signal/timer/event: timerfd compat code

This patch implements the necessary compat code for the timerfd system call.

Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/compat.c b/fs/compat.c
index 2487b83..7b21b0a 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -2225,3 +2225,26 @@
 
 #endif /* CONFIG_SIGNALFD */
 
+#ifdef CONFIG_TIMERFD
+
+asmlinkage long compat_sys_timerfd(int ufd, int clockid, int flags,
+				   const struct compat_itimerspec __user *utmr)
+{
+	long res;
+	struct itimerspec t;
+	struct itimerspec __user *ut;
+
+	res = -EFAULT;
+	if (get_compat_itimerspec(&t, utmr))
+		goto err_exit;
+	ut = compat_alloc_user_space(sizeof(*ut));
+	if (copy_to_user(ut, &t, sizeof(t)) )
+		goto err_exit;
+
+	res = sys_timerfd(ufd, clockid, flags, ut);
+err_exit:
+	return res;
+}
+
+#endif /* CONFIG_TIMERFD */
+