diff options
Diffstat (limited to 'drivers/xen')
| -rw-r--r-- | drivers/xen/events.c | 25 |
1 files changed, 20 insertions, 5 deletions
diff --git a/drivers/xen/events.c b/drivers/xen/events.c index 1e39908d02f9..bab5ac18fe0e 100644 --- a/drivers/xen/events.c +++ b/drivers/xen/events.c @@ -368,8 +368,13 @@ static int find_unbound_irq(void) { struct irq_data *data; int irq, res; + int start = get_nr_hw_irqs(); - for (irq = 0; irq < nr_irqs; irq++) { + if (start == nr_irqs) + goto no_irqs; + + /* nr_irqs is a magic value. Must not use it.*/ + for (irq = nr_irqs-1; irq > start; irq--) { data = irq_get_irq_data(irq); /* only 0->15 have init'd desc; handle irq > 16 */ if (!data) @@ -382,8 +387,8 @@ static int find_unbound_irq(void) return irq; } - if (irq == nr_irqs) - panic("No available IRQ to bind to: increase nr_irqs!\n"); + if (irq == start) + goto no_irqs; res = irq_alloc_desc_at(irq, 0); @@ -391,6 +396,9 @@ static int find_unbound_irq(void) return -1; return irq; + +no_irqs: + panic("No available IRQ to bind to: increase nr_irqs!\n"); } static bool identity_mapped_irq(unsigned irq) @@ -544,8 +552,15 @@ static int find_irq_by_gsi(unsigned gsi) return -1; } -/* - * Allocate a physical irq, along with a vector. We don't assign an +/* xen_allocate_irq might allocate irqs from the top down, as a + * consequence don't assume that the irq number returned has a low value + * or can be used as a pirq number unless you know otherwise. + * + * One notable exception is when xen_allocate_irq is called passing an + * hardware gsi as argument, in that case the irq number returned + * matches the gsi number passed as first argument. + + * Note: We don't assign an * event channel until the irq actually started up. Return an * existing irq if we've already got one for the gsi. */ |