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Commit | Line | Data |
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23f78d4a IM |
1 | /* |
2 | * RT-Mutexes: simple blocking mutual exclusion locks with PI support | |
3 | * | |
4 | * started by Ingo Molnar and Thomas Gleixner. | |
5 | * | |
6 | * Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> | |
7 | * Copyright (C) 2005-2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com> | |
8 | * Copyright (C) 2005 Kihon Technologies Inc., Steven Rostedt | |
9 | * Copyright (C) 2006 Esben Nielsen | |
d07fe82c SR |
10 | * |
11 | * See Documentation/rt-mutex-design.txt for details. | |
23f78d4a IM |
12 | */ |
13 | #include <linux/spinlock.h> | |
9984de1a | 14 | #include <linux/export.h> |
23f78d4a | 15 | #include <linux/sched.h> |
8bd75c77 | 16 | #include <linux/sched/rt.h> |
23f78d4a IM |
17 | #include <linux/timer.h> |
18 | ||
19 | #include "rtmutex_common.h" | |
20 | ||
23f78d4a IM |
21 | /* |
22 | * lock->owner state tracking: | |
23 | * | |
8161239a LJ |
24 | * lock->owner holds the task_struct pointer of the owner. Bit 0 |
25 | * is used to keep track of the "lock has waiters" state. | |
23f78d4a | 26 | * |
8161239a LJ |
27 | * owner bit0 |
28 | * NULL 0 lock is free (fast acquire possible) | |
29 | * NULL 1 lock is free and has waiters and the top waiter | |
30 | * is going to take the lock* | |
31 | * taskpointer 0 lock is held (fast release possible) | |
32 | * taskpointer 1 lock is held and has waiters** | |
23f78d4a IM |
33 | * |
34 | * The fast atomic compare exchange based acquire and release is only | |
8161239a LJ |
35 | * possible when bit 0 of lock->owner is 0. |
36 | * | |
37 | * (*) It also can be a transitional state when grabbing the lock | |
38 | * with ->wait_lock is held. To prevent any fast path cmpxchg to the lock, | |
39 | * we need to set the bit0 before looking at the lock, and the owner may be | |
40 | * NULL in this small time, hence this can be a transitional state. | |
23f78d4a | 41 | * |
8161239a LJ |
42 | * (**) There is a small time when bit 0 is set but there are no |
43 | * waiters. This can happen when grabbing the lock in the slow path. | |
44 | * To prevent a cmpxchg of the owner releasing the lock, we need to | |
45 | * set this bit before looking at the lock. | |
23f78d4a IM |
46 | */ |
47 | ||
bd197234 | 48 | static void |
8161239a | 49 | rt_mutex_set_owner(struct rt_mutex *lock, struct task_struct *owner) |
23f78d4a | 50 | { |
8161239a | 51 | unsigned long val = (unsigned long)owner; |
23f78d4a IM |
52 | |
53 | if (rt_mutex_has_waiters(lock)) | |
54 | val |= RT_MUTEX_HAS_WAITERS; | |
55 | ||
56 | lock->owner = (struct task_struct *)val; | |
57 | } | |
58 | ||
59 | static inline void clear_rt_mutex_waiters(struct rt_mutex *lock) | |
60 | { | |
61 | lock->owner = (struct task_struct *) | |
62 | ((unsigned long)lock->owner & ~RT_MUTEX_HAS_WAITERS); | |
63 | } | |
64 | ||
65 | static void fixup_rt_mutex_waiters(struct rt_mutex *lock) | |
66 | { | |
67 | if (!rt_mutex_has_waiters(lock)) | |
68 | clear_rt_mutex_waiters(lock); | |
69 | } | |
70 | ||
bd197234 TG |
71 | /* |
72 | * We can speed up the acquire/release, if the architecture | |
73 | * supports cmpxchg and if there's no debugging state to be set up | |
74 | */ | |
75 | #if defined(__HAVE_ARCH_CMPXCHG) && !defined(CONFIG_DEBUG_RT_MUTEXES) | |
76 | # define rt_mutex_cmpxchg(l,c,n) (cmpxchg(&l->owner, c, n) == c) | |
77 | static inline void mark_rt_mutex_waiters(struct rt_mutex *lock) | |
78 | { | |
79 | unsigned long owner, *p = (unsigned long *) &lock->owner; | |
80 | ||
81 | do { | |
82 | owner = *p; | |
83 | } while (cmpxchg(p, owner, owner | RT_MUTEX_HAS_WAITERS) != owner); | |
84 | } | |
85 | #else | |
86 | # define rt_mutex_cmpxchg(l,c,n) (0) | |
87 | static inline void mark_rt_mutex_waiters(struct rt_mutex *lock) | |
88 | { | |
89 | lock->owner = (struct task_struct *) | |
90 | ((unsigned long)lock->owner | RT_MUTEX_HAS_WAITERS); | |
91 | } | |
92 | #endif | |
93 | ||
23f78d4a IM |
94 | /* |
95 | * Calculate task priority from the waiter list priority | |
96 | * | |
97 | * Return task->normal_prio when the waiter list is empty or when | |
98 | * the waiter is not allowed to do priority boosting | |
99 | */ | |
100 | int rt_mutex_getprio(struct task_struct *task) | |
101 | { | |
102 | if (likely(!task_has_pi_waiters(task))) | |
103 | return task->normal_prio; | |
104 | ||
105 | return min(task_top_pi_waiter(task)->pi_list_entry.prio, | |
106 | task->normal_prio); | |
107 | } | |
108 | ||
109 | /* | |
110 | * Adjust the priority of a task, after its pi_waiters got modified. | |
111 | * | |
112 | * This can be both boosting and unboosting. task->pi_lock must be held. | |
113 | */ | |
bd197234 | 114 | static void __rt_mutex_adjust_prio(struct task_struct *task) |
23f78d4a IM |
115 | { |
116 | int prio = rt_mutex_getprio(task); | |
117 | ||
118 | if (task->prio != prio) | |
