |
251 | break; |
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252 | /* |
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253 | * Create the layer below if it is missing. |
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254 | */ |
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255 | if (!p->ary[m]) { |
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3391 | Serge | 256 | new = idr_layer_alloc(gfp_mask, layer_idr); |
1412 | serge | 257 | if (!new) |
3391 | Serge | 258 | return -ENOMEM; |
1412 | serge | 259 | new->layer = l-1; |
3391 | Serge | 260 | new->prefix = id & idr_layer_prefix_mask(new->layer); |
1412 | serge | 261 | rcu_assign_pointer(p->ary[m], new); |
262 | p->count++; |
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263 | } |
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264 | pa[l--] = p; |
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265 | p = p->ary[m]; |
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266 | } |
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267 | |||
268 | pa[l] = p; |
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269 | return id; |
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270 | } |
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271 | |||
272 | static int idr_get_empty_slot(struct idr *idp, int starting_id, |
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3391 | Serge | 273 | struct idr_layer **pa, gfp_t gfp_mask, |
274 | struct idr *layer_idr) |
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1412 | serge | 275 | { |
276 | struct idr_layer *p, *new; |
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277 | int layers, v, id; |
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278 | unsigned long flags; |
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279 | |||
280 | id = starting_id; |
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281 | build_up: |
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282 | p = idp->top; |
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283 | layers = idp->layers; |
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284 | if (unlikely(!p)) { |
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3391 | Serge | 285 | if (!(p = idr_layer_alloc(gfp_mask, layer_idr))) |
286 | return -ENOMEM; |
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1412 | serge | 287 | p->layer = 0; |
288 | layers = 1; |
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289 | } |
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290 | /* |
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291 | * Add a new layer to the top of the tree if the requested |
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292 | * id is larger than the currently allocated space. |
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293 | */ |
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3391 | Serge | 294 | while (id > idr_max(layers)) { |
1412 | serge | 295 | layers++; |
296 | if (!p->count) { |
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297 | /* special case: if the tree is currently empty, |
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298 | * then we grow the tree by moving the top node |
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299 | * upwards. |
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300 | */ |
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301 | p->layer++; |
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3391 | Serge | 302 | WARN_ON_ONCE(p->prefix); |
1412 | serge | 303 | continue; |
304 | } |
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3391 | Serge | 305 | if (!(new = idr_layer_alloc(gfp_mask, layer_idr))) { |
1412 | serge | 306 | /* |
307 | * The allocation failed. If we built part of |
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308 | * the structure tear it down. |
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309 | */ |
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3391 | Serge | 310 | spin_lock_irqsave(&idp->lock, flags); |
1412 | serge | 311 | for (new = p; p && p != idp->top; new = p) { |
312 | p = p->ary[0]; |
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313 | new->ary[0] = NULL; |
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3391 | Serge | 314 | new->count = 0; |
315 | bitmap_clear(new->bitmap, 0, IDR_SIZE); |
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1412 | serge | 316 | __move_to_free_list(idp, new); |
317 | } |
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3391 | Serge | 318 | spin_unlock_irqrestore(&idp->lock, flags); |
319 | return -ENOMEM; |
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1412 | serge | 320 | } |
321 | new->ary[0] = p; |
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322 | new->count = 1; |
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323 | new->layer = layers-1; |
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3391 | Serge | 324 | new->prefix = id & idr_layer_prefix_mask(new->layer); |
