[dpdk-stable] patch 'net/virtio: fix vector Rx flushing' has been queued to LTS release 17.11.1

[Yuanhan Liu]

Hi,

FYI, your patch has been queued to LTS release 17.11.1

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 01/26/18. So please
shout if anyone has objections.

Thanks.

	--yliu

---
>From 82b3cc87817cd1a66df0f57cbe1cd85bb55b6071 Mon Sep 17 00:00:00 2001
From: Tiwei Bie <tiwei.bie at intel.com>
Date: Mon, 11 Dec 2017 13:13:29 +0800
Subject: [PATCH] net/virtio: fix vector Rx flushing

[ upstream commit bcf55c93026ff1db8ff2838766bbaaa38741579e ]

The vector Rx will be broken if backend has consumed all
the descs in the avail ring before the device is started.
Because in current implementation, vector Rx will return
immediately without refilling the avail ring if the used
ring is empty. So we have to refill the avail ring after
flushing the elements in the used ring for vector Rx.

Besides, vector Rx has a different ring layout assumption
and mbuf management. So we need to handle it differently.

Fixes: d8227497ec5c ("net/virtio: flush Rx queues on start")

Reported-by: Antonio Fischetti <antonio.fischetti at intel.com>
Signed-off-by: Tiwei Bie <tiwei.bie at intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin at redhat.com>
Tested-by: Antonio Fischetti <antonio.fischetti at intel.com>
Acked-by: Yuanhan Liu <yliu at fridaylinux.org>
---
 drivers/net/virtio/virtio_ethdev.c |  2 +-
 drivers/net/virtio/virtqueue.c     | 31 ++++++++++++++++++++++++-------
 drivers/net/virtio/virtqueue.h     |  2 +-
 3 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index 770c039..0b243f2 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -1860,7 +1860,7 @@ virtio_dev_start(struct rte_eth_dev *dev)
 	for (i = 0; i < dev->data->nb_rx_queues; i++) {
 		rxvq = dev->data->rx_queues[i];
 		/* Flush the old packets */
-		virtqueue_flush(rxvq->vq);
+		virtqueue_rxvq_flush(rxvq->vq);
 		virtqueue_notify(rxvq->vq);
 	}
 
diff --git a/drivers/net/virtio/virtqueue.c b/drivers/net/virtio/virtqueue.c
index c3a536f..696d0e4 100644
--- a/drivers/net/virtio/virtqueue.c
+++ b/drivers/net/virtio/virtqueue.c
@@ -37,6 +37,7 @@
 #include "virtqueue.h"
 #include "virtio_logs.h"
 #include "virtio_pci.h"
+#include "virtio_rxtx_simple.h"
 
 /*
  * Two types of mbuf to be cleaned:
@@ -62,8 +63,10 @@ virtqueue_detatch_unused(struct virtqueue *vq)
 
 /* Flush the elements in the used ring. */
 void
-virtqueue_flush(struct virtqueue *vq)
+virtqueue_rxvq_flush(struct virtqueue *vq)
 {
+	struct virtnet_rx *rxq = &vq->rxq;
+	struct virtio_hw *hw = vq->hw;
 	struct vring_used_elem *uep;
 	struct vq_desc_extra *dxp;
 	uint16_t used_idx, desc_idx;
@@ -74,13 +77,27 @@ virtqueue_flush(struct virtqueue *vq)
 	for (i = 0; i < nb_used; i++) {
 		used_idx = vq->vq_used_cons_idx & (vq->vq_nentries - 1);
 		uep = &vq->vq_ring.used->ring[used_idx];
-		desc_idx = (uint16_t)uep->id;
-		dxp = &vq->vq_descx[desc_idx];
-		if (dxp->cookie != NULL) {
-			rte_pktmbuf_free(dxp->cookie);
-			dxp->cookie = NULL;
+		if (hw->use_simple_rx) {
+			desc_idx = used_idx;
+			rte_pktmbuf_free(vq->sw_ring[desc_idx]);
+			vq->vq_free_cnt++;
+		} else {
+			desc_idx = (uint16_t)uep->id;
+			dxp = &vq->vq_descx[desc_idx];
+			if (dxp->cookie != NULL) {
+				rte_pktmbuf_free(dxp->cookie);
+				dxp->cookie = NULL;
+			}
+			vq_ring_free_chain(vq, desc_idx);
 		}
 		vq->vq_used_cons_idx++;
-		vq_ring_free_chain(vq, desc_idx);
+	}
+
+	if (hw->use_simple_rx) {
+		while (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
+			virtio_rxq_rearm_vec(rxq);
+			if (virtqueue_kick_prepare(vq))
+				virtqueue_notify(vq);
+		}
 	}
 }
diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
index 2305d91..ab466c2 100644
--- a/drivers/net/virtio/virtqueue.h
+++ b/drivers/net/virtio/virtqueue.h
@@ -304,7 +304,7 @@ void virtqueue_dump(struct virtqueue *vq);
 struct rte_mbuf *virtqueue_detatch_unused(struct virtqueue *vq);
 
 /* Flush the elements in the used ring. */
-void virtqueue_flush(struct virtqueue *vq);
+void virtqueue_rxvq_flush(struct virtqueue *vq);
 
 static inline int
 virtqueue_full(const struct virtqueue *vq)
-- 
2.7.4