[PATCH] powerpc: xive: ensure active irqd when setting affinity

[Benjamin Herrenschmidt]

Ensure irqd is active before attempting to set affinity. This should
make the set affinity code more robust. For instance, this prevents
these messages seen on a 4.12 based kernel when taking cpus offline:

   [  123.053037264,3] XIVE[ IC 00  ] ISN 2 lead to invalid IVE !
   [   77.885859] xive: Error -6 reconfiguring irq 17
   [   77.885862] IRQ17: set affinity failed(-6).

The underlying problem with taking cpus offline was fixed in 4.13-rc1 by:

   commit 91f26cb4cd3c ("genirq/cpuhotplug: Do not migrated shutdown irqs")

Signed-off-by: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
---
 arch/powerpc/sysdev/xive/common.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/powerpc/sysdev/xive/common.c b/arch/powerpc/sysdev/xive/common.c
index 6595462..2708d42 100644
--- a/arch/powerpc/sysdev/xive/common.c
+++ b/arch/powerpc/sysdev/xive/common.c
@@ -672,6 +672,10 @@ static int xive_irq_set_affinity(struct irq_data *d,
 	if (cpumask_any_and(cpumask, cpu_online_mask) >= nr_cpu_ids)
 		return -EINVAL;
 
+	/* Don't do anything if the interrupt isn't started */
+	if (!irqd_is_started(d))
+		return IRQ_SET_MASK_OK;
+
 	/*
 	 * If existing target is already in the new mask, and is
 	 * online then do nothing.
-- 
1.8.3.1