kernel/notifier.c: remove blocking_notifier_chain_cond_register()

blocking_notifier_chain_cond_register() does not consider system_booting
state, which is the only difference between this function and
blocking_notifier_cain_register().  This can be a bug and is a piece of
duplicate code.

Delete blocking_notifier_chain_cond_register()

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Xiaoming Ni <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Cc: Alan Stern <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Anna Schumaker <[email protected]>
Cc: Arjan van de Ven <[email protected]>
Cc: Chuck Lever <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: J. Bruce Fields <[email protected]>
Cc: Jeff Layton <[email protected]>
Cc: Nadia Derbey <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Sam Protsenko <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Trond Myklebust <[email protected]>
Cc: Vasily Averin <[email protected]>
Cc: Viresh Kumar <[email protected]>
Cc: YueHaibing <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

include/linux/notifier.h

@@ -150,10 +150,6 @@ extern int raw_notifier_chain_register(struct raw_notifier_head *nh,
 extern int srcu_notifier_chain_register(struct srcu_notifier_head *nh,
  struct notifier_block *nb);
 
-extern int blocking_notifier_chain_cond_register(
- struct blocking_notifier_head *nh,
- struct notifier_block *nb);
-
 extern int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh,
  struct notifier_block *nb);
 extern int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh,

kernel/notifier.c

@@ -220,29 +220,6 @@ int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
 }
 EXPORT_SYMBOL_GPL(blocking_notifier_chain_register);
 
-/**
- * blocking_notifier_chain_cond_register - Cond add notifier to a blocking notifier chain
- * @nh: Pointer to head of the blocking notifier chain
- * @n: New entry in notifier chain
- *
- * Adds a notifier to a blocking notifier chain, only if not already
- * present in the chain.
- * Must be called in process context.
- *
- * Currently always returns zero.
- */
-int blocking_notifier_chain_cond_register(struct blocking_notifier_head *nh,
- struct notifier_block *n)
-{
- int ret;
-
- down_write(&nh->rwsem);
- ret = notifier_chain_register(&nh->head, n);
- up_write(&nh->rwsem);
- return ret;
-}
-EXPORT_SYMBOL_GPL(blocking_notifier_chain_cond_register);
-
 /**
  * blocking_notifier_chain_unregister - Remove notifier from a blocking notifier chain
  * @nh: Pointer to head of the blocking notifier chain

net/sunrpc/rpc_pipe.c

@@ -51,7 +51,7 @@ static BLOCKING_NOTIFIER_HEAD(rpc_pipefs_notifier_list);
 
 int rpc_pipefs_notifier_register(struct notifier_block *nb)
 {
- return blocking_notifier_chain_cond_register(&rpc_pipefs_notifier_list, nb);
+ return blocking_notifier_chain_register(&rpc_pipefs_notifier_list, nb);
 }
 EXPORT_SYMBOL_GPL(rpc_pipefs_notifier_register);