Modify if_ndis.c so that the MiniportISR function runs in ndis_intr()

and MiniportHandleInterrupt() is fired off later via a task queue in
ndis_intrtask(). This more accurately follows the NDIS interrupt handling
model, where the ISR does a minimal amount of work in interrupt context
and the handler is defered and run at a lower priority.

Create a separate ndis_intrmtx mutex just for the guarding the ISR.

Modify NdisSynchronizeWithInterrupt() to aquire the ndis_intrmtx
mutex before invoking the synchronized procedure. (The purpose of
this function is to provide mutual exclusion for code that shares
variables with the ISR.)

Modify NdisMRegisterInterrupt() to save a pointer to the miniport
block in the ndis_miniport_interrupt structure so that
NdisSynchronizeWithInterrupt() can grab it later and derive
ndis_intrmtx from it.

sys/compat/ndis/kern_ndis.c

@@ -45,6 +45,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/lock.h>
 #include <sys/mutex.h>
 #include <sys/conf.h>
+#include <sys/taskqueue.h>
 
 #include <sys/kernel.h>
 #include <machine/bus.h>

sys/compat/ndis/subr_ndis.c

@@ -1894,7 +1894,7 @@ ndis_register_intr(intr, adapter, ivec, ilevel, reqisr, shared, imode)
 	uint8_t			shared;
 	ndis_interrupt_mode	imode;
 {
-	
+	intr->ni_block = adapter;
 	return(NDIS_STATUS_SUCCESS);
 }	
 
@@ -2124,13 +2124,20 @@ ndis_sync_with_intr(intr, syncfunc, syncctx)
 	void			*syncfunc;
 	void			*syncctx;
 {
+	struct ndis_softc	*sc;
 	__stdcall uint8_t (*sync)(void *);
+	uint8_t			rval;
 
 	if (syncfunc == NULL || syncctx == NULL)
 		return(0);
 
+	sc = (struct ndis_softc *)intr->ni_block->nmb_ifp;
 	sync = syncfunc;
-	return(sync(syncctx));
+	mtx_lock(&sc->ndis_intrmtx);
+	rval = sync(syncctx);
+	mtx_unlock(&sc->ndis_intrmtx);
+
+	return(rval);
 }
 
 /*

sys/dev/if_ndis/if_ndis.c

@@ -44,6 +44,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/socket.h>
 #include <sys/queue.h>
 #include <sys/sysctl.h>
+#include <sys/taskqueue.h>
 
 #include <net/if.h>
 #include <net/if_arp.h>
@@ -105,6 +106,7 @@ static __stdcall void ndis_linksts	(ndis_handle,
 static __stdcall void ndis_linksts_done	(ndis_handle);
 
 static void ndis_intr		(void *);
+static void ndis_intrtask	(void *, int);
 static void ndis_tick		(void *);
 static void ndis_start		(struct ifnet *);
 static int ndis_ioctl		(struct ifnet *, u_long, caddr_t);
@@ -327,6 +329,10 @@ ndis_attach(dev)
 		goto fail;
 	}
 
+	mtx_init(&sc->ndis_intrmtx, device_get_nameunit(dev), "ndisisrlock",
+	    MTX_DEF | MTX_RECURSE);
+	TASK_INIT(&sc->ndis_intrtask, 0, ndis_intrtask, sc);
+
 	/*
 	 * Allocate the parent bus DMA tag appropriate for PCI.
 	 */
@@ -656,6 +662,7 @@ ndis_detach(dev)
 
 	sysctl_ctx_free(&sc->ndis_ctx);
 
+	mtx_destroy(&sc->ndis_intrmtx);
 	mtx_destroy(&sc->ndis_mtx);
 
 	return(0);
@@ -822,6 +829,25 @@ ndis_linksts_done(adapter)
 	return;
 }
 
+static void
+ndis_intrtask(arg, pending)
+	void			*arg;
+	int			pending;
+{
+	struct ndis_softc	*sc;
+	struct ifnet		*ifp;
+
+	sc = arg;
+	ifp = &sc->arpcom.ac_if;
+
+	ndis_intrhand(sc);
+
+	if (ifp->if_snd.ifq_head != NULL)
+		ndis_start(ifp);
+
+	return;
+}
+
 static void
 ndis_intr(arg)
 	void			*arg;
@@ -837,13 +863,12 @@ ndis_intr(arg)
 	if (!(ifp->if_flags & IFF_UP))
 		return;
 
+	mtx_lock(&sc->ndis_intrmtx);
 	ndis_isr(sc, &is_our_intr, &call_isr);
+	mtx_unlock(&sc->ndis_intrmtx);
 
 	if (is_our_intr || call_isr)
-		ndis_intrhand(sc);
-
-	if (ifp->if_snd.ifq_head != NULL)
-		ndis_start(ifp);
+		taskqueue_enqueue(taskqueue_swi, &sc->ndis_intrtask);
 
 	return;
 }

sys/dev/if_ndis/if_ndisvar.h

@@ -91,6 +91,8 @@ struct ndis_softc {
 	struct resource		*ndis_res_cm;	/* common mem (pccard) */
 	int			ndis_rescnt;
 	struct mtx		ndis_mtx;
+	struct mtx		ndis_intrmtx;
+	struct task		ndis_intrtask;
 	device_t		ndis_dev;
 	int			ndis_unit;
 	ndis_miniport_block	ndis_block;