genirq: Clear CPU mask in affinity_hint when none is provided

When an interrupt is disabled and torn down, the CPU mask returned
through affinity_hint right now is all CPUs. Also, for drivers that
don't provide an affinity_hint mask, this can be misleading. There
should be no hint at all, meaning an empty CPU mask.

[ tglx: use zalloc_cpumask_var instead of clearing it under the lock ]

Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Cc: davem@davemloft.net
Cc: arjan@linux.jf.intel.com
Cc: bhutchings@solarflare.com
LKML-Reference: <20100505205638.5426.87189.stgit@ppwaskie-hc2.jf.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index 4f9427a..09a2ee5 100644 (file)
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -38,14 +38,12 @@ static int irq_affinity_hint_proc_show(struct seq_file *m, void *v)
        unsigned long flags;
        cpumask_var_t mask;
 
-       if (!alloc_cpumask_var(&mask, GFP_KERNEL))
+       if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
                return -ENOMEM;
 
        raw_spin_lock_irqsave(&desc->lock, flags);
        if (desc->affinity_hint)
                cpumask_copy(mask, desc->affinity_hint);
-       else
-               cpumask_setall(mask);
        raw_spin_unlock_irqrestore(&desc->lock, flags);
 
        seq_cpumask(m, mask);