[PATCH 1/6] audit: refactor hold queue flush
The hold queue flush code is an autonomous chunk of code that can be
refactored, removed from kauditd_thread() into flush_hold_queue() and
flattenned for better legibility.
Signed-off-by: Richard Guy Briggs <rbriggs(a)redhat.com>
---
This is a code clean up in preparation to add a multicast netlink socket to
kaudit for read-only userspace clients such as systemd, in addition to the
bidirectional audit userspace client.
kernel/audit.c | 62 +++++++++++++++++++++++++++++++++++++---------------------
1 file changed, 40 insertions(+), 22 deletions(-)
diff --git a/kernel/audit.c b/kernel/audit.c
index d596e53..4bf486c 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -417,34 +417,52 @@ static void kauditd_send_skb(struct sk_buff *skb)
consume_skb(skb);
}
+/*
+ * flush_hold_queue - empty the hold queue if auditd appears
+ *
+ * If auditd just started, drain the queue of messages already
+ * sent to syslog/printk. Remember loss here is ok. We already
+ * called audit_log_lost() if it didn't go out normally. so the
+ * race between the skb_dequeue and the next check for audit_pid
+ * doesn't matter.
+ *
+ * If you ever find kauditd to be too slow we can get a perf win
+ * by doing our own locking and keeping better track if there
+ * are messages in this queue. I don't see the need now, but
+ * in 5 years when I want to play with this again I'll see this
+ * note and still have no friggin idea what i'm thinking today.
+ */
+static void flush_hold_queue(void)
+{
+ struct sk_buff *skb;
+
+ if (!audit_default || !audit_pid)
+ return;
+
+ skb = skb_dequeue(&audit_skb_hold_queue);
+ if (likely(!skb))
+ return;
+
+ while (skb && audit_pid) {
+ kauditd_send_skb(skb);
+ skb = skb_dequeue(&audit_skb_hold_queue);
+ }
+
+ /*
+ * if auditd just disappeared but we
+ * dequeued an skb we need to drop ref
+ */
+ if (skb)
+ consume_skb(skb);
+}
+
static int kauditd_thread(void *dummy)
{
struct sk_buff *skb;
set_freezable();
while (!kthread_should_stop()) {
- /*
- * if auditd just started drain the queue of messages already
- * sent to syslog/printk. remember loss here is ok. we already
- * called audit_log_lost() if it didn't go out normally. so the
- * race between the skb_dequeue and the next check for audit_pid
- * doesn't matter.
- *
- * if you ever find kauditd to be too slow we can get a perf win
- * by doing our own locking and keeping better track if there
- * are messages in this queue. I don't see the need now, but
- * in 5 years when I want to play with this again I'll see this
- * note and still have no friggin idea what i'm thinking today.
- */
- if (audit_default && audit_pid) {
- skb = skb_dequeue(&audit_skb_hold_queue);
- if (unlikely(skb)) {
- while (skb && audit_pid) {
- kauditd_send_skb(skb);
- skb = skb_dequeue(&audit_skb_hold_queue);
- }
- }
- }
+ flush_hold_queue();
skb = skb_dequeue(&audit_skb_queue);
wake_up(&audit_backlog_wait);
--
1.8.0.2