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>

security/integrity/ima/ima_api.c

@@ -325,11 +325,11 @@ const char *ima_d_path(struct path *path, char **pathbuf)
 {
 	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;
 		}

security/integrity/ima/ima_main.c

@@ -246,7 +246,8 @@ static int process_measurement(struct file *file, int mask, int function,
 		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))