[IA64] SN: validate smp_affinity mask on intr redirect

On SN, only allow one bit to be set in the smp_affinty mask when
redirecting an interrupt.  Currently setting multiple bits is allowed, but
only the first bit is used in determining the CPU to redirect to.  This has
caused confusion among some customers.

[akpm@linux-foundation.org: fixes]
Signed-off-by: John Keller <jpk@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/arch/ia64/kernel/irq.c b/arch/ia64/kernel/irq.c
index ce49c85c928f..b4c239685d2e 100644
--- a/arch/ia64/kernel/irq.c
+++ b/arch/ia64/kernel/irq.c
@@ -104,6 +104,17 @@ void set_irq_affinity_info (unsigned int irq, int hwid, int redir)
                 irq_redir[irq] = (char) (redir & 0xff);
         }
 }
+
+bool is_affinity_mask_valid(cpumask_t cpumask)
+{
+        if (ia64_platform_is("sn2")) {
+                /* Only allow one CPU to be specified in the smp_affinity mask */
+                if (cpus_weight(cpumask) != 1)
+                        return false;
+        }
+        return true;
+}
+
 #endif /* CONFIG_SMP */
 
 #ifdef CONFIG_HOTPLUG_CPU