selinux: use kmem_cache for ebitmap

The allocated size for each ebitmap_node is 192byte by kzalloc().
Then, ebitmap_node size is fixed, so it's possible to use only 144byte
for each object by kmem_cache_zalloc().
It can reduce some dynamic allocation size.

Signed-off-by: Junil Lee <junil0814.lee@lge.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

security/selinux/ss/services.c

@@ -2054,9 +2054,11 @@ int security_load_policy(void *data, size_t len)
 
 	if (!ss_initialized) {
 		avtab_cache_init();
+		ebitmap_cache_init();
 		rc = policydb_read(&policydb, fp);
 		if (rc) {
 			avtab_cache_destroy();
+			ebitmap_cache_destroy();
 			goto out;
 		}
 
@@ -2067,6 +2069,7 @@ int security_load_policy(void *data, size_t len)
 		if (rc) {
 			policydb_destroy(&policydb);
 			avtab_cache_destroy();
+			ebitmap_cache_destroy();
 			goto out;
 		}
 
@@ -2074,6 +2077,7 @@ int security_load_policy(void *data, size_t len)
 		if (rc) {
 			policydb_destroy(&policydb);
 			avtab_cache_destroy();
+			ebitmap_cache_destroy();
 			goto out;
 		}