Commit | Line | Data |
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f8de50eb KA |
1 | /* |
2 | * Copyright (c) 2006, Intel Corporation. | |
3 | * | |
4 | * This file is released under the GPLv2. | |
5 | * | |
6 | * Copyright (C) 2006 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> | |
7 | */ | |
8 | ||
9 | #include "iova.h" | |
10 | ||
11 | void | |
12 | init_iova_domain(struct iova_domain *iovad) | |
13 | { | |
14 | spin_lock_init(&iovad->iova_alloc_lock); | |
15 | spin_lock_init(&iovad->iova_rbtree_lock); | |
16 | iovad->rbroot = RB_ROOT; | |
17 | iovad->cached32_node = NULL; | |
18 | ||
19 | } | |
20 | ||
21 | static struct rb_node * | |
22 | __get_cached_rbnode(struct iova_domain *iovad, unsigned long *limit_pfn) | |
23 | { | |
24 | if ((*limit_pfn != DMA_32BIT_PFN) || | |
25 | (iovad->cached32_node == NULL)) | |
26 | return rb_last(&iovad->rbroot); | |
27 | else { | |
28 | struct rb_node *prev_node = rb_prev(iovad->cached32_node); | |
29 | struct iova *curr_iova = | |
30 | container_of(iovad->cached32_node, struct iova, node); | |
31 | *limit_pfn = curr_iova->pfn_lo - 1; | |
32 | return prev_node; | |
33 | } | |
34 | } | |
35 | ||
36 | static void | |
37 | __cached_rbnode_insert_update(struct iova_domain *iovad, | |
38 | unsigned long limit_pfn, struct iova *new) | |
39 | { | |
40 | if (limit_pfn != DMA_32BIT_PFN) | |
41 | return; | |
42 | iovad->cached32_node = &new->node; | |
43 | } | |
44 | ||
45 | static void | |
46 | __cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free) | |
47 | { | |
48 | struct iova *cached_iova; | |
49 | struct rb_node *curr; | |
50 | ||
51 | if (!iovad->cached32_node) | |
52 | return; | |
53 | curr = iovad->cached32_node; | |
54 | cached_iova = container_of(curr, struct iova, node); | |
55 | ||
56 | if (free->pfn_lo >= cached_iova->pfn_lo) | |
57 | iovad->cached32_node = rb_next(&free->node); | |
58 | } | |
59 | ||
60 | static int __alloc_iova_range(struct iova_domain *iovad, | |
61 | unsigned long size, unsigned long limit_pfn, struct iova *new) | |
62 | { | |
63 | struct rb_node *curr = NULL; | |
64 | unsigned long flags; | |
65 | unsigned long saved_pfn; | |
66 | ||
67 | /* Walk the tree backwards */ | |
68 | spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); | |
69 | saved_pfn = limit_pfn; | |
70 | curr = __get_cached_rbnode(iovad, &limit_pfn); | |
71 | while (curr) { | |
72 | struct iova *curr_iova = container_of(curr, struct iova, node); | |
73 | if (limit_pfn < curr_iova->pfn_lo) | |
74 | goto move_left; | |
75 | if (limit_pfn < curr_iova->pfn_hi) | |
76 | goto adjust_limit_pfn; | |
77 | if ((curr_iova->pfn_hi + size) <= limit_pfn) | |
78 | break; /* found a free slot */ | |
79 | adjust_limit_pfn: | |
80 | limit_pfn = curr_iova->pfn_lo - 1; | |
81 | move_left: | |
82 | curr = rb_prev(curr); | |
83 | } | |
84 | ||
85 | if ((!curr) && !(IOVA_START_PFN + size <= limit_pfn)) { | |
86 | spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); | |
87 | return -ENOMEM; | |
88 | } | |
89 | new->pfn_hi = limit_pfn; | |
90 | new->pfn_lo = limit_pfn - size + 1; | |
91 | ||
92 | spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); | |
93 | return 0; | |
94 | } | |
95 | ||
96 | static void | |
97 | iova_insert_rbtree(struct rb_root *root, struct iova *iova) | |
98 | { | |
99 | struct rb_node **new = &(root->rb_node), *parent = NULL; | |
100 | /* Figure out where to put new node */ | |
101 | while (*new) { | |
102 | struct iova *this = container_of(*new, struct iova, node); | |
103 | parent = *new; | |
104 | ||
105 | if (iova->pfn_lo < this->pfn_lo) | |
106 | new = &((*new)->rb_left); | |
107 | else if (iova->pfn_lo > this->pfn_lo) | |
108 | new = &((*new)->rb_right); | |
109 | else | |
110 | BUG(); /* this should not happen */ | |
111 | } | |
112 | /* Add new node and rebalance tree. */ | |
113 | rb_link_node(&iova->node, parent, new); | |
114 | rb_insert_color(&iova->node, root); | |
115 | } | |
116 | ||
117 | /** | |
118 | * alloc_iova - allocates an iova | |
119 | * @iovad - iova domain in question | |
120 | * @size - size of page frames to allocate | |
121 | * @limit_pfn - max limit address | |
122 | * This function allocates an iova in the range limit_pfn to IOVA_START_PFN | |
