free_pidmap: turn it into free_pidmap(struct upid *)

The callers of free_pidmap() pass 2 members of "struct upid", we can just
pass "struct upid *" instead.  Shaves off 10 bytes from pid.o.

Also, simplify the alloc_pid's "out_free:" error path a little bit.  This
way it looks more clear which subset of pid->numbers[] we are freeing.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc :Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/pid.c

@@ -111,10 +111,11 @@ EXPORT_SYMBOL(is_container_init);
 
 static  __cacheline_aligned_in_smp DEFINE_SPINLOCK(pidmap_lock);
 
-static void free_pidmap(struct pid_namespace *pid_ns, int pid)
+static void free_pidmap(struct upid *upid)
 {
-	struct pidmap *map = pid_ns->pidmap + pid / BITS_PER_PAGE;
-	int offset = pid & BITS_PER_PAGE_MASK;
+	int nr = upid->nr;
+	struct pidmap *map = upid->ns->pidmap + nr / BITS_PER_PAGE;
+	int offset = nr & BITS_PER_PAGE_MASK;
 
 	clear_bit(offset, map->page);
 	atomic_inc(&map->nr_free);
@@ -232,7 +233,7 @@ void free_pid(struct pid *pid)
 	spin_unlock_irqrestore(&pidmap_lock, flags);
 
 	for (i = 0; i <= pid->level; i++)
-		free_pidmap(pid->numbers[i].ns, pid->numbers[i].nr);
+		free_pidmap(pid->numbers + i);
 
 	call_rcu(&pid->rcu, delayed_put_pid);
 }
@@ -278,8 +279,8 @@ out:
 	return pid;
 
 out_free:
-	for (i++; i <= ns->level; i++)
-		free_pidmap(pid->numbers[i].ns, pid->numbers[i].nr);
+	while (++i <= ns->level)
+		free_pidmap(pid->numbers + i);
 
 	kmem_cache_free(ns->pid_cachep, pid);
 	pid = NULL;