325 | if (bitmap_full(p->bitmap, IDR_SIZE)) |
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326 | __set_bit(0, new->bitmap); |
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1412 | serge | 327 | p = new; |
328 | } |
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329 | rcu_assign_pointer(idp->top, p); |
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330 | idp->layers = layers; |
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3391 | Serge | 331 | v = sub_alloc(idp, &id, pa, gfp_mask, layer_idr); |
332 | if (v == -EAGAIN) |
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1412 | serge | 333 | goto build_up; |
334 | return(v); |
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335 | } |
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336 | |||
3391 | Serge | 337 | /* |
338 | * @id and @pa are from a successful allocation from idr_get_empty_slot(). |
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339 | * Install the user pointer @ptr and mark the slot full. |
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340 | */ |
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341 | static void idr_fill_slot(struct idr *idr, void *ptr, int id, |
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342 | struct idr_layer **pa) |
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1412 | serge | 343 | { |
3391 | Serge | 344 | /* update hint used for lookup, cleared from free_layer() */ |
345 | rcu_assign_pointer(idr->hint, pa[0]); |
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1412 | serge | 346 | |
3391 | Serge | 347 | rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], (struct idr_layer *)ptr); |
7143 | serge | 348 | pa[0]->count++; |
349 | idr_mark_full(pa, id); |
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1412 | serge | 350 | } |
351 | |||
2966 | Serge | 352 | |
1412 | serge | 353 | /** |
3391 | Serge | 354 | * idr_preload - preload for idr_alloc() |
355 | * @gfp_mask: allocation mask to use for preloading |
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1412 | serge | 356 | * |
3391 | Serge | 357 | * Preload per-cpu layer buffer for idr_alloc(). Can only be used from |
358 | * process context and each idr_preload() invocation should be matched with |
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359 | * idr_preload_end(). Note that preemption is disabled while preloaded. |
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1412 | serge | 360 | * |
3391 | Serge | 361 | * The first idr_alloc() in the preloaded section can be treated as if it |
362 | * were invoked with @gfp_mask used for preloading. This allows using more |
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363 | * permissive allocation masks for idrs protected by spinlocks. |
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1412 | serge | 364 | * |
3391 | Serge | 365 | * For example, if idr_alloc() below fails, the failure can be treated as |
366 | * if idr_alloc() were called with GFP_KERNEL rather than GFP_NOWAIT. |
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367 | * |
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368 | * idr_preload(GFP_KERNEL); |
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369 | * spin_lock(lock); |
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370 | * |
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371 | * id = idr_alloc(idr, ptr, start, end, GFP_NOWAIT); |
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372 | * |
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373 | * spin_unlock(lock); |
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374 | * idr_preload_end(); |
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375 | * if (id < 0) |
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376 | * error; |
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1412 | serge | 377 | */ |
3391 | Serge | 378 | void idr_preload(gfp_t gfp_mask) |
1412 | serge | 379 | { |
380 | |||
381 | /* |
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3391 | Serge | 382 | * idr_alloc() is likely to succeed w/o full idr_layer buffer and |
383 | * return value from idr_alloc() needs to be checked for failure |
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384 | * anyway. Silently give up if allocation fails. The caller can |
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385 | * treat failures from idr_alloc() as if idr_alloc() were called |
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386 | * with @gfp_mask which should be enough. |
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1412 | serge | 387 | */ |
3391 | Serge | 388 | while (idr_preload_cnt < MAX_IDR_FREE) { |
389 | struct idr_layer *new; |
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390 | |||
391 | new = kzalloc(sizeof(struct idr_layer), gfp_mask); |
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392 | if (!new) |
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393 | break; |
