fs/9p: Add direct IO support in cached mode

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index ee45552..2524e4c 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -254,8 +254,9 @@
  * with an error.
  *
  */
-ssize_t v9fs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
-		loff_t pos, unsigned long nr_segs)
+static ssize_t
+v9fs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
+	       loff_t pos, unsigned long nr_segs)
 {
 	/*
 	 * FIXME