ubifs: Implement ubifs_lpt_lookup using ubifs_pnode_lookup

ubifs_lpt_lookup() starts by looking up the nth pnode in the LPT. We
already have this functionality in ubifs_pnode_lookup(). Use this
function rather than open coding its functionality.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>

fs/ubifs/lpt.c

@@ -1480,27 +1480,11 @@ struct ubifs_pnode *ubifs_pnode_lookup(struct ubifs_info *c, int i)
  */
 struct ubifs_lprops *ubifs_lpt_lookup(struct ubifs_info *c, int lnum)
 {
-	int err, i, h, iip, shft;
-	struct ubifs_nnode *nnode;
+	int i, iip;
 	struct ubifs_pnode *pnode;
 
-	if (!c->nroot) {
-		err = ubifs_read_nnode(c, NULL, 0);
-		if (err)
-			return ERR_PTR(err);
-	}
-	nnode = c->nroot;
 	i = lnum - c->main_first;
-	shft = c->lpt_hght * UBIFS_LPT_FANOUT_SHIFT;
-	for (h = 1; h < c->lpt_hght; h++) {
-		iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
-		shft -= UBIFS_LPT_FANOUT_SHIFT;
-		nnode = ubifs_get_nnode(c, nnode, iip);
-		if (IS_ERR(nnode))
-			return ERR_CAST(nnode);
-	}
-	iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
-	pnode = ubifs_get_pnode(c, nnode, iip);
+	pnode = ubifs_pnode_lookup(c, i >> UBIFS_LPT_FANOUT_SHIFT);
 	if (IS_ERR(pnode))
 		return ERR_CAST(pnode);
 	iip = (i & (UBIFS_LPT_FANOUT - 1));