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394 | |||
395 | /* link the new one to per-cpu preload list */ |
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396 | new->ary[0] = idr_preload_head; |
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397 | idr_preload_head = new; |
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398 | idr_preload_cnt++; |
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399 | } |
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1412 | serge | 400 | } |
3391 | Serge | 401 | EXPORT_SYMBOL(idr_preload); |
1412 | serge | 402 | |
3391 | Serge | 403 | /** |
404 | * idr_alloc - allocate new idr entry |
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405 | * @idr: the (initialized) idr |
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406 | * @ptr: pointer to be associated with the new id |
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407 | * @start: the minimum id (inclusive) |
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408 | * @end: the maximum id (exclusive, <= 0 for max) |
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409 | * @gfp_mask: memory allocation flags |
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410 | * |
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411 | * Allocate an id in [start, end) and associate it with @ptr. If no ID is |
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412 | * available in the specified range, returns -ENOSPC. On memory allocation |
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413 | * failure, returns -ENOMEM. |
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414 | * |
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415 | * Note that @end is treated as max when <= 0. This is to always allow |
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416 | * using @start + N as @end as long as N is inside integer range. |
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417 | * |
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418 | * The user is responsible for exclusively synchronizing all operations |
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419 | * which may modify @idr. However, read-only accesses such as idr_find() |
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420 | * or iteration can be performed under RCU read lock provided the user |
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421 | * destroys @ptr in RCU-safe way after removal from idr. |
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422 | */ |
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423 | int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask) |
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424 | { |
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425 | int max = end > 0 ? end - 1 : INT_MAX; /* inclusive upper limit */ |
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426 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
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427 | int id; |
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428 | |||
429 | /* sanity checks */ |
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430 | if (WARN_ON_ONCE(start < 0)) |
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431 | return -EINVAL; |
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432 | if (unlikely(max < start)) |
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433 | return -ENOSPC; |
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434 | |||
435 | /* allocate id */ |
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436 | id = idr_get_empty_slot(idr, start, pa, gfp_mask, NULL); |
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437 | if (unlikely(id < 0)) |
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438 | return id; |
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439 | if (unlikely(id > max)) |
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440 | return -ENOSPC; |
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441 | |||
442 | idr_fill_slot(idr, ptr, id, pa); |
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443 | return id; |
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444 | } |
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445 | EXPORT_SYMBOL_GPL(idr_alloc); |
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446 | |||
4103 | Serge | 447 | /** |
448 | * idr_alloc_cyclic - allocate new idr entry in a cyclical fashion |
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449 | * @idr: the (initialized) idr |
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450 | * @ptr: pointer to be associated with the new id |
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451 | * @start: the minimum id (inclusive) |
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452 | * @end: the maximum id (exclusive, <= 0 for max) |
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453 | * @gfp_mask: memory allocation flags |