119 | rt_mutex_setprio(task, prio); | |
120 | } | |
121 | ||
122 | /* | |
123 | * Adjust task priority (undo boosting). Called from the exit path of | |
124 | * rt_mutex_slowunlock() and rt_mutex_slowlock(). | |
125 | * | |
126 | * (Note: We do this outside of the protection of lock->wait_lock to | |
127 | * allow the lock to be taken while or before we readjust the priority | |
128 | * of task. We do not use the spin_xx_mutex() variants here as we are | |
129 | * outside of the debug path.) | |
130 | */ | |
131 | static void rt_mutex_adjust_prio(struct task_struct *task) | |
132 | { | |
133 | unsigned long flags; | |
134 | ||
1d615482 | 135 | raw_spin_lock_irqsave(&task->pi_lock, flags); |
23f78d4a | 136 | __rt_mutex_adjust_prio(task); |
1d615482 | 137 | raw_spin_unlock_irqrestore(&task->pi_lock, flags); |
23f78d4a IM |
138 | } |
139 | ||
140 | /* | |
141 | * Max number of times we'll walk the boosting chain: | |
142 | */ | |
143 | int max_lock_depth = 1024; | |
144 | ||
145 | /* | |
146 | * Adjust the priority chain. Also used for deadlock detection. | |
147 | * Decreases task's usage by one - may thus free the task. | |
0c106173 JL |
148 | * |
149 | * @task: the task owning the mutex (owner) for which a chain walk is probably | |
150 | * needed | |
151 | * @deadlock_detect: do we have to carry out deadlock detection? | |
152 | * @orig_lock: the mutex (can be NULL if we are walking the chain to recheck | |
153 | * things for a task that has just got its priority adjusted, and | |
154 | * is waiting on a mutex) | |
155 | * @orig_waiter: rt_mutex_waiter struct for the task that has just donated | |
156 | * its priority to the mutex owner (can be NULL in the case | |
157 | * depicted above or if the top waiter is gone away and we are | |
158 | * actually deboosting the owner) | |
159 | * @top_task: the current top waiter | |
160 | * | |
23f78d4a IM |
161 | * Returns 0 or -EDEADLK. |
162 | */ | |
bd197234 TG |
163 | static int rt_mutex_adjust_prio_chain(struct task_struct *task, |
164 | int deadlock_detect, | |
165 | struct rt_mutex *orig_lock, | |
166 | struct rt_mutex_waiter *orig_waiter, | |
167 | struct task_struct *top_task) | |
23f78d4a IM |
168 | { |
169 | struct rt_mutex *lock; | |
170 | struct rt_mutex_waiter *waiter, *top_waiter = orig_waiter; | |
171 | int detect_deadlock, ret = 0, depth = 0; | |
172 | unsigned long flags; | |
173 | ||
174 | detect_deadlock = debug_rt_mutex_detect_deadlock(orig_waiter, | |
175 | deadlock_detect); | |
176 | ||
177 | /* | |
178 | * The (de)boosting is a step by step approach with a lot of | |
179 | * pitfalls. We want this to be preemptible and we want hold a | |
180 | * maximum of two locks per step. So we have to check | |
181 | * carefully whether things change under us. | |
182 | */ | |
183 | again: | |
184 | if (++depth > max_lock_depth) { | |
185 | static int prev_max; | |
186 | ||
187 | /* | |
188 | * Print this only once. If the admin changes the limit, | |
189 | * print a new message when reaching the limit again. | |
190 | */ | |
191 | if (prev_max != max_lock_depth) { | |
192 | prev_max = max_lock_depth; | |
193 | printk(KERN_WARNING "Maximum lock depth %d reached " | |
194 | "task: %s (%d)\n", max_lock_depth, | |
ba25f9dc | 195 | top_task->comm, task_pid_nr(top_task)); |
23f78d4a IM |
196 | } |
197 | put_task_struct(task); | |
198 | ||
199 | return deadlock_detect ? -EDEADLK : 0; | |
200 | } | |
201 | retry: | |
202 | /* | |
203 | * Task can not go away as we did a get_task() before ! | |
204 | */ | |
1d615482 | 205 | raw_spin_lock_irqsave(&task->pi_lock, flags); |
23f78d4a IM |
206 | |
207 | waiter = task->pi_blocked_on; | |
208 | /* | |
209 | * Check whether the end of the boosting chain has been | |
210 | * reached or the state of the chain has changed while we | |
211 | * dropped the locks. | |
212 | */ | |
8161239a | 213 | if (!waiter) |
23f78d4a IM |
214 | goto out_unlock_pi; |
215 | ||
1a539a87 TG |
216 | /* |
217 | * Check the orig_waiter state. After we dropped the locks, | |
8161239a | 218 | * the previous owner of the lock might have released the lock. |
1a539a87 | 219 | */ |
8161239a | 220 | if (orig_waiter && !rt_mutex_owner(orig_lock)) |
1a539a87 TG |
221 | goto out_unlock_pi; |
222 | ||
223 | /* | |
224 | * Drop out, when the task has no waiters. Note, | |
225 | * top_waiter can be NULL, when we are in the deboosting | |
226 | * mode! | |
227 | */ | |
23f78d4a IM |
228 | if (top_waiter && (!task_has_pi_waiters(task) || |
229 | top_waiter != task_top_pi_waiter(task))) | |
230 | goto out_unlock_pi; | |
231 | ||
232 | /* | |
233 | * When deadlock detection is off then we check, if further | |
234 | * priority adjustment is necessary. | |
235 | */ | |
236 | if (!detect_deadlock && waiter->list_entry.prio == task->prio) | |
237 | goto out_unlock_pi; | |
238 | ||
239 | lock = waiter->lock; | |
d209d74d | 240 | if (!raw_spin_trylock(&lock->wait_lock)) { |
