net/virtio: fix control VQ

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>

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index ee5a98b..a3fe655 100644 (file)
--- 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(vq->hw->weak_barriers);
+       desc[head].flags = VRING_DESC_F_NEXT |
+               VRING_DESC_F_AVAIL(avail_wrap_counter) |
+               VRING_DESC_F_USED(!avail_wrap_counter);
+
+       virtio_wmb(vq->hw->weak_barriers);
        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(vq->hw->weak_barriers);
 
        /* 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 7fcde56..ca9d8e6 100644 (file)
--- a/drivers/net/virtio/virtqueue.h
+++ b/drivers/net/virtio/virtqueue.h
@@ -281,7 +281,7 @@ 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;
 
@@ -289,16 +289,9 @@ __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)
 {
@@ -354,7 +347,6 @@ 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->hw->weak_barriers);
                vq->event_flags_shadow = RING_EVENT_FLAGS_ENABLE;