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454 | * |
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455 | * Essentially the same as idr_alloc, but prefers to allocate progressively |
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456 | * higher ids if it can. If the "cur" counter wraps, then it will start again |
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457 | * at the "start" end of the range and allocate one that has already been used. |
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458 | */ |
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459 | int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, |
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460 | gfp_t gfp_mask) |
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461 | { |
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462 | int id; |
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463 | |||
464 | id = idr_alloc(idr, ptr, max(start, idr->cur), end, gfp_mask); |
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465 | if (id == -ENOSPC) |
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466 | id = idr_alloc(idr, ptr, start, end, gfp_mask); |
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467 | |||
468 | if (likely(id >= 0)) |
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469 | idr->cur = id + 1; |
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470 | return id; |
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471 | } |
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472 | EXPORT_SYMBOL(idr_alloc_cyclic); |
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473 | |||
1412 | serge | 474 | static void idr_remove_warning(int id) |
475 | { |
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4065 | Serge | 476 | WARN(1, "idr_remove called for id=%d which is not allocated.\n", id); |
1412 | serge | 477 | } |
478 | |||
479 | static void sub_remove(struct idr *idp, int shift, int id) |
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480 | { |
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481 | struct idr_layer *p = idp->top; |
||
3391 | Serge | 482 | struct idr_layer **pa[MAX_IDR_LEVEL + 1]; |
1412 | serge | 483 | struct idr_layer ***paa = &pa[0]; |
484 | struct idr_layer *to_free; |
||
485 | int n; |
||
486 | |||
487 | *paa = NULL; |
||
488 | *++paa = &idp->top; |
||
489 | |||
490 | while ((shift > 0) && p) { |
||
491 | n = (id >> shift) & IDR_MASK; |
||
3391 | Serge | 492 | __clear_bit(n, p->bitmap); |
1412 | serge | 493 | *++paa = &p->ary[n]; |
494 | p = p->ary[n]; |
||
495 | shift -= IDR_BITS; |
||
496 | } |
||
497 | n = id & IDR_MASK; |
||
3391 | Serge | 498 | if (likely(p != NULL && test_bit(n, p->bitmap))) { |
499 | __clear_bit(n, p->bitmap); |
||
5270 | serge | 500 | RCU_INIT_POINTER(p->ary[n], NULL); |
1412 | serge | 501 | to_free = NULL; |
502 | while(*paa && ! --((**paa)->count)){ |
||
503 | if (to_free) |
||
3391 | Serge | 504 | free_layer(idp, to_free); |
1412 | serge | 505 | to_free = **paa; |
506 | **paa-- = NULL; |
||
507 | } |
||
508 | if (!*paa) |
||
509 | idp->layers = 0; |
||
510 | if (to_free) |
||
3391 | Serge | 511 | free_layer(idp, to_free); |
1412 | serge | 512 | } else |
513 | idr_remove_warning(id); |
||
514 | } |
||
515 | |||
516 | /** |
||
2966 | Serge | 517 | * idr_remove - remove the given id and free its slot |
1412 | serge | 518 | * @idp: idr handle |
519 | * @id: unique key |
||
520 | */ |
||
521 | void idr_remove(struct idr *idp, int id) |
||
522 | { |
||
523 | struct idr_layer *p; |
||
524 | struct idr_layer *to_free; |
||
525 | |||
4065 | Serge | 526 | if (id < 0) |
3391 | Serge | 527 | return; |
1412 | serge | 528 | |
5056 | serge | 529 | if (id > idr_max(idp->layers)) { |
530 | idr_remove_warning(id); |
||
531 | return; |
||
532 | } |
||
533 | |||
1412 | serge | 534 | sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); |
535 | if (idp->top && idp->top->count == 1 && (idp->layers > 1) && |
||
536 | idp->top->ary[0]) { |
||
537 | /* |
||
538 | * Single child at leftmost slot: we can shrink the tree. |
||
539 | * This level is not needed anymore since when layers are |
||
540 | * inserted, they are inserted at the top of the existing |
||
541 | * tree. |
||
542 | */ |
||
543 | to_free = idp->top; |
||
544 | p = idp->top->ary[0]; |
||
545 | rcu_assign_pointer(idp->top, p); |
||
546 | --idp->layers; |
||
3391 | Serge | 547 | to_free->count = 0; |
548 | bitmap_clear(to_free->bitmap, 0, IDR_SIZE); |
||
549 | free_layer(idp, to_free); |
||
1412 | serge | 550 | } |
551 | } |
||
3391 | Serge | 552 | EXPORT_SYMBOL(idr_remove); |
1412 | serge | 553 | |
5056 | serge | 554 | static void __idr_remove_all(struct idr *idp) |
1412 | serge | 555 | { |
556 | int n, id, max; |
||
2966 | Serge | 557 | int bt_mask; |
1412 | serge | 558 | struct idr_layer *p; |
3391 | Serge | 559 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
1412 | serge | 560 | struct idr_layer **paa = &pa[0]; |
561 | |||
562 | n = idp->layers * IDR_BITS; |
