kernfs: fix off by one error.

The hash values 0 and 1 are reserved for magic directory entries, but
the code only prevents names hashing to 0. This patch fixes the test
to also prevent hash value 1.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Cc: <stable@vger.kernel.org>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/kernfs/dir.c

@@ -190,7 +190,7 @@ static unsigned int kernfs_name_hash(const char *name, const void *ns)
 	hash = (end_name_hash(hash) ^ hash_ptr((void *)ns, 31));
 	hash &= 0x7fffffffU;
 	/* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */
-	if (hash < 1)
+	if (hash < 2)
 		hash += 2;
 	if (hash >= INT_MAX)
 		hash = INT_MAX - 1;