kernel/notifier.c: remove notifier_chain_cond_register()

The only difference between notifier_chain_cond_register() and
notifier_chain_register() is the lack of warning hints for duplicate
registrations.  Use notifier_chain_register() instead of
notifier_chain_cond_register() to avoid duplicate code

Link: http://lkml.kernel.org/r/1568861888-34045-3-git-send-email-nixiaoming@huawei.comSigned-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: J. Bruce Fields <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Sam Protsenko <semen.protsenko@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Vasily Averin <vvs@virtuozzo.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/notifier.c

@@ -36,21 +36,6 @@ static int notifier_chain_register(struct notifier_block **nl,
 	return 0;
 }
 
-static int notifier_chain_cond_register(struct notifier_block **nl,
-		struct notifier_block *n)
-{
-	while ((*nl) != NULL) {
-		if ((*nl) == n)
-			return 0;
-		if (n->priority > (*nl)->priority)
-			break;
-		nl = &((*nl)->next);
-	}
-	n->next = *nl;
-	rcu_assign_pointer(*nl, n);
-	return 0;
-}
-
 static int notifier_chain_unregister(struct notifier_block **nl,
 		struct notifier_block *n)
 {
@@ -252,7 +237,7 @@ int blocking_notifier_chain_cond_register(struct blocking_notifier_head *nh,
 	int ret;
 
 	down_write(&nh->rwsem);
-	ret = notifier_chain_cond_register(&nh->head, n);
+	ret = notifier_chain_register(&nh->head, n);
 	up_write(&nh->rwsem);
 	return ret;
 }