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>

9 files changed, 12 insertions, 14 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 6a9cc0d22a6..75fdc65136e 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2048,7 +2048,7 @@ int __init blk_dev_init(void)
 	for_each_possible_cpu(i)
 		INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i));
 
-	open_softirq(BLOCK_SOFTIRQ, blk_done_softirq, NULL);
+	open_softirq(BLOCK_SOFTIRQ, blk_done_softirq);
 	register_hotcpu_notifier(&blk_cpu_notifier);
 
 	return 0;
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index f1fc7470d26..a86186dd047 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -285,12 +285,11 @@ enum
 struct softirq_action
 {
 	void	(*action)(struct softirq_action *);
-	void	*data;
 };
 
 asmlinkage void do_softirq(void);
 asmlinkage void __do_softirq(void);
-extern void open_softirq(int nr, void (*action)(struct softirq_action*), void *data);
+extern void open_softirq(int nr, void (*action)(struct softirq_action *));
 extern void softirq_init(void);
 #define __raise_softirq_irqoff(nr) do { or_softirq_pending(1UL << (nr)); } while (0)
 extern void raise_softirq_irqoff(unsigned int nr);
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);
 }
 
 /**
diff --git a/net/core/dev.c b/net/core/dev.c
index 58296307787..cf0e16731dc 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4563,8 +4563,8 @@ static int __init net_dev_init(void)
 
 	dev_boot_phase = 0;
 
-	open_softirq(NET_TX_SOFTIRQ, net_tx_action, NULL);
-	open_softirq(NET_RX_SOFTIRQ, net_rx_action, NULL);
+	open_softirq(NET_TX_SOFTIRQ, net_tx_action);
+	open_softirq(NET_RX_SOFTIRQ, net_rx_action);
 
 	hotcpu_notifier(dev_cpu_callback, 0);
 	dst_init();