1 | /* Copyright (C) 2002-2017 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. |
3 | Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. |
4 | |
5 | The GNU C Library is free software; you can redistribute it and/or |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either |
8 | version 2.1 of the License, or (at your option) any later version. |
9 | |
10 | The GNU C Library is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | Lesser General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library; if not, see |
17 | <http://www.gnu.org/licenses/>. */ |
18 | |
19 | #include <assert.h> |
20 | #include <errno.h> |
21 | #include <stdlib.h> |
22 | #include <unistd.h> |
23 | #include <sys/param.h> |
24 | #include <not-cancel.h> |
25 | #include "pthreadP.h" |
26 | #include <atomic.h> |
27 | #include <lowlevellock.h> |
28 | #include <stap-probe.h> |
29 | |
30 | #ifndef lll_lock_elision |
31 | #define lll_lock_elision(lock, try_lock, private) ({ \ |
32 | lll_lock (lock, private); 0; }) |
33 | #endif |
34 | |
35 | #ifndef lll_trylock_elision |
36 | #define lll_trylock_elision(a,t) lll_trylock(a) |
37 | #endif |
38 | |
39 | /* Some of the following definitions differ when pthread_mutex_cond_lock.c |
40 | includes this file. */ |
41 | #ifndef LLL_MUTEX_LOCK |
42 | # define LLL_MUTEX_LOCK(mutex) \ |
43 | lll_lock ((mutex)->__data.__lock, PTHREAD_MUTEX_PSHARED (mutex)) |
44 | # define LLL_MUTEX_TRYLOCK(mutex) \ |
45 | lll_trylock ((mutex)->__data.__lock) |
46 | # define LLL_ROBUST_MUTEX_LOCK_MODIFIER 0 |
47 | # define LLL_MUTEX_LOCK_ELISION(mutex) \ |
48 | lll_lock_elision ((mutex)->__data.__lock, (mutex)->__data.__elision, \ |
49 | PTHREAD_MUTEX_PSHARED (mutex)) |
50 | # define LLL_MUTEX_TRYLOCK_ELISION(mutex) \ |
51 | lll_trylock_elision((mutex)->__data.__lock, (mutex)->__data.__elision, \ |
52 | PTHREAD_MUTEX_PSHARED (mutex)) |
53 | #endif |
54 | |
55 | #ifndef FORCE_ELISION |
56 | #define FORCE_ELISION(m, s) |
57 | #endif |
58 | |
59 | static int __pthread_mutex_lock_full (pthread_mutex_t *mutex) |
60 | __attribute_noinline__; |
61 | |
62 | int |
63 | __pthread_mutex_lock (pthread_mutex_t *mutex) |
64 | { |
65 | assert (sizeof (mutex->__size) >= sizeof (mutex->__data)); |
66 | |
67 | unsigned int type = PTHREAD_MUTEX_TYPE_ELISION (mutex); |
68 | |
69 | LIBC_PROBE (mutex_entry, 1, mutex); |
70 | |
71 | if (__builtin_expect (type & ~(PTHREAD_MUTEX_KIND_MASK_NP |
72 | | PTHREAD_MUTEX_ELISION_FLAGS_NP), 0)) |
73 | return __pthread_mutex_lock_full (mutex); |
74 | |
75 | if (__glibc_likely (type == PTHREAD_MUTEX_TIMED_NP)) |
76 | { |
77 | FORCE_ELISION (mutex, goto elision); |
78 | simple: |
79 | /* Normal mutex. */ |
80 | LLL_MUTEX_LOCK (mutex); |
81 | assert (mutex->__data.__owner == 0); |
82 | } |
83 | #ifdef HAVE_ELISION |
84 | else if (__glibc_likely (type == PTHREAD_MUTEX_TIMED_ELISION_NP)) |
85 | { |
86 | elision: __attribute__((unused)) |
87 | /* This case can never happen on a system without elision, |
88 | as the mutex type initialization functions will not |
89 | allow to set the elision flags. */ |
90 | /* Don't record owner or users for elision case. This is a |
91 | tail call. */ |
92 | return LLL_MUTEX_LOCK_ELISION (mutex); |
93 | } |
94 | #endif |
95 | else if (__builtin_expect (PTHREAD_MUTEX_TYPE (mutex) |
96 | == PTHREAD_MUTEX_RECURSIVE_NP, 1)) |
97 | { |
98 | /* Recursive mutex. */ |
99 | pid_t id = THREAD_GETMEM (THREAD_SELF, tid); |
100 | |
101 | /* Check whether we already hold the mutex. */ |
102 | if (mutex->__data.__owner == id) |
