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, 4 insertions, 0 deletions

diff --git a/sys/pci/if_wxvar.h b/sys/pci/if_wxvar.h
index 71fec0e..c665ef0 100644
--- a/sys/pci/if_wxvar.h
+++ b/sys/pci/if_wxvar.h
@@ -375,8 +375,12 @@ typedef struct wx_softc {
 	wxtd_t	*tdescriptors;		/* transmit descriptor ring */
 	u_int16_t tnxtfree;		/* next free index (circular) */
 	u_int16_t tactive;		/* # active */
+	struct	mtx wx_mtx;
 } wx_softc_t;
 
+#define WX_LOCK(_sc)            mtx_enter(&(_sc)->wx_mtx, MTX_DEF)
+#define WX_UNLOCK(_sc)          mtx_exit(&(_sc)->wx_mtx, MTX_DEF)
+
 /*
  * We offset the the receive frame header by two bytes so that the actual
  * payload is 32 bit aligned. On platforms that require strict structure