From c276398e43bec444eb207c3184f667b3d97361f8 Mon Sep 17 00:00:00 2001

From: Tiwei Bie <tiwei.bie@intel.com>

Date: Wed, 23 Jan 2019 01:01:40 +0800

Subject: [PATCH 16/18] net/virtio: fix control VQ

[ upstream commit 2923b8f9c41da37d63bd196ba2f037c154a6ebd5 ]

This patch mainly fixed below issues in the packed ring based

control vq support in virtio driver:

1. When parsing the used descriptors, we have to track the

   number of descs that we need to skip;

2. vq->vq_free_cnt was decreased twice for a same desc;

Meanwhile, make the function name consistent with other parts.

Fixes: ec194c2f1895 ("net/virtio: support packed queue in send command")

Fixes: a4270ea4ff79 ("net/virtio: check head desc with correct wrap counter")

Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

[changed parameters to virtio_rmb/_wmb()]

(cherry picked from commit 2923b8f9c41da37d63bd196ba2f037c154a6ebd5)

Signed-off-by: Jens Freimann <jfreimann@redhat.com>

---

 drivers/net/virtio/virtio_ethdev.c | 62 ++++++++++++++----------------

 drivers/net/virtio/virtqueue.h     | 12 +-----

 2 files changed, 31 insertions(+), 43 deletions(-)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c

index 7bd38a292..c12fb157e 100644

--- a/drivers/net/virtio/virtio_ethdev.c

+++ b/drivers/net/virtio/virtio_ethdev.c

@@ -142,16 +142,17 @@ static const struct rte_virtio_xstats_name_off rte_virtio_txq_stat_strings[] = {

 struct virtio_hw_internal virtio_hw_internal[RTE_MAX_ETHPORTS];

 static struct virtio_pmd_ctrl *

-virtio_pq_send_command(struct virtnet_ctl *cvq, struct virtio_pmd_ctrl *ctrl,

-		       int *dlen, int pkt_num)

+virtio_send_command_packed(struct virtnet_ctl *cvq,

+			   struct virtio_pmd_ctrl *ctrl,

+			   int *dlen, int pkt_num)

 {

 	struct virtqueue *vq = cvq->vq;

 	int head;

 	struct vring_packed_desc *desc = vq->ring_packed.desc_packed;

 	struct virtio_pmd_ctrl *result;

-	bool avail_wrap_counter, used_wrap_counter;

-	uint16_t flags;

+	bool avail_wrap_counter;

 	int sum = 0;

+	int nb_descs = 0;

 	int k;

 	/*

@@ -162,11 +163,10 @@ virtio_pq_send_command(struct virtnet_ctl *cvq, struct virtio_pmd_ctrl *ctrl,

 	 */

 	head = vq->vq_avail_idx;

 	avail_wrap_counter = vq->avail_wrap_counter;

-	used_wrap_counter = vq->used_wrap_counter;

-	desc[head].flags = VRING_DESC_F_NEXT;

 	desc[head].addr = cvq->virtio_net_hdr_mem;

 	desc[head].len = sizeof(struct virtio_net_ctrl_hdr);

 	vq->vq_free_cnt--;

+	nb_descs++;

 	if (++vq->vq_avail_idx >= vq->vq_nentries) {

 		vq->vq_avail_idx -= vq->vq_nentries;

 		vq->avail_wrap_counter ^= 1;

@@ -177,55 +177,51 @@ virtio_pq_send_command(struct virtnet_ctl *cvq, struct virtio_pmd_ctrl *ctrl,

 			+ sizeof(struct virtio_net_ctrl_hdr)

 			+ sizeof(ctrl->status) + sizeof(uint8_t) * sum;

 		desc[vq->vq_avail_idx].len = dlen[k];

-		flags = VRING_DESC_F_NEXT;

+		desc[vq->vq_avail_idx].flags = VRING_DESC_F_NEXT |

+			VRING_DESC_F_AVAIL(vq->avail_wrap_counter) |

+			VRING_DESC_F_USED(!vq->avail_wrap_counter);

 		sum += dlen[k];

 		vq->vq_free_cnt--;

-		flags |= VRING_DESC_F_AVAIL(vq->avail_wrap_counter) |

-			 VRING_DESC_F_USED(!vq->avail_wrap_counter);

-		desc[vq->vq_avail_idx].flags = flags;

-		rte_smp_wmb();

-		vq->vq_free_cnt--;

+		nb_descs++;

 		if (++vq->vq_avail_idx >= vq->vq_nentries) {

 			vq->vq_avail_idx -= vq->vq_nentries;

 			vq->avail_wrap_counter ^= 1;

