[PATCH 4.9 23/27] genirq/ipi: Fixup checks against nr_cpu_ids

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alexey Dobriyan <adobriyan@gmail.com>

commit 8fbbe2d7cc478d1544f41f2271787c993c23a4f6 upstream.

Valid CPU ids are [0, nr_cpu_ids-1] inclusive.

Fixes: 3b8e29a82dd1 ("genirq: Implement ipi_send_mask/single()")
Fixes: f9bce791ae2a ("genirq: Add a new function to get IPI reverse mapping")
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170819095751.GB27864@avx2
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 kernel/irq/ipi.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/kernel/irq/ipi.c
+++ b/kernel/irq/ipi.c
@@ -165,7 +165,7 @@ irq_hw_number_t ipi_get_hwirq(unsigned i
 	struct irq_data *data = irq_get_irq_data(irq);
 	struct cpumask *ipimask = data ? irq_data_get_affinity_mask(data) : NULL;
 
-	if (!data || !ipimask || cpu > nr_cpu_ids)
+	if (!data || !ipimask || cpu >= nr_cpu_ids)
 		return INVALID_HWIRQ;
 
 	if (!cpumask_test_cpu(cpu, ipimask))
@@ -195,7 +195,7 @@ static int ipi_send_verify(struct irq_ch
 	if (!chip->ipi_send_single && !chip->ipi_send_mask)
 		return -EINVAL;
 
-	if (cpu > nr_cpu_ids)
+	if (cpu >= nr_cpu_ids)
 		return -EINVAL;
 
 	if (dest) {