signal: Hand SIGQUEUE_PREALLOC flag to __sigqueue_alloc()

There is no point in having the conditional at the callsite.

Just hand in the allocation mode flag to __sigqueue_alloc() and use it to
initialize sigqueue::flags.

No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210322092258.898677147@linutronix.de

kernel/signal.c

@@ -410,7 +410,8 @@ void task_join_group_stop(struct task_struct *task)
  *   appropriate lock must be held to stop the target task from exiting
  */
 static struct sigqueue *
-__sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
+__sigqueue_alloc(int sig, struct task_struct *t, gfp_t gfp_flags,
+		 int override_rlimit, const unsigned int sigqueue_flags)
 {
 	struct sigqueue *q = NULL;
 	struct user_struct *user;
@@ -432,7 +433,7 @@ __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimi
 	rcu_read_unlock();
 
 	if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) {
-		q = kmem_cache_alloc(sigqueue_cachep, flags);
+		q = kmem_cache_alloc(sigqueue_cachep, gfp_flags);
 	} else {
 		print_dropped_signal(sig);
 	}
@@ -442,7 +443,7 @@ __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimi
 			free_uid(user);
 	} else {
 		INIT_LIST_HEAD(&q->list);
-		q->flags = 0;
+		q->flags = sigqueue_flags;
 		q->user = user;
 	}
 
@@ -1113,7 +1114,8 @@ static int __send_signal(int sig, struct kernel_siginfo *info, struct task_struc
 	else
 		override_rlimit = 0;
 
-	q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit);
+	q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit, 0);
+
 	if (q) {
 		list_add_tail(&q->list, &pending->list);
 		switch ((unsigned long) info) {
@@ -1807,12 +1809,7 @@ EXPORT_SYMBOL(kill_pid);
  */
 struct sigqueue *sigqueue_alloc(void)
 {
-	struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
-
-	if (q)
-		q->flags |= SIGQUEUE_PREALLOC;
-
-	return q;
+	return __sigqueue_alloc(-1, current, GFP_KERNEL, 0, SIGQUEUE_PREALLOC);
 }
 
 void sigqueue_free(struct sigqueue *q)