[PATCH v3 1/4] net/virtio: fix queue flushing with vector Rx enabled

[Olivier Matz <olivier.matz@6wind.com>]

When using vector Rx mode (use_simple_rx = 1), vq->vq_descx[] is not
kept up to date. To properly detach the mbufs in this case, browse
sw_ring[] instead, as it's done in virtqueue_rxvq_flush().

Since we need virtio_get_queue_type(), also move this function in
virtqueue.h as a static inline.

Fixes: fc3d66212fed ("virtio: add vector Rx")
Cc: stable@dpdk.org

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
---
 drivers/net/virtio/virtio_ethdev.c | 11 -----------
 drivers/net/virtio/virtqueue.c     | 28 +++++++++++++++++++++++++---
 drivers/net/virtio/virtqueue.h     | 11 +++++++++++
 3 files changed, 36 insertions(+), 14 deletions(-)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index 17ac04931..24ffbeeb2 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -279,17 +279,6 @@ virtio_dev_queue_release(void *queue __rte_unused)
 	/* do nothing */
 }
 
-static int
-virtio_get_queue_type(struct virtio_hw *hw, uint16_t vtpci_queue_idx)
-{
-	if (vtpci_queue_idx == hw->max_queue_pairs * 2)
-		return VTNET_CQ;
-	else if (vtpci_queue_idx % 2 == 0)
-		return VTNET_RQ;
-	else
-		return VTNET_TQ;
-}
-
 static uint16_t
 virtio_get_nr_vq(struct virtio_hw *hw)
 {
diff --git a/drivers/net/virtio/virtqueue.c b/drivers/net/virtio/virtqueue.c
index 1ada4fe08..5a8b21204 100644
--- a/drivers/net/virtio/virtqueue.c
+++ b/drivers/net/virtio/virtqueue.c
@@ -19,16 +19,38 @@ struct rte_mbuf *
 virtqueue_detatch_unused(struct virtqueue *vq)
 {
 	struct rte_mbuf *cookie;
-	int idx;
+	struct virtio_hw *hw;
+	uint16_t start, end;
+	int type, idx;
 
-	if (vq != NULL)
-		for (idx = 0; idx < vq->vq_nentries; idx++) {
+	if (vq == NULL)
+		return NULL;
+
+	hw = vq->hw;
+	type = virtio_get_queue_type(hw, vq->vq_queue_index);
+	start = vq->vq_avail_idx & (vq->vq_nentries - 1);
+	end = (vq->vq_avail_idx + vq->vq_free_cnt) & (vq->vq_nentries - 1);
+
+	for (idx = 0; idx < vq->vq_nentries; idx++) {
+		if (hw->use_simple_rx && type == VTNET_RQ) {
+			if (start <= end && idx >= start && idx < end)
+				continue;
+			if (start > end && (idx >= start || idx < end))
+				continue;
+			cookie = vq->sw_ring[idx];
+			if (cookie != NULL) {
+				vq->sw_ring[idx] = NULL;
+				return cookie;
+			}
+		} else {
 			cookie = vq->vq_descx[idx].cookie;
 			if (cookie != NULL) {
 				vq->vq_descx[idx].cookie = NULL;
 				return cookie;
 			}
 		}
+	}
+
 	return NULL;
 }
 
diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
index 2d9599218..e46de1583 100644
--- a/drivers/net/virtio/virtqueue.h
+++ b/drivers/net/virtio/virtqueue.h
@@ -292,6 +292,17 @@ virtqueue_full(const struct virtqueue *vq)
 	return vq->vq_free_cnt == 0;
 }
 
+static inline int
+virtio_get_queue_type(struct virtio_hw *hw, uint16_t vtpci_queue_idx)
+{
+	if (vtpci_queue_idx == hw->max_queue_pairs * 2)
+		return VTNET_CQ;
+	else if (vtpci_queue_idx % 2 == 0)
+		return VTNET_RQ;
+	else
+		return VTNET_TQ;
+}
+
 #define VIRTQUEUE_NUSED(vq) ((uint16_t)((vq)->vq_ring.used->idx - (vq)->vq_used_cons_idx))
 
 void vq_ring_free_chain(struct virtqueue *vq, uint16_t desc_idx);
-- 
2.11.0