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, 2 insertions, 7 deletions

diff --git a/sys/dev/iicbus/if_ic.c b/sys/dev/iicbus/if_ic.c
index c001110..fa8ffdf 100644
--- a/sys/dev/iicbus/if_ic.c
+++ b/sys/dev/iicbus/if_ic.c
@@ -306,11 +306,6 @@ icintr (device_t dev, int event, char *ptr)
 	  if (len <= ICHDRLEN)
 	    goto err;
 
-	  if (IF_QFULL(&ipintrq)) {
-	    IF_DROP(&ipintrq);
-	    break;
-	  }
-
 	  len -= ICHDRLEN;
 	  sc->ic_if.if_ipackets ++;
 	  sc->ic_if.if_ibytes += len;
@@ -321,8 +316,8 @@ icintr (device_t dev, int event, char *ptr)
 	  top = m_devget(sc->ic_ifbuf + ICHDRLEN, len, 0, &sc->ic_if, 0);
 
 	  if (top) {
-	    IF_ENQUEUE(&ipintrq, top);
-	    schednetisr(NETISR_IP);
+	    if (IF_HANDOFF(&ipintrq, top, NULL))
+	      schednetisr(NETISR_IP);
 	  }
 	  break;