signal: make sig_task_ignored() return bool

sig_task_ignored() already behaves like a boolean function.  Let's
actually declare it as such too.

Link: http://lkml.kernel.org/r/20180602103653.18181-9-christian@brauner.io
Signed-off-by: Christian Brauner <christian@brauner.io>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: James Morris <james.morris@microsoft.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/signal.c

@@ -72,7 +72,7 @@ static inline bool sig_handler_ignored(void __user *handler, int sig)
 	       (handler == SIG_DFL && sig_kernel_ignore(sig));
 }
 
-static int sig_task_ignored(struct task_struct *t, int sig, bool force)
+static bool sig_task_ignored(struct task_struct *t, int sig, bool force)
 {
 	void __user *handler;
 
@@ -80,7 +80,7 @@ static int sig_task_ignored(struct task_struct *t, int sig, bool force)
 
 	if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
 	    handler == SIG_DFL && !(force && sig_kernel_only(sig)))
-		return 1;
+		return true;
 
 	return sig_handler_ignored(handler, sig);
 }