[PATCH] x86-64: Extend clear_irq_vector

Clear the irq releated entries in irq_vector, irq_domain and vector_irq
instead of clearing irq_vector only. So when new irq is created, it
could reuse that vector. (actually is the second loop scanning from
FIRST_DEVICE_VECTOR+8). This could avoid the vectors are used up
with enough module inserting and removing

Cc: Eric W. Biedierman <ebiederm@xmission.com>
Cc: Muli Ben-Yehuda <muli@il.ibm.com>
Signed-off-By: Yinghai Lu <yinghai.lu@amd.com>
Signed-off-by: Andi Kleen <ak@suse.de>

1 files changed, 17 insertions, 1 deletions

diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c
index c80081a6ba41..f71461b1f03d 100644
--- a/arch/x86_64/kernel/io_apic.c
+++ b/arch/x86_64/kernel/io_apic.c
@@ -750,6 +750,22 @@ static int assign_irq_vector(int irq, cpumask_t mask, cpumask_t *result)
         return vector;
 }
 
+static void __clear_irq_vector(int irq)
+{
+        cpumask_t mask;
+        int cpu, vector;
+
+        BUG_ON(!irq_vector[irq]);
+
+        vector = irq_vector[irq];
+        cpus_and(mask, irq_domain[irq], cpu_online_map);
+        for_each_cpu_mask(cpu, mask)
+                per_cpu(vector_irq, cpu)[vector] = -1;
+
+        irq_vector[irq] = 0;
+        irq_domain[irq] = CPU_MASK_NONE;
+}
+
 void __setup_vector_irq(int cpu)
 {
         /* Initialize vector_irq on a new cpu */
@@ -1837,7 +1853,7 @@ void destroy_irq(unsigned int irq)
         dynamic_irq_cleanup(irq);
 
         spin_lock_irqsave(&vector_lock, flags);
-        irq_vector[irq] = 0;
+        __clear_irq_vector(irq);
         spin_unlock_irqrestore(&vector_lock, flags);
 }