Changes in kernel/generic/src/synch/condvar.c [497bd656:9d58539] in mainline

File:

• kernel/generic/src/synch/condvar.c (modified) (3 diffs)

kernel/generic/src/synch/condvar.c

@@ -38 +38 @@
 #include <synch/condvar.h>
 #include <synch/mutex.h>
-#include <synch/spinlock.h>
 #include <synch/waitq.h>
 #include <arch.h>
@@ -91 +90 @@
 
         ipl = waitq_sleep_prepare(&cv->wq);
-        /* Unlock only after the waitq is locked so we don't miss a wakeup. */
         mutex_unlock(mtx);
 
@@ -97 +95 @@
         rc = waitq_sleep_timeout_unsafe(&cv->wq, usec, flags);
 
+        mutex_lock(mtx);
         waitq_sleep_finish(&cv->wq, rc, ipl);
-        /* Lock only after releasing the waitq to avoid a possible deadlock. */
-        mutex_lock(mtx);
 
         return rc;
 }
 
-/** Wait for the condition to become true with a locked spinlock.
- * 
- * The function is not aware of irq_spinlock. Therefore do not even
- * try passing irq_spinlock_t to it. Use _condvar_wait_timeout_irq_spinlock()
- * instead.
- *
- * @param cv            Condition variable.
- * @param lock          Locked spinlock.
- * @param usec          Timeout value in microseconds.
- * @param flags         Select mode of operation.
- *
- * For exact description of meaning of possible combinations of usec and flags,
- * see comment for waitq_sleep_timeout().  Note that when
- * SYNCH_FLAGS_NON_BLOCKING is specified here, ESYNCH_WOULD_BLOCK is always
- * returned.
- *
- * @return See comment for waitq_sleep_timeout().
- */
-int _condvar_wait_timeout_spinlock_impl(condvar_t *cv, spinlock_t *lock, 
-        uint32_t usec, int flags)
-{
-        int rc;
-        ipl_t ipl;
-        
-        ipl = waitq_sleep_prepare(&cv->wq);
-
-        /* Unlock only after the waitq is locked so we don't miss a wakeup. */
-        spinlock_unlock(lock);
-
-        cv->wq.missed_wakeups = 0;      /* Enforce blocking. */
-        rc = waitq_sleep_timeout_unsafe(&cv->wq, usec, flags);
-
-        waitq_sleep_finish(&cv->wq, rc, ipl);
-        /* Lock only after releasing the waitq to avoid a possible deadlock. */
-        spinlock_lock(lock);
-        
-        return rc;
-}
-
-/** Wait for the condition to become true with a locked irq spinlock.
- * 
- * @param cv            Condition variable.
- * @param lock          Locked irq spinlock.
- * @param usec          Timeout value in microseconds.
- * @param flags         Select mode of operation.
- *
- * For exact description of meaning of possible combinations of usec and flags,
- * see comment for waitq_sleep_timeout().  Note that when
- * SYNCH_FLAGS_NON_BLOCKING is specified here, ESYNCH_WOULD_BLOCK is always
- * returned.
- *
- * @return See comment for waitq_sleep_timeout().
- */
-int _condvar_wait_timeout_irq_spinlock(condvar_t *cv, irq_spinlock_t *irq_lock, 
-        uint32_t usec, int flags)
-{
-        int rc;
-        /* Save spinlock's state so we can restore it correctly later on. */
-        ipl_t ipl = irq_lock->ipl;
-        bool guard = irq_lock->guard;
-        
-        irq_lock->guard = false;
-        
-        /* 
-         * waitq_prepare() restores interrupts to the current state, 
-         * ie disabled. Therefore, interrupts will remain disabled while 
-         * it spins waiting for a pending timeout handler to complete. 
-         * Although it spins with interrupts disabled there can only
-         * be a pending timeout if we failed to cancel an imminent
-         * timeout (on another cpu) during a wakeup. As a result the 
-         * timeout handler is guaranteed to run (it is most likely already 
-         * running) and there is no danger of a deadlock.
-         */
-        rc = _condvar_wait_timeout_spinlock(cv, &irq_lock->lock, usec, flags);
-        
-        irq_lock->guard = guard;
-        irq_lock->ipl = ipl;
-        
-        return rc;
-}
-
-
 /** @}
  */