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Re: [Qemu-devel] [net-next RFC PATCH 7/7] virtio-net changes


From: Sasha Levin
Subject: Re: [Qemu-devel] [net-next RFC PATCH 7/7] virtio-net changes
Date: Fri, 12 Aug 2011 12:09:16 +0300

On Fri, 2011-08-12 at 09:55 +0800, Jason Wang wrote:
> From: Krishna Kumar <address@hidden>
> 
> Implement mq virtio-net driver.
> 
> Though struct virtio_net_config changes, it works with the old
> qemu since the last element is not accessed unless qemu sets
> VIRTIO_NET_F_MULTIQUEUE.
> 
> Signed-off-by: Krishna Kumar <address@hidden>
> Signed-off-by: Jason Wang <address@hidden>
> ---

Could these changes be documented to virtio-spec as well?

>  drivers/net/virtio_net.c   |  578 
> +++++++++++++++++++++++++++++++-------------
>  include/linux/virtio_net.h |    3 
>  2 files changed, 411 insertions(+), 170 deletions(-)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 0c7321c..03a199d 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -49,16 +49,48 @@ struct virtnet_stats {
>       u64 rx_packets;
>  };
>  
> -struct virtnet_info {
> -     struct virtio_device *vdev;
> -     struct virtqueue *rvq, *svq, *cvq;
> -     struct net_device *dev;
> +/* Internal representation of a send virtqueue */
> +struct send_queue {
> +     /* Virtqueue associated with this send _queue */
> +     struct virtqueue *svq;
> +
> +     /* TX: fragments + linear part + virtio header */
> +     struct scatterlist tx_sg[MAX_SKB_FRAGS + 2];
> +};
> +
> +/* Internal representation of a receive virtqueue */
> +struct receive_queue {
> +     /* Virtqueue associated with this receive_queue */
> +     struct virtqueue *rvq;
> +
> +     /* Back pointer to the virtnet_info */
> +     struct virtnet_info *vi;
> +
>       struct napi_struct napi;
> -     unsigned int status;
>  
>       /* Number of input buffers, and max we've ever had. */
>       unsigned int num, max;
>  
> +     /* Work struct for refilling if we run low on memory. */
> +     struct delayed_work refill;
> +
> +     /* Chain pages by the private ptr. */
> +     struct page *pages;
> +
> +     /* RX: fragments + linear part + virtio header */
> +     struct scatterlist rx_sg[MAX_SKB_FRAGS + 2];
> +};
> +
> +struct virtnet_info {
> +     struct send_queue **sq;
> +     struct receive_queue **rq;
> +
> +     int numtxqs; /* # of rxqs/txqs */
> +     struct virtio_device *vdev;
> +     struct virtqueue *cvq;
> +     struct net_device *dev;
> +     unsigned int status;
> +
>       /* I like... big packets and I cannot lie! */
>       bool big_packets;
>  
> @@ -67,16 +99,6 @@ struct virtnet_info {
>  
>       /* Active statistics */
>       struct virtnet_stats __percpu *stats;
> -
> -     /* Work struct for refilling if we run low on memory. */
> -     struct delayed_work refill;
> -
> -     /* Chain pages by the private ptr. */
> -     struct page *pages;
> -
> -     /* fragments + linear part + virtio header */
> -     struct scatterlist rx_sg[MAX_SKB_FRAGS + 2];
> -     struct scatterlist tx_sg[MAX_SKB_FRAGS + 2];
>  };
>  
>  struct skb_vnet_hdr {
> @@ -106,22 +128,22 @@ static inline struct skb_vnet_hdr *skb_vnet_hdr(struct 
> sk_buff *skb)
>   * private is used to chain pages for big packets, put the whole
>   * most recent used list in the beginning for reuse
>   */
> -static void give_pages(struct virtnet_info *vi, struct page *page)
> +static void give_pages(struct receive_queue *rq, struct page *page)
>  {
>       struct page *end;
>  
>       /* Find end of list, sew whole thing into vi->pages. */
>       for (end = page; end->private; end = (struct page *)end->private);