103 | { |
104 | /* Just bump the counter. */ |
105 | if (__glibc_unlikely (mutex->__data.__count + 1 == 0)) |
106 | /* Overflow of the counter. */ |
107 | return EAGAIN; |
108 | |
109 | ++mutex->__data.__count; |
110 | |
111 | return 0; |
112 | } |
113 | |
114 | /* We have to get the mutex. */ |
115 | LLL_MUTEX_LOCK (mutex); |
116 | |
117 | assert (mutex->__data.__owner == 0); |
118 | mutex->__data.__count = 1; |
119 | } |
120 | else if (__builtin_expect (PTHREAD_MUTEX_TYPE (mutex) |
121 | == PTHREAD_MUTEX_ADAPTIVE_NP, 1)) |
122 | { |
123 | if (! __is_smp) |
124 | goto simple; |
125 | |
126 | if (LLL_MUTEX_TRYLOCK (mutex) != 0) |
127 | { |
128 | int cnt = 0; |
129 | int max_cnt = MIN (MAX_ADAPTIVE_COUNT, |
130 | mutex->__data.__spins * 2 + 10); |
131 | do |
132 | { |
133 | if (cnt++ >= max_cnt) |
134 | { |
135 | LLL_MUTEX_LOCK (mutex); |
136 | break; |
137 | } |
138 | atomic_spin_nop (); |
139 | } |
140 | while (LLL_MUTEX_TRYLOCK (mutex) != 0); |
141 | |
142 | mutex->__data.__spins += (cnt - mutex->__data.__spins) / 8; |
143 | } |
144 | assert (mutex->__data.__owner == 0); |
145 | } |
146 | else |
147 | { |
148 | pid_t id = THREAD_GETMEM (THREAD_SELF, tid); |
149 | assert (PTHREAD_MUTEX_TYPE (mutex) == PTHREAD_MUTEX_ERRORCHECK_NP); |
150 | /* Check whether we already hold the mutex. */ |
151 | if (__glibc_unlikely (mutex->__data.__owner == id)) |
152 | return EDEADLK; |
153 | goto simple; |
154 | } |
155 | |
156 | pid_t id = THREAD_GETMEM (THREAD_SELF, tid); |
157 | |
158 | /* Record the ownership. */ |
159 | mutex->__data.__owner = id; |
160 | #ifndef NO_INCR |
161 | ++mutex->__data.__nusers; |
162 | #endif |
163 | |
164 | LIBC_PROBE (mutex_acquired, 1, mutex); |
165 | |
166 | return 0; |
167 | } |
168 | |
169 | static int |
170 | __pthread_mutex_lock_full (pthread_mutex_t *mutex) |
171 | { |
172 | int oldval; |
173 | pid_t id = THREAD_GETMEM (THREAD_SELF, tid); |
174 | |
175 | switch (PTHREAD_MUTEX_TYPE (mutex)) |
176 | { |
177 | case PTHREAD_MUTEX_ROBUST_RECURSIVE_NP: |
178 | case PTHREAD_MUTEX_ROBUST_ERRORCHECK_NP: |
179 | case PTHREAD_MUTEX_ROBUST_NORMAL_NP: |
180 | case PTHREAD_MUTEX_ROBUST_ADAPTIVE_NP: |
181 | THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, |
182 | &mutex->__data.__list.__next); |
183 | /* We need to set op_pending before starting the operation. Also |
184 | see comments at ENQUEUE_MUTEX. */ |
185 | __asm ("" ::: "memory" ); |
186 | |
187 | oldval = mutex->__data.__lock; |
188 | /* This is set to FUTEX_WAITERS iff we might have shared the |
189 | FUTEX_WAITERS flag with other threads, and therefore need to keep it |
190 | set to avoid lost wake-ups. We have the same requirement in the |
191 | simple mutex algorithm. |
192 | We start with value zero for a normal mutex, and FUTEX_WAITERS if we |
193 | are building the special case mutexes for use from within condition |
194 | variables. */ |
195 | unsigned int assume_other_futex_waiters = LLL_ROBUST_MUTEX_LOCK_MODIFIER; |
196 | while (1) |
197 | { |
198 | /* Try to acquire the lock through a CAS from 0 (not acquired) to |
199 | our TID | assume_other_futex_waiters. */ |
200 | if (__glibc_likely (oldval == 0)) |
201 | { |
202 | oldval |
203 | = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, |
204 | id | assume_other_futex_waiters, 0); |
205 | if (__glibc_likely (oldval == 0)) |
206 | break; |
207 | } |
208 | |
209 | if ((oldval & FUTEX_OWNER_DIED) != 0) |
210 | { |
211 | /* The previous owner died. Try locking the mutex. */ |
212 | int newval = id; |
