diff options
Diffstat (limited to 'kernel/locking')
| -rw-r--r-- | kernel/locking/lockdep.c | 177 | ||||
| -rw-r--r-- | kernel/locking/rtmutex.c | 87 | ||||
| -rw-r--r-- | kernel/locking/rtmutex_common.h | 3 |
3 files changed, 146 insertions, 121 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 456614136f1a..8acfbf773e06 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -3157,6 +3157,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, hlock->waittime_stamp = 0; hlock->holdtime_stamp = lockstat_clock(); #endif + hlock->pin_count = 0; if (check && !mark_irqflags(curr, hlock)) return 0; @@ -3260,26 +3261,6 @@ print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock, return 0; } -/* - * Common debugging checks for both nested and non-nested unlock: - */ -static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, - unsigned long ip) -{ - if (unlikely(!debug_locks)) - return 0; - /* - * Lockdep should run with IRQs disabled, recursion, head-ache, etc.. - */ - if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) - return 0; - - if (curr->lockdep_depth <= 0) - return print_unlock_imbalance_bug(curr, lock, ip); - - return 1; -} - static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) { if (hlock->instance == lock) @@ -3376,31 +3357,35 @@ found_it: } /* - * Remove the lock to the list of currently held locks in a - * potentially non-nested (out of order) manner. This is a - * relatively rare operation, as all the unlock APIs default - * to nested mode (which uses lock_release()): + * Remove the lock to the list of currently held locks - this gets + * called on mutex_unlock()/spin_unlock*() (or on a failed + * mutex_lock_interruptible()). + * + * @nested is an hysterical artifact, needs a tree wide cleanup. */ static int -lock_release_non_nested(struct task_struct *curr, - struct lockdep_map *lock, unsigned long ip) +__lock_release(struct lockdep_map *lock, int nested, unsigned long ip) { + struct task_struct *curr = current; struct held_lock *hlock, *prev_hlock; unsigned int depth; int i; - /* - * Check whether the lock exists in the current stack - * of held locks: - */ + if (unlikely(!debug_locks)) + return 0; + depth = curr->lockdep_depth; /* * So we're all set to release this lock.. wait what lock? We don't * own any locks, you've been drinking again? */ - if (DEBUG_LOCKS_WARN_ON(!depth)) - return 0; + if (DEBUG_LOCKS_WARN_ON(depth <= 0)) + return print_unlock_imbalance_bug(curr, lock, ip); + /* + * Check whether the lock exists in the current stack + * of held locks: + */ prev_hlock = NULL; for (i = depth-1; i >= 0; i--) { hlock = curr->held_locks + i; @@ -3419,6 +3404,8 @@ found_it: if (hlock->instance == lock) lock_release_holdtime(hlock); + WARN(hlock->pin_count, "releasing a pinned lock\n"); + if (hlock->references) { hlock->references--; if (hlock->references) { @@ -3456,91 +3443,66 @@ found_it: */ if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) return 0; + return 1; } -/* - * Remove the lock to the list of currently held locks - this gets - * called on mutex_unlock()/spin_unlock*() (or on a failed - * mutex_lock_interruptible()). This is done for unlocks that nest - * perfectly. (i.e. the current top of the lock-stack is unlocked) - */ -static int lock_release_nested(struct task_struct *curr, - struct lockdep_map *lock, unsigned long ip) +static int __lock_is_held(struct lockdep_map *lock) { - struct held_lock *hlock; - unsigned int depth; - - /* - * Pop off the top of the lock stack: - */ - depth = curr->lockdep_depth - 1; - hlock = curr->held_locks + depth; - - /* - * Is the unlock non-nested: - */ - if (hlock->instance != lock || hlock->references) - return lock_release_non_nested(curr, lock, ip); - curr->lockdep_depth--; - - /* - * No more locks, but somehow we've got hash left over, who left it? - */ - if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) - return 0; + struct task_struct *curr = current; + int i; - curr->curr_chain_key = hlock->prev_chain_key; + for (i = 0; i < curr->lockdep_depth; i++) { + struct held_lock *hlock = curr->held_locks + i; - lock_release_holdtime(hlock); + if (match_held_lock(hlock, lock)) + return 1; + } -#ifdef CONFIG_DEBUG_LOCKDEP - hlock->prev_chain_key = 0; - hlock->class_idx = 0; - hlock->acquire_ip = 0; - hlock->irq_context = 0; -#endif - return 1; + return 0; } -/* - * Remove the lock to the list of currently held locks - this gets - * called on mutex_unlock()/spin_unlock*() (or on a failed - * mutex_lock_interruptible()). This is done for unlocks that nest - * perfectly. (i.e. the current top of the lock-stack is unlocked) - */ -static void -__lock_release(struct lockdep_map *lock, int nested, unsigned long ip) +static void __lock_pin_lock(struct