> -     end->private = (unsigned long)vi->pages;
> -     vi->pages = page;
> +     end->private = (unsigned long)rq->pages;
> +     rq->pages = page;
>  }
>  
> -static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask)
> +static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask)
>  {
> -     struct page *p = vi->pages;
> +     struct page *p = rq->pages;
>  
>       if (p) {
> -             vi->pages = (struct page *)p->private;
> +             rq->pages = (struct page *)p->private;
>               /* clear private here, it is used to chain pages */
>               p->private = 0;
>       } else
> @@ -132,12 +154,13 @@ static struct page *get_a_page(struct virtnet_info *vi, 
> gfp_t gfp_mask)
>  static void skb_xmit_done(struct virtqueue *svq)
>  {
>       struct virtnet_info *vi = svq->vdev->priv;
> +     int qnum = svq->queue_index / 2; /* RX/TX vqs are allocated in pairs */
>  
>       /* Suppress further interrupts. */
>       virtqueue_disable_cb(svq);
>  
>       /* We were probably waiting for more output buffers. */
> -     netif_wake_queue(vi->dev);
> +     netif_wake_subqueue(vi->dev, qnum);
>  }
>  
>  static void set_skb_frag(struct sk_buff *skb, struct page *page,
> @@ -157,9 +180,10 @@ static void set_skb_frag(struct sk_buff *skb, struct 
> page *page,
>       *len -= f->size;
>  }
>  
> -static struct sk_buff *page_to_skb(struct virtnet_info *vi,
> +static struct sk_buff *page_to_skb(struct receive_queue *rq,
>                                  struct page *page, unsigned int len)
>  {
> +     struct virtnet_info *vi = rq->vi;
>       struct sk_buff *skb;
>       struct skb_vnet_hdr *hdr;
>       unsigned int copy, hdr_len, offset;
> @@ -202,12 +226,12 @@ static struct sk_buff *page_to_skb(struct virtnet_info 
> *vi,
>       }
>  
>       if (page)
> -             give_pages(vi, page);
> +             give_pages(rq, page);
>  
>       return skb;
>  }
>  
> -static int receive_mergeable(struct virtnet_info *vi, struct sk_buff *skb)
> +static int receive_mergeable(struct receive_queue *rq, struct sk_buff *skb)
>  {
>       struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
>       struct page *page;
> @@ -221,7 +245,8 @@ static int receive_mergeable(struct virtnet_info *vi, 
> struct sk_buff *skb)
>                       skb->dev->stats.rx_length_errors++;
>                       return -EINVAL;
>               }
> -             page = virtqueue_get_buf(vi->rvq, &len);
> +
> +             page = virtqueue_get_buf(rq->rvq, &len);
>               if (!page) {
>                       pr_debug("%s: rx error: %d buffers missing\n",
>                                skb->dev->name, hdr->mhdr.num_buffers);
> @@ -234,13 +259,14 @@ static int receive_mergeable(struct virtnet_info *vi, 
> struct sk_buff *skb)
>  
>               set_skb_frag(skb, page, 0, &len);
>  
> -             --vi->num;
> +             --rq->num;
>       }
>       return 0;
>  }
>  
> -static void receive_buf(struct net_device *dev, void *buf, unsigned int len)
> +static void receive_buf(struct receive_queue *rq, void *buf, unsigned int 
> len)
>  {
> +     struct net_device *dev = rq->vi->dev;
>       struct virtnet_info *vi = netdev_priv(dev);
>       struct virtnet_stats __percpu *stats = this_cpu_ptr(vi->stats);
>       struct sk_buff *skb;
> @@ -251,7 +277,7 @@ static void receive_buf(struct net_device *dev, void 
> *buf, unsigned int len)
>               pr_debug("%s: short packet %i\n", dev->name, len);
>               dev->stats.rx_length_errors++;
>               if (vi->mergeable_rx_bufs || vi->big_packets)
> -                     give_pages(vi, buf);
> +                     give_pages(rq, buf);