213 | #ifdef NO_INCR |
214 | /* We are not taking assume_other_futex_waiters into accoount |
215 | here simply because we'll set FUTEX_WAITERS anyway. */ |
216 | newval |= FUTEX_WAITERS; |
217 | #else |
218 | newval |= (oldval & FUTEX_WAITERS) | assume_other_futex_waiters; |
219 | #endif |
220 | |
221 | newval |
222 | = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, |
223 | newval, oldval); |
224 | |
225 | if (newval != oldval) |
226 | { |
227 | oldval = newval; |
228 | continue; |
229 | } |
230 | |
231 | /* We got the mutex. */ |
232 | mutex->__data.__count = 1; |
233 | /* But it is inconsistent unless marked otherwise. */ |
234 | mutex->__data.__owner = PTHREAD_MUTEX_INCONSISTENT; |
235 | |
236 | /* We must not enqueue the mutex before we have acquired it. |
237 | Also see comments at ENQUEUE_MUTEX. */ |
238 | __asm ("" ::: "memory" ); |
239 | ENQUEUE_MUTEX (mutex); |
240 | /* We need to clear op_pending after we enqueue the mutex. */ |
241 | __asm ("" ::: "memory" ); |
242 | THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); |
243 | |
244 | /* Note that we deliberately exit here. If we fall |
245 | through to the end of the function __nusers would be |
246 | incremented which is not correct because the old |
247 | owner has to be discounted. If we are not supposed |
248 | to increment __nusers we actually have to decrement |
249 | it here. */ |
250 | #ifdef NO_INCR |
251 | --mutex->__data.__nusers; |
252 | #endif |
253 | |
254 | return EOWNERDEAD; |
255 | } |
256 | |
257 | /* Check whether we already hold the mutex. */ |
258 | if (__glibc_unlikely ((oldval & FUTEX_TID_MASK) == id)) |
259 | { |
260 | int kind = PTHREAD_MUTEX_TYPE (mutex); |
261 | if (kind == PTHREAD_MUTEX_ROBUST_ERRORCHECK_NP) |
262 | { |
263 | /* We do not need to ensure ordering wrt another memory |
264 | access. Also see comments at ENQUEUE_MUTEX. */ |
265 | THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, |
266 | NULL); |
267 | return EDEADLK; |
268 | } |
269 | |
270 | if (kind == PTHREAD_MUTEX_ROBUST_RECURSIVE_NP) |
271 | { |
272 | /* We do not need to ensure ordering wrt another memory |
273 | access. */ |
274 | THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, |
275 | NULL); |
276 | |
277 | /* Just bump the counter. */ |
278 | if (__glibc_unlikely (mutex->__data.__count + 1 == 0)) |
279 | /* Overflow of the counter. */ |
280 | return EAGAIN; |
281 | |
282 | ++mutex->__data.__count; |
283 | |
284 | return 0; |
285 | } |
286 | } |
287 | |
288 | /* We cannot acquire the mutex nor has its owner died. Thus, try |
289 | to block using futexes. Set FUTEX_WAITERS if necessary so that |
290 | other threads are aware that there are potentially threads |
291 | blocked on the futex. Restart if oldval changed in the |
292 | meantime. */ |
293 | if ((oldval & FUTEX_WAITERS) == 0) |
294 | { |
295 | if (atomic_compare_and_exchange_bool_acq (&mutex->__data.__lock, |
296 | oldval | FUTEX_WAITERS, |
297 | oldval) |
298 | != 0) |
299 | { |
300 | oldval = mutex->__data.__lock; |
301 | continue; |
302 | } |
303 | oldval |= FUTEX_WAITERS; |
304 | } |
305 | |
306 | /* It is now possible that we share the FUTEX_WAITERS flag with |
307 | another thread; therefore, update assume_other_futex_waiters so |
308 | that we do not forget about this when handling other cases |
309 | above and thus do not cause lost wake-ups. */ |
310 | assume_other_futex_waiters |= FUTEX_WAITERS; |
311 | |
312 | /* Block using the futex and reload current lock value. */ |