||
5056 | serge | 563 | *paa = idp->top; |
5270 | serge | 564 | RCU_INIT_POINTER(idp->top, NULL); |
3391 | Serge | 565 | max = idr_max(idp->layers); |
1412 | serge | 566 | |
567 | id = 0; |
||
3391 | Serge | 568 | while (id >= 0 && id <= max) { |
5056 | serge | 569 | p = *paa; |
1412 | serge | 570 | while (n > IDR_BITS && p) { |
571 | n -= IDR_BITS; |
||
572 | p = p->ary[(id >> n) & IDR_MASK]; |
||
5056 | serge | 573 | *++paa = p; |
1412 | serge | 574 | } |
575 | |||
2966 | Serge | 576 | bt_mask = id; |
1412 | serge | 577 | id += 1 << n; |
2966 | Serge | 578 | /* Get the highest bit that the above add changed from 0->1. */ |
579 | while (n < fls(id ^ bt_mask)) { |
||
5056 | serge | 580 | if (*paa) |
581 | free_layer(idp, *paa); |
||
1412 | serge | 582 | n += IDR_BITS; |
5056 | serge | 583 | --paa; |
1412 | serge | 584 | } |
585 | } |
||
586 | idp->layers = 0; |
||
587 | } |
||
588 | |||
589 | /** |
||
590 | * idr_destroy - release all cached layers within an idr tree |
||
2966 | Serge | 591 | * @idp: idr handle |
3391 | Serge | 592 | * |
593 | * Free all id mappings and all idp_layers. After this function, @idp is |
||
594 | * completely unused and can be freed / recycled. The caller is |
||
595 | * responsible for ensuring that no one else accesses @idp during or after |
||
596 | * idr_destroy(). |
||
597 | * |
||
598 | * A typical clean-up sequence for objects stored in an idr tree will use |
||
5270 | serge | 599 | * idr_for_each() to free all objects, if necessary, then idr_destroy() to |
3391 | Serge | 600 | * free up the id mappings and cached idr_layers. |
1412 | serge | 601 | */ |
602 | void idr_destroy(struct idr *idp) |
||
603 | { |
||
3391 | Serge | 604 | __idr_remove_all(idp); |
605 | |||
1412 | serge | 606 | while (idp->id_free_cnt) { |
607 | struct idr_layer *p = get_from_free_list(idp); |
||
608 | kfree(p); |
||
609 | } |
||
610 | } |
||
3391 | Serge | 611 | EXPORT_SYMBOL(idr_destroy); |
1412 | serge | 612 | |
3391 | Serge | 613 | void *idr_find_slowpath(struct idr *idp, int id) |
1412 | serge | 614 | { |
615 | int n; |
||
616 | struct idr_layer *p; |
||
617 | |||
4065 | Serge | 618 | if (id < 0) |
3391 | Serge | 619 | return NULL; |
620 | |||
621 | p = rcu_dereference_raw(idp->top); |
||
1412 | serge | 622 | if (!p) |
623 | return NULL; |
||
624 | n = (p->layer+1) * IDR_BITS; |
||
625 | |||
3391 | Serge | 626 | if (id > idr_max(p->layer + 1)) |
1412 | serge | 627 | return NULL; |
628 | BUG_ON(n == 0); |
||
629 | |||
630 | while (n > 0 && p) { |
||
631 | n -= IDR_BITS; |
||
632 | BUG_ON(n != p->layer*IDR_BITS); |
||
3391 | Serge | 633 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
1412 | serge | 634 | } |
635 | return((void *)p); |
||
636 | } |
||
3391 | Serge | 637 | EXPORT_SYMBOL(idr_find_slowpath); |
1412 | serge | 638 | |
639 | /** |
||
640 | * idr_for_each - iterate through all stored pointers |
||
641 | * @idp: idr handle |
||
642 | * @fn: function to be called for each pointer |
||
643 | * @data: data passed back to callback function |
||
644 | * |
||
645 | * Iterate over the pointers registered with the given idr. The |
||
646 | * callback function will be called for each pointer currently |
||
647 | * registered, passing the id, the pointer and the data pointer passed |
||
648 | * to this function. It is not safe to modify the idr tree while in |
||
649 | * the callback, so functions such as idr_get_new and idr_remove are |
||
650 | * not allowed. |
||
651 | * |
||
652 | * We check the return of @fn each time. If it returns anything other |
||
2966 | Serge | 653 | * than %0, we break out and return that value. |
1412 | serge | 654 | * |
655 | * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). |
||
656 | */ |
||
657 | int idr_for_each(struct idr *idp, |
||
658 | int (*fn)(int id, void *p, void *data), void *data) |
||
659 | { |
||
660 | int n, id, max, error = 0; |
||
661 | struct idr_layer *p; |
||
3391 | Serge | 662 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
1412 | serge | 663 | struct idr_layer **paa = &pa[0]; |
664 | |||
665 | n = idp->layers * IDR_BITS; |
||
5056 | serge | 666 | *paa = rcu_dereference_raw(idp->top); |
3391 | Serge | 667 | max = idr_max(idp->layers); |
1412 | serge | 668 | |
669 | id = 0; |
||
3391 | Serge | 670 | while (id >= 0 && id <= max) { |
5056 | serge | 671 | p = *paa; |
1412 | serge | 672 | while (n > 0 && p) { |
673 | n -= IDR_BITS; |
||
3391 | Serge | 674 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
5056 | serge | 675 | *++paa = p; |
1412 | serge | 676 | } |
677 | |||
678 | if (p) { |
||
679 | error = fn(id, (void *)p, data); |
||
680 | if (error) |
||
681 | break; |
||
682 | } |
||
683 | |||
684 | id += 1 << n; |
||
685 | while (n < fls(id)) { |
||
686 | n += IDR_BITS; |
||
5056 | serge | 687 | --paa; |
1412 | serge | 688 | } |
689 | } |
||
690 | |||
691 | return error; |
||
692 | } |
||
693 | EXPORT_SYMBOL(idr_for_each); |
||
694 | |||
695 | /** |
||
696 | * idr_get_next - lookup next object of id to given id. |
||
697 | * @idp: idr handle |
||
2966 | Serge | 698 | * @nextidp: pointer to lookup key |
1412 | serge | 699 | * |
700 | * Returns pointer to registered object with id, which is next number to |
||
2966 | Serge | 701 | * given id. After being looked up, *@nextidp will be updated for the next |
702 | * iteration. |
||
3391 | Serge | 703 | * |
704 | * This function can be called under rcu_read_lock(), given that the leaf |
||
705 | * pointers lifetimes are correctly managed. |
||
1412 | serge | 706 | */ |
707 | void *idr_get_next(struct idr *idp, int *nextidp) |
||
708 | { |
||
3391 | Serge | 709 | struct idr_layer *p, *pa[MAX_IDR_LEVEL + 1]; |
1412 | serge | 710 | struct idr_layer **paa = &pa[0]; |
711 | int id = *nextidp; |
||
712 | int n, max; |
||
713 | |||
714 | /* find first ent */ |
||
5056 | serge | 715 | p = *paa = rcu_dereference_raw(idp->top); |
1412 | serge | 716 | if (!p) |
717 | return NULL; |
||
3391 | Serge | 718 | n = (p->layer + 1) * IDR_BITS; |
719 | max = idr_max(p->layer + 1); |
||
1412 | serge | 720 | |
3391 | Serge | 721 | while (id >= 0 && id <= max) { |
5056 | serge | 722 | p = *paa; |
1412 | serge | 723 | while (n > 0 && p) { |
724 | n -= IDR_BITS; |
||
3391 | Serge | 725 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
5056 | serge | 726 | *++paa = p; |
1412 | serge | 727 | } |
728 | |||
729 | if (p) { |
||
730 | *nextidp = id; |
||
731 | return p; |
||
732 | } |
||
733 | |||
3391 | Serge | 734 | /* |
735 | * Proceed to the next layer at the current level. Unlike |
||
736 | * idr_for_each(), @id isn't guaranteed to be aligned to |
||
737 | * layer boundary at this point and adding 1 << n may |
||
738 | * incorrectly skip IDs. Make sure we jump to the |
||
739 | * beginning of the next layer using round_up(). |
||
740 | */ |
||
741 | id = round_up(id + 1, 1 << n); |
||
1412 | serge | 742 | while (n < fls(id)) { |
743 | n += IDR_BITS; |
||
5056 | serge | 744 | --paa; |
1412 | serge | 745 | } |
746 | } |
||
747 | return NULL; |
||
748 | } |
||
3391 | Serge | 749 | EXPORT_SYMBOL(idr_get_next); |
1412 | serge | 750 | |
751 | |||
752 | /** |
||
753 | * idr_replace - replace pointer for given id |
||
754 | * @idp: idr handle |
||
755 | * @ptr: pointer you want associated with the id |
||
756 | * @id: lookup key |
||
757 | * |
||
758 | * Replace the pointer registered with an id and return the old value. |
||
2966 | Serge | 759 | * A %-ENOENT return indicates that @id was not found. |
760 | * A %-EINVAL return indicates that @id was not within valid constraints. |
||
1412 | serge | 761 | * |
762 | * The caller must serialize with writers. |
||
763 | */ |
||
764 | void *idr_replace(struct idr *idp, void *ptr, int id) |
||
765 | { |
||
766 | int n; |
||
767 | struct idr_layer *p, *old_p; |
||
768 | |||
4065 | Serge | 769 | if (id < 0) |
3391 | Serge | 770 | return ERR_PTR(-EINVAL); |
771 | |||
1412 | serge | 772 | p = idp->top; |
773 | if (!p) |
||
5056 | serge | 774 | return ERR_PTR(-ENOENT); |
1412 | serge | 775 | |
5056 | serge | 776 | if (id > idr_max(p->layer + 1)) |
777 | return ERR_PTR(-ENOENT); |
||
1412 | serge | 778 | |
5056 | serge | 779 | n = p->layer * IDR_BITS; |
1412 | serge | 780 | while ((n > 0) && p) { |
781 | p = p->ary[(id >> n) & IDR_MASK]; |
||
782 | n -= IDR_BITS; |
||
783 | } |
||
784 | |||
785 | n = id & IDR_MASK; |
||
3391 | Serge | 786 | if (unlikely(p == NULL || !test_bit(n, p->bitmap))) |
1412 | serge | 787 | return ERR_PTR(-ENOENT); |
788 | |||
789 | old_p = p->ary[n]; |
||
790 | rcu_assign_pointer(p->ary[n], ptr); |
||
791 | |||
792 | return old_p; |
||
793 | } |
||
794 | EXPORT_SYMBOL(idr_replace); |
||
795 | |||
4065 | Serge | 796 | void __init idr_init_cache(void) |
1412 | serge | 797 | { |
798 | //idr_layer_cache = kmem_cache_create("idr_layer_cache", |
||
799 | // sizeof(struct idr_layer), 0, SLAB_PANIC, NULL); |
||
800 | } |
||
801 | |||
802 | /** |
||
803 | * idr_init - initialize idr handle |
||
804 | * @idp: idr handle |
||
805 | * |
||
806 | * This function is use to set up the handle (@idp) that you will pass |
||
807 | * to the rest of the functions. |
||
808 | */ |
||
809 | void idr_init(struct idr *idp) |
||
810 | { |
||
811 | memset(idp, 0, sizeof(struct idr)); |
||
3391 | Serge | 812 | spin_lock_init(&idp->lock); |
1412 | serge | 813 | } |
3391 | Serge | 814 | EXPORT_SYMBOL(idr_init); |
1412 | serge | 815 | |
5056 | serge | 816 | static int idr_has_entry(int id, void *p, void *data) |
817 | { |
||
818 | return 1; |
||
819 | } |
||
1412 | serge | 820 | |
5056 | serge | 821 | bool idr_is_empty(struct idr *idp) |
822 | { |
||
823 | return !idr_for_each(idp, idr_has_entry, NULL); |
||
824 | } |
||
825 | EXPORT_SYMBOL(idr_is_empty); |
||
826 | |||
3391 | Serge | 827 | /** |
828 | * DOC: IDA description |
||
1412 | serge | 829 | * IDA - IDR based ID allocator |
830 | * |
||
2966 | Serge | 831 | * This is id allocator without id -> pointer translation. Memory |
1412 | serge | 832 | * usage is much lower than full blown idr because each id only |