1d615482 | 241 | raw_spin_unlock_irqrestore(&task->pi_lock, flags); |
23f78d4a IM |
242 | cpu_relax(); |
243 | goto retry; | |
244 | } | |
245 | ||
246 | /* Deadlock detection */ | |
95e02ca9 | 247 | if (lock == orig_lock || rt_mutex_owner(lock) == top_task) { |
23f78d4a | 248 | debug_rt_mutex_deadlock(deadlock_detect, orig_waiter, lock); |
d209d74d | 249 | raw_spin_unlock(&lock->wait_lock); |
23f78d4a IM |
250 | ret = deadlock_detect ? -EDEADLK : 0; |
251 | goto out_unlock_pi; | |
252 | } | |
253 | ||
254 | top_waiter = rt_mutex_top_waiter(lock); | |
255 | ||
256 | /* Requeue the waiter */ | |
257 | plist_del(&waiter->list_entry, &lock->wait_list); | |
258 | waiter->list_entry.prio = task->prio; | |
259 | plist_add(&waiter->list_entry, &lock->wait_list); | |
260 | ||
261 | /* Release the task */ | |
1d615482 | 262 | raw_spin_unlock_irqrestore(&task->pi_lock, flags); |
8161239a LJ |
263 | if (!rt_mutex_owner(lock)) { |
264 | /* | |
265 | * If the requeue above changed the top waiter, then we need | |
266 | * to wake the new top waiter up to try to get the lock. | |
267 | */ | |
268 | ||
269 | if (top_waiter != rt_mutex_top_waiter(lock)) | |
270 | wake_up_process(rt_mutex_top_waiter(lock)->task); | |
271 | raw_spin_unlock(&lock->wait_lock); | |
272 | goto out_put_task; | |
273 | } | |
23f78d4a IM |
274 | put_task_struct(task); |
275 | ||
276 | /* Grab the next task */ | |
277 | task = rt_mutex_owner(lock); | |
db630637 | 278 | get_task_struct(task); |
1d615482 | 279 | raw_spin_lock_irqsave(&task->pi_lock, flags); |
23f78d4a IM |
280 | |
281 | if (waiter == rt_mutex_top_waiter(lock)) { | |
282 | /* Boost the owner */ | |
283 | plist_del(&top_waiter->pi_list_entry, &task->pi_waiters); | |
284 | waiter->pi_list_entry.prio = waiter->list_entry.prio; | |
285 | plist_add(&waiter->pi_list_entry, &task->pi_waiters); | |
286 | __rt_mutex_adjust_prio(task); | |
287 | ||
288 | } else if (top_waiter == waiter) { | |
289 | /* Deboost the owner */ | |
290 | plist_del(&waiter->pi_list_entry, &task->pi_waiters); | |
291 | waiter = rt_mutex_top_waiter(lock); | |
292 | waiter->pi_list_entry.prio = waiter->list_entry.prio; | |
293 | plist_add(&waiter->pi_list_entry, &task->pi_waiters); | |
294 | __rt_mutex_adjust_prio(task); | |
295 | } | |
296 | ||
1d615482 | 297 | raw_spin_unlock_irqrestore(&task->pi_lock, flags); |
23f78d4a IM |
298 | |
299 | top_waiter = rt_mutex_top_waiter(lock); | |
d209d74d | 300 | raw_spin_unlock(&lock->wait_lock); |
23f78d4a IM |
301 | |
302 | if (!detect_deadlock && waiter != top_waiter) | |
303 | goto out_put_task; | |
304 | ||
305 | goto again; | |
306 | ||
307 | out_unlock_pi: | |
1d615482 | 308 | raw_spin_unlock_irqrestore(&task->pi_lock, flags); |
23f78d4a IM |
309 | out_put_task: |
310 | put_task_struct(task); | |
36c8b586 | 311 | |
23f78d4a IM |
312 | return ret; |
313 | } | |
314 | ||
23f78d4a IM |
315 | /* |
316 | * Try to take an rt-mutex | |
317 | * | |
23f78d4a | 318 | * Must be called with lock->wait_lock held. |
8161239a LJ |
319 | * |
320 | * @lock: the lock to be acquired. | |
321 | * @task: the task which wants to acquire the lock | |
322 | * @waiter: the waiter that is queued to the lock's wait list. (could be NULL) | |
23f78d4a | 323 | */ |
8161239a LJ |
324 | static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task, |
325 | struct rt_mutex_waiter *waiter) | |
23f78d4a IM |
326 | { |
327 | /* | |
328 | * We have to be careful here if the atomic speedups are | |
329 | * enabled, such that, when | |
330 | * - no other waiter is on the lock | |
331 | * - the lock has been released since we did the cmpxchg | |
332 | * the lock can be released or taken while we are doing the | |
333 | * checks and marking the lock with RT_MUTEX_HAS_WAITERS. | |
334 | * | |
335 | * The atomic acquire/release aware variant of | |
336 | * mark_rt_mutex_waiters uses a cmpxchg loop. After setting | |
337 | * the WAITERS bit, the atomic release / acquire can not | |
338 | * happen anymore and lock->wait_lock protects us from the | |
339 | * non-atomic case. | |
340 | * | |
341 | * Note, that this might set lock->owner = | |
342 | * RT_MUTEX_HAS_WAITERS in the case the lock is not contended | |
343 | * any more. This is fixed up when we take the ownership. | |
344 | * This is the transitional state explained at the top of this file. | |
345 | */ | |
346 | mark_rt_mutex_waiters(lock); | |
347 | ||
8161239a | 348 | if (rt_mutex_owner(lock)) |
23f78d4a IM |
349 | return 0; |
350 | ||
8161239a LJ |
351 | /* |
352 | * It will get the lock because of one of these conditions: | |
353 | * 1) there is no waiter | |
354 | * 2) higher priority than waiters | |
355 | * 3) it is top waiter | |
356 | */ | |
357 | if (rt_mutex_has_waiters(lock)) { | |
358 | if (task->prio >= rt_mutex_top_waiter(lock)->list_entry.prio) { | |
359 | if (!waiter || waiter != rt_mutex_top_waiter(lock)) | |
360 | return 0; | |
361 | } | |
362 | } | |
363 | ||