 		}

 	}

-

 	desc[vq->vq_avail_idx].addr = cvq->virtio_net_hdr_mem

 		+ sizeof(struct virtio_net_ctrl_hdr);

 	desc[vq->vq_avail_idx].len = sizeof(ctrl->status);

-	flags = VRING_DESC_F_WRITE;

-	flags |= VRING_DESC_F_AVAIL(vq->avail_wrap_counter) |

-		 VRING_DESC_F_USED(!vq->avail_wrap_counter);

-	desc[vq->vq_avail_idx].flags = flags;

-	flags = VRING_DESC_F_NEXT;

-	flags |= VRING_DESC_F_AVAIL(avail_wrap_counter) |

-		 VRING_DESC_F_USED(!avail_wrap_counter);

-	desc[head].flags = flags;

-	rte_smp_wmb();

-

+	desc[vq->vq_avail_idx].flags = VRING_DESC_F_WRITE |

+		VRING_DESC_F_AVAIL(vq->avail_wrap_counter) |

+		VRING_DESC_F_USED(!vq->avail_wrap_counter);

 	vq->vq_free_cnt--;

+	nb_descs++;

 	if (++vq->vq_avail_idx >= vq->vq_nentries) {

 		vq->vq_avail_idx -= vq->vq_nentries;

 		vq->avail_wrap_counter ^= 1;

 	}

+	virtio_wmb();

+	desc[head].flags = VRING_DESC_F_NEXT |

+		VRING_DESC_F_AVAIL(avail_wrap_counter) |

+		VRING_DESC_F_USED(!avail_wrap_counter);

+

+	virtio_wmb();

 	virtqueue_notify(vq);

 	/* wait for used descriptors in virtqueue */

-	do {

-		rte_rmb();

+	while (!desc_is_used(&desc[head], vq))

 		usleep(100);

-	} while (!__desc_is_used(&desc[head], used_wrap_counter));

+

+	virtio_rmb();

 	/* now get used descriptors */

-	while (desc_is_used(&desc[vq->vq_used_cons_idx], vq)) {

-		vq->vq_free_cnt++;

-		if (++vq->vq_used_cons_idx >= vq->vq_nentries) {

-			vq->vq_used_cons_idx -= vq->vq_nentries;

-			vq->used_wrap_counter ^= 1;

-		}

+	vq->vq_free_cnt += nb_descs;

+	vq->vq_used_cons_idx += nb_descs;

+	if (vq->vq_used_cons_idx >= vq->vq_nentries) {

+		vq->vq_used_cons_idx -= vq->vq_nentries;

+		vq->used_wrap_counter ^= 1;

 	}

 	result = cvq->virtio_net_hdr_mz->addr;

@@ -266,7 +262,7 @@ virtio_send_command(struct virtnet_ctl *cvq, struct virtio_pmd_ctrl *ctrl,

 		sizeof(struct virtio_pmd_ctrl));

 	if (vtpci_packed_queue(vq->hw)) {

-		result = virtio_pq_send_command(cvq, ctrl, dlen, pkt_num);

+		result = virtio_send_command_packed(cvq, ctrl, dlen, pkt_num);

 		goto out_unlock;

 	}

diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h

index 75f5782bc..9e74b7bd0 100644

--- a/drivers/net/virtio/virtqueue.h

+++ b/drivers/net/virtio/virtqueue.h

@@ -256,7 +256,7 @@ struct virtio_tx_region {

 };

 static inline int

-__desc_is_used(struct vring_packed_desc *desc, bool wrap_counter)

+desc_is_used(struct vring_packed_desc *desc, struct virtqueue *vq)

 {

 	uint16_t used, avail, flags;

@@ -264,16 +264,9 @@ __desc_is_used(struct vring_packed_desc *desc, bool wrap_counter)

 	used = !!(flags & VRING_DESC_F_USED(1));

 	avail = !!(flags & VRING_DESC_F_AVAIL(1));

-	return avail == used && used == wrap_counter;

-}

-

-static inline int

-desc_is_used(struct vring_packed_desc *desc, struct virtqueue *vq)

-{

-	return __desc_is_used(desc, vq->used_wrap_counter);

+	return avail == used && used == vq->used_wrap_counter;

 }

-

 static inline void

 vring_desc_init_packed(struct virtqueue *vq, int n)

 {

@@ -329,7 +322,6 @@ virtqueue_enable_intr_packed(struct virtqueue *vq)

 {

 	uint16_t *event_flags = &vq->ring_packed.driver_event->desc_event_flags;

-

 	if (vq->event_flags_shadow == RING_EVENT_FLAGS_DISABLE) {

 		virtio_wmb();

 		vq->event_flags_shadow = RING_EVENT_FLAGS_ENABLE;

-- 

2.21.0