>               else
>                       dev_kfree_skb(buf);
>               return;
> @@ -263,14 +289,14 @@ static void receive_buf(struct net_device *dev, void 
> *buf, unsigned int len)
>               skb_trim(skb, len);
>       } else {
>               page = buf;
> -             skb = page_to_skb(vi, page, len);
> +             skb = page_to_skb(rq, page, len);
>               if (unlikely(!skb)) {
>                       dev->stats.rx_dropped++;
> -                     give_pages(vi, page);
> +                     give_pages(rq, page);
>                       return;
>               }
>               if (vi->mergeable_rx_bufs)
> -                     if (receive_mergeable(vi, skb)) {
> +                     if (receive_mergeable(rq, skb)) {
>                               dev_kfree_skb(skb);
>                               return;
>                       }
> @@ -341,184 +367,200 @@ frame_err:
>       dev_kfree_skb(skb);
>  }
>  
> -static int add_recvbuf_small(struct virtnet_info *vi, gfp_t gfp)
> +static int add_recvbuf_small(struct receive_queue *rq, gfp_t gfp)
>  {
>       struct sk_buff *skb;
>       struct skb_vnet_hdr *hdr;
>       int err;
>  
> -     skb = netdev_alloc_skb_ip_align(vi->dev, MAX_PACKET_LEN);
> +     skb = netdev_alloc_skb_ip_align(rq->vi->dev, MAX_PACKET_LEN);
>       if (unlikely(!skb))
>               return -ENOMEM;
>  
>       skb_put(skb, MAX_PACKET_LEN);
>  
>       hdr = skb_vnet_hdr(skb);
> -     sg_set_buf(vi->rx_sg, &hdr->hdr, sizeof hdr->hdr);
> +     sg_set_buf(rq->rx_sg, &hdr->hdr, sizeof hdr->hdr);
>  
> -     skb_to_sgvec(skb, vi->rx_sg + 1, 0, skb->len);
> +     skb_to_sgvec(skb, rq->rx_sg + 1, 0, skb->len);
>  
> -     err = virtqueue_add_buf_gfp(vi->rvq, vi->rx_sg, 0, 2, skb, gfp);
> +     err = virtqueue_add_buf_gfp(rq->rvq, rq->rx_sg, 0, 2, skb, gfp);
>       if (err < 0)
>               dev_kfree_skb(skb);
>  
>       return err;
>  }
>  
> -static int add_recvbuf_big(struct virtnet_info *vi, gfp_t gfp)
> +static int add_recvbuf_big(struct receive_queue *rq, gfp_t gfp)
>  {
>       struct page *first, *list = NULL;
>       char *p;
>       int i, err, offset;
>  
> -     /* page in vi->rx_sg[MAX_SKB_FRAGS + 1] is list tail */
> +     /* page in rq->rx_sg[MAX_SKB_FRAGS + 1] is list tail */
>       for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
> -             first = get_a_page(vi, gfp);
> +             first = get_a_page(rq, gfp);
>               if (!first) {
>                       if (list)
> -                             give_pages(vi, list);
> +                             give_pages(rq, list);
>                       return -ENOMEM;
>               }
> -             sg_set_buf(&vi->rx_sg[i], page_address(first), PAGE_SIZE);
> +             sg_set_buf(&rq->rx_sg[i], page_address(first), PAGE_SIZE);
>  
>               /* chain new page in list head to match sg */
>               first->private = (unsigned long)list;
>               list = first;
>       }
>  
> -     first = get_a_page(vi, gfp);
> +     first = get_a_page(rq, gfp);
>       if (!first) {
> -             give_pages(vi, list);
> +             give_pages(rq, list);
>               return -ENOMEM;
>       }
>       p = page_address(first);
>  
> -     /* vi->rx_sg[0], vi->rx_sg[1] share the same page */
> -     /* a separated vi->rx_sg[0] for virtio_net_hdr only due to QEMU bug */
> -     sg_set_buf(&vi->rx_sg[0], p, sizeof(struct virtio_net_hdr));
> +     /* rq->rx_sg[0], rq->rx_sg[1] share the same page */
> +     /* a separated rq->rx_sg[0] for virtio_net_hdr only due to QEMU bug */
> +     sg_set_buf(&rq->rx_sg[0], p, sizeof(struct virtio_net_hdr));