364 | if (waiter || rt_mutex_has_waiters(lock)) { | |
365 | unsigned long flags; | |
366 | struct rt_mutex_waiter *top; | |
367 | ||
368 | raw_spin_lock_irqsave(&task->pi_lock, flags); | |
369 | ||
370 | /* remove the queued waiter. */ | |
371 | if (waiter) { | |
372 | plist_del(&waiter->list_entry, &lock->wait_list); | |
373 | task->pi_blocked_on = NULL; | |
374 | } | |
375 | ||
376 | /* | |
377 | * We have to enqueue the top waiter(if it exists) into | |
378 | * task->pi_waiters list. | |
379 | */ | |
380 | if (rt_mutex_has_waiters(lock)) { | |
381 | top = rt_mutex_top_waiter(lock); | |
382 | top->pi_list_entry.prio = top->list_entry.prio; | |
383 | plist_add(&top->pi_list_entry, &task->pi_waiters); | |
384 | } | |
385 | raw_spin_unlock_irqrestore(&task->pi_lock, flags); | |
386 | } | |
387 | ||
23f78d4a | 388 | /* We got the lock. */ |
9a11b49a | 389 | debug_rt_mutex_lock(lock); |
23f78d4a | 390 | |
8161239a | 391 | rt_mutex_set_owner(lock, task); |
23f78d4a | 392 | |
8161239a | 393 | rt_mutex_deadlock_account_lock(lock, task); |
23f78d4a IM |
394 | |
395 | return 1; | |
396 | } | |
397 | ||
398 | /* | |
399 | * Task blocks on lock. | |
400 | * | |
401 | * Prepare waiter and propagate pi chain | |
402 | * | |
403 | * This must be called with lock->wait_lock held. | |
404 | */ | |
405 | static int task_blocks_on_rt_mutex(struct rt_mutex *lock, | |
406 | struct rt_mutex_waiter *waiter, | |
8dac456a | 407 | struct task_struct *task, |
9a11b49a | 408 | int detect_deadlock) |
23f78d4a | 409 | { |
36c8b586 | 410 | struct task_struct *owner = rt_mutex_owner(lock); |
23f78d4a | 411 | struct rt_mutex_waiter *top_waiter = waiter; |
23f78d4a | 412 | unsigned long flags; |
db630637 | 413 | int chain_walk = 0, res; |
23f78d4a | 414 | |
1d615482 | 415 | raw_spin_lock_irqsave(&task->pi_lock, flags); |
8dac456a DH |
416 | __rt_mutex_adjust_prio(task); |
417 | waiter->task = task; | |
23f78d4a | 418 | waiter->lock = lock; |
8dac456a DH |
419 | plist_node_init(&waiter->list_entry, task->prio); |
420 | plist_node_init(&waiter->pi_list_entry, task->prio); | |
23f78d4a IM |
421 | |
422 | /* Get the top priority waiter on the lock */ | |
423 | if (rt_mutex_has_waiters(lock)) | |
424 | top_waiter = rt_mutex_top_waiter(lock); | |
425 | plist_add(&waiter->list_entry, &lock->wait_list); | |
426 | ||
8dac456a | 427 | task->pi_blocked_on = waiter; |
23f78d4a | 428 | |
1d615482 | 429 | raw_spin_unlock_irqrestore(&task->pi_lock, flags); |
23f78d4a | 430 | |
8161239a LJ |
431 | if (!owner) |
432 | return 0; | |
433 | ||
23f78d4a | 434 | if (waiter == rt_mutex_top_waiter(lock)) { |
1d615482 | 435 | raw_spin_lock_irqsave(&owner->pi_lock, flags); |
23f78d4a IM |
436 | plist_del(&top_waiter->pi_list_entry, &owner->pi_waiters); |
437 | plist_add(&waiter->pi_list_entry, &owner->pi_waiters); | |
438 | ||
439 | __rt_mutex_adjust_prio(owner); | |
db630637 SR |
440 | if (owner->pi_blocked_on) |
441 | chain_walk = 1; | |
1d615482 | 442 | raw_spin_unlock_irqrestore(&owner->pi_lock, flags); |
23f78d4a | 443 | } |
db630637 SR |
444 | else if (debug_rt_mutex_detect_deadlock(waiter, detect_deadlock)) |
445 | chain_walk = 1; | |
446 | ||
447 | if (!chain_walk) | |
23f78d4a IM |
448 | return 0; |
449 | ||
db630637 SR |
450 | /* |
451 | * The owner can't disappear while holding a lock, | |
452 | * so the owner struct is protected by wait_lock. | |
453 | * Gets dropped in rt_mutex_adjust_prio_chain()! | |
454 | */ | |
455 | get_task_struct(owner); | |
456 | ||
d209d74d | 457 | raw_spin_unlock(&lock->wait_lock); |
23f78d4a | 458 | |
95e02ca9 | 459 | res = rt_mutex_adjust_prio_chain(owner, detect_deadlock, lock, waiter, |
8dac456a | 460 | task); |
23f78d4a | 461 | |
d209d74d | 462 | raw_spin_lock(&lock->wait_lock); |
23f78d4a IM |
463 | |
464 | return res; | |
465 | } | |
466 | ||
467 | /* | |
468 | * Wake up the next waiter on the lock. | |
469 | * | |
8161239a | 470 | * Remove the top waiter from the current tasks waiter list and wake it up. |
23f78d4a IM |
471 | * |
472 | * Called with lock->wait_lock held. | |
473 | */ | |
474 | static void wakeup_next_waiter(struct rt_mutex *lock) | |
475 | { | |
476 | struct rt_mutex_waiter *waiter; | |
23f78d4a IM |
477 | unsigned long flags; |
478 | ||
1d615482 | 479 | raw_spin_lock_irqsave(¤t->pi_lock, flags); |
23f78d4a IM |
480 | |
481 | waiter = rt_mutex_top_waiter(lock); | |
23f78d4a IM |
482 | |
483 | /* | |
484 | * Remove it from current->pi_waiters. We do not adjust a | |
485 | * possible priority boost right now. We execute wakeup in the | |
486 | * boosted mode and go back to normal after releasing | |
487 | * lock->wait_lock. | |
488 | */ | |
489 | plist_del(&waiter->pi_list_entry, ¤t->pi_waiters); | |
23f78d4a | 490 | |
8161239a | 491 | rt_mutex_set_owner(lock, NULL); |
23f78d4a | 492 | |
1d615482 | 493 | raw_spin_unlock_irqrestore(¤t->pi_lock, flags); |
23f78d4a | 494 | |
8161239a | 495 | wake_up_process(waiter->task); |
