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/arch/s390/hypfs/inode.c b/arch/s390/hypfs/inode.c
index b2e5902..0f3da2c 100644
--- a/arch/s390/hypfs/inode.c
+++ b/arch/s390/hypfs/inode.c
@@ -67,7 +67,7 @@
 	struct dentry *parent;
 
 	parent = dentry->d_parent;
-	mutex_lock(&d_inode(parent)->i_mutex);
+	inode_lock(d_inode(parent));
 	if (simple_positive(dentry)) {
 		if (d_is_dir(dentry))
 			simple_rmdir(d_inode(parent), dentry);
@@ -76,7 +76,7 @@
 	}
 	d_delete(dentry);
 	dput(dentry);
-	mutex_unlock(&d_inode(parent)->i_mutex);
+	inode_unlock(d_inode(parent));
 }
 
 static void hypfs_delete_tree(struct dentry *root)
@@ -331,7 +331,7 @@
 	struct dentry *dentry;
 	struct inode *inode;
 
-	mutex_lock(&d_inode(parent)->i_mutex);
+	inode_lock(d_inode(parent));
 	dentry = lookup_one_len(name, parent, strlen(name));
 	if (IS_ERR(dentry)) {
 		dentry = ERR_PTR(-ENOMEM);
@@ -359,7 +359,7 @@
 	d_instantiate(dentry, inode);
 	dget(dentry);
 fail:
-	mutex_unlock(&d_inode(parent)->i_mutex);
+	inode_unlock(d_inode(parent));
 	return dentry;
 }