833 | * occupies a bit. ida uses a custom leaf node which contains |
||
834 | * IDA_BITMAP_BITS slots. |
||
835 | * |
||
836 | * 2007-04-25 written by Tejun Heo |
||
837 | */ |
||
838 | |||
839 | static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) |
||
840 | { |
||
841 | unsigned long flags; |
||
842 | |||
843 | if (!ida->free_bitmap) { |
||
844 | spin_lock_irqsave(&ida->idr.lock, flags); |
||
845 | if (!ida->free_bitmap) { |
||
846 | ida->free_bitmap = bitmap; |
||
847 | bitmap = NULL; |
||
848 | } |
||
849 | spin_unlock_irqrestore(&ida->idr.lock, flags); |
||
850 | } |
||
851 | |||
852 | kfree(bitmap); |
||
853 | } |
||
854 | |||
855 | /** |
||
856 | * ida_pre_get - reserve resources for ida allocation |
||
857 | * @ida: ida handle |
||
858 | * @gfp_mask: memory allocation flag |
||
859 | * |
||
860 | * This function should be called prior to locking and calling the |
||
861 | * following function. It preallocates enough memory to satisfy the |
||
862 | * worst possible allocation. |
||
863 | * |
||
2966 | Serge | 864 | * If the system is REALLY out of memory this function returns %0, |
865 | * otherwise %1. |
||
1412 | serge | 866 | */ |
867 | int ida_pre_get(struct ida *ida, gfp_t gfp_mask) |
||
868 | { |
||
869 | /* allocate idr_layers */ |
||
4103 | Serge | 870 | if (!__idr_pre_get(&ida->idr, gfp_mask)) |
1412 | serge | 871 | return 0; |
872 | |||
873 | /* allocate free_bitmap */ |
||
874 | if (!ida->free_bitmap) { |
||
875 | struct ida_bitmap *bitmap; |
||
876 | |||
3391 | Serge | 877 | bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask); |
1412 | serge | 878 | if (!bitmap) |
879 | return 0; |
||
880 | |||
881 | free_bitmap(ida, bitmap); |
||
882 | } |
||
883 | |||
884 | return 1; |
||
885 | } |
||
886 | EXPORT_SYMBOL(ida_pre_get); |
||
887 | |||
888 | /** |
||
889 | * ida_get_new_above - allocate new ID above or equal to a start id |
||
890 | * @ida: ida handle |
||
2966 | Serge | 891 | * @starting_id: id to start search at |
1412 | serge | 892 | * @p_id: pointer to the allocated handle |
893 | * |
||
2966 | Serge | 894 | * Allocate new ID above or equal to @starting_id. It should be called |
895 | * with any required locks. |
||
1412 | serge | 896 | * |
2966 | Serge | 897 | * If memory is required, it will return %-EAGAIN, you should unlock |
1412 | serge | 898 | * and go back to the ida_pre_get() call. If the ida is full, it will |
2966 | Serge | 899 | * return %-ENOSPC. |
1412 | serge | 900 | * |
2966 | Serge | 901 | * @p_id returns a value in the range @starting_id ... %0x7fffffff. |
1412 | serge | 902 | */ |
903 | int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) |
||
904 | { |
||
3391 | Serge | 905 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
1412 | serge | 906 | struct ida_bitmap *bitmap; |
907 | unsigned long flags; |
||
908 | int idr_id = starting_id / IDA_BITMAP_BITS; |
||
909 | int offset = starting_id % IDA_BITMAP_BITS; |
||
910 | int t, id; |
||
911 | |||
912 | restart: |
||
913 | /* get vacant slot */ |
||
3391 | Serge | 914 | t = idr_get_empty_slot(&ida->idr, idr_id, pa, 0, &ida->idr); |
1412 | serge | 915 | if (t < 0) |
3391 | Serge | 916 | return t == -ENOMEM ? -EAGAIN : t; |
1412 | serge | 917 | |
3391 | Serge | 918 | if (t * IDA_BITMAP_BITS >= MAX_IDR_BIT) |
1412 | serge | 919 | return -ENOSPC; |
920 | |||
921 | if (t != idr_id) |
||
922 | offset = 0; |
||
923 | idr_id = t; |
||
924 | |||
925 | /* if bitmap isn't there, create a new one */ |
||
926 | bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; |
||
927 | if (!bitmap) { |
||
928 | spin_lock_irqsave(&ida->idr.lock, flags); |
||
929 | bitmap = ida->free_bitmap; |
||
930 | ida->free_bitmap = NULL; |
||
931 | spin_unlock_irqrestore(&ida->idr.lock, flags); |
||
932 | |||
933 | if (!bitmap) |
||
934 | return -EAGAIN; |
||
935 | |||
936 | memset(bitmap, 0, sizeof(struct ida_bitmap)); |
||
937 | rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], |
||
938 | (void *)bitmap); |
||
939 | pa[0]->count++; |
||
940 | } |
||
941 | |||
942 | /* lookup for empty slot */ |
||
943 | t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); |
||
944 | if (t == IDA_BITMAP_BITS) { |
||
945 | /* no empty slot after offset, continue to the next chunk */ |
||
946 | idr_id++; |
||
947 | offset = 0; |
||
948 | goto restart; |
||
949 | } |
||
950 | |||
951 | id = idr_id * IDA_BITMAP_BITS + t; |
||
3391 | Serge | 952 | if (id >= MAX_IDR_BIT) |
1412 | serge | 953 | return -ENOSPC; |
954 | |||
955 | __set_bit(t, bitmap->bitmap); |
||
956 | if (++bitmap->nr_busy == IDA_BITMAP_BITS) |
||
957 | idr_mark_full(pa, idr_id); |
||
958 | |||
959 | *p_id = id; |
||
960 | |||
961 | /* Each leaf node can handle nearly a thousand slots and the |
||
962 | * whole idea of ida is to have small memory foot print. |
||
963 | * Throw away extra resources one by one after each successful |
||
964 | * allocation. |
||
965 | */ |
||
966 | if (ida->idr.id_free_cnt || ida->free_bitmap) { |
||
967 | struct idr_layer *p = get_from_free_list(&ida->idr); |
