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, 4 insertions, 10 deletions

diff --git a/sys/netatm/atm_device.c b/sys/netatm/atm_device.c
index e458bf4..ecca8ad 100644
--- a/sys/netatm/atm_device.c
+++ b/sys/netatm/atm_device.c
@@ -314,6 +314,7 @@ atm_dev_lower(cmd, tok, arg1, arg2)
 		 * Free any buffers from this VCC on the ATM interrupt queue
 		 */
 		prev = NULL;
+		IF_LOCK(&atm_intrq);
 		for (m = atm_intrq.ifq_head; m; m = next) {
 			next = KB_QNEXT(m);
 
@@ -344,6 +345,7 @@ atm_dev_lower(cmd, tok, arg1, arg2)
 				prev = m;
 			}
 		}
+		IF_UNLOCK(&atm_intrq);
 		(void) splx(s);
 
 		/*
diff --git a/sys/netatm/atm_subr.c b/sys/netatm/atm_subr.c
index e1478df..25003e6 100644
--- a/sys/netatm/atm_subr.c
+++ b/sys/netatm/atm_subr.c
@@ -135,6 +135,7 @@ atm_initialize()
 
 
 	atm_intrq.ifq_maxlen = ATM_INTRQ_MAX;
+	mtx_init(&atm_intrq.ifq_mtx, "atm_inq", MTX_DEF);
 #ifdef sgi
 	atm_intr_index = register_isr(atm_intr);
 #endif
diff --git a/sys/netatm/ipatm/ipatm_input.c b/sys/netatm/ipatm/ipatm_input.c
index 8480506..30f6326 100644
--- a/sys/netatm/ipatm/ipatm_input.c
+++ b/sys/netatm/ipatm/ipatm_input.c
@@ -127,7 +127,6 @@ ipatm_ipinput(inp, m)
 	struct ip_nif	*inp;
 	KBuffer		*m;
 {
-	int		s;
 #if	BSD < 199103
 	int		space;
 #endif
@@ -207,16 +206,8 @@ ipatm_ipinput(inp, m)
 	 * just call IP directly to avoid the extra unnecessary 
 	 * kernel scheduling.
 	 */
-	s = splimp();
-	if (IF_QFULL(&ipintrq)) {
-		IF_DROP(&ipintrq);
-		(void) splx(s);
-		KB_FREEALL(m);
+	if (! IF_HANDOFF(&ipintrq, m, NULL))
 		return (1);
-	}
-
-	IF_ENQUEUE(&ipintrq, m);
-	(void) splx(s);
 #if	BSD < 199506
 	ipintr();
 #else