1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35#include <linux/reservation.h>
36#include <linux/export.h>
37
38DEFINE_WW_CLASS(reservation_ww_class);
39EXPORT_SYMBOL(reservation_ww_class);
40
41struct lock_class_key reservation_seqcount_class;
42EXPORT_SYMBOL(reservation_seqcount_class);
43
44const char reservation_seqcount_string[] = "reservation_seqcount";
45EXPORT_SYMBOL(reservation_seqcount_string);
46
47
48
49
50int reservation_object_reserve_shared(struct reservation_object *obj)
51{
52 struct reservation_object_list *fobj, *old;
53 u32 max;
54
55 old = reservation_object_get_list(obj);
56
57 if (old && old->shared_max) {
58 if (old->shared_count < old->shared_max) {
59
60 kfree(obj->staged);
61 obj->staged = NULL;
62 return 0;
63 } else
64 max = old->shared_max * 2;
65 } else
66 max = 4;
67
68
69
70
71
72 fobj = krealloc(obj->staged, offsetof(typeof(*fobj), shared[max]),
73 GFP_KERNEL);
74 if (!fobj)
75 return -ENOMEM;
76
77 obj->staged = fobj;
78 fobj->shared_max = max;
79 return 0;
80}
81EXPORT_SYMBOL(reservation_object_reserve_shared);
82
83static void
84reservation_object_add_shared_inplace(struct reservation_object *obj,
85 struct reservation_object_list *fobj,
86 struct fence *fence)
87{
88 u32 i;
89
90 fence_get(fence);
91
92 preempt_disable();
93 write_seqcount_begin(&obj->seq);
94
95 for (i = 0; i < fobj->shared_count; ++i) {
96 struct fence *old_fence;
97
98 old_fence = rcu_dereference_protected(fobj->shared[i],
99 reservation_object_held(obj));
100
101 if (old_fence->context == fence->context) {
102
103 RCU_INIT_POINTER(fobj->shared[i], fence);
104 write_seqcount_end(&obj->seq);
105 preempt_enable();
106
107 fence_put(old_fence);
108 return;
109 }
110 }
111
112
113
114
115
116 RCU_INIT_POINTER(fobj->shared[fobj->shared_count], fence);
117 fobj->shared_count++;
118
119 write_seqcount_end(&obj->seq);
120 preempt_enable();
121}
122
123static void
124reservation_object_add_shared_replace(struct reservation_object *obj,
125 struct reservation_object_list *old,
126 struct reservation_object_list *fobj,
127 struct fence *fence)
128{
129 unsigned i;
130 struct fence *old_fence = NULL;
131
132 fence_get(fence);
133
134 if (!old) {
135 RCU_INIT_POINTER(fobj->shared[0], fence);
136 fobj->shared_count = 1;
137 goto done;
138 }
139
140
141
142
143
144
145
146 fobj->shared_count = old->shared_count;
147
148 for (i = 0; i < old->shared_count; ++i) {
149 struct fence *check;
150
151 check = rcu_dereference_protected(old->shared[i],
152 reservation_object_held(obj));
153
154 if (!old_fence && check->context == fence->context) {
155 old_fence = check;
156 RCU_INIT_POINTER(fobj->shared[i], fence);
157 } else
158 RCU_INIT_POINTER(fobj->shared[i], check);
159 }
160 if (!old_fence) {
161 RCU_INIT_POINTER(fobj->shared[fobj->shared_count], fence);
162 fobj->shared_count++;
163 }
164
165done:
166 preempt_disable();
167 write_seqcount_begin(&obj->seq);
168
169
170
171
172 RCU_INIT_POINTER(obj->fence, fobj);
173 write_seqcount_end(&obj->seq);
174 preempt_enable();
175
176 if (old)
177 kfree_rcu(old, rcu);
178
179 if (old_fence)
180 fence_put(old_fence);
181}
182
183
184
185
186
187void reservation_object_add_shared_fence(struct reservation_object *obj,
188 struct fence *fence)
