new helper: iter_is_iovec()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/mm/filemap.c b/mm/filemap.c
index e8905bc..bd8543c 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2464,7 +2464,7 @@
 	/*
 	 * Copies from kernel address space cannot fail (NFSD is a big user).
 	 */
-	if (segment_eq(get_fs(), KERNEL_DS))
+	if (!iter_is_iovec(i))
 		flags |= AOP_FLAG_UNINTERRUPTIBLE;
 
 	do {