23f78d4a IM |
496 | } |
497 | ||
498 | /* | |
8161239a | 499 | * Remove a waiter from a lock and give up |
23f78d4a | 500 | * |
8161239a LJ |
501 | * Must be called with lock->wait_lock held and |
502 | * have just failed to try_to_take_rt_mutex(). | |
23f78d4a | 503 | */ |
bd197234 TG |
504 | static void remove_waiter(struct rt_mutex *lock, |
505 | struct rt_mutex_waiter *waiter) | |
23f78d4a IM |
506 | { |
507 | int first = (waiter == rt_mutex_top_waiter(lock)); | |
36c8b586 | 508 | struct task_struct *owner = rt_mutex_owner(lock); |
23f78d4a | 509 | unsigned long flags; |
db630637 | 510 | int chain_walk = 0; |
23f78d4a | 511 | |
1d615482 | 512 | raw_spin_lock_irqsave(¤t->pi_lock, flags); |
23f78d4a | 513 | plist_del(&waiter->list_entry, &lock->wait_list); |
23f78d4a | 514 | current->pi_blocked_on = NULL; |
1d615482 | 515 | raw_spin_unlock_irqrestore(¤t->pi_lock, flags); |
23f78d4a | 516 | |
8161239a LJ |
517 | if (!owner) |
518 | return; | |
519 | ||
520 | if (first) { | |
23f78d4a | 521 | |
1d615482 | 522 | raw_spin_lock_irqsave(&owner->pi_lock, flags); |
23f78d4a IM |
523 | |
524 | plist_del(&waiter->pi_list_entry, &owner->pi_waiters); | |
525 | ||
526 | if (rt_mutex_has_waiters(lock)) { | |
527 | struct rt_mutex_waiter *next; | |
528 | ||
529 | next = rt_mutex_top_waiter(lock); | |
530 | plist_add(&next->pi_list_entry, &owner->pi_waiters); | |
531 | } | |
532 | __rt_mutex_adjust_prio(owner); | |
533 | ||
db630637 SR |
534 | if (owner->pi_blocked_on) |
535 | chain_walk = 1; | |
536 | ||
1d615482 | 537 | raw_spin_unlock_irqrestore(&owner->pi_lock, flags); |
23f78d4a IM |
538 | } |
539 | ||
540 | WARN_ON(!plist_node_empty(&waiter->pi_list_entry)); | |
541 | ||
db630637 | 542 | if (!chain_walk) |
23f78d4a IM |
543 | return; |
544 | ||
db630637 SR |
545 | /* gets dropped in rt_mutex_adjust_prio_chain()! */ |
546 | get_task_struct(owner); | |
547 | ||
d209d74d | 548 | raw_spin_unlock(&lock->wait_lock); |
23f78d4a | 549 | |
9a11b49a | 550 | rt_mutex_adjust_prio_chain(owner, 0, lock, NULL, current); |
23f78d4a | 551 | |
d209d74d | 552 | raw_spin_lock(&lock->wait_lock); |
23f78d4a IM |
553 | } |
554 | ||
95e02ca9 TG |
555 | /* |
556 | * Recheck the pi chain, in case we got a priority setting | |
557 | * | |
558 | * Called from sched_setscheduler | |
559 | */ | |
560 | void rt_mutex_adjust_pi(struct task_struct *task) | |
561 | { | |
562 | struct rt_mutex_waiter *waiter; | |
563 | unsigned long flags; | |
564 | ||
1d615482 | 565 | raw_spin_lock_irqsave(&task->pi_lock, flags); |
95e02ca9 TG |
566 | |
567 | waiter = task->pi_blocked_on; | |
568 | if (!waiter || waiter->list_entry.prio == task->prio) { | |
1d615482 | 569 | raw_spin_unlock_irqrestore(&task->pi_lock, flags); |
95e02ca9 TG |
570 | return; |
571 | } | |
572 | ||
1d615482 | 573 | raw_spin_unlock_irqrestore(&task->pi_lock, flags); |
95e02ca9 | 574 | |
db630637 SR |
575 | /* gets dropped in rt_mutex_adjust_prio_chain()! */ |
576 | get_task_struct(task); | |
9a11b49a | 577 | rt_mutex_adjust_prio_chain(task, 0, NULL, NULL, task); |
95e02ca9 TG |
578 | } |
579 | ||
8dac456a DH |
580 | /** |
581 | * __rt_mutex_slowlock() - Perform the wait-wake-try-to-take loop | |
582 | * @lock: the rt_mutex to take | |
583 | * @state: the state the task should block in (TASK_INTERRUPTIBLE | |
584 | * or TASK_UNINTERRUPTIBLE) | |
585 | * @timeout: the pre-initialized and started timer, or NULL for none | |
586 | * @waiter: the pre-initialized rt_mutex_waiter | |
8dac456a DH |
587 | * |
588 | * lock->wait_lock must be held by the caller. | |
23f78d4a IM |
589 | */ |
590 | static int __sched | |
8dac456a DH |
591 | __rt_mutex_slowlock(struct rt_mutex *lock, int state, |
592 | struct hrtimer_sleeper *timeout, | |
8161239a | 593 | struct rt_mutex_waiter *waiter) |
23f78d4a | 594 | { |
23f78d4a IM |
595 | int ret = 0; |
596 | ||
23f78d4a IM |
597 | for (;;) { |
598 | /* Try to acquire the lock: */ | |
8161239a | 599 | if (try_to_take_rt_mutex(lock, current, waiter)) |
23f78d4a IM |
600 | break; |
601 | ||
602 | /* | |
603 | * TASK_INTERRUPTIBLE checks for signals and | |
604 | * timeout. Ignored otherwise. | |
605 | */ | |
606 | if (unlikely(state == TASK_INTERRUPTIBLE)) { | |
607 | /* Signal pending? */ | |
608 | if (signal_pending(current)) | |
609 | ret = -EINTR; | |
610 | if (timeout && !timeout->task) | |
611 | ret = -ETIMEDOUT; | |
612 | if (ret) | |
613 | break; | |
614 | } | |
615 | ||
d209d74d | 616 | raw_spin_unlock(&lock->wait_lock); |
23f78d4a | 617 | |
8dac456a | 618 | debug_rt_mutex_print_deadlock(waiter); |
23f78d4a | 619 | |
8161239a | 620 | schedule_rt_mutex(lock); |
23f78d4a | 621 | |
d209d74d | 622 | raw_spin_lock(&lock->wait_lock); |
23f78d4a IM |
623 | set_current_state(state); |
624 | } | |
625 | ||
8dac456a DH |
626 | return ret; |
627 | } | |
628 | ||
629 | /* | |
630 | * Slow path lock function: | |
631 | */ | |
632 | static int __sched | |
633 | rt_mutex_slowlock(struct rt_mutex *lock, int state, | |
