exfat: fix pointer error checking

Fix missing result check of exfat_build_inode().
And use PTR_ERR_OR_ZERO instead of PTR_ERR.
Signed-off-by: Tetsuhiro Kohada <kohada.t2@gmail.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

fs/exfat/namei.c

@@ -578,7 +578,8 @@ static int exfat_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 
 	i_pos = exfat_make_i_pos(&info);
 	inode = exfat_build_inode(sb, &info, i_pos);
-	if (IS_ERR(inode))
+	err = PTR_ERR_OR_ZERO(inode);
+	if (err)
 		goto unlock;
 
 	inode_inc_iversion(inode);
@@ -745,10 +746,9 @@ static struct dentry *exfat_lookup(struct inode *dir, struct dentry *dentry,
 
 	i_pos = exfat_make_i_pos(&info);
 	inode = exfat_build_inode(sb, &info, i_pos);
-	if (IS_ERR(inode)) {
-		err = PTR_ERR(inode);
+	err = PTR_ERR_OR_ZERO(inode);
+	if (err)
 		goto unlock;
-	}
 
 	i_mode = inode->i_mode;
 	alias = d_find_alias(inode);
@@ -890,10 +890,9 @@ static int exfat_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 
 	i_pos = exfat_make_i_pos(&info);
 	inode = exfat_build_inode(sb, &info, i_pos);
-	if (IS_ERR(inode)) {
-		err = PTR_ERR(inode);
+	err = PTR_ERR_OR_ZERO(inode);
+	if (err)
 		goto unlock;
-	}
 
 	inode_inc_iversion(inode);
 	inode->i_mtime = inode->i_atime = inode->i_ctime =