[POWERPC] spufs: add mode= mount option

Add a 'mode=' option to spufs mount arguments. This allows more
control over access to the top-level spufs directory.

Tested on Cell.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
diff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c
index 6b52dfa..8f6cd87 100644
--- a/arch/powerpc/platforms/cell/spufs/inode.c
+++ b/arch/powerpc/platforms/cell/spufs/inode.c
@@ -521,13 +521,14 @@
 
 /* File system initialization */
 enum {
-	Opt_uid, Opt_gid, Opt_err,
+	Opt_uid, Opt_gid, Opt_mode, Opt_err,
 };
 
 static match_table_t spufs_tokens = {
-	{ Opt_uid, "uid=%d" },
-	{ Opt_gid, "gid=%d" },
-	{ Opt_err, NULL  },
+	{ Opt_uid,  "uid=%d" },
+	{ Opt_gid,  "gid=%d" },
+	{ Opt_mode, "mode=%o" },
+	{ Opt_err,   NULL  },
 };
 
 static int
@@ -554,6 +555,11 @@
 				return 0;
 			root->i_gid = option;
 			break;
+		case Opt_mode:
+			if (match_octal(&args[0], &option))
+				return 0;
+			root->i_mode = option | S_IFDIR;
+			break;
 		default:
 			return 0;
 		}