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Fix race of chopstx_cond_wait.

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NIIBE Yutaka
2013-05-29 08:28:05 +09:00
parent 5552a9590d
commit b5cdd769ee
2 changed files with 57 additions and 30 deletions
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6
ChangeLog
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@@ -1,3 +1,9 @@
2013-05-29 Niibe Yutaka <gniibe@fsij.org>
* chopstx.c (chx_mutex_unlock, chopstx_exit): New.
(chopstx_mutex_unlock): Use chx_mutex_unlock.
(chopstx_cond_wait): Fix race condition.
2013-05-28 Niibe Yutaka <gniibe@fsij.org>
* chopstx.c (chopstx_intr_wait): Rename from chopstx_wait_intr.

81
chopstx.c
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@@ -700,6 +700,39 @@ chx_exit (void *retval)
/* never comes here. */
for (;;);
}
static chopstx_prio_t
chx_mutex_unlock (chopstx_mutex_t *mutex)
{
struct chx_thread *tp;
chopstx_prio_t prio = 0;
mutex->owner = NULL;
running->mutex_list = mutex->list;
mutex->list = NULL;
tp = ll_pop (&mutex->q);
if (tp)
{
uint16_t newprio = running->prio_orig;
chopstx_mutex_t *m;
chx_ready_enqueue (tp);
/* Examine mutexes we hold, and determine new priority for running. */
for (m = running->mutex_list; m; m = m->list)
if (!ll_empty (&m->q) && m->q.next->prio > newprio)
newprio = m->q.next->prio;
/* Then, assign it. */
running->prio = newprio;
if (prio < tp->prio)
prio = tp->prio;
}
return prio;
}
void
chopstx_attr_init (chopstx_attr_t *attr)
@@ -851,37 +884,15 @@ chopstx_mutex_lock (chopstx_mutex_t *mutex)
void
chopstx_mutex_unlock (chopstx_mutex_t *mutex)
{
struct chx_thread *tp;
int yield = 0;
chopstx_prio_t prio;
asm volatile ("cpsid i" : : : "memory");
chx_LOCK (&mutex->lock);
mutex->owner = NULL;
running->mutex_list = mutex->list;
mutex->list = NULL;
tp = ll_pop (&mutex->q);
if (tp)
{
uint16_t newprio = running->prio_orig;
chopstx_mutex_t *m;
chx_ready_enqueue (tp);
/* Examine mutexes we hold, and determine new priority for running. */
for (m = running->mutex_list; m; m = m->list)
if (!ll_empty (&m->q) && m->q.next->prio > newprio)
newprio = m->q.next->prio;
/* Then, assign it. */
running->prio = newprio;
if (tp->prio > running->prio)
yield = 1;
}
prio = chx_mutex_unlock (mutex);
chx_UNLOCK (&mutex->lock);
asm volatile ("cpsie i" : : : "memory");
if (yield)
if (prio > running->prio)
chx_yield ();
}
@@ -898,10 +909,15 @@ chopstx_cond_wait (chopstx_cond_t *cond, chopstx_mutex_t *mutex)
{
struct chx_thread *tp = running;
if (mutex)
chopstx_mutex_unlock (mutex);
asm volatile ("cpsid i" : : : "memory");
if (mutex)
{
chx_LOCK (&mutex->lock);
chx_mutex_unlock (mutex);
chx_UNLOCK (&mutex->lock);
}
chx_LOCK (&cond->lock);
ll_prio_enqueue (tp, &cond->q);
tp->state = THREAD_WAIT_CND;
@@ -1048,7 +1064,12 @@ chopstx_exit (void *retval)
for (m = running->mutex_list; m; m = m_next)
{
m_next = m->list;
chopstx_mutex_unlock (m);
asm volatile ("cpsid i" : : : "memory");
chx_LOCK (&m->lock);
chx_mutex_unlock (m);
chx_UNLOCK (&m->lock);
asm volatile ("cpsie i" : : : "memory");
}
chopstx_release_irq_thread (running);