[dpdk-stable] patch 'net/virtio: fix vector Rx flushing' has been queued to LTS release 16.11.5

[luca.boccassi at gmail.com]

Hi,

FYI, your patch has been queued to LTS release 16.11.5

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 01/28/18. So please
shout if anyone has objections.

Thanks.

Luca Boccassi

---
>From 1b41fae3d2d5af298627dda9d35c25656450c861 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 3abaeabb2..4d6efd5ac 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -1565,7 +1565,7 @@ 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 4f8707ae3..0e24194a5 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"
 
 void
 virtqueue_disable_intr(struct virtqueue *vq)
@@ -73,8 +74,10 @@ 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;
@@ -85,13 +88,27 @@ 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_rxtx) {
+			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_rxtx) {
+		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 ec967a5bd..421485473 100644
--- a/drivers/net/virtio/virtqueue.h
+++ b/drivers/net/virtio/virtqueue.h
@@ -291,7 +291,7 @@ 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)
-- 
2.14.2