>  
> -     /* vi->rx_sg[1] for data packet, from offset */
> +     /* rq->rx_sg[1] for data packet, from offset */
>       offset = sizeof(struct padded_vnet_hdr);
> -     sg_set_buf(&vi->rx_sg[1], p + offset, PAGE_SIZE - offset);
> +     sg_set_buf(&rq->rx_sg[1], p + offset, PAGE_SIZE - offset);
>  
>       /* chain first in list head */
>       first->private = (unsigned long)list;
> -     err = virtqueue_add_buf_gfp(vi->rvq, vi->rx_sg, 0, MAX_SKB_FRAGS + 2,
> +     err = virtqueue_add_buf_gfp(rq->rvq, rq->rx_sg, 0, MAX_SKB_FRAGS + 2,
>                                   first, gfp);
>       if (err < 0)
> -             give_pages(vi, first);
> +             give_pages(rq, first);
>  
>       return err;
>  }
>  
> -static int add_recvbuf_mergeable(struct virtnet_info *vi, gfp_t gfp)
> +static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp)
>  {
>       struct page *page;
>       int err;
>  
> -     page = get_a_page(vi, gfp);
> +     page = get_a_page(rq, gfp);
>       if (!page)
>               return -ENOMEM;
>  
> -     sg_init_one(vi->rx_sg, page_address(page), PAGE_SIZE);
> +     sg_init_one(rq->rx_sg, page_address(page), PAGE_SIZE);
>  
> -     err = virtqueue_add_buf_gfp(vi->rvq, vi->rx_sg, 0, 1, page, gfp);
> +     err = virtqueue_add_buf_gfp(rq->rvq, rq->rx_sg, 0, 1, page, gfp);
>       if (err < 0)
> -             give_pages(vi, page);
> +             give_pages(rq, page);
>  
>       return err;
>  }
>  
>  /* Returns false if we couldn't fill entirely (OOM). */
> -static bool try_fill_recv(struct virtnet_info *vi, gfp_t gfp)
> +static bool try_fill_recv(struct receive_queue *rq, gfp_t gfp)
>  {
> +     struct virtnet_info *vi = rq->vi;
>       int err;
>       bool oom;
>  
>       do {
>               if (vi->mergeable_rx_bufs)
> -                     err = add_recvbuf_mergeable(vi, gfp);
> +                     err = add_recvbuf_mergeable(rq, gfp);
>               else if (vi->big_packets)
> -                     err = add_recvbuf_big(vi, gfp);
> +                     err = add_recvbuf_big(rq, gfp);
>               else
> -                     err = add_recvbuf_small(vi, gfp);
> +                     err = add_recvbuf_small(rq, gfp);
>  
>               oom = err == -ENOMEM;
>               if (err < 0)
>                       break;
> -             ++vi->num;
> +             ++rq->num;
>       } while (err > 0);
> -     if (unlikely(vi->num > vi->max))
> -             vi->max = vi->num;
> -     virtqueue_kick(vi->rvq);
> +     if (unlikely(rq->num > rq->max))
> +             rq->max = rq->num;
> +     virtqueue_kick(rq->rvq);
>       return !oom;
>  }
>  
>  static void skb_recv_done(struct virtqueue *rvq)
>  {
> +     int qnum = rvq->queue_index / 2; /* RX/TX vqs are allocated in pairs */
>       struct virtnet_info *vi = rvq->vdev->priv;
> +     struct napi_struct *napi = &vi->rq[qnum]->napi;
> +
>       /* Schedule NAPI, Suppress further interrupts if successful. */
> -     if (napi_schedule_prep(&vi->napi)) {
> +     if (napi_schedule_prep(napi)) {
>               virtqueue_disable_cb(rvq);
> -             __napi_schedule(&vi->napi);
> +             __napi_schedule(napi);
>       }
>  }
>  
> -static void virtnet_napi_enable(struct virtnet_info *vi)
> +static void virtnet_napi_enable(struct receive_queue *rq)
>  {
> -     napi_enable(&vi->napi);
> +     napi_enable(&rq->napi);
>  
>       /* If all buffers were filled by other side before we napi_enabled, we
>        * won't get another interrupt, so process any outstanding packets
>        * now.  virtnet_poll wants re-enable the queue, so we disable here.
