[PATCH 14/14] xen: events: propagate irq allocation failure instead of panicking

From: Ian Campbell
Date: Thu Mar 10 2011 - 11:09:24 EST


Running out of IRQs need not be fatal to the machine as a whole.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
---
drivers/xen/events.c | 22 ++++++++++++++--------
1 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 7c36689..3566c00 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -406,7 +406,7 @@ static void xen_irq_init(unsigned irq)
list_add_tail(&info->list, &xen_irq_list_head);
}

-static int xen_allocate_irq_dynamic(void)
+static int __must_check xen_allocate_irq_dynamic(void)
{
int first = 0;
int irq;
@@ -425,15 +425,12 @@ static int xen_allocate_irq_dynamic(void)

irq = irq_alloc_desc_from(first, -1);

- if (irq < 0)
- panic("No available IRQ to bind to: increase nr_irqs!\n");
-
xen_irq_init(irq);

return irq;
}

-static int xen_allocate_irq_gsi(unsigned gsi)
+static int __must_check xen_allocate_irq_gsi(unsigned gsi)
{
int irq;

@@ -452,9 +449,6 @@ static int xen_allocate_irq_gsi(unsigned gsi)
else
irq = irq_alloc_desc_at(gsi, -1);

- if (irq < 0)
- panic("Unable to allocate to IRQ%d (%d)\n", gsi, irq);
-
xen_irq_init(irq);

return irq;
@@ -640,6 +634,8 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi,
}

irq = xen_allocate_irq_gsi(gsi);
+ if (irq < 0)
+ goto out;

set_irq_chip_and_handler_name(irq, &xen_pirq_chip,
handle_level_irq, name);
@@ -771,6 +767,8 @@ int bind_evtchn_to_irq(unsigned int evtchn)

if (irq == -1) {
irq = xen_allocate_irq_dynamic();
+ if (irq == -1)
+ goto out;

set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
handle_fasteoi_irq, "event");
@@ -778,6 +776,7 @@ int bind_evtchn_to_irq(unsigned int evtchn)
xen_irq_info_evtchn_init(irq, evtchn);
}

+out:
spin_unlock(&irq_mapping_update_lock);

return irq;
@@ -829,6 +828,8 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu)

if (irq == -1) {
irq = xen_allocate_irq_dynamic();
+ if (irq == -1)
+ goto out;

set_irq_chip_and_handler_name(irq, &xen_percpu_chip,
handle_percpu_irq, "virq");
@@ -845,6 +846,7 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
bind_evtchn_to_cpu(evtchn, cpu);
}

+out:
spin_unlock(&irq_mapping_update_lock);

return irq;
@@ -897,6 +899,8 @@ int bind_evtchn_to_irqhandler(unsigned int evtchn,
int retval;

irq = bind_evtchn_to_irq(evtchn);
+ if (irq < 0)
+ return irq;
retval = request_irq(irq, handler, irqflags, devname, dev_id);
if (retval != 0) {
unbind_from_irq(irq);
@@ -915,6 +919,8 @@ int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
int retval;

irq = bind_virq_to_irq(virq, cpu);
+ if (irq < 0)
+ return irq;
retval = request_irq(irq, handler, irqflags, devname, dev_id);
if (retval != 0) {
unbind_from_irq(irq);
--
1.5.6.5

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