123 | * looking from limit_pfn instead from IOVA_START_PFN. | |
124 | */ | |
125 | struct iova * | |
126 | alloc_iova(struct iova_domain *iovad, unsigned long size, | |
127 | unsigned long limit_pfn) | |
128 | { | |
129 | unsigned long flags; | |
130 | struct iova *new_iova; | |
131 | int ret; | |
132 | ||
133 | new_iova = alloc_iova_mem(); | |
134 | if (!new_iova) | |
135 | return NULL; | |
136 | ||
137 | spin_lock_irqsave(&iovad->iova_alloc_lock, flags); | |
138 | ret = __alloc_iova_range(iovad, size, limit_pfn, new_iova); | |
139 | ||
140 | if (ret) { | |
141 | spin_unlock_irqrestore(&iovad->iova_alloc_lock, flags); | |
142 | free_iova_mem(new_iova); | |
143 | return NULL; | |
144 | } | |
145 | ||
146 | /* Insert the new_iova into domain rbtree by holding writer lock */ | |
147 | spin_lock(&iovad->iova_rbtree_lock); | |
148 | iova_insert_rbtree(&iovad->rbroot, new_iova); | |
149 | __cached_rbnode_insert_update(iovad, limit_pfn, new_iova); | |
150 | spin_unlock(&iovad->iova_rbtree_lock); | |
151 | ||
152 | spin_unlock_irqrestore(&iovad->iova_alloc_lock, flags); | |
153 | ||
154 | return new_iova; | |
155 | } | |
156 | ||
157 | /** | |
158 | * find_iova - find's an iova for a given pfn | |
159 | * @iovad - iova domain in question. | |
160 | * pfn - page frame number | |
161 | * This function finds and returns an iova belonging to the | |
162 | * given doamin which matches the given pfn. | |
163 | */ | |
164 | struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn) | |
165 | { | |
166 | unsigned long flags; | |
167 | struct rb_node *node; | |
168 | ||
169 | /* Take the lock so that no other thread is manipulating the rbtree */ | |
170 | spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); | |
171 | node = iovad->rbroot.rb_node; | |
172 | while (node) { | |
173 | struct iova *iova = container_of(node, struct iova, node); | |
174 | ||
175 | /* If pfn falls within iova's range, return iova */ | |
176 | if ((pfn >= iova->pfn_lo) && (pfn <= iova->pfn_hi)) { | |
177 | spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); | |
178 | /* We are not holding the lock while this iova | |
179 | * is referenced by the caller as the same thread | |
180 | * which called this function also calls __free_iova() | |
181 | * and it is by desing that only one thread can possibly | |
182 | * reference a particular iova and hence no conflict. | |
183 | */ | |
184 | return iova; | |
185 | } | |
186 | ||
187 | if (pfn < iova->pfn_lo) | |
188 | node = node->rb_left; | |
189 | else if (pfn > iova->pfn_lo) | |
190 | node = node->rb_right; | |
191 | } | |
192 | ||
193 | spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); | |
194 | return NULL; | |
195 | } | |
196 | ||
197 | /** | |
198 | * __free_iova - frees the given iova | |
199 | * @iovad: iova domain in question. | |
200 | * @iova: iova in question. | |
201 | * Frees the given iova belonging to the giving domain | |
202 | */ | |
203 | void | |
204 | __free_iova(struct iova_domain *iovad, struct iova *iova) | |
205 | { | |
206 | unsigned long flags; | |
207 | ||
208 | spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); | |
209 | __cached_rbnode_delete_update(iovad, iova); | |
210 | rb_erase(&iova->node, &iovad->rbroot); | |
211 | spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); | |
212 | free_iova_mem(iova); | |
213 | } | |
214 | ||
215 | /** | |
216 | * free_iova - finds and frees the iova for a given pfn | |
217 | * @iovad: - iova domain in question. | |
218 | * @pfn: - pfn that is allocated previously | |
219 | * This functions finds an iova for a given pfn and then | |
220 | * frees the iova from that domain. | |
221 | */ | |
222 | void | |
223 | free_iova(struct iova_domain *iovad, unsigned long pfn) | |
224 | { | |
225 | struct iova *iova = find_iova(iovad, pfn); | |
226 | if (iova) | |
227 | __free_iova(iovad, iova); | |
228 | ||
229 | } | |
230 | ||
231 | /** | |
232 | * put_iova_domain - destroys the iova doamin | |
233 | * @iovad: - iova domain in question. | |
234 | * All the iova's in that domain are destroyed. | |
235 | */ | |
236 | void put_iova_domain(struct iova_domain *iovad) | |
237 | { | |
238 | struct rb_node *node; | |
239 | unsigned long flags; | |
