irq: optimize init_kstat_irqs/init_copy_kstat_irqs

Simplify and make init_kstat_irqs etc more type proof, suggested by
Andrew.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 14 insertions, 17 deletions

diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 1b473e7569aa..49d642b62c64 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -71,19 +71,21 @@ static struct irq_desc irq_desc_init = {
 
 void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr)
 {
-        unsigned long bytes;
-        char *ptr;
         int node;
-
-        /* Compute how many bytes we need per irq and allocate them */
-        bytes = nr * sizeof(unsigned int);
+        void *ptr;
 
         node = cpu_to_node(cpu);
-        ptr = kzalloc_node(bytes, GFP_ATOMIC, node);
-        printk(KERN_DEBUG "  alloc kstat_irqs on cpu %d node %d\n", cpu, node);
+        ptr = kzalloc_node(nr * sizeof(*desc->kstat_irqs), GFP_ATOMIC, node);
 
-        if (ptr)
-                desc->kstat_irqs = (unsigned int *)ptr;
+        /*
+         * don't overwite if can not get new one
+         * init_copy_kstat_irqs() could still use old one
+         */
+        if (ptr) {
+                printk(KERN_DEBUG "  alloc kstat_irqs on cpu %d node %d\n",
+                         cpu, node);
+                desc->kstat_irqs = ptr;
+        }
 }
 
 static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
diff --git a/kernel/irq/numa_migrate.c b/kernel/irq/numa_migrate.c
index ecf765c6a77a..c500cfe422b6 100644
--- a/kernel/irq/numa_migrate.c
+++ b/kernel/irq/numa_migrate.c
@@ -17,16 +17,11 @@ static void init_copy_kstat_irqs(struct irq_desc *old_desc,
                                  struct irq_desc *desc,
                                  int cpu, int nr)
 {
-        unsigned long bytes;
-
         init_kstat_irqs(desc, cpu, nr);
 
-        if (desc->kstat_irqs != old_desc->kstat_irqs) {
-                /* Compute how many bytes we need per irq and allocate them */
-                bytes = nr * sizeof(unsigned int);
-
-                memcpy(desc->kstat_irqs, old_desc->kstat_irqs, bytes);
-        }
+        if (desc->kstat_irqs != old_desc->kstat_irqs)
+                memcpy(desc->kstat_irqs, old_desc->kstat_irqs,
+                         nr * sizeof(*desc->kstat_irqs));
 }
 
 static void free_kstat_irqs(struct irq_desc *old_desc, struct irq_desc *desc)