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Subject[patch 4/7] genirq: Add return value to check_irq_resend()
In preparation for an interrupt injection interface which can be used
safely by error injection mechanisms. e.g. PCI-E/ AER, add a return value
to check_irq_resend() so errors can be propagated to the caller.

Split out the software resend code so the ugly #ifdef in check_irq_resend()
goes away and the whole thing becomes readable.

Fix up the caller in debugfs. The caller in irq_startup() does not care
about the return value as this is unconditionally invoked for all
interrupts and the resend is best effort anyway.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/irq/debugfs.c | 3 -
kernel/irq/internals.h | 2 -
kernel/irq/resend.c | 83 ++++++++++++++++++++++++++++---------------------
3 files changed, 51 insertions(+), 37 deletions(-)

--- a/kernel/irq/debugfs.c
+++ b/kernel/irq/debugfs.c
@@ -218,8 +218,7 @@ static ssize_t irq_debug_write(struct fi
err = -EINVAL;
} else {
desc->istate |= IRQS_PENDING;
- check_irq_resend(desc);
- err = 0;
+ err = check_irq_resend(desc);
}

raw_spin_unlock_irqrestore(&desc->lock, flags);
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -108,7 +108,7 @@ irqreturn_t handle_irq_event_percpu(stru
irqreturn_t handle_irq_event(struct irq_desc *desc);

/* Resending of interrupts :*/
-void check_irq_resend(struct irq_desc *desc);
+int check_irq_resend(struct irq_desc *desc);
bool irq_wait_for_poll(struct irq_desc *desc);
void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action);

--- a/kernel/irq/resend.c
+++ b/kernel/irq/resend.c
@@ -47,6 +47,43 @@ static void resend_irqs(unsigned long ar
/* Tasklet to handle resend: */
static DECLARE_TASKLET(resend_tasklet, resend_irqs, 0);

+static int irq_sw_resend(struct irq_desc *desc)
+{
+ unsigned int irq = irq_desc_get_irq(desc);
+
+ /*
+ * Validate whether this interrupt can be safely injected from
+ * non interrupt context
+ */
+ if (handle_enforce_irqctx(&desc->irq_data))
+ return -EINVAL;
+
+ /*
+ * If the interrupt is running in the thread context of the parent
+ * irq we need to be careful, because we cannot trigger it
+ * directly.
+ */
+ if (irq_settings_is_nested_thread(desc)) {
+ /*
+ * If the parent_irq is valid, we retrigger the parent,
+ * otherwise we do nothing.
+ */
+ if (!desc->parent_irq)
+ return -EINVAL;
+ irq = desc->parent_irq;
+ }
+
+ /* Set it pending and activate the softirq: */
+ set_bit(irq, irqs_resend);
+ tasklet_schedule(&resend_tasklet);
+ return 0;
+}
+
+#else
+static int irq_sw_resend(struct irq_desc *desc)
+{
+ return -EINVAL;
+}
#endif

/*
@@ -54,50 +91,28 @@ static DECLARE_TASKLET(resend_tasklet, r
*
* Is called with interrupts disabled and desc->lock held.
*/
-void check_irq_resend(struct irq_desc *desc)
+int check_irq_resend(struct irq_desc *desc)
{
/*
- * We do not resend level type interrupts. Level type
- * interrupts are resent by hardware when they are still
- * active. Clear the pending bit so suspend/resume does not
- * get confused.
+ * We do not resend level type interrupts. Level type interrupts
+ * are resent by hardware when they are still active. Clear the
+ * pending bit so suspend/resume does not get confused.
*/
if (irq_settings_is_level(desc)) {
desc->istate &= ~IRQS_PENDING;
- return;
+ return -EINVAL;
}
+
if (desc->istate & IRQS_REPLAY)
- return;
+ return -EBUSY;
+
if (desc->istate & IRQS_PENDING) {
desc->istate &= ~IRQS_PENDING;
desc->istate |= IRQS_REPLAY;

- if ((!desc->irq_data.chip->irq_retrigger ||
- !desc->irq_data.chip->irq_retrigger(&desc->irq_data)) &&
- !handle_enforce_irqctx(&desc->irq_data)) {
-#ifdef CONFIG_HARDIRQS_SW_RESEND
- unsigned int irq = irq_desc_get_irq(desc);
-
- /*
- * If the interrupt is running in the thread
- * context of the parent irq we need to be
- * careful, because we cannot trigger it
- * directly.
- */
- if (irq_settings_is_nested_thread(desc)) {
- /*
- * If the parent_irq is valid, we
- * retrigger the parent, otherwise we
- * do nothing.
- */
- if (!desc->parent_irq)
- return;
- irq = desc->parent_irq;
- }
- /* Set it pending and activate the softirq: */
- set_bit(irq, irqs_resend);
- tasklet_schedule(&resend_tasklet);
-#endif
- }
+ if (!desc->irq_data.chip->irq_retrigger ||
+ !desc->irq_data.chip->irq_retrigger(&desc->irq_data))
+ return irq_sw_resend(desc);
}
+ return 0;
}
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