Remove argument from open_softirq which is always NULL

As git-grep shows, open_softirq() is always called with the last argument
being NULL

block/blk-core.c:       open_softirq(BLOCK_SOFTIRQ, blk_done_softirq, NULL);
kernel/hrtimer.c:       open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq, NULL);
kernel/rcuclassic.c:    open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL);
kernel/rcupreempt.c:    open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL);
kernel/sched.c: open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL);
kernel/softirq.c:       open_softirq(TASKLET_SOFTIRQ, tasklet_action, NULL);
kernel/softirq.c:       open_softirq(HI_SOFTIRQ, tasklet_hi_action, NULL);
kernel/timer.c: open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);
net/core/dev.c: open_softirq(NET_TX_SOFTIRQ, net_tx_action, NULL);
net/core/dev.c: open_softirq(NET_RX_SOFTIRQ, net_rx_action, NULL);

This observation has already been made by Matthew Wilcox in June 2002
(http://www.cs.helsinki.fi/linux/linux-kernel/2002-25/0687.html)

"I notice that none of the current softirq routines use the data element
passed to them."

and the situation hasn't changed since them. So it appears we can safely
remove that extra argument to save 128 (54) bytes of kernel data (text).

Signed-off-by: Carlos R. Mafra <crmafra@ift.unesp.br>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

6 files changed, 8 insertions, 9 deletions

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 421be5fe5cc..861b4088092 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1669,7 +1669,7 @@ void __init hrtimers_init(void)
 			  (void *)(long)smp_processor_id());
 	register_cpu_notifier(&hrtimers_nb);
 #ifdef CONFIG_HIGH_RES_TIMERS
-	open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq, NULL);
+	open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq);
 #endif
 }
 
diff --git a/kernel/rcuclassic.c b/kernel/rcuclassic.c
index f4ffbd0f306..f6e01f3ae9c 100644
--- a/kernel/rcuclassic.c
+++ b/kernel/rcuclassic.c
@@ -529,7 +529,7 @@ static void __cpuinit rcu_online_cpu(int cpu)
 
 	rcu_init_percpu_data(cpu, &rcu_ctrlblk, rdp);
 	rcu_init_percpu_data(cpu, &rcu_bh_ctrlblk, bh_rdp);
-	open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL);
+	open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
 }
 
 static int __cpuinit rcu_cpu_notify(struct notifier_block *self,
diff --git a/kernel/rcupreempt.c b/kernel/rcupreempt.c
index e1cdf196a51..9dd827db359 100644
--- a/kernel/rcupreempt.c
+++ b/kernel/rcupreempt.c
@@ -1125,7 +1125,7 @@ void __init __rcu_init(void)
 	for_each_online_cpu(cpu)
 		rcu_cpu_notify(&rcu_nb, CPU_UP_PREPARE,	(void *)(long) cpu);
 
-	open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL);
+	open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
 }
 
 /*
diff --git a/kernel/sched.c b/kernel/sched.c
index cfa222a9153..56ea3a203a5 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -8154,7 +8154,7 @@ void __init sched_init(void)
 #endif
 
 #ifdef CONFIG_SMP
-	open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL);
+	open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
 #endif
 
 #ifdef CONFIG_RT_MUTEXES
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 36e06174004..059256874e9 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -347,9 +347,8 @@ void raise_softirq(unsigned int nr)
 	local_irq_restore(flags);
 }
 
-void open_softirq(int nr, void (*action)(struct softirq_action*), void *data)
+void open_softirq(int nr, void (*action)(struct softirq_action *))
 {
-	softirq_vec[nr].data = data;
 	softirq_vec[nr].action = action;
 }
 
@@ -503,8 +502,8 @@ void __init softirq_init(void)
 			&per_cpu(tasklet_hi_vec, cpu).head;
 	}
 
-	open_softirq(TASKLET_SOFTIRQ, tasklet_action, NULL);
-	open_softirq(HI_SOFTIRQ, tasklet_hi_action, NULL);
+	open_softirq(TASKLET_SOFTIRQ, tasklet_action);
+	open_softirq(HI_SOFTIRQ, tasklet_hi_action);
 }
 
 static int ksoftirqd(void * __bind_cpu)
diff --git a/kernel/timer.c b/kernel/timer.c
index ceacc662657..b4da888497f 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1502,7 +1502,7 @@ void __init init_timers(void)
 
 	BUG_ON(err == NOTIFY_BAD);
 	register_cpu_notifier(&timers_nb);
-	open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);
+	open_softirq(TIMER_SOFTIRQ, run_timer_softirq);
 }
 
 /**