189{
190 struct reservation_object_list *old, *fobj = obj->staged;
191
192 old = reservation_object_get_list(obj);
193 obj->staged = NULL;
194
195 if (!fobj) {
196 BUG_ON(old->shared_count >= old->shared_max);
197 reservation_object_add_shared_inplace(obj, old, fence);
198 } else
199 reservation_object_add_shared_replace(obj, old, fobj, fence);
200}
201EXPORT_SYMBOL(reservation_object_add_shared_fence);
202
203void reservation_object_add_excl_fence(struct reservation_object *obj,
204 struct fence *fence)
205{
206 struct fence *old_fence = reservation_object_get_excl(obj);
207 struct reservation_object_list *old;
208 u32 i = 0;
209
210 old = reservation_object_get_list(obj);
211 if (old)
212 i = old->shared_count;
213
214 if (fence)
215 fence_get(fence);
216
217 preempt_disable();
218 write_seqcount_begin(&obj->seq);
219
220 RCU_INIT_POINTER(obj->fence_excl, fence);
221 if (old)
222 old->shared_count = 0;
223 write_seqcount_end(&obj->seq);
224 preempt_enable();
225
226
227 while (i--)
228 fence_put(rcu_dereference_protected(old->shared[i],
229 reservation_object_held(obj)));
230
231 if (old_fence)
232 fence_put(old_fence);
233}
234EXPORT_SYMBOL(reservation_object_add_excl_fence);
235
236int reservation_object_get_fences_rcu(struct reservation_object *obj,
237 struct fence **pfence_excl,
238 unsigned *pshared_count,
239 struct fence ***pshared)
240{
241 unsigned shared_count = 0;
242 unsigned retry = 1;
243 struct fence **shared = NULL, *fence_excl = NULL;
244 int ret = 0;
245
246 while (retry) {
247 struct reservation_object_list *fobj;
248 unsigned seq;
249
250 seq = read_seqcount_begin(&obj->seq);
251
252 rcu_read_lock();
253
254 fobj = rcu_dereference(obj->fence);
255 if (fobj) {
256 struct fence **nshared;
257 size_t sz = sizeof(*shared) * fobj->shared_max;
258
259 nshared = krealloc(shared, sz,
260 GFP_NOWAIT | __GFP_NOWARN);
261 if (!nshared) {
262 rcu_read_unlock();
263 nshared = krealloc(shared, sz, GFP_KERNEL);
264 if (nshared) {
265 shared = nshared;
266 continue;
267 }
268
269 ret = -ENOMEM;
270 shared_count = 0;
271 break;
272 }
273 shared = nshared;
274 memcpy(shared, fobj->shared, sz);
275 shared_count = fobj->shared_count;
276 } else
277 shared_count = 0;
278 fence_excl = rcu_dereference(obj->fence_excl);
279
280 retry = read_seqcount_retry(&obj->seq, seq);
281 if (retry)
282 goto unlock;
283
284 if (!fence_excl || fence_get_rcu(fence_excl)) {
285 unsigned i;
286
287 for (i = 0; i < shared_count; ++i) {
288 if (fence_get_rcu(shared[i]))
289 continue;
290
291
292 while (i--)
293 fence_put(shared[i]);
294
295 if (fence_excl) {
296 fence_put(fence_excl);
297 fence_excl = NULL;
298 }
299
300 retry = 1;
301 break;
302 }
303 } else
304 retry = 1;
305
306unlock:
307 rcu_read_unlock();
308 }
309 *pshared_count = shared_count;
310 if (shared_count)
311 *pshared = shared;
312 else {
313 *pshared = NULL;
314 kfree(shared);
315 }
316 *pfence_excl = fence_excl;
317
318 return ret;
319}
320EXPORT_SYMBOL_GPL(reservation_object_get_fences_rcu);
321
322long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
323 bool wait_all, bool intr,
324 unsigned long timeout)
325{
326 struct fence *fence;
327 unsigned seq, shared_count, i = 0;
328 long ret = timeout;
