[PATCH] (5/5) improved notifier callback mechanism -- remove old locking V2

[Stephen Hemminger <shemminger@osdl.org>]

After the previous patches, the notifier interface now has it's own
locking.  Therefore the existing locking done by the oprofile interface
is superfluous.
diff -Nru a/arch/i386/kernel/profile.c b/arch/i386/kernel/profile.c
--- a/arch/i386/kernel/profile.c	Tue Dec 17 11:25:47 2002
+++ b/arch/i386/kernel/profile.c	Tue Dec 17 11:25:47 2002
@@ -6,40 +6,25 @@
  */
 
 #include <linux/profile.h>
-#include <linux/spinlock.h>
 #include <linux/notifier.h>
 #include <linux/irq.h>
 #include <asm/hw_irq.h> 
  
 static LIST_HEAD(profile_listeners);
-static rwlock_t profile_lock = RW_LOCK_UNLOCKED;
  
 int register_profile_notifier(struct notifier_block * nb)
 {
-	int err;
-	write_lock_irq(&profile_lock);
-	err = notifier_chain_register(&profile_listeners, nb);
-	write_unlock_irq(&profile_lock);
-	return err;
+	return notifier_chain_register(&profile_listeners, nb);
 }
 
 
 int unregister_profile_notifier(struct notifier_block * nb)
 {
-	int err;
-	write_lock_irq(&profile_lock);
-	err = notifier_chain_unregister(&profile_listeners, nb);
-	write_unlock_irq(&profile_lock);
-	return err;
+	return notifier_chain_unregister(&profile_listeners, nb);
 }
 
 
 void x86_profile_hook(struct pt_regs * regs)
 {
-	/* we would not even need this lock if
-	 * we had a global cli() on register/unregister
-	 */ 
-	read_lock(&profile_lock);
 	notifier_call_chain(&profile_listeners, 0, regs);
-	read_unlock(&profile_lock);
 }