634 | struct hrtimer_sleeper *timeout, | |
635 | int detect_deadlock) | |
636 | { | |
637 | struct rt_mutex_waiter waiter; | |
638 | int ret = 0; | |
639 | ||
640 | debug_rt_mutex_init_waiter(&waiter); | |
8dac456a | 641 | |
d209d74d | 642 | raw_spin_lock(&lock->wait_lock); |
8dac456a DH |
643 | |
644 | /* Try to acquire the lock again: */ | |
8161239a | 645 | if (try_to_take_rt_mutex(lock, current, NULL)) { |
d209d74d | 646 | raw_spin_unlock(&lock->wait_lock); |
8dac456a DH |
647 | return 0; |
648 | } | |
649 | ||
650 | set_current_state(state); | |
651 | ||
652 | /* Setup the timer, when timeout != NULL */ | |
653 | if (unlikely(timeout)) { | |
654 | hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS); | |
655 | if (!hrtimer_active(&timeout->timer)) | |
656 | timeout->task = NULL; | |
657 | } | |
658 | ||
8161239a LJ |
659 | ret = task_blocks_on_rt_mutex(lock, &waiter, current, detect_deadlock); |
660 | ||
661 | if (likely(!ret)) | |
662 | ret = __rt_mutex_slowlock(lock, state, timeout, &waiter); | |
8dac456a | 663 | |
23f78d4a IM |
664 | set_current_state(TASK_RUNNING); |
665 | ||
8161239a | 666 | if (unlikely(ret)) |
9a11b49a | 667 | remove_waiter(lock, &waiter); |
23f78d4a IM |
668 | |
669 | /* | |
670 | * try_to_take_rt_mutex() sets the waiter bit | |
671 | * unconditionally. We might have to fix that up. | |
672 | */ | |
673 | fixup_rt_mutex_waiters(lock); | |
674 | ||
d209d74d | 675 | raw_spin_unlock(&lock->wait_lock); |
23f78d4a IM |
676 | |
677 | /* Remove pending timer: */ | |
678 | if (unlikely(timeout)) | |
679 | hrtimer_cancel(&timeout->timer); | |
680 | ||
23f78d4a IM |
681 | debug_rt_mutex_free_waiter(&waiter); |
682 | ||
683 | return ret; | |
684 | } | |
685 | ||
686 | /* | |
687 | * Slow path try-lock function: | |
688 | */ | |
689 | static inline int | |
9a11b49a | 690 | rt_mutex_slowtrylock(struct rt_mutex *lock) |
23f78d4a IM |
691 | { |
692 | int ret = 0; | |
693 | ||
d209d74d | 694 | raw_spin_lock(&lock->wait_lock); |
23f78d4a IM |
695 | |
696 | if (likely(rt_mutex_owner(lock) != current)) { | |
697 | ||
8161239a | 698 | ret = try_to_take_rt_mutex(lock, current, NULL); |
23f78d4a IM |
699 | /* |
700 | * try_to_take_rt_mutex() sets the lock waiters | |
701 | * bit unconditionally. Clean this up. | |
702 | */ | |
703 | fixup_rt_mutex_waiters(lock); | |
704 | } | |
705 | ||
d209d74d | 706 | raw_spin_unlock(&lock->wait_lock); |
23f78d4a IM |
707 | |
708 | return ret; | |
709 | } | |
710 | ||
711 | /* | |
712 | * Slow path to release a rt-mutex: | |
713 | */ | |
714 | static void __sched | |
715 | rt_mutex_slowunlock(struct rt_mutex *lock) | |
716 | { | |
d209d74d | 717 | raw_spin_lock(&lock->wait_lock); |
23f78d4a IM |
718 | |
719 | debug_rt_mutex_unlock(lock); | |
720 | ||
721 | rt_mutex_deadlock_account_unlock(current); | |
722 | ||
723 | if (!rt_mutex_has_waiters(lock)) { | |
724 | lock->owner = NULL; | |
d209d74d | 725 | raw_spin_unlock(&lock->wait_lock); |
23f78d4a IM |
726 | return; |
727 | } | |
728 | ||
729 | wakeup_next_waiter(lock); | |
730 | ||
d209d74d | 731 | raw_spin_unlock(&lock->wait_lock); |
23f78d4a IM |
732 | |
733 | /* Undo pi boosting if necessary: */ | |
734 | rt_mutex_adjust_prio(current); | |
735 | } | |
736 | ||
737 | /* | |
738 | * debug aware fast / slowpath lock,trylock,unlock | |
739 | * | |
740 | * The atomic acquire/release ops are compiled away, when either the | |
741 | * architecture does not support cmpxchg or when debugging is enabled. | |
742 | */ | |
743 | static inline int | |
744 | rt_mutex_fastlock(struct rt_mutex *lock, int state, | |
745 | int detect_deadlock, | |
746 | int (*slowfn)(struct rt_mutex *lock, int state, | |
747 | struct hrtimer_sleeper *timeout, | |
9a11b49a | 748 | int detect_deadlock)) |
23f78d4a IM |
749 | { |
750 | if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) { | |
751 | rt_mutex_deadlock_account_lock(lock, current); | |
752 | return 0; | |
753 | } else | |
9a11b49a | 754 | return slowfn(lock, state, NULL, detect_deadlock); |
23f78d4a IM |
755 | } |
756 | ||
757 | static inline int | |
758 | rt_mutex_timed_fastlock(struct rt_mutex *lock, int state, | |
759 | struct hrtimer_sleeper *timeout, int detect_deadlock, | |
760 | int (*slowfn)(struct rt_mutex *lock, int state, | |
761 | struct hrtimer_sleeper *timeout, | |
9a11b49a | 762 | int detect_deadlock)) |
23f78d4a IM |
763 | { |
764 | if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) { | |
765 | rt_mutex_deadlock_account_lock(lock, current); | |
766 | return 0; | |
767 | } else | |
9a11b49a | 768 | return slowfn(lock, state, timeout, detect_deadlock); |
23f78d4a IM |
769 | } |
770 | ||
771 | static inline int | |
772 | rt_mutex_fasttrylock(struct rt_mutex *lock, | |
9a11b49a | 773 | int (*slowfn)(struct rt_mutex *lock)) |
23f78d4a IM |
774 | { |
775 | if (likely(rt_mutex_cmpxchg(lock, NULL, current))) { | |
776 | rt_mutex_deadlock_account_lock(lock, current); | |