lockdep_map *lock) { struct task_struct *curr = current; + int i; - if (!check_unlock(curr, lock, ip)) + if (unlikely(!debug_locks)) return; - if (nested) { - if (!lock_release_nested(curr, lock, ip)) - return; - } else { - if (!lock_release_non_nested(curr, lock, ip)) + for (i = 0; i < curr->lockdep_depth; i++) { + struct held_lock *hlock = curr->held_locks + i; + + if (match_held_lock(hlock, lock)) { + hlock->pin_count++; return; + } } - check_chain_key(curr); + WARN(1, "pinning an unheld lock\n"); } -static int __lock_is_held(struct lockdep_map *lock) +static void __lock_unpin_lock(struct lockdep_map *lock) { struct task_struct *curr = current; int i; + if (unlikely(!debug_locks)) + return; + for (i = 0; i < curr->lockdep_depth; i++) { struct held_lock *hlock = curr->held_locks + i; - if (match_held_lock(hlock, lock)) - return 1; + if (match_held_lock(hlock, lock)) { + if (WARN(!hlock->pin_count, "unpinning an unpinned lock\n")) + return; + + hlock->pin_count--; + return; + } } - return 0; + WARN(1, "unpinning an unheld lock\n"); } /* @@ -3639,7 +3601,8 @@ void lock_release(struct lockdep_map *lock, int nested, check_flags(flags); current->lockdep_recursion = 1; trace_lock_release(lock, ip); - __lock_release(lock, nested, ip); + if (__lock_release(lock, nested, ip)) + check_chain_key(current); current->lockdep_recursion = 0; raw_local_irq_restore(flags); } @@ -3665,6 +3628,40 @@ int lock_is_held(struct lockdep_map *lock) } EXPORT_SYMBOL_GPL(lock_is_held); +void lock_pin_lock(struct lockdep_map *lock) +{ + unsigned long flags; + + if (unlikely(current->lockdep_recursion)) + return; + + raw_local_irq_save(flags); + check_flags(flags); + + current->lockdep_recursion = 1; + __lock_pin_lock(lock); + current->lockdep_recursion = 0; + raw_local_irq_restore(flags); +} +EXPORT_SYMBOL_GPL(lock_pin_lock); + +void lock_unpin_lock(struct lockdep_map *lock) +{ + unsigned long flags; + + if (unlikely(current->lockdep_recursion)) + return; + + raw_local_irq_save(flags); + check_flags(flags); + + current->lockdep_recursion = 1; + __lock_unpin_lock(lock); + current->lockdep_recursion = 0; + raw_local_irq_restore(flags); +} +EXPORT_SYMBOL_GPL(lock_unpin_lock); + void lockdep_set_current_reclaim_state(gfp_t gfp_mask) { current->lockdep_reclaim_gfp = gfp_mask; diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 36573e96a477..5674b073473c 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -300,7 +300,7 @@ static void __rt_mutex_adjust_prio(struct task_struct *task) * of task. We do not use the spin_xx_mutex() variants here as we are * outside of the debug path.) */ -static void rt_mutex_adjust_prio(struct task_struct *task) +void rt_mutex_adjust_prio(struct task_struct *task) { unsigned long flags; @@ -624,7 +624,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task, */ prerequeue_top_waiter = rt_mutex_top_waiter(lock); - /* [7] Requeue the waiter in the lock waiter list. */ + /* [7] Requeue the waiter in the lock waiter tree. */ rt_mutex_dequeue(lock, waiter); waiter->prio = task->prio; rt_mutex_enqueue(lock, waiter); @@ -662,7 +662,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task, /* * The waiter became the new top (highest priority) * waiter on the lock. Replace the previous top waiter - * in the owner tasks pi waiters list with this waiter + * in the owner tasks pi waiters tree with this waiter * and adjust the priority of the owner. */ rt_mutex_dequeue_pi(task, prerequeue_top_waiter); @@ -673,7 +673,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task, /* * The waiter was the top waiter on the lock, but is * no longer the top prority waiter. Replace waiter in - * the owner tasks pi waiters list with the new top + * the owner tasks pi waiters tree with the new top * (highest priority) waiter and adjust the priority * of the owner. * The new top waiter is stored in @waiter so that @@ -747,7 +747,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task, * * @lock: The lock to be acquired. * @task: The task which wants to acquire the lock - * @waiter: The waiter that is queued to the lock's wait list if the + * @waiter: The waiter that is queued to the lock's wait tree if the * callsite called task_blocked_on_lock(), otherwise NULL */ static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task, @@ -782,7 +782,7 @@ static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task, /* * If @waiter != NULL, @task has already enqueued the waiter - * into @lock waiter list. If @waiter == NULL then this is a + * into @lock waiter tree. If @waiter == NULL then this is a * trylock attempt. */ if (waiter) { @@ -795,7 +795,7 @@ static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task, /* * We can acquire the lock. Remove the waiter from the - * lock waiters list. + * lock waiters tree. */ rt_mutex_dequeue(lock, waiter); @@ -827,7 +827,7 @@ static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task, * No waiters. Take the lock without the * pi_lock dance.