240 | ||
241 | spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); | |
242 | node = rb_first(&iovad->rbroot); | |
243 | while (node) { | |
244 | struct iova *iova = container_of(node, struct iova, node); | |
245 | rb_erase(node, &iovad->rbroot); | |
246 | free_iova_mem(iova); | |
247 | node = rb_first(&iovad->rbroot); | |
248 | } | |
249 | spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); | |
250 | } | |
251 | ||
252 | static int | |
253 | __is_range_overlap(struct rb_node *node, | |
254 | unsigned long pfn_lo, unsigned long pfn_hi) | |
255 | { | |
256 | struct iova *iova = container_of(node, struct iova, node); | |
257 | ||
258 | if ((pfn_lo <= iova->pfn_hi) && (pfn_hi >= iova->pfn_lo)) | |
259 | return 1; | |
260 | return 0; | |
261 | } | |
262 | ||
263 | static struct iova * | |
264 | __insert_new_range(struct iova_domain *iovad, | |
265 | unsigned long pfn_lo, unsigned long pfn_hi) | |
266 | { | |
267 | struct iova *iova; | |
268 | ||
269 | iova = alloc_iova_mem(); | |
270 | if (!iova) | |
271 | return iova; | |
272 | ||
273 | iova->pfn_hi = pfn_hi; | |
274 | iova->pfn_lo = pfn_lo; | |
275 | iova_insert_rbtree(&iovad->rbroot, iova); | |
276 | return iova; | |
277 | } | |
278 | ||
279 | static void | |
280 | __adjust_overlap_range(struct iova *iova, | |
281 | unsigned long *pfn_lo, unsigned long *pfn_hi) | |
282 | { | |
283 | if (*pfn_lo < iova->pfn_lo) | |
284 | iova->pfn_lo = *pfn_lo; | |
285 | if (*pfn_hi > iova->pfn_hi) | |
286 | *pfn_lo = iova->pfn_hi + 1; | |
287 | } | |
288 | ||
289 | /** | |
290 | * reserve_iova - reserves an iova in the given range | |
291 | * @iovad: - iova domain pointer | |
292 | * @pfn_lo: - lower page frame address | |
293 | * @pfn_hi:- higher pfn adderss | |
294 | * This function allocates reserves the address range from pfn_lo to pfn_hi so | |
295 | * that this address is not dished out as part of alloc_iova. | |
296 | */ | |
297 | struct iova * | |
298 | reserve_iova(struct iova_domain *iovad, | |
299 | unsigned long pfn_lo, unsigned long pfn_hi) | |
300 | { | |
301 | struct rb_node *node; | |
302 | unsigned long flags; | |
303 | struct iova *iova; | |
304 | unsigned int overlap = 0; | |
305 | ||
306 | spin_lock_irqsave(&iovad->iova_alloc_lock, flags); | |
307 | spin_lock(&iovad->iova_rbtree_lock); | |
308 | for (node = rb_first(&iovad->rbroot); node; node = rb_next(node)) { | |
309 | if (__is_range_overlap(node, pfn_lo, pfn_hi)) { | |
310 | iova = container_of(node, struct iova, node); | |
311 | __adjust_overlap_range(iova, &pfn_lo, &pfn_hi); | |
312 | if ((pfn_lo >= iova->pfn_lo) && | |
313 | (pfn_hi <= iova->pfn_hi)) | |
314 | goto finish; | |
315 | overlap = 1; | |
316 | ||
317 | } else if (overlap) | |
318 | break; | |
319 | } | |
320 | ||
321 | /* We are here either becasue this is the first reserver node | |
322 | * or need to insert remaining non overlap addr range | |
323 | */ | |
324 | iova = __insert_new_range(iovad, pfn_lo, pfn_hi); | |
325 | finish: | |
326 | ||
327 | spin_unlock(&iovad->iova_rbtree_lock); | |
328 | spin_unlock_irqrestore(&iovad->iova_alloc_lock, flags); | |
329 | return iova; | |
330 | } | |
331 | ||
332 | /** | |
333 | * copy_reserved_iova - copies the reserved between domains | |
334 | * @from: - source doamin from where to copy | |
335 | * @to: - destination domin where to copy | |
336 | * This function copies reserved iova's from one doamin to | |
337 | * other. | |
338 | */ | |
339 | void | |
340 | copy_reserved_iova(struct iova_domain *from, struct iova_domain *to) | |
341 | { | |
342 | unsigned long flags; | |
343 | struct rb_node *node; | |
344 | ||
345 | spin_lock_irqsave(&from->iova_alloc_lock, flags); | |
346 | spin_lock(&from->iova_rbtree_lock); | |
347 | for (node = rb_first(&from->rbroot); node; node = rb_next(node)) { | |
348 | struct iova *iova = container_of(node, struct iova, node); | |
349 | struct iova *new_iova; | |
350 | new_iova = reserve_iova(to, iova->pfn_lo, iova->pfn_hi); | |
351 | if (!new_iova) | |
352 | printk(KERN_ERR "Reserve iova range %lx@%lx failed\n", | |
353 | iova->pfn_lo, iova->pfn_lo); | |
354 | } | |
355 | spin_unlock(&from->iova_rbtree_lock); | |
356 | spin_unlock_irqrestore(&from->iova_alloc_lock, flags); | |
357 | } |