wrappers for ->i_mutex access

parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).

Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index 78f005f..3a3ced7 100644
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -638,11 +638,11 @@
 	case 3:
 		/* Delete this handler. */
 		root = dget(file->f_path.dentry->d_sb->s_root);
-		mutex_lock(&d_inode(root)->i_mutex);
+		inode_lock(d_inode(root));
 
 		kill_node(e);
 
-		mutex_unlock(&d_inode(root)->i_mutex);
+		inode_unlock(d_inode(root));
 		dput(root);
 		break;
 	default:
@@ -675,7 +675,7 @@
 		return PTR_ERR(e);
 
 	root = dget(sb->s_root);
-	mutex_lock(&d_inode(root)->i_mutex);
+	inode_lock(d_inode(root));
 	dentry = lookup_one_len(e->name, root, strlen(e->name));
 	err = PTR_ERR(dentry);
 	if (IS_ERR(dentry))
@@ -711,7 +711,7 @@
 out2:
 	dput(dentry);
 out:
-	mutex_unlock(&d_inode(root)->i_mutex);
+	inode_unlock(d_inode(root));
 	dput(root);
 
 	if (err) {
@@ -754,12 +754,12 @@
 	case 3:
 		/* Delete all handlers. */
 		root = dget(file->f_path.dentry->d_sb->s_root);
-		mutex_lock(&d_inode(root)->i_mutex);
+		inode_lock(d_inode(root));
 
 		while (!list_empty(&entries))
 			kill_node(list_entry(entries.next, Node, list));
 
-		mutex_unlock(&d_inode(root)->i_mutex);
+		inode_unlock(d_inode(root));
 		dput(root);
 		break;
 	default: