Author: sephe
Date: Wed Sep 28 04:34:21 2016
New Revision: 306390
URL: https://svnweb.freebsd.org/changeset/base/306390
Log:
hyperv/hn: Suspend and resume the backend properly upon MTU change.
Suspend:
- Prevent the backend from being touched on TX path.
- Clear the RNDIS RX filter, and wait for RX to drain.
- Make sure that NVS see the chimney sending buffer and RXBUF
disconnection, before unlink these buffers from the channel.
Resume:
- Reconfigure the RNDIS filter.
- Allow TX path to work on the backend.
- Kick start the TX eof task, in case the OACTIVE is set.
This fixes various panics, when the interface has traffic and MTU
is being changed.
MFC after: 1 week
Sponsored by: Microsoft
Differential Revision: https://reviews.freebsd.org/D8046
Modified:
head/sys/dev/hyperv/netvsc/hv_net_vsc.c
head/sys/dev/hyperv/netvsc/hv_net_vsc.h
head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c
Modified: head/sys/dev/hyperv/netvsc/hv_net_vsc.c
==============================================================================
--- head/sys/dev/hyperv/netvsc/hv_net_vsc.c Wed Sep 28 04:25:25 2016
(r306389)
+++ head/sys/dev/hyperv/netvsc/hv_net_vsc.c Wed Sep 28 04:34:21 2016
(r306390)
@@ -348,6 +348,16 @@ hn_nvs_disconn_rxbuf(struct hn_softc *sc
return (error);
}
sc->hn_flags &= ~HN_FLAG_RXBUF_CONNECTED;
+
+ /*
+ * Wait for the hypervisor to receive this NVS request.
+ */
+ while (!vmbus_chan_tx_empty(sc->hn_prichan))
+ pause("waittx", 1);
+ /*
+ * Linger long enough for NVS to disconnect RXBUF.
+ */
+ pause("lingtx", (200 * hz) / 1000);
}
if (sc->hn_rxbuf_gpadl != 0) {
@@ -389,6 +399,17 @@ hn_nvs_disconn_chim(struct hn_softc *sc)
return (error);
}
sc->hn_flags &= ~HN_FLAG_CHIM_CONNECTED;
+
+ /*
+ * Wait for the hypervisor to receive this NVS request.
+ */
+ while (!vmbus_chan_tx_empty(sc->hn_prichan))
+ pause("waittx", 1);
+ /*
+ * Linger long enough for NVS to disconnect chimney
+ * sending buffer.
+ */
+ pause("lingtx", (200 * hz) / 1000);
}
if (sc->hn_chim_gpadl != 0) {
Modified: head/sys/dev/hyperv/netvsc/hv_net_vsc.h
==============================================================================
--- head/sys/dev/hyperv/netvsc/hv_net_vsc.h Wed Sep 28 04:25:25 2016
(r306389)
+++ head/sys/dev/hyperv/netvsc/hv_net_vsc.h Wed Sep 28 04:34:21 2016
(r306390)
@@ -178,6 +178,7 @@ struct hn_tx_ring {
bus_dma_tag_t hn_tx_data_dtag;
uint64_t hn_csum_assist;
+ int hn_suspended;
int hn_gpa_cnt;
struct vmbus_gpa hn_gpa[NETVSC_PACKET_MAXPAGE];
Modified: head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c
==============================================================================
--- head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c Wed Sep 28 04:25:25
2016 (r306389)
+++ head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c Wed Sep 28 04:34:21
2016 (r306390)
@@ -348,6 +348,10 @@ static void hn_detach_allchans(struct hn
static void hn_chan_callback(struct vmbus_channel *chan, void *xrxr);
static void hn_set_ring_inuse(struct hn_softc *, int);
static int hn_synth_attach(struct hn_softc *, int);
+static bool hn_tx_ring_pending(struct hn_tx_ring *);
+static void hn_suspend(struct hn_softc *);
+static void hn_resume(struct hn_softc *);
+static void hn_tx_ring_qflush(struct hn_tx_ring *);
static void hn_nvs_handle_notify(struct hn_softc *sc,
const struct vmbus_chanpkt_hdr *pkt);
@@ -905,6 +909,23 @@ hn_txdesc_hold(struct hn_txdesc *txd)
atomic_add_int(&txd->refs, 1);
}
+static bool
+hn_tx_ring_pending(struct hn_tx_ring *txr)
+{
+ bool pending = false;
+
+#ifndef HN_USE_TXDESC_BUFRING
+ mtx_lock_spin(&txr->hn_txlist_spin);
+ if (txr->hn_txdesc_avail != txr->hn_txdesc_cnt)
+ pending = true;
+ mtx_unlock_spin(&txr->hn_txlist_spin);
+#else
+ if (!buf_ring_full(txr->hn_txdesc_br))
+ pending = true;
+#endif
+ return (pending);
+}
+
static __inline void
hn_txeof(struct hn_tx_ring *txr)
{
@@ -1241,6 +1262,9 @@ hn_start_locked(struct hn_tx_ring *txr,
KASSERT(txr == &sc->hn_tx_ring[0], ("not the first TX ring"));
mtx_assert(&txr->hn_tx_lock, MA_OWNED);
+ if (__predict_false(txr->hn_suspended))
+ return 0;
+
if ((ifp->if_drv_flags & (IFF_DRV_RUNNING | IFF_DRV_OACTIVE)) !=
IFF_DRV_RUNNING)
return 0;
@@ -1627,6 +1651,9 @@ hn_ioctl(struct ifnet *ifp, u_long cmd,
hn_set_lro_lenlim(sc, HN_LRO_LENLIM_MIN(ifp));
#endif
+ if (ifp->if_drv_flags & IFF_DRV_RUNNING)
+ hn_suspend(sc);
+
/* We must remove and add back the device to cause the new
* MTU to take effect. This includes tearing down, but not
* deleting the channel, then bringing it back up.
@@ -1651,7 +1678,9 @@ hn_ioctl(struct ifnet *ifp, u_long cmd,
if (sc->hn_tx_ring[0].hn_chim_size > sc->hn_chim_szmax)
hn_set_chim_size(sc, sc->hn_chim_szmax);
- hn_init_locked(sc);
+ /* All done! Resume now. */
+ if (ifp->if_drv_flags & IFF_DRV_RUNNING)
+ hn_resume(sc);
HN_UNLOCK(sc);
break;
@@ -2984,6 +3013,9 @@ hn_xmit(struct hn_tx_ring *txr, int len)
KASSERT(hn_use_if_start == 0,
("hn_xmit is called, when if_start is enabled"));
+ if (__predict_false(txr->hn_suspended))
+ return 0;
+
if ((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0 || txr->hn_oactive)
return 0;
@@ -3070,20 +3102,24 @@ do_sched:
}
static void
+hn_tx_ring_qflush(struct hn_tx_ring *txr)
+{
+ struct mbuf *m;
+
+ mtx_lock(&txr->hn_tx_lock);
+ while ((m = buf_ring_dequeue_sc(txr->hn_mbuf_br)) != NULL)
+ m_freem(m);
+ mtx_unlock(&txr->hn_tx_lock);
+}
+
+static void
hn_xmit_qflush(struct ifnet *ifp)
{
struct hn_softc *sc = ifp->if_softc;
int i;
- for (i = 0; i < sc->hn_tx_ring_inuse; ++i) {
- struct hn_tx_ring *txr = &sc->hn_tx_ring[i];
- struct mbuf *m;
-
- mtx_lock(&txr->hn_tx_lock);
- while ((m = buf_ring_dequeue_sc(txr->hn_mbuf_br)) != NULL)
- m_freem(m);
- mtx_unlock(&txr->hn_tx_lock);
- }
+ for (i = 0; i < sc->hn_tx_ring_inuse; ++i)
+ hn_tx_ring_qflush(&sc->hn_tx_ring[i]);
if_qflush(ifp);
}
@@ -3503,6 +3539,111 @@ hn_set_ring_inuse(struct hn_softc *sc, i
}
static void
+hn_rx_drain(struct vmbus_channel *chan)
+{
+
+ while (!vmbus_chan_rx_empty(chan) || !vmbus_chan_tx_empty(chan))
+ pause("waitch", 1);
+ vmbus_chan_intr_drain(chan);
+}
+
+static void
+hn_suspend(struct hn_softc *sc)
+{
+ struct vmbus_channel **subch = NULL;
+ int i, nsubch;
+
+ HN_LOCK_ASSERT(sc);
+
+ /*
+ * Suspend TX.
+ */
+ for (i = 0; i < sc->hn_tx_ring_inuse; ++i) {
+ struct hn_tx_ring *txr = &sc->hn_tx_ring[i];
+
+ mtx_lock(&txr->hn_tx_lock);
+ txr->hn_suspended = 1;
+ mtx_unlock(&txr->hn_tx_lock);
+ /* No one is able send more packets now. */
+
+ /* Wait for all pending sends to finish. */
+ while (hn_tx_ring_pending(txr))
+ pause("hnwtx", 1 /* 1 tick */);
+ }
+
+ /*
+ * Disable RX.
+ */
+ hv_rf_on_close(sc);
+
+ /* Give RNDIS enough time to flush all pending data packets. */
+ pause("waitrx", (200 * hz) / 1000);
+
+ nsubch = sc->hn_rx_ring_inuse - 1;
+ if (nsubch > 0)
+ subch = vmbus_subchan_get(sc->hn_prichan, nsubch);
+
+ /*
+ * Drain RX/TX bufrings and interrupts.
+ */
+ if (subch != NULL) {
+ for (i = 0; i < nsubch; ++i)
+ hn_rx_drain(subch[i]);
+ }
+ hn_rx_drain(sc->hn_prichan);
+
+ if (subch != NULL)
+ vmbus_subchan_rel(subch, nsubch);
+}
+
+static void
+hn_resume(struct hn_softc *sc)
+{
+ struct hn_tx_ring *txr;
+ int i;
+
+ HN_LOCK_ASSERT(sc);
+
+ /*
+ * Re-enable RX.
+ */
+ hv_rf_on_open(sc);
+
+ /*
+ * Make sure to clear suspend status on "all" TX rings,
+ * since hn_tx_ring_inuse can be changed after hn_suspend().
+ */
+ for (i = 0; i < sc->hn_tx_ring_cnt; ++i) {
+ txr = &sc->hn_tx_ring[i];
+
+ mtx_lock(&txr->hn_tx_lock);
+ txr->hn_suspended = 0;
+ mtx_unlock(&txr->hn_tx_lock);
+ }
+
+ if (!hn_use_if_start) {
+ /*
+ * Flush unused drbrs, since hn_tx_ring_inuse may be
+ * reduced.
+ */
+ for (i = sc->hn_tx_ring_inuse; i < sc->hn_tx_ring_cnt; ++i)
+ hn_tx_ring_qflush(&sc->hn_tx_ring[i]);
+ }
+
+ /*
+ * Kick start TX.
+ */
+ for (i = 0; i < sc->hn_tx_ring_inuse; ++i) {
+ txr = &sc->hn_tx_ring[i];
+ /*
+ * Use txeof task, so that any pending oactive can be
+ * cleared properly.
+ */
+ taskqueue_enqueue(txr->hn_tx_taskq, &txr->hn_txeof_task);
+ }
+}
+
+static void
hn_nvs_handle_notify(struct hn_softc *sc, const struct vmbus_chanpkt_hdr *pkt)
{
const struct hn_nvs_hdr *hdr;
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