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786d7257 | 1 | /* |
04a5faa8 | 2 | * Copyright (C) 2012-2014 Canonical Ltd (Maarten Lankhorst) |
786d7257 ML |
3 | * |
4 | * Based on bo.c which bears the following copyright notice, | |
5 | * but is dual licensed: | |
6 | * | |
7 | * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA | |
8 | * All Rights Reserved. | |
9 | * | |
10 | * Permission is hereby granted, free of charge, to any person obtaining a | |
11 | * copy of this software and associated documentation files (the | |
12 | * "Software"), to deal in the Software without restriction, including | |
13 | * without limitation the rights to use, copy, modify, merge, publish, | |
14 | * distribute, sub license, and/or sell copies of the Software, and to | |
15 | * permit persons to whom the Software is furnished to do so, subject to | |
16 | * the following conditions: | |
17 | * | |
18 | * The above copyright notice and this permission notice (including the | |
19 | * next paragraph) shall be included in all copies or substantial portions | |
20 | * of the Software. | |
21 | * | |
22 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
23 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
24 | * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL | |
25 | * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, | |
26 | * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR | |
27 | * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE | |
28 | * USE OR OTHER DEALINGS IN THE SOFTWARE. | |
29 | * | |
30 | **************************************************************************/ | |
31 | /* | |
32 | * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com> | |
33 | */ | |
34 | ||
35 | #include <linux/reservation.h> | |
36 | #include <linux/export.h> | |
37 | ||
dad6c394 RC |
38 | /** |
39 | * DOC: Reservation Object Overview | |
40 | * | |
41 | * The reservation object provides a mechanism to manage shared and | |
42 | * exclusive fences associated with a buffer. A reservation object | |
43 | * can have attached one exclusive fence (normally associated with | |
44 | * write operations) or N shared fences (read operations). The RCU | |
45 | * mechanism is used to protect read access to fences from locked | |
46 | * write-side updates. | |
47 | */ | |
48 | ||
786d7257 ML |
49 | DEFINE_WW_CLASS(reservation_ww_class); |
50 | EXPORT_SYMBOL(reservation_ww_class); | |
04a5faa8 | 51 | |
3c3b177a ML |
52 | struct lock_class_key reservation_seqcount_class; |
53 | EXPORT_SYMBOL(reservation_seqcount_class); | |
54 | ||
55 | const char reservation_seqcount_string[] = "reservation_seqcount"; | |
56 | EXPORT_SYMBOL(reservation_seqcount_string); | |
dad6c394 RC |
57 | |
58 | /** | |
59 | * reservation_object_reserve_shared - Reserve space to add a shared | |
60 | * fence to a reservation_object. | |
61 | * @obj: reservation object | |
62 | * | |
63 | * Should be called before reservation_object_add_shared_fence(). Must | |
64 | * be called with obj->lock held. | |
65 | * | |
66 | * RETURNS | |
67 | * Zero for success, or -errno | |
04a5faa8 ML |
68 | */ |
69 | int reservation_object_reserve_shared(struct reservation_object *obj) | |
