parisc: Validate online cpus in irq_set_affinity() callbacks

The [user space] interface does not filter out offline cpus. It merily
guarantees that the mask contains at least one online cpu.

So the selector in the irq chip implementation needs to make sure to
pick only an online cpu because otherwise:

     Offline Core 1
     Set affinity to 0xe (is valid due to online mask 0xd)
     cpumask_first will pick core 1, which is offline

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: James E.J. Bottomley <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
Link: http://lkml.kernel.org/r/20140304203100.859489993@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/parisc/kernel/irq.c b/arch/parisc/kernel/irq.c
index 8ceac4785609279079e321384ec8e6b59a2b4cc7..cfe056fe7f5c636f45f642950a01e0ce4cb7e536 100644 (file)
--- a/arch/parisc/kernel/irq.c
+++ b/arch/parisc/kernel/irq.c
@@ -117,7 +117,7 @@ int cpu_check_affinity(struct irq_data *d, const struct cpumask *dest)
                return -EINVAL;
 
        /* whatever mask they set, we just allow one CPU */
-       cpu_dest = first_cpu(*dest);
+       cpu_dest = cpumask_first_and(dest, cpu_online_mask);
 
        return cpu_dest;
 }