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.

3 files changed, 5 insertions, 16 deletions

diff --git a/sys/i4b/layer2/i4b_l2.c b/sys/i4b/layer2/i4b_l2.c
index 59a09ba..b3f79a6 100644
--- a/sys/i4b/layer2/i4b_l2.c
+++ b/sys/i4b/layer2/i4b_l2.c
@@ -163,7 +163,7 @@ int i4b_dl_data_req(int unit, struct mbuf *m)
 		case ST_MULTIFR:
 		case ST_TIMREC:
 		
-		        if(IF_QFULL(&l2sc->i_queue))
+		        if(_IF_QFULL(&l2sc->i_queue))
 		        {
 		        	NDBGL2(L2_ERROR, "i_queue full!!");
 		        	i4b_Dfreembuf(m);
@@ -277,6 +277,7 @@ i4b_mph_status_ind(int unit, int status, int parm)
 		case STI_ATTACH:
 			l2sc->unit = unit;
 			l2sc->i_queue.ifq_maxlen = IQUEUE_MAXLEN;
+			mtx_init(&l2sc->i_queue.ifq_mtx, "i4b_l2sc", MTX_DEF);
 			l2sc->ua_frame = NULL;
 			bzero(&l2sc->stat, sizeof(lapdstat_t));			
 			i4b_l2_unit_init(unit);
diff --git a/sys/i4b/layer2/i4b_mbuf.c b/sys/i4b/layer2/i4b_mbuf.c
index a0f1013..0537a5e 100644
--- a/sys/i4b/layer2/i4b_mbuf.c
+++ b/sys/i4b/layer2/i4b_mbuf.c
@@ -140,15 +140,9 @@ i4b_Dfreembuf(struct mbuf *m)
 void
 i4b_Dcleanifq(struct ifqueue *ifq)
 {
-	struct mbuf *m;
 	int x = splimp();
 	
-	while(!IF_QEMPTY(ifq))
-	{
-		IF_DEQUEUE(ifq, m);
-		i4b_Dfreembuf(m);
-	}
-
+	IF_DRAIN(ifq);
 	splx(x);
 }
 
@@ -222,15 +216,9 @@ i4b_Bfreembuf(struct mbuf *m)
 void
 i4b_Bcleanifq(struct ifqueue *ifq)
 {
-	struct mbuf *m;
 	int x = splimp();
 	
-	while(!IF_QEMPTY(ifq))
-	{
-		IF_DEQUEUE(ifq, m);
-		i4b_Bfreembuf(m);
-	}
-
+	IF_DRAIN(ifq);
 	splx(x);
 }
 
diff --git a/sys/i4b/layer2/i4b_util.c b/sys/i4b/layer2/i4b_util.c
index 982760d..0569a84 100644
--- a/sys/i4b/layer2/i4b_util.c
+++ b/sys/i4b/layer2/i4b_util.c
@@ -182,7 +182,7 @@ i4b_invoke_retransmission(l2_softc_t *l2sc, int nr)
 
 		if((l2sc->ua_num != UA_EMPTY) && (l2sc->vs == l2sc->ua_num))
 		{
-			if(IF_QFULL(&l2sc->i_queue))
+			if(_IF_QFULL(&l2sc->i_queue))
 			{
 				NDBGL2(L2_ERROR, "ERROR, I-queue full!");
 			}