70 | { | |
71 | struct reservation_object_list *fobj, *old; | |
72 | u32 max; | |
73 | ||
74 | old = reservation_object_get_list(obj); | |
75 | ||
76 | if (old && old->shared_max) { | |
77 | if (old->shared_count < old->shared_max) { | |
78 | /* perform an in-place update */ | |
79 | kfree(obj->staged); | |
80 | obj->staged = NULL; | |
81 | return 0; | |
82 | } else | |
83 | max = old->shared_max * 2; | |
84 | } else | |
85 | max = 4; | |
86 | ||
87 | /* | |
88 | * resize obj->staged or allocate if it doesn't exist, | |
89 | * noop if already correct size | |
90 | */ | |
91 | fobj = krealloc(obj->staged, offsetof(typeof(*fobj), shared[max]), | |
92 | GFP_KERNEL); | |
93 | if (!fobj) | |
94 | return -ENOMEM; | |
95 | ||
96 | obj->staged = fobj; | |
97 | fobj->shared_max = max; | |
98 | return 0; | |
99 | } | |
100 | EXPORT_SYMBOL(reservation_object_reserve_shared); | |
101 | ||
102 | static void | |
103 | reservation_object_add_shared_inplace(struct reservation_object *obj, | |
104 | struct reservation_object_list *fobj, | |
f54d1867 | 105 | struct dma_fence *fence) |
04a5faa8 ML |
106 | { |
107 | u32 i; | |
108 | ||
f54d1867 | 109 | dma_fence_get(fence); |
3c3b177a ML |
110 | |
111 | preempt_disable(); | |
112 | write_seqcount_begin(&obj->seq); | |
113 | ||
04a5faa8 | 114 | for (i = 0; i < fobj->shared_count; ++i) { |
f54d1867 | 115 | struct dma_fence *old_fence; |
04a5faa8 | 116 | |
3c3b177a ML |
117 | old_fence = rcu_dereference_protected(fobj->shared[i], |
118 | reservation_object_held(obj)); | |
04a5faa8 | 119 | |
3c3b177a ML |
120 | if (old_fence->context == fence->context) { |
121 | /* memory barrier is added by write_seqcount_begin */ | |
122 | RCU_INIT_POINTER(fobj->shared[i], fence); | |
123 | write_seqcount_end(&obj->seq); | |
124 | preempt_enable(); | |
04a5faa8 | 125 | |
f54d1867 | 126 | dma_fence_put(old_fence); |
04a5faa8 ML |
127 | return; |
128 | } | |
129 | } | |
130 | ||
04a5faa8 | 131 | /* |
3c3b177a ML |
132 | * memory barrier is added by write_seqcount_begin, |
133 | * fobj->shared_count is protected by this lock too | |
04a5faa8 | 134 | */ |
3c3b177a | 135 | RCU_INIT_POINTER(fobj->shared[fobj->shared_count], fence); |
04a5faa8 | 136 | fobj->shared_count++; |
3c3b177a ML |
137 | |
138 | write_seqcount_end(&obj->seq); | |
139 | preempt_enable(); | |
04a5faa8 ML |
140 | } |
141 | ||
142 | static void | |
143 | reservation_object_add_shared_replace(struct reservation_object *obj, | |
144 | struct reservation_object_list *old, | |
145 | struct reservation_object_list *fobj, | |
f54d1867 | 146 | struct dma_fence *fence) |
04a5faa8 ML |
147 | { |
148 | unsigned i; | |
f54d1867 | 149 | struct dma_fence *old_fence = NULL; |
04a5faa8 | 150 | |
f54d1867 | 151 | dma_fence_get(fence); |
04a5faa8 ML |
152 | |
153 | if (!old) { | |
3c3b177a | 154 | RCU_INIT_POINTER(fobj->shared[0], fence); |
04a5faa8 ML |
155 | fobj->shared_count = 1; |
156 | goto done; | |
157 | } | |
158 | ||
159 | /* | |
160 | * no need to bump fence refcounts, rcu_read access | |
161 | * requires the use of kref_get_unless_zero, and the | |
162 | * references from the old struct are carried over to | |
163 | * the new. | |
164 | */ | |
165 | fobj->shared_count = old->shared_count; | |