>        * We synchronize against interrupts via NAPI_STATE_SCHED */
> -     if (napi_schedule_prep(&vi->napi)) {
> -             virtqueue_disable_cb(vi->rvq);
> -             __napi_schedule(&vi->napi);
> +     if (napi_schedule_prep(&rq->napi)) {
> +             virtqueue_disable_cb(rq->rvq);
> +             __napi_schedule(&rq->napi);
>       }
>  }
>  
> +static void virtnet_napi_enable_all_queues(struct virtnet_info *vi)
> +{
> +     int i;
> +
> +     for (i = 0; i < vi->numtxqs; i++)
> +             virtnet_napi_enable(vi->rq[i]);
> +}
> +
>  static void refill_work(struct work_struct *work)
>  {
> -     struct virtnet_info *vi;
> +     struct napi_struct *napi;
> +     struct receive_queue *rq;
>       bool still_empty;
>  
> -     vi = container_of(work, struct virtnet_info, refill.work);
> -     napi_disable(&vi->napi);
> -     still_empty = !try_fill_recv(vi, GFP_KERNEL);
> -     virtnet_napi_enable(vi);
> +     rq = container_of(work, struct receive_queue, refill.work);
> +     napi = &rq->napi;
> +
> +     napi_disable(napi);
> +     still_empty = !try_fill_recv(rq, GFP_KERNEL);
> +     virtnet_napi_enable(rq);
>  
>       /* In theory, this can happen: if we don't get any buffers in
>        * we will *never* try to fill again. */
>       if (still_empty)
> -             schedule_delayed_work(&vi->refill, HZ/2);
> +             schedule_delayed_work(&rq->refill, HZ/2);
>  }
>  
>  static int virtnet_poll(struct napi_struct *napi, int budget)
>  {
> -     struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
> +     struct receive_queue *rq = container_of(napi, struct receive_queue,
> +                                             napi);
>       void *buf;
>       unsigned int len, received = 0;
>  
>  again:
>       while (received < budget &&
> -            (buf = virtqueue_get_buf(vi->rvq, &len)) != NULL) {
> -             receive_buf(vi->dev, buf, len);
> -             --vi->num;
> +            (buf = virtqueue_get_buf(rq->rvq, &len)) != NULL) {
> +             receive_buf(rq, buf, len);
> +             --rq->num;
>               received++;
>       }
>  
> -     if (vi->num < vi->max / 2) {
> -             if (!try_fill_recv(vi, GFP_ATOMIC))
> -                     schedule_delayed_work(&vi->refill, 0);
> +     if (rq->num < rq->max / 2) {
> +             if (!try_fill_recv(rq, GFP_ATOMIC))
> +                     schedule_delayed_work(&rq->refill, 0);
>       }
>  
>       /* Out of packets? */
>       if (received < budget) {
>               napi_complete(napi);
> -             if (unlikely(!virtqueue_enable_cb(vi->rvq)) &&
> +             if (unlikely(!virtqueue_enable_cb(rq->rvq)) &&
>                   napi_schedule_prep(napi)) {
> -                     virtqueue_disable_cb(vi->rvq);
> +                     virtqueue_disable_cb(rq->rvq);
>                       __napi_schedule(napi);
>                       goto again;
>               }
> @@ -527,13 +569,14 @@ again:
>       return received;
>  }
>  
> -static unsigned int free_old_xmit_skbs(struct virtnet_info *vi)
> +static unsigned int free_old_xmit_skbs(struct virtnet_info *vi,
> +                                    struct virtqueue *svq)
>  {
>       struct sk_buff *skb;
>       unsigned int len, tot_sgs = 0;
>       struct virtnet_stats __percpu *stats = this_cpu_ptr(vi->stats);
>  
> -     while ((skb = virtqueue_get_buf(vi->svq, &len)) != NULL) {
> +     while ((skb = virtqueue_get_buf(svq, &len)) != NULL) {
>               pr_debug("Sent skb %p\n", skb);
>  
>               u64_stats_update_begin(&stats->syncp);
> @@ -547,7 +590,8 @@ static unsigned int free_old_xmit_skbs(struct 
> virtnet_info *vi)
>       return tot_sgs;
>  }
>  
> -static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
> +static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb,
> +                 struct virtqueue *svq, struct scatterlist *tx_sg)
>  {
>       struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
>       const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
> @@ -585,12 +629,12 @@ static int xmit_skb(struct virtnet_info *vi, struct 
> sk_buff *skb)
>  
>       /* Encode metadata