Changes in kernel/generic/src/synch/condvar.c [cc106e4:9d58539] in mainline
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kernel/generic/src/synch/condvar.c
rcc106e4 r9d58539 38 38 #include <synch/condvar.h> 39 39 #include <synch/mutex.h> 40 #include <synch/spinlock.h>41 40 #include <synch/waitq.h> 42 41 #include <arch.h> … … 102 101 } 103 102 104 /** Wait for the condition to become true with a locked spinlock.105 *106 * The function is not aware of irq_spinlock. Therefore do not even107 * try passing irq_spinlock_t to it. Use _condvar_wait_timeout_irq_spinlock()108 * instead.109 *110 * @param cv Condition variable.111 * @param lock Locked spinlock.112 * @param usec Timeout value in microseconds.113 * @param flags Select mode of operation.114 *115 * For exact description of meaning of possible combinations of usec and flags,116 * see comment for waitq_sleep_timeout(). Note that when117 * SYNCH_FLAGS_NON_BLOCKING is specified here, ESYNCH_WOULD_BLOCK is always118 * returned.119 *120 * @return See comment for waitq_sleep_timeout().121 */122 int _condvar_wait_timeout_spinlock_impl(condvar_t *cv, spinlock_t *lock,123 uint32_t usec, int flags)124 {125 int rc;126 ipl_t ipl;127 128 ipl = waitq_sleep_prepare(&cv->wq);129 130 spinlock_unlock(lock);131 132 cv->wq.missed_wakeups = 0; /* Enforce blocking. */133 rc = waitq_sleep_timeout_unsafe(&cv->wq, usec, flags);134 135 waitq_sleep_finish(&cv->wq, rc, ipl);136 137 spinlock_lock(lock);138 139 return rc;140 }141 142 /** Wait for the condition to become true with a locked irq spinlock.143 *144 * @param cv Condition variable.145 * @param lock Locked irq spinlock.146 * @param usec Timeout value in microseconds.147 * @param flags Select mode of operation.148 *149 * For exact description of meaning of possible combinations of usec and flags,150 * see comment for waitq_sleep_timeout(). Note that when151 * SYNCH_FLAGS_NON_BLOCKING is specified here, ESYNCH_WOULD_BLOCK is always152 * returned.153 *154 * @return See comment for waitq_sleep_timeout().155 */156 int _condvar_wait_timeout_irq_spinlock(condvar_t *cv, irq_spinlock_t *irq_lock,157 uint32_t usec, int flags)158 {159 int rc;160 /* Save spinlock's state so we can restore it correctly later on. */161 ipl_t ipl = irq_lock->ipl;162 bool guard = irq_lock->guard;163 164 irq_lock->guard = false;165 166 /*167 * waitq_prepare() restores interrupts to the current state,168 * ie disabled. Therefore, interrupts will remain disabled while169 * it spins waiting for a pending timeout handler to complete.170 * Although it spins with interrupts disabled there can only171 * be a pending timeout if we failed to cancel an imminent172 * timeout (on another cpu) during a wakeup. As a result the173 * timeout handler is guaranteed to run (it is most likely already174 * running) and there is no danger of a deadlock.175 */176 rc = _condvar_wait_timeout_spinlock(cv, &irq_lock->lock, usec, flags);177 178 irq_lock->guard = guard;179 irq_lock->ipl = ipl;180 181 return rc;182 }183 184 185 103 /** @} 186 104 */
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