329
330 if (!timeout)
331 return reservation_object_test_signaled_rcu(obj, wait_all);
332
333retry:
334 fence = NULL;
335 shared_count = 0;
336 seq = read_seqcount_begin(&obj->seq);
337 rcu_read_lock();
338
339 if (wait_all) {
340 struct reservation_object_list *fobj =
341 rcu_dereference(obj->fence);
342
343 if (fobj)
344 shared_count = fobj->shared_count;
345
346 if (read_seqcount_retry(&obj->seq, seq))
347 goto unlock_retry;
348
349 for (i = 0; i < shared_count; ++i) {
350 struct fence *lfence = rcu_dereference(fobj->shared[i]);
351
352 if (test_bit(FENCE_FLAG_SIGNALED_BIT, &lfence->flags))
353 continue;
354
355 if (!fence_get_rcu(lfence))
356 goto unlock_retry;
357
358 if (fence_is_signaled(lfence)) {
359 fence_put(lfence);
360 continue;
361 }
362
363 fence = lfence;
364 break;
365 }
366 }
367
368 if (!shared_count) {
369 struct fence *fence_excl = rcu_dereference(obj->fence_excl);
370
371 if (read_seqcount_retry(&obj->seq, seq))
372 goto unlock_retry;
373
374 if (fence_excl &&
375 !test_bit(FENCE_FLAG_SIGNALED_BIT, &fence_excl->flags)) {
376 if (!fence_get_rcu(fence_excl))
377 goto unlock_retry;
378
379 if (fence_is_signaled(fence_excl))
380 fence_put(fence_excl);
381 else
382 fence = fence_excl;
383 }
384 }
385
386 rcu_read_unlock();
387 if (fence) {
388 ret = fence_wait_timeout(fence, intr, ret);
389 fence_put(fence);
390 if (ret > 0 && wait_all && (i + 1 < shared_count))
391 goto retry;
392 }
393 return ret;
394
395unlock_retry:
396 rcu_read_unlock();
397 goto retry;
398}
399EXPORT_SYMBOL_GPL(reservation_object_wait_timeout_rcu);
400
401
402static inline int
403reservation_object_test_signaled_single(struct fence *passed_fence)
404{
405 struct fence *fence, *lfence = passed_fence;
406 int ret = 1;
407
408 if (!test_bit(FENCE_FLAG_SIGNALED_BIT, &lfence->flags)) {
409 fence = fence_get_rcu(lfence);
410 if (!fence)
411 return -1;
412
413 ret = !!fence_is_signaled(fence);
414 fence_put(fence);
415 }
416 return ret;
417}
418
419bool reservation_object_test_signaled_rcu(struct reservation_object *obj,
420 bool test_all)
421{
422 unsigned seq, shared_count;
423 int ret = true;
424
425retry:
426 shared_count = 0;
427 seq = read_seqcount_begin(&obj->seq);
428 rcu_read_lock();
429
430 if (test_all) {
431 unsigned i;
432
433 struct reservation_object_list *fobj =
434 rcu_dereference(obj->fence);
435
436 if (fobj)
437 shared_count = fobj->shared_count;
438
439 if (read_seqcount_retry(&obj->seq, seq))
440 goto unlock_retry;
441
442 for (i = 0; i < shared_count; ++i) {
443 struct fence *fence = rcu_dereference(fobj->shared[i]);
444
445 ret = reservation_object_test_signaled_single(fence);
446 if (ret < 0)
447 goto unlock_retry;
448 else if (!ret)
449 break;
450 }
451
452
453
454
455
456
457
458 }
459
460 if (!shared_count) {
461 struct fence *fence_excl = rcu_dereference(obj->fence_excl);
462
463 if (read_seqcount_retry(&obj->seq, seq))
464 goto unlock_retry;
465
466 if (fence_excl) {
467 ret = reservation_object_test_signaled_single(
468 fence_excl);
469 if (ret < 0)
470 goto unlock_retry;
471 }
472 }
473
474 rcu_read_unlock();
475 return ret;
476
477unlock_retry:
478 rcu_read_unlock();
479 goto retry;
480}
481EXPORT_SYMBOL_GPL(reservation_object_test_signaled_rcu);
482