777 | return 1; | |
778 | } | |
9a11b49a | 779 | return slowfn(lock); |
23f78d4a IM |
780 | } |
781 | ||
782 | static inline void | |
783 | rt_mutex_fastunlock(struct rt_mutex *lock, | |
784 | void (*slowfn)(struct rt_mutex *lock)) | |
785 | { | |
786 | if (likely(rt_mutex_cmpxchg(lock, current, NULL))) | |
787 | rt_mutex_deadlock_account_unlock(current); | |
788 | else | |
789 | slowfn(lock); | |
790 | } | |
791 | ||
792 | /** | |
793 | * rt_mutex_lock - lock a rt_mutex | |
794 | * | |
795 | * @lock: the rt_mutex to be locked | |
796 | */ | |
797 | void __sched rt_mutex_lock(struct rt_mutex *lock) | |
798 | { | |
799 | might_sleep(); | |
800 | ||
801 | rt_mutex_fastlock(lock, TASK_UNINTERRUPTIBLE, 0, rt_mutex_slowlock); | |
802 | } | |
803 | EXPORT_SYMBOL_GPL(rt_mutex_lock); | |
804 | ||
805 | /** | |
806 | * rt_mutex_lock_interruptible - lock a rt_mutex interruptible | |
807 | * | |
808 | * @lock: the rt_mutex to be locked | |
809 | * @detect_deadlock: deadlock detection on/off | |
810 | * | |
811 | * Returns: | |
812 | * 0 on success | |
813 | * -EINTR when interrupted by a signal | |
814 | * -EDEADLK when the lock would deadlock (when deadlock detection is on) | |
815 | */ | |
816 | int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock, | |
817 | int detect_deadlock) | |
818 | { | |
819 | might_sleep(); | |
820 | ||
821 | return rt_mutex_fastlock(lock, TASK_INTERRUPTIBLE, | |
822 | detect_deadlock, rt_mutex_slowlock); | |
823 | } | |
824 | EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible); | |
825 | ||
826 | /** | |
23b94b96 LH |
827 | * rt_mutex_timed_lock - lock a rt_mutex interruptible |
828 | * the timeout structure is provided | |
829 | * by the caller | |
23f78d4a IM |
830 | * |
831 | * @lock: the rt_mutex to be locked | |
832 | * @timeout: timeout structure or NULL (no timeout) | |
833 | * @detect_deadlock: deadlock detection on/off | |
834 | * | |
835 | * Returns: | |
836 | * 0 on success | |
837 | * -EINTR when interrupted by a signal | |
3ac49a1c | 838 | * -ETIMEDOUT when the timeout expired |
23f78d4a IM |
839 | * -EDEADLK when the lock would deadlock (when deadlock detection is on) |
840 | */ | |
841 | int | |
842 | rt_mutex_timed_lock(struct rt_mutex *lock, struct hrtimer_sleeper *timeout, | |
843 | int detect_deadlock) | |
844 | { | |
845 | might_sleep(); | |
846 | ||
847 | return rt_mutex_timed_fastlock(lock, TASK_INTERRUPTIBLE, timeout, | |
848 | detect_deadlock, rt_mutex_slowlock); | |
849 | } | |
850 | EXPORT_SYMBOL_GPL(rt_mutex_timed_lock); | |
851 | ||
852 | /** | |
853 | * rt_mutex_trylock - try to lock a rt_mutex | |
854 | * | |
855 | * @lock: the rt_mutex to be locked | |
856 | * | |
857 | * Returns 1 on success and 0 on contention | |
858 | */ | |
859 | int __sched rt_mutex_trylock(struct rt_mutex *lock) | |
860 | { | |
861 | return rt_mutex_fasttrylock(lock, rt_mutex_slowtrylock); | |
862 | } | |
863 | EXPORT_SYMBOL_GPL(rt_mutex_trylock); | |
864 | ||
865 | /** | |
866 | * rt_mutex_unlock - unlock a rt_mutex | |
867 | * | |
868 | * @lock: the rt_mutex to be unlocked | |
869 | */ | |
870 | void __sched rt_mutex_unlock(struct rt_mutex *lock) | |
871 | { | |
872 | rt_mutex_fastunlock(lock, rt_mutex_slowunlock); | |
873 | } | |
874 | EXPORT_SYMBOL_GPL(rt_mutex_unlock); | |
875 | ||
23b94b96 | 876 | /** |
23f78d4a IM |
877 | * rt_mutex_destroy - mark a mutex unusable |
878 | * @lock: the mutex to be destroyed | |
879 | * | |
880 | * This function marks the mutex uninitialized, and any subsequent | |
881 | * use of the mutex is forbidden. The mutex must not be locked when | |
882 | * this function is called. | |
883 | */ | |
884 | void rt_mutex_destroy(struct rt_mutex *lock) | |
885 | { | |
886 | WARN_ON(rt_mutex_is_locked(lock)); | |
887 | #ifdef CONFIG_DEBUG_RT_MUTEXES | |
888 | lock->magic = NULL; | |
889 | #endif | |
890 | } | |
891 | ||
892 | EXPORT_SYMBOL_GPL(rt_mutex_destroy); | |
893 | ||
894 | /** | |
895 | * __rt_mutex_init - initialize the rt lock | |
896 | * | |
897 | * @lock: the rt lock to be initialized | |
898 | * | |
899 | * Initialize the rt lock to unlocked state. | |
900 | * | |
901 | * Initializing of a locked rt lock is not allowed | |
902 | */ | |
903 | void __rt_mutex_init(struct rt_mutex *lock, const char *name) | |
904 | { | |
905 | lock->owner = NULL; | |
d209d74d | 906 | raw_spin_lock_init(&lock->wait_lock); |
732375c6 | 907 | plist_head_init(&lock->wait_list); |
23f78d4a IM |
908 | |
909 | debug_rt_mutex_init(lock, name); | |
910 | } | |
911 | EXPORT_SYMBOL_GPL(__rt_mutex_init); | |
0cdbee99 IM |
912 | |
913 | /** | |
914 | * rt_mutex_init_proxy_locked - initialize and lock a rt_mutex on behalf of a | |
915 | * proxy owner | |
916 | * | |
917 | * @lock: the rt_mutex to be locked | |
918 | * @proxy_owner:the task to set as owner | |
919 | * | |
920 | * No locking. Caller has to do serializing itself | |
921 | * Special API call for PI-futex support | |
