ima: use path names cache

__getname() uses slab allocation which is faster than kmalloc.
Make use of it.

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index 8688597..a99eb6d 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -325,11 +325,11 @@
 {
 	char *pathname = NULL;
 
-	*pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
+	*pathbuf = __getname();
 	if (*pathbuf) {
 		pathname = d_absolute_path(path, *pathbuf, PATH_MAX);
 		if (IS_ERR(pathname)) {
-			kfree(*pathbuf);
+			__putname(*pathbuf);
 			*pathbuf = NULL;
 			pathname = NULL;
 		}
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 72faf0b..eeee00dc 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -246,7 +246,8 @@
 		rc = -EACCES;
 	kfree(xattr_value);
 out_free:
-	kfree(pathbuf);
+	if (pathbuf)
+		__putname(pathbuf);
 out:
 	mutex_unlock(&inode->i_mutex);
 	if ((rc && must_appraise) && (ima_appraise & IMA_APPRAISE_ENFORCE))