fs/romfs: correct error-handling code

Author: Julia Lawall <julia@diku.dk>

romfs_iget returns an ERR_PTR value in an error case instead of NULL.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// 
@match exists@
expression x, E;
statement S1, S2;
@@

x = romfs_iget(...)
... when != x = E
(
*  if (x == NULL || ...) S1 else S2
|
*  if (x == NULL && ...) S1 else S2
)
// 

Signed-off-by: Julia Lawall 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 

---
 fs/romfs/super.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
 
diff --git a/fs/romfs/super.c b/fs/romfs/super.c
index 47f132d..c117fa8 100644
--- a/fs/romfs/super.c
+++ b/fs/romfs/super.c
@@ -528,7 +528,7 @@ static int romfs_fill_super(struct super_block *sb, void *data, int silent)
 	pos = (ROMFH_SIZE + len + 1 + ROMFH_PAD) & ROMFH_MASK;
 
 	root = romfs_iget(sb, pos);
-	if (!root)
+	if (IS_ERR(root))
 		goto error;
 
 	sb->s_root = d_alloc_root(root);