313 | lll_futex_wait (&mutex->__data.__lock, oldval, |
314 | PTHREAD_ROBUST_MUTEX_PSHARED (mutex)); |
315 | oldval = mutex->__data.__lock; |
316 | } |
317 | |
318 | /* We have acquired the mutex; check if it is still consistent. */ |
319 | if (__builtin_expect (mutex->__data.__owner |
320 | == PTHREAD_MUTEX_NOTRECOVERABLE, 0)) |
321 | { |
322 | /* This mutex is now not recoverable. */ |
323 | mutex->__data.__count = 0; |
324 | int private = PTHREAD_ROBUST_MUTEX_PSHARED (mutex); |
325 | lll_unlock (mutex->__data.__lock, private); |
326 | /* FIXME This violates the mutex destruction requirements. See |
327 | __pthread_mutex_unlock_full. */ |
328 | THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); |
329 | return ENOTRECOVERABLE; |
330 | } |
331 | |
332 | mutex->__data.__count = 1; |
333 | /* We must not enqueue the mutex before we have acquired it. |
334 | Also see comments at ENQUEUE_MUTEX. */ |
335 | __asm ("" ::: "memory" ); |
336 | ENQUEUE_MUTEX (mutex); |
337 | /* We need to clear op_pending after we enqueue the mutex. */ |
338 | __asm ("" ::: "memory" ); |
339 | THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); |
340 | break; |
341 | |
342 | /* The PI support requires the Linux futex system call. If that's not |
343 | available, pthread_mutex_init should never have allowed the type to |
344 | be set. So it will get the default case for an invalid type. */ |
345 | #ifdef __NR_futex |
346 | case PTHREAD_MUTEX_PI_RECURSIVE_NP: |
347 | case PTHREAD_MUTEX_PI_ERRORCHECK_NP: |
348 | case PTHREAD_MUTEX_PI_NORMAL_NP: |
349 | case PTHREAD_MUTEX_PI_ADAPTIVE_NP: |
350 | case PTHREAD_MUTEX_PI_ROBUST_RECURSIVE_NP: |
351 | case PTHREAD_MUTEX_PI_ROBUST_ERRORCHECK_NP: |
352 | case PTHREAD_MUTEX_PI_ROBUST_NORMAL_NP: |
353 | case PTHREAD_MUTEX_PI_ROBUST_ADAPTIVE_NP: |
354 | { |
355 | int kind = mutex->__data.__kind & PTHREAD_MUTEX_KIND_MASK_NP; |
356 | int robust = mutex->__data.__kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP; |
357 | |
358 | if (robust) |
359 | { |
360 | /* Note: robust PI futexes are signaled by setting bit 0. */ |
361 | THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, |
362 | (void *) (((uintptr_t) &mutex->__data.__list.__next) |
363 | | 1)); |
364 | /* We need to set op_pending before starting the operation. Also |
365 | see comments at ENQUEUE_MUTEX. */ |
366 | __asm ("" ::: "memory" ); |
367 | } |
368 | |
369 | oldval = mutex->__data.__lock; |
370 | |
371 | /* Check whether we already hold the mutex. */ |
372 | if (__glibc_unlikely ((oldval & FUTEX_TID_MASK) == id)) |
373 | { |
374 | if (kind == PTHREAD_MUTEX_ERRORCHECK_NP) |
375 | { |
376 | /* We do not need to ensure ordering wrt another memory |
377 | access. */ |
378 | THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); |
379 | return EDEADLK; |
380 | } |
381 | |
382 | if (kind == PTHREAD_MUTEX_RECURSIVE_NP) |
383 | { |
384 | /* We do not need to ensure ordering wrt another memory |
385 | access. */ |
386 | THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); |
387 | |
388 | /* Just bump the counter. */ |
389 | if (__glibc_unlikely (mutex->__data.__count + 1 == 0)) |
390 | /* Overflow of the counter. */ |
391 | return EAGAIN; |
392 | |
393 | ++mutex->__data.__count; |
394 | |
395 | return 0; |
396 | } |
397 | } |
398 | |
399 | int newval = id; |
400 | # ifdef NO_INCR |
401 | newval |= FUTEX_WAITERS; |
402 | # endif |
403 | oldval = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, |
404 | newval, 0); |
405 | |
406 | if (oldval != 0) |
407 | { |