166 | ||
167 | for (i = 0; i < old->shared_count; ++i) { | |
f54d1867 | 168 | struct dma_fence *check; |
3c3b177a ML |
169 | |
170 | check = rcu_dereference_protected(old->shared[i], | |
171 | reservation_object_held(obj)); | |
172 | ||
173 | if (!old_fence && check->context == fence->context) { | |
174 | old_fence = check; | |
175 | RCU_INIT_POINTER(fobj->shared[i], fence); | |
04a5faa8 | 176 | } else |
3c3b177a ML |
177 | RCU_INIT_POINTER(fobj->shared[i], check); |
178 | } | |
179 | if (!old_fence) { | |
180 | RCU_INIT_POINTER(fobj->shared[fobj->shared_count], fence); | |
181 | fobj->shared_count++; | |
04a5faa8 | 182 | } |
04a5faa8 ML |
183 | |
184 | done: | |
3c3b177a ML |
185 | preempt_disable(); |
186 | write_seqcount_begin(&obj->seq); | |
187 | /* | |
188 | * RCU_INIT_POINTER can be used here, | |
189 | * seqcount provides the necessary barriers | |
190 | */ | |
191 | RCU_INIT_POINTER(obj->fence, fobj); | |
192 | write_seqcount_end(&obj->seq); | |
193 | preempt_enable(); | |
194 | ||
195 | if (old) | |
196 | kfree_rcu(old, rcu); | |
197 | ||
198 | if (old_fence) | |
f54d1867 | 199 | dma_fence_put(old_fence); |
04a5faa8 ML |
200 | } |
201 | ||
dad6c394 RC |
202 | /** |
203 | * reservation_object_add_shared_fence - Add a fence to a shared slot | |
204 | * @obj: the reservation object | |
205 | * @fence: the shared fence to add | |
206 | * | |
04a5faa8 | 207 | * Add a fence to a shared slot, obj->lock must be held, and |
f5bef0b8 | 208 | * reservation_object_reserve_shared() has been called. |
04a5faa8 ML |
209 | */ |
210 | void reservation_object_add_shared_fence(struct reservation_object *obj, | |
f54d1867 | 211 | struct dma_fence *fence) |
04a5faa8 ML |
212 | { |
213 | struct reservation_object_list *old, *fobj = obj->staged; | |
214 | ||
215 | old = reservation_object_get_list(obj); | |
216 | obj->staged = NULL; | |
217 | ||
218 | if (!fobj) { | |
3c3b177a | 219 | BUG_ON(old->shared_count >= old->shared_max); |
04a5faa8 ML |
220 | reservation_object_add_shared_inplace(obj, old, fence); |
221 | } else | |
222 | reservation_object_add_shared_replace(obj, old, fobj, fence); | |
223 | } | |
224 | EXPORT_SYMBOL(reservation_object_add_shared_fence); | |
225 | ||
dad6c394 RC |
226 | /** |
227 | * reservation_object_add_excl_fence - Add an exclusive fence. | |
228 | * @obj: the reservation object | |
229 | * @fence: the shared fence to add | |
230 | * | |
231 | * Add a fence to the exclusive slot. The obj->lock must be held. | |
232 | */ | |
04a5faa8 | 233 | void reservation_object_add_excl_fence(struct reservation_object *obj, |
f54d1867 | 234 | struct dma_fence *fence) |
04a5faa8 | 235 | { |
f54d1867 | 236 | struct dma_fence *old_fence = reservation_object_get_excl(obj); |
04a5faa8 ML |
237 | struct reservation_object_list *old; |
238 | u32 i = 0; | |
239 | ||
240 | old = reservation_object_get_list(obj); | |
3c3b177a | 241 | if (old) |
04a5faa8 | 242 | i = old->shared_count; |
04a5faa8 ML |
243 | |
244 | if (fence) | |
f54d1867 | 245 | dma_fence_get(fence); |
04a5faa8 | 246 | |
3c3b177a ML |
247 | preempt_disable(); |
248 | write_seqcount_begin(&obj->seq); | |
249 | /* write_seqcount_begin provides the necessary memory barrier */ | |