||
968 | if (p) |
||
4065 | Serge | 969 | kfree(p); |
1412 | serge | 970 | } |
971 | |||
972 | return 0; |
||
973 | } |
||
974 | EXPORT_SYMBOL(ida_get_new_above); |
||
975 | |||
976 | /** |
||
977 | * ida_remove - remove the given ID |
||
978 | * @ida: ida handle |
||
979 | * @id: ID to free |
||
980 | */ |
||
981 | void ida_remove(struct ida *ida, int id) |
||
982 | { |
||
983 | struct idr_layer *p = ida->idr.top; |
||
984 | int shift = (ida->idr.layers - 1) * IDR_BITS; |
||
985 | int idr_id = id / IDA_BITMAP_BITS; |
||
986 | int offset = id % IDA_BITMAP_BITS; |
||
987 | int n; |
||
988 | struct ida_bitmap *bitmap; |
||
989 | |||
5056 | serge | 990 | if (idr_id > idr_max(ida->idr.layers)) |
991 | goto err; |
||
992 | |||
1412 | serge | 993 | /* clear full bits while looking up the leaf idr_layer */ |
994 | while ((shift > 0) && p) { |
||
995 | n = (idr_id >> shift) & IDR_MASK; |
||
3391 | Serge | 996 | __clear_bit(n, p->bitmap); |
1412 | serge | 997 | p = p->ary[n]; |
998 | shift -= IDR_BITS; |
||
999 | } |
||
1000 | |||
1001 | if (p == NULL) |
||
1002 | goto err; |
||
1003 | |||
1004 | n = idr_id & IDR_MASK; |
||
3391 | Serge | 1005 | __clear_bit(n, p->bitmap); |
1412 | serge | 1006 | |
1007 | bitmap = (void *)p->ary[n]; |
||
5056 | serge | 1008 | if (!bitmap || !test_bit(offset, bitmap->bitmap)) |
1412 | serge | 1009 | goto err; |
1010 | |||
1011 | /* update bitmap and remove it if empty */ |
||
1012 | __clear_bit(offset, bitmap->bitmap); |
||
1013 | if (--bitmap->nr_busy == 0) { |
||
3391 | Serge | 1014 | __set_bit(n, p->bitmap); /* to please idr_remove() */ |
1412 | serge | 1015 | idr_remove(&ida->idr, idr_id); |
1016 | free_bitmap(ida, bitmap); |
||
1017 | } |
||
1018 | |||
1019 | return; |
||
1020 | |||
1021 | err: |
||
4065 | Serge | 1022 | WARN(1, "ida_remove called for id=%d which is not allocated.\n", id); |
1412 | serge | 1023 | } |
1024 | EXPORT_SYMBOL(ida_remove); |
||
1025 | |||
1026 | /** |
||
1027 | * ida_destroy - release all cached layers within an ida tree |
||
2966 | Serge | 1028 | * @ida: ida handle |
1412 | serge | 1029 | */ |
1030 | void ida_destroy(struct ida *ida) |
||
1031 | { |
||
1032 | idr_destroy(&ida->idr); |
||
1033 | kfree(ida->free_bitmap); |
||
1034 | } |
||
1035 | EXPORT_SYMBOL(ida_destroy); |
||
1036 | |||
1037 | /** |
||
4103 | Serge | 1038 | * ida_simple_get - get a new id. |
1039 | * @ida: the (initialized) ida. |
||
1040 | * @start: the minimum id (inclusive, < 0x8000000) |
||
1041 | * @end: the maximum id (exclusive, < 0x8000000 or 0) |
||
1042 | * @gfp_mask: memory allocation flags |
||
1043 | * |
||
1044 | * Allocates an id in the range start <= id < end, or returns -ENOSPC. |
||
1045 | * On memory allocation failure, returns -ENOMEM. |
||
1046 | * |
||
1047 | * Use ida_simple_remove() to get rid of an id. |
||
1048 | */ |
||
1049 | int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end, |
||
1050 | gfp_t gfp_mask) |
||
1051 | { |
||
1052 | int ret, id; |
||
1053 | unsigned int max; |
||
1054 | unsigned long flags; |
||
1055 | |||
1056 | BUG_ON((int)start < 0); |
||
1057 | BUG_ON((int)end < 0); |
||
1058 | |||
1059 | if (end == 0) |
||
1060 | max = 0x80000000; |
||
1061 | else { |
||
1062 | BUG_ON(end < start); |
||
1063 | max = end - 1; |
||
1064 | } |
||
1065 | |||
1066 | again: |
||
1067 | if (!ida_pre_get(ida, gfp_mask)) |
||
1068 | return -ENOMEM; |
||
1069 | |||
1070 | spin_lock_irqsave(&simple_ida_lock, flags); |
||
1071 | ret = ida_get_new_above(ida, start, &id); |
||
1072 | if (!ret) { |
||
1073 | if (id > max) { |
||
1074 | ida_remove(ida, id); |
||
1075 | ret = -ENOSPC; |
||
1076 | } else { |
||
1077 | ret = id; |
||
1078 | } |
||
1079 | } |
||
1080 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
||
1081 | |||
1082 | if (unlikely(ret == -EAGAIN)) |
||
1083 | goto again; |
||
1084 | |||
1085 | return ret; |
||
1086 | } |
||
1087 | EXPORT_SYMBOL(ida_simple_get); |
||
1088 | |||
1089 | /** |
||
1090 | * ida_simple_remove - remove an allocated id. |
||
1091 | * @ida: the (initialized) ida. |
||
1092 | * @id: the id returned by ida_simple_get. |
||
1093 | */ |
||
1094 | void ida_simple_remove(struct ida *ida, unsigned int id) |
||
1095 | { |
||
1096 | unsigned long flags; |
||
1097 | |||
1098 | BUG_ON((int)id < 0); |
||
1099 | spin_lock_irqsave(&simple_ida_lock, flags); |
||
1100 | ida_remove(ida, id); |
||
1101 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
||
1102 | } |
||
1103 | EXPORT_SYMBOL(ida_simple_remove); |
||
1104 | |||
1105 | /** |
||
1412 | serge | 1106 | * ida_init - initialize ida handle |
1107 | * @ida: ida handle |
||
1108 | * |
||
1109 | * This function is use to set up the handle (@ida) that you will pass |
||
1110 | * to the rest of the functions. |
||
1111 | */ |
||
1112 | void ida_init(struct ida *ida) |
||
1113 | { |
||
1114 | memset(ida, 0, sizeof(struct ida)); |
||
1115 | idr_init(&ida->idr); |
||
1116 | |||
1117 | } |
||
1118 | EXPORT_SYMBOL(ida_init);>>>>>=>>>>>>><>><>=>>><>=>>>><>=>>=>>>>=>=>>>>><>><>>><>><> |