922 | */ | |
923 | void rt_mutex_init_proxy_locked(struct rt_mutex *lock, | |
924 | struct task_struct *proxy_owner) | |
925 | { | |
926 | __rt_mutex_init(lock, NULL); | |
9a11b49a | 927 | debug_rt_mutex_proxy_lock(lock, proxy_owner); |
8161239a | 928 | rt_mutex_set_owner(lock, proxy_owner); |
0cdbee99 IM |
929 | rt_mutex_deadlock_account_lock(lock, proxy_owner); |
930 | } | |
931 | ||
932 | /** | |
933 | * rt_mutex_proxy_unlock - release a lock on behalf of owner | |
934 | * | |
935 | * @lock: the rt_mutex to be locked | |
936 | * | |
937 | * No locking. Caller has to do serializing itself | |
938 | * Special API call for PI-futex support | |
939 | */ | |
940 | void rt_mutex_proxy_unlock(struct rt_mutex *lock, | |
941 | struct task_struct *proxy_owner) | |
942 | { | |
943 | debug_rt_mutex_proxy_unlock(lock); | |
8161239a | 944 | rt_mutex_set_owner(lock, NULL); |
0cdbee99 IM |
945 | rt_mutex_deadlock_account_unlock(proxy_owner); |
946 | } | |
947 | ||
8dac456a DH |
948 | /** |
949 | * rt_mutex_start_proxy_lock() - Start lock acquisition for another task | |
950 | * @lock: the rt_mutex to take | |
951 | * @waiter: the pre-initialized rt_mutex_waiter | |
952 | * @task: the task to prepare | |
953 | * @detect_deadlock: perform deadlock detection (1) or not (0) | |
954 | * | |
955 | * Returns: | |
956 | * 0 - task blocked on lock | |
957 | * 1 - acquired the lock for task, caller should wake it up | |
958 | * <0 - error | |
959 | * | |
960 | * Special API call for FUTEX_REQUEUE_PI support. | |
961 | */ | |
962 | int rt_mutex_start_proxy_lock(struct rt_mutex *lock, | |
963 | struct rt_mutex_waiter *waiter, | |
964 | struct task_struct *task, int detect_deadlock) | |
965 | { | |
966 | int ret; | |
967 | ||
d209d74d | 968 | raw_spin_lock(&lock->wait_lock); |
8dac456a | 969 | |
8161239a | 970 | if (try_to_take_rt_mutex(lock, task, NULL)) { |
d209d74d | 971 | raw_spin_unlock(&lock->wait_lock); |
8dac456a DH |
972 | return 1; |
973 | } | |
974 | ||
975 | ret = task_blocks_on_rt_mutex(lock, waiter, task, detect_deadlock); | |
976 | ||
8161239a | 977 | if (ret && !rt_mutex_owner(lock)) { |
8dac456a DH |
978 | /* |
979 | * Reset the return value. We might have | |
980 | * returned with -EDEADLK and the owner | |
981 | * released the lock while we were walking the | |
982 | * pi chain. Let the waiter sort it out. | |
983 | */ | |
984 | ret = 0; | |
985 | } | |
8161239a LJ |
986 | |
987 | if (unlikely(ret)) | |
988 | remove_waiter(lock, waiter); | |
989 | ||
d209d74d | 990 | raw_spin_unlock(&lock->wait_lock); |
8dac456a DH |
991 | |
992 | debug_rt_mutex_print_deadlock(waiter); | |
993 | ||
994 | return ret; | |
995 | } | |
996 | ||
0cdbee99 IM |
997 | /** |
998 | * rt_mutex_next_owner - return the next owner of the lock | |
999 | * | |
1000 | * @lock: the rt lock query | |
1001 | * | |
1002 | * Returns the next owner of the lock or NULL | |
1003 | * | |
1004 | * Caller has to serialize against other accessors to the lock | |
1005 | * itself. | |
1006 | * | |
1007 | * Special API call for PI-futex support | |
1008 | */ | |
1009 | struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock) | |
1010 | { | |
1011 | if (!rt_mutex_has_waiters(lock)) | |
1012 | return NULL; | |
1013 | ||
1014 | return rt_mutex_top_waiter(lock)->task; | |
1015 | } | |
8dac456a DH |
1016 | |
1017 | /** | |
1018 | * rt_mutex_finish_proxy_lock() - Complete lock acquisition | |
1019 | * @lock: the rt_mutex we were woken on | |
1020 | * @to: the timeout, null if none. hrtimer should already have | |
1021 | * been started. | |
1022 | * @waiter: the pre-initialized rt_mutex_waiter | |
1023 | * @detect_deadlock: perform deadlock detection (1) or not (0) | |
1024 | * | |
1025 | * Complete the lock acquisition started our behalf by another thread. | |
1026 | * | |
1027 | * Returns: | |
1028 | * 0 - success | |
1029 | * <0 - error, one of -EINTR, -ETIMEDOUT, or -EDEADLK | |
1030 | * | |
1031 | * Special API call for PI-futex requeue support | |
1032 | */ | |
1033 | int rt_mutex_finish_proxy_lock(struct rt_mutex *lock, | |
1034 | struct hrtimer_sleeper *to, | |
1035 | struct rt_mutex_waiter *waiter, | |
1036 | int detect_deadlock) | |
1037 | { | |
1038 | int ret; | |
1039 | ||
d209d74d | 1040 | raw_spin_lock(&lock->wait_lock); |
8dac456a DH |
1041 | |
1042 | set_current_state(TASK_INTERRUPTIBLE); | |
1043 | ||
8161239a | 1044 | ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter); |
8dac456a DH |
1045 | |
1046 | set_current_state(TASK_RUNNING); | |
1047 | ||
8161239a | 1048 | if (unlikely(ret)) |
8dac456a DH |
1049 | remove_waiter(lock, waiter); |
1050 | ||
1051 | /* | |
1052 | * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might | |
1053 | * have to fix that up. | |
1054 | */ | |
1055 | fixup_rt_mutex_waiters(lock); | |
1056 | ||
d209d74d | 1057 | raw_spin_unlock(&lock->wait_lock); |
8dac456a | 1058 | |
8dac456a DH |
1059 | return ret; |
1060 | } |