Lock down the network interface queues. The queue mutex must be obtained

before adding/removing packets from the queue.  Also, the if_obytes and
if_omcasts fields should only be manipulated under protection of the mutex.

IF_ENQUEUE, IF_PREPEND, and IF_DEQUEUE perform all necessary locking on
the queue.  An IF_LOCK macro is provided, as well as the old (mutex-less)
versions of the macros in the form _IF_ENQUEUE, _IF_QFULL, for code which
needs them, but their use is discouraged.

Two new macros are introduced: IF_DRAIN() to drain a queue, and IF_HANDOFF,
which takes care of locking/enqueue, and also statistics updating/start
if necessary.

1 files changed, 1 insertions, 7 deletions

diff --git a/sys/dev/pdq/pdq_ifsubr.c b/sys/dev/pdq/pdq_ifsubr.c
index fab0c44..ac9d3d2 100644
--- a/sys/dev/pdq/pdq_ifsubr.c
+++ b/sys/dev/pdq/pdq_ifsubr.c
@@ -131,13 +131,7 @@ pdq_ifwatchdog(
 
     ifp->if_flags &= ~IFF_OACTIVE;
     ifp->if_timer = 0;
-    for (;;) {
-	struct mbuf *m;
-	IF_DEQUEUE(&ifp->if_snd, m);
-	if (m == NULL)
-	    return;
-	m_freem(m);
-    }
+    IF_DRAIN(&ifp->if_snd);
 }
 
 ifnet_ret_t