250 | RCU_INIT_POINTER(obj->fence_excl, fence); | |
251 | if (old) | |
252 | old->shared_count = 0; | |
253 | write_seqcount_end(&obj->seq); | |
254 | preempt_enable(); | |
04a5faa8 ML |
255 | |
256 | /* inplace update, no shared fences */ | |
257 | while (i--) | |
f54d1867 | 258 | dma_fence_put(rcu_dereference_protected(old->shared[i], |
3c3b177a | 259 | reservation_object_held(obj))); |
04a5faa8 ML |
260 | |
261 | if (old_fence) | |
f54d1867 | 262 | dma_fence_put(old_fence); |
04a5faa8 ML |
263 | } |
264 | EXPORT_SYMBOL(reservation_object_add_excl_fence); | |
3c3b177a | 265 | |
dad6c394 RC |
266 | /** |
267 | * reservation_object_get_fences_rcu - Get an object's shared and exclusive | |
268 | * fences without update side lock held | |
269 | * @obj: the reservation object | |
270 | * @pfence_excl: the returned exclusive fence (or NULL) | |
271 | * @pshared_count: the number of shared fences returned | |
272 | * @pshared: the array of shared fence ptrs returned (array is krealloc'd to | |
273 | * the required size, and must be freed by caller) | |
274 | * | |
275 | * RETURNS | |
276 | * Zero or -errno | |
277 | */ | |
3c3b177a | 278 | int reservation_object_get_fences_rcu(struct reservation_object *obj, |
f54d1867 | 279 | struct dma_fence **pfence_excl, |
3c3b177a | 280 | unsigned *pshared_count, |
f54d1867 | 281 | struct dma_fence ***pshared) |
3c3b177a | 282 | { |
f54d1867 CW |
283 | struct dma_fence **shared = NULL; |
284 | struct dma_fence *fence_excl; | |
fedf5413 CW |
285 | unsigned int shared_count; |
286 | int ret = 1; | |
3c3b177a | 287 | |
fedf5413 | 288 | do { |
3c3b177a ML |
289 | struct reservation_object_list *fobj; |
290 | unsigned seq; | |
fedf5413 | 291 | unsigned int i; |
3c3b177a | 292 | |
fedf5413 | 293 | shared_count = i = 0; |
3c3b177a ML |
294 | |
295 | rcu_read_lock(); | |
fedf5413 CW |
296 | seq = read_seqcount_begin(&obj->seq); |
297 | ||
298 | fence_excl = rcu_dereference(obj->fence_excl); | |
f54d1867 | 299 | if (fence_excl && !dma_fence_get_rcu(fence_excl)) |
fedf5413 | 300 | goto unlock; |
3c3b177a ML |
301 | |
302 | fobj = rcu_dereference(obj->fence); | |
303 | if (fobj) { | |
f54d1867 | 304 | struct dma_fence **nshared; |
3c3b177a ML |
305 | size_t sz = sizeof(*shared) * fobj->shared_max; |
306 | ||
307 | nshared = krealloc(shared, sz, | |
308 | GFP_NOWAIT | __GFP_NOWARN); | |
309 | if (!nshared) { | |
310 | rcu_read_unlock(); | |
311 | nshared = krealloc(shared, sz, GFP_KERNEL); | |
312 | if (nshared) { | |
313 | shared = nshared; | |
314 | continue; | |
315 | } | |
316 | ||
317 | ret = -ENOMEM; | |
3c3b177a ML |
318 | break; |
319 | } | |
320 | shared = nshared; | |
3c3b177a | 321 | shared_count = fobj->shared_count; |
3c3b177a ML |
322 | |
323 | for (i = 0; i < shared_count; ++i) { | |
fedf5413 | 324 | shared[i] = rcu_dereference(fobj->shared[i]); |
f54d1867 | 325 | if (!dma_fence_get_rcu(shared[i])) |
fedf5413 | 326 | break; |
3c3b177a | 327 | } |
fedf5413 | 328 | } |
3c3b177a | 329 | |
fedf5413 CW |
330 | if (i != shared_count || read_seqcount_retry(&obj->seq, seq)) { |
331 | while (i--) | |
f54d1867 CW |
332 | dma_fence_put(shared[i]); |
333 | dma_fence_put(fence_excl); | |
fedf5413 CW |
