diff options
Diffstat (limited to 'kernel/irq/manage.c')
| -rw-r--r-- | kernel/irq/manage.c | 54 |
1 files changed, 48 insertions, 6 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 01f8a9519e6..2301de19ac7 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -617,8 +617,11 @@ static int irq_wait_for_interrupt(struct irqaction *action) * handler finished. unmask if the interrupt has not been disabled and * is marked MASKED. */ -static void irq_finalize_oneshot(unsigned int irq, struct irq_desc *desc) +static void irq_finalize_oneshot(struct irq_desc *desc, + struct irqaction *action, bool force) { + if (!(desc->istate & IRQS_ONESHOT)) + return; again: chip_bus_lock(desc); raw_spin_lock_irq(&desc->lock); @@ -631,6 +634,11 @@ again: * on the other CPU. If we unmask the irq line then the * interrupt can come in again and masks the line, leaves due * to IRQS_INPROGRESS and the irq line is masked forever. + * + * This also serializes the state of shared oneshot handlers + * versus "desc->threads_onehsot |= action->thread_mask;" in + * irq_wake_thread(). See the comment there which explains the + * serialization. */ if (unlikely(desc->istate & IRQS_INPROGRESS)) { raw_spin_unlock_irq(&desc->lock); @@ -639,11 +647,23 @@ again: goto again; } - if (!(desc->istate & IRQS_DISABLED) && (desc->istate & IRQS_MASKED)) { + /* + * Now check again, whether the thread should run. Otherwise + * we would clear the threads_oneshot bit of this thread which + * was just set. + */ + if (!force && test_bit(IRQTF_RUNTHREAD, &action->thread_flags)) + goto out_unlock; + + desc->threads_oneshot &= ~action->thread_mask; + + if (!desc->threads_oneshot && !(desc->istate & IRQS_DISABLED) && + (desc->istate & IRQS_MASKED)) { irq_compat_clr_masked(desc); desc->istate &= ~IRQS_MASKED; desc->irq_data.chip->irq_unmask(&desc->irq_data); } +out_unlock: raw_spin_unlock_irq(&desc->lock); chip_bus_sync_unlock(desc); } @@ -691,7 +711,7 @@ static int irq_thread(void *data) }; struct irqaction *action = data; struct irq_desc *desc = irq_to_desc(action->irq); - int wake, oneshot = desc->istate & IRQS_ONESHOT; + int wake; sched_setscheduler(current, SCHED_FIFO, ¶m); current->irqaction = action; @@ -719,8 +739,7 @@ static int irq_thread(void *data) action->thread_fn(action->irq, action->dev_id); - if (oneshot) - irq_finalize_oneshot(action->irq, desc); + irq_finalize_oneshot(desc, action, false); } wake = atomic_dec_and_test(&desc->threads_active); @@ -729,6 +748,9 @@ static int irq_thread(void *data) wake_up(&desc->wait_for_threads); } + /* Prevent a stale desc->threads_oneshot */ + irq_finalize_oneshot(desc, action, true); + /* * Clear irqaction. Otherwise exit_irq_thread() would make * fuzz about an active irq thread going into nirvana. @@ -743,6 +765,7 @@ static int irq_thread(void *data) void exit_irq_thread(void) { struct task_struct *tsk = current; + struct irq_desc *desc; if (!tsk->irqaction) return; @@ -751,6 +774,14 @@ void exit_irq_thread(void) "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n", tsk->comm ? tsk->comm : "", tsk->pid, tsk->irqaction->irq); + desc = irq_to_desc(tsk->irqaction->irq); + + /* + * Prevent a stale desc->threads_oneshot. Must be called + * before setting the IRQTF_DIED flag. + */ + irq_finalize_oneshot(desc, tsk->irqaction, true); + /* * Set the THREAD DIED flag to prevent further wakeups of the * soon to be gone threaded handler. @@ -767,7 +798,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) { struct irqaction *old, **old_ptr; const char *old_name = NULL; - unsigned long flags; + unsigned long flags, thread_mask = 0; int ret, nested, shared = 0; cpumask_var_t mask; @@ -865,12 +896,23 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) /* add new interrupt at end of irq queue */ do { + thread_mask |= old->thread_mask; old_ptr = &old->next; old = *old_ptr; } while (old); shared = 1; } + /* + * Setup the thread mask for this irqaction. Unlikely to have + * 32 resp 64 irqs sharing one line, but who knows. + */ + if (new->flags & IRQF_ONESHOT && thread_mask == ~0UL) { + ret = -EBUSY; + goto out_mask; + } + new->thread_mask = 1 << ffz(thread_mask); + if (!shared) { irq_chip_set_defaults(desc->irq_data.chip); |