408 | /* The mutex is locked. The kernel will now take care of |
409 | everything. */ |
410 | int private = (robust |
411 | ? PTHREAD_ROBUST_MUTEX_PSHARED (mutex) |
412 | : PTHREAD_MUTEX_PSHARED (mutex)); |
413 | INTERNAL_SYSCALL_DECL (__err); |
414 | int e = INTERNAL_SYSCALL (futex, __err, 4, &mutex->__data.__lock, |
415 | __lll_private_flag (FUTEX_LOCK_PI, |
416 | private), 1, 0); |
417 | |
418 | if (INTERNAL_SYSCALL_ERROR_P (e, __err) |
419 | && (INTERNAL_SYSCALL_ERRNO (e, __err) == ESRCH |
420 | || INTERNAL_SYSCALL_ERRNO (e, __err) == EDEADLK)) |
421 | { |
422 | assert (INTERNAL_SYSCALL_ERRNO (e, __err) != EDEADLK |
423 | || (kind != PTHREAD_MUTEX_ERRORCHECK_NP |
424 | && kind != PTHREAD_MUTEX_RECURSIVE_NP)); |
425 | /* ESRCH can happen only for non-robust PI mutexes where |
426 | the owner of the lock died. */ |
427 | assert (INTERNAL_SYSCALL_ERRNO (e, __err) != ESRCH || !robust); |
428 | |
429 | /* Delay the thread indefinitely. */ |
430 | while (1) |
431 | pause_not_cancel (); |
432 | } |
433 | |
434 | oldval = mutex->__data.__lock; |
435 | |
436 | assert (robust || (oldval & FUTEX_OWNER_DIED) == 0); |
437 | } |
438 | |
439 | if (__glibc_unlikely (oldval & FUTEX_OWNER_DIED)) |
440 | { |
441 | atomic_and (&mutex->__data.__lock, ~FUTEX_OWNER_DIED); |
442 | |
443 | /* We got the mutex. */ |
444 | mutex->__data.__count = 1; |
445 | /* But it is inconsistent unless marked otherwise. */ |
446 | mutex->__data.__owner = PTHREAD_MUTEX_INCONSISTENT; |
447 | |
448 | /* We must not enqueue the mutex before we have acquired it. |
449 | Also see comments at ENQUEUE_MUTEX. */ |
450 | __asm ("" ::: "memory" ); |
451 | ENQUEUE_MUTEX_PI (mutex); |
452 | /* We need to clear op_pending after we enqueue the mutex. */ |
453 | __asm ("" ::: "memory" ); |
454 | THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); |
455 | |
456 | /* Note that we deliberately exit here. If we fall |
457 | through to the end of the function __nusers would be |
458 | incremented which is not correct because the old owner |
459 | has to be discounted. If we are not supposed to |
460 | increment __nusers we actually have to decrement it here. */ |
461 | # ifdef NO_INCR |
462 | --mutex->__data.__nusers; |
463 | # endif |
464 | |
465 | return EOWNERDEAD; |
466 | } |
467 | |
468 | if (robust |
469 | && __builtin_expect (mutex->__data.__owner |
470 | == PTHREAD_MUTEX_NOTRECOVERABLE, 0)) |
471 | { |
472 | /* This mutex is now not recoverable. */ |
473 | mutex->__data.__count = 0; |
474 | |
475 | INTERNAL_SYSCALL_DECL (__err); |
476 | INTERNAL_SYSCALL (futex, __err, 4, &mutex->__data.__lock, |
477 | __lll_private_flag (FUTEX_UNLOCK_PI, |
478 | PTHREAD_ROBUST_MUTEX_PSHARED (mutex)), |
479 | 0, 0); |
480 | |
481 | /* To the kernel, this will be visible after the kernel has |
482 | acquired the mutex in the syscall. */ |
483 | THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); |
484 | return ENOTRECOVERABLE; |
485 | } |
486 | |
487 | mutex->__data.__count = 1; |
488 | if (robust) |
489 | { |
490 | /* We must not enqueue the mutex before we have acquired it. |
491 | Also see comments at ENQUEUE_MUTEX. */ |
492 | __asm ("" ::: "memory" ); |
493 | ENQUEUE_MUTEX_PI (mutex); |
494 | /* We need to clear op_pending after we enqueue the mutex. */ |
495 | __asm ("" ::: "memory" ); |
496 | THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); |
497 | } |
498 | } |
499 | break; |
500 | #endif /* __NR_futex. */ |
501 | |
502 | case PTHREAD_MUTEX_PP_RECURSIVE_NP: |