@task->pi_blocked_on is NULL * and we have no waiters to enqueue in @task - * pi waiters list. + * pi waiters tree. */ goto takeit; } @@ -844,7 +844,7 @@ static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task, /* * Finish the lock acquisition. @task is the new owner. If * other waiters exist we have to insert the highest priority - * waiter into @task->pi_waiters list. + * waiter into @task->pi_waiters tree. */ if (rt_mutex_has_waiters(lock)) rt_mutex_enqueue_pi(task, rt_mutex_top_waiter(lock)); @@ -955,14 +955,13 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock, } /* - * Wake up the next waiter on the lock. - * - * Remove the top waiter from the current tasks pi waiter list and - * wake it up. + * Remove the top waiter from the current tasks pi waiter tree and + * queue it up. * * Called with lock->wait_lock held. */ -static void wakeup_next_waiter(struct rt_mutex *lock) +static void mark_wakeup_next_waiter(struct wake_q_head *wake_q, + struct rt_mutex *lock) { struct rt_mutex_waiter *waiter; unsigned long flags; @@ -991,12 +990,7 @@ static void wakeup_next_waiter(struct rt_mutex *lock) raw_spin_unlock_irqrestore(¤t->pi_lock, flags); - /* - * It's safe to dereference waiter as it cannot go away as - * long as we hold lock->wait_lock. The waiter task needs to - * acquire it in order to dequeue the waiter. - */ - wake_up_process(waiter->task); + wake_q_add(wake_q, waiter->task); } /* @@ -1250,10 +1244,11 @@ static inline int rt_mutex_slowtrylock(struct rt_mutex *lock) } /* - * Slow path to release a rt-mutex: + * Slow path to release a rt-mutex. + * Return whether the current task needs to undo a potential priority boosting. */ -static void __sched -rt_mutex_slowunlock(struct rt_mutex *lock) +static bool __sched rt_mutex_slowunlock(struct rt_mutex *lock, + struct wake_q_head *wake_q) { raw_spin_lock(&lock->wait_lock); @@ -1295,7 +1290,7 @@ rt_mutex_slowunlock(struct rt_mutex *lock) while (!rt_mutex_has_waiters(lock)) { /* Drops lock->wait_lock ! */ if (unlock_rt_mutex_safe(lock) == true) - return; + return false; /* Relock the rtmutex and try again */ raw_spin_lock(&lock->wait_lock); } @@ -1303,13 +1298,15 @@ rt_mutex_slowunlock(struct rt_mutex *lock) /* * The wakeup next waiter path does not suffer from the above * race. See the comments there. + * + * Queue the next waiter for wakeup once we release the wait_lock. */ - wakeup_next_waiter(lock); + mark_wakeup_next_waiter(wake_q, lock); raw_spin_unlock(&lock->wait_lock); - /* Undo pi boosting if necessary: */ - rt_mutex_adjust_prio(current); + /* check PI boosting */ + return true; } /* @@ -1360,12 +1357,23 @@ rt_mutex_fasttrylock(struct rt_mutex *lock, static inline void rt_mutex_fastunlock(struct rt_mutex *lock, - void (*slowfn)(struct rt_mutex *lock)) + bool (*slowfn)(struct rt_mutex *lock, + struct wake_q_head *wqh)) { - if (likely(rt_mutex_cmpxchg(lock, current, NULL))) + WAKE_Q(wake_q); + + if (likely(rt_mutex_cmpxchg(lock, current, NULL))) { rt_mutex_deadlock_account_unlock(current); - else - slowfn(lock); + + } else { + bool deboost = slowfn(lock, &wake_q); + + wake_up_q(&wake_q); + + /* Undo pi boosting if necessary: */ + if (deboost) + rt_mutex_adjust_prio(current); + } } /** @@ -1467,6 +1475,23 @@ void __sched rt_mutex_unlock(struct rt_mutex *lock) EXPORT_SYMBOL_GPL(rt_mutex_unlock); /** + * rt_mutex_futex_unlock - Futex variant of rt_mutex_unlock + * @lock: the rt_mutex to be unlocked + * + * Returns: true/false indicating whether priority adjustment is + * required or not. + */ +bool __sched rt_mutex_futex_unlock(struct rt_mutex *lock, + struct wake_q_head *wqh) +{ + if (likely(rt_mutex_cmpxchg(lock, current, NULL))) { + rt_mutex_deadlock_account_unlock(current); + return false; + } + return rt_mutex_slowunlock(lock, wqh); +} + +/** * rt_mutex_destroy - mark a mutex unusable * @lock: the mutex to be destroyed * diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h index 855212501407..7844f8f0e639 100644 --- a/kernel/locking/rtmutex_common.h +++ b/kernel/locking/rtmutex_common.h @@ -131,6 +131,9 @@ extern int rt_mutex_finish_proxy_lock(struct rt_mutex *lock, struct hrtimer_sleeper *to, struct rt_mutex_waiter *waiter); extern int rt_mutex_timed_futex_lock(struct rt_mutex *l, struct hrtimer_sleeper *to); +extern bool rt_mutex_futex_unlock(struct rt_mutex *lock, + struct wake_q_head *wqh); +extern void rt_mutex_adjust_prio(struct task_struct *task); #ifdef CONFIG_DEBUG_RT_MUTEXES # include "rtmutex-debug.h" |
