take check for new events in namespace (guts of mounts_poll()) to namespace.c

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 58324c2..746895d 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -647,17 +647,11 @@
 static unsigned mounts_poll(struct file *file, poll_table *wait)
 {
 	struct proc_mounts *p = file->private_data;
-	struct mnt_namespace *ns = p->ns;
 	unsigned res = POLLIN | POLLRDNORM;
 
-	poll_wait(file, &ns->poll, wait);
-
-	spin_lock(&vfsmount_lock);
-	if (p->event != ns->event) {
-		p->event = ns->event;
+	poll_wait(file, &p->ns->poll, wait);
+	if (mnt_had_events(p))
 		res |= POLLERR | POLLPRI;
-	}
-	spin_unlock(&vfsmount_lock);
 
 	return res;
 }