503 | case PTHREAD_MUTEX_PP_ERRORCHECK_NP: |
504 | case PTHREAD_MUTEX_PP_NORMAL_NP: |
505 | case PTHREAD_MUTEX_PP_ADAPTIVE_NP: |
506 | { |
507 | int kind = mutex->__data.__kind & PTHREAD_MUTEX_KIND_MASK_NP; |
508 | |
509 | oldval = mutex->__data.__lock; |
510 | |
511 | /* Check whether we already hold the mutex. */ |
512 | if (mutex->__data.__owner == id) |
513 | { |
514 | if (kind == PTHREAD_MUTEX_ERRORCHECK_NP) |
515 | return EDEADLK; |
516 | |
517 | if (kind == PTHREAD_MUTEX_RECURSIVE_NP) |
518 | { |
519 | /* Just bump the counter. */ |
520 | if (__glibc_unlikely (mutex->__data.__count + 1 == 0)) |
521 | /* Overflow of the counter. */ |
522 | return EAGAIN; |
523 | |
524 | ++mutex->__data.__count; |
525 | |
526 | return 0; |
527 | } |
528 | } |
529 | |
530 | int oldprio = -1, ceilval; |
531 | do |
532 | { |
533 | int ceiling = (oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) |
534 | >> PTHREAD_MUTEX_PRIO_CEILING_SHIFT; |
535 | |
536 | if (__pthread_current_priority () > ceiling) |
537 | { |
538 | if (oldprio != -1) |
539 | __pthread_tpp_change_priority (oldprio, -1); |
540 | return EINVAL; |
541 | } |
542 | |
543 | int retval = __pthread_tpp_change_priority (oldprio, ceiling); |
544 | if (retval) |
545 | return retval; |
546 | |
547 | ceilval = ceiling << PTHREAD_MUTEX_PRIO_CEILING_SHIFT; |
548 | oldprio = ceiling; |
549 | |
550 | oldval |
551 | = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, |
552 | #ifdef NO_INCR |
553 | ceilval | 2, |
554 | #else |
555 | ceilval | 1, |
556 | #endif |
557 | ceilval); |
558 | |
559 | if (oldval == ceilval) |
560 | break; |
561 | |
562 | do |
563 | { |
564 | oldval |
565 | = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, |
566 | ceilval | 2, |
567 | ceilval | 1); |
568 | |
569 | if ((oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) != ceilval) |
570 | break; |
571 | |
572 | if (oldval != ceilval) |
573 | lll_futex_wait (&mutex->__data.__lock, ceilval | 2, |
574 | PTHREAD_MUTEX_PSHARED (mutex)); |
575 | } |
576 | while (atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, |
577 | ceilval | 2, ceilval) |
578 | != ceilval); |
579 | } |
580 | while ((oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) != ceilval); |
581 | |
582 | assert (mutex->__data.__owner == 0); |
583 | mutex->__data.__count = 1; |
584 | } |
585 | break; |
586 | |
587 | default: |
588 | /* Correct code cannot set any other type. */ |
589 | return EINVAL; |
590 | } |
591 | |
592 | /* Record the ownership. */ |
593 | mutex->__data.__owner = id; |
594 | #ifndef NO_INCR |
595 | ++mutex->__data.__nusers; |
596 | #endif |
597 | |
598 | LIBC_PROBE (mutex_acquired, 1, mutex); |
599 | |
600 | return 0; |
601 | } |
602 | #ifndef __pthread_mutex_lock |
603 | strong_alias (__pthread_mutex_lock, pthread_mutex_lock) |
604 | hidden_def (__pthread_mutex_lock) |
605 | #endif |
606 | |
607 | |
608 | #ifdef NO_INCR |
609 | void |
610 | internal_function |
611 | __pthread_mutex_cond_lock_adjust (pthread_mutex_t *mutex) |
612 | { |
613 | assert ((mutex->__data.__kind & PTHREAD_MUTEX_PRIO_INHERIT_NP) != 0); |
614 | assert ((mutex->__data.__kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP) == 0); |
615 | assert ((mutex->__data.__kind & PTHREAD_MUTEX_PSHARED_BIT) == 0); |
616 | |
617 | /* Record the ownership. */ |
618 | pid_t id = THREAD_GETMEM (THREAD_SELF, tid); |
619 | mutex->__data.__owner = id; |
620 | |
621 | if (mutex->__data.__kind == PTHREAD_MUTEX_PI_RECURSIVE_NP) |
622 | ++mutex->__data.__count; |
623 | } |
624 | #endif |
625 | |