334 | goto unlock; |
335 | } | |
336 | ||
337 | ret = 0; | |
3c3b177a ML |
338 | unlock: |
339 | rcu_read_unlock(); | |
fedf5413 CW |
340 | } while (ret); |
341 | ||
342 | if (!shared_count) { | |
3c3b177a | 343 | kfree(shared); |
fedf5413 | 344 | shared = NULL; |
3c3b177a | 345 | } |
fedf5413 CW |
346 | |
347 | *pshared_count = shared_count; | |
348 | *pshared = shared; | |
3c3b177a ML |
349 | *pfence_excl = fence_excl; |
350 | ||
351 | return ret; | |
352 | } | |
353 | EXPORT_SYMBOL_GPL(reservation_object_get_fences_rcu); | |
354 | ||
dad6c394 RC |
355 | /** |
356 | * reservation_object_wait_timeout_rcu - Wait on reservation's objects | |
357 | * shared and/or exclusive fences. | |
358 | * @obj: the reservation object | |
359 | * @wait_all: if true, wait on all fences, else wait on just exclusive fence | |
360 | * @intr: if true, do interruptible wait | |
361 | * @timeout: timeout value in jiffies or zero to return immediately | |
362 | * | |
363 | * RETURNS | |
364 | * Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or | |
365 | * greater than zer on success. | |
366 | */ | |
3c3b177a ML |
367 | long reservation_object_wait_timeout_rcu(struct reservation_object *obj, |
368 | bool wait_all, bool intr, | |
369 | unsigned long timeout) | |
370 | { | |
f54d1867 | 371 | struct dma_fence *fence; |
3c3b177a | 372 | unsigned seq, shared_count, i = 0; |
06a66b5c | 373 | long ret = timeout ? timeout : 1; |
fb8b7d2b | 374 | |
3c3b177a ML |
375 | retry: |
376 | fence = NULL; | |
377 | shared_count = 0; | |
378 | seq = read_seqcount_begin(&obj->seq); | |
379 | rcu_read_lock(); | |
380 | ||
381 | if (wait_all) { | |
5136629d JT |
382 | struct reservation_object_list *fobj = |
383 | rcu_dereference(obj->fence); | |
3c3b177a ML |
384 | |
385 | if (fobj) | |
386 | shared_count = fobj->shared_count; | |
387 | ||
3c3b177a | 388 | for (i = 0; i < shared_count; ++i) { |
f54d1867 | 389 | struct dma_fence *lfence = rcu_dereference(fobj->shared[i]); |
3c3b177a | 390 | |
f54d1867 CW |
391 | if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, |
392 | &lfence->flags)) | |
3c3b177a ML |
393 | continue; |
394 | ||
f54d1867 | 395 | if (!dma_fence_get_rcu(lfence)) |
3c3b177a ML |
396 | goto unlock_retry; |
397 | ||
f54d1867 CW |
398 | if (dma_fence_is_signaled(lfence)) { |
399 | dma_fence_put(lfence); | |
3c3b177a ML |
400 | continue; |
401 | } | |
402 | ||
403 | fence = lfence; | |
404 | break; | |
405 | } | |
406 | } | |
407 | ||
408 | if (!shared_count) { | |
f54d1867 | 409 | struct dma_fence *fence_excl = rcu_dereference(obj->fence_excl); |
3c3b177a | 410 | |
3c3b177a | 411 | if (fence_excl && |
f54d1867 CW |
412 | !test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, |
413 | &fence_excl->flags)) { | |
414 | if (!dma_fence_get_rcu(fence_excl)) | |
3c3b177a ML |
415 | goto unlock_retry; |
416 | ||
f54d1867 CW |
417 | if (dma_fence_is_signaled(fence_excl)) |
418 | dma_fence_put(fence_excl); | |
3c3b177a ML |
419 | else |
420 | fence = fence_excl; | |
421 | } | |
422 | } | |
423 | ||
424 | rcu_read_unlock(); | |
425 | if (fence) { | |
1cec20f0 | 426 | if (read_seqcount_retry(&obj->seq, seq)) { |
f54d1867 | 427 | dma_fence_put(fence); |
1cec20f0 CW |
