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 421be5fe5cc7..861b4088092a 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 f4ffbd0f306f..f6e01f3ae9c6 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 e1cdf196a515..9dd827db359f 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 cfa222a91539..56ea3a203a5a 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 36e061740047..059256874e9b 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 ceacc6626572..b4da888497fa 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);
 }
 
 /**