selinux: reduce the number of calls to synchronize_net() when flushing caches

When flushing the AVC, such as during a policy load, the various
network caches are also flushed, with each making a call to
synchronize_net() which has shown to be expensive in some cases.
This patch consolidates the network cache flushes into a single AVC
callback which only calls synchronize_net() once for each AVC cache
flush.

Reported-by: Jaejyn Shin <flagon22bass@gmail.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>

1 files changed, 1 insertions, 14 deletions

diff --git a/security/selinux/netif.c b/security/selinux/netif.c
index 694e9e4..3c3de4c 100644
--- a/security/selinux/netif.c
+++ b/security/selinux/netif.c
@@ -240,7 +240,7 @@ static void sel_netif_kill(int ifindex)
  * Remove all entries from the network interface table.
  *
  */
-static void sel_netif_flush(void)
+void sel_netif_flush(void)
 {
 	int idx;
 	struct sel_netif *netif;
@@ -252,15 +252,6 @@ static void sel_netif_flush(void)
 	spin_unlock_bh(&sel_netif_lock);
 }
 
-static int sel_netif_avc_callback(u32 event)
-{
-	if (event == AVC_CALLBACK_RESET) {
-		sel_netif_flush();
-		synchronize_net();
-	}
-	return 0;
-}
-
 static int sel_netif_netdev_notifier_handler(struct notifier_block *this,
 					     unsigned long event, void *ptr)
 {
@@ -291,10 +282,6 @@ static __init int sel_netif_init(void)
 
 	register_netdevice_notifier(&sel_netif_netdev_notifier);
 
-	err = avc_add_callback(sel_netif_avc_callback, AVC_CALLBACK_RESET);
-	if (err)
-		panic("avc_add_callback() failed, error %d\n", err);
-
 	return err;
 }