428 | goto retry; |
429 | } | |
430 | ||
f54d1867 CW |
431 | ret = dma_fence_wait_timeout(fence, intr, ret); |
432 | dma_fence_put(fence); | |
3c3b177a ML |
433 | if (ret > 0 && wait_all && (i + 1 < shared_count)) |
434 | goto retry; | |
435 | } | |
436 | return ret; | |
437 | ||
438 | unlock_retry: | |
439 | rcu_read_unlock(); | |
440 | goto retry; | |
441 | } | |
442 | EXPORT_SYMBOL_GPL(reservation_object_wait_timeout_rcu); | |
443 | ||
444 | ||
445 | static inline int | |
f54d1867 | 446 | reservation_object_test_signaled_single(struct dma_fence *passed_fence) |
3c3b177a | 447 | { |
f54d1867 | 448 | struct dma_fence *fence, *lfence = passed_fence; |
3c3b177a ML |
449 | int ret = 1; |
450 | ||
f54d1867 CW |
451 | if (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &lfence->flags)) { |
452 | fence = dma_fence_get_rcu(lfence); | |
3c3b177a ML |
453 | if (!fence) |
454 | return -1; | |
455 | ||
f54d1867 CW |
456 | ret = !!dma_fence_is_signaled(fence); |
457 | dma_fence_put(fence); | |
3c3b177a ML |
458 | } |
459 | return ret; | |
460 | } | |
461 | ||
dad6c394 RC |
462 | /** |
463 | * reservation_object_test_signaled_rcu - Test if a reservation object's | |
464 | * fences have been signaled. | |
465 | * @obj: the reservation object | |
466 | * @test_all: if true, test all fences, otherwise only test the exclusive | |
467 | * fence | |
468 | * | |
469 | * RETURNS | |
470 | * true if all fences signaled, else false | |
471 | */ | |
3c3b177a ML |
472 | bool reservation_object_test_signaled_rcu(struct reservation_object *obj, |
473 | bool test_all) | |
474 | { | |
475 | unsigned seq, shared_count; | |
b68d8379 | 476 | int ret; |
3c3b177a | 477 | |
b68d8379 | 478 | rcu_read_lock(); |
3c3b177a | 479 | retry: |
b68d8379 | 480 | ret = true; |
3c3b177a ML |
481 | shared_count = 0; |
482 | seq = read_seqcount_begin(&obj->seq); | |
3c3b177a ML |
483 | |
484 | if (test_all) { | |
485 | unsigned i; | |
486 | ||
5136629d JT |
487 | struct reservation_object_list *fobj = |
488 | rcu_dereference(obj->fence); | |
3c3b177a ML |
489 | |
490 | if (fobj) | |
491 | shared_count = fobj->shared_count; | |
492 | ||
3c3b177a | 493 | for (i = 0; i < shared_count; ++i) { |
f54d1867 | 494 | struct dma_fence *fence = rcu_dereference(fobj->shared[i]); |
3c3b177a ML |
495 | |
496 | ret = reservation_object_test_signaled_single(fence); | |
497 | if (ret < 0) | |
b68d8379 | 498 | goto retry; |
3c3b177a ML |
499 | else if (!ret) |
500 | break; | |
501 | } | |
502 | ||
b68d8379 CW |
503 | if (read_seqcount_retry(&obj->seq, seq)) |
504 | goto retry; | |
3c3b177a ML |
505 | } |
506 | ||
507 | if (!shared_count) { | |
f54d1867 | 508 | struct dma_fence *fence_excl = rcu_dereference(obj->fence_excl); |
3c3b177a | 509 | |
3c3b177a | 510 | if (fence_excl) { |
5136629d JT |
511 | ret = reservation_object_test_signaled_single( |
512 | fence_excl); | |
3c3b177a | 513 | if (ret < 0) |
b68d8379 CW |
514 | goto retry; |
515 | ||
516 | if (read_seqcount_retry(&obj->seq, seq)) | |
517 | goto retry; | |
3c3b177a ML |
518 | } |
519 | } | |
520 | ||
521 | rcu_read_unlock(); | |
522 | return ret; | |
3c3b177a ML |
523 | } |
524 | EXPORT_SYMBOL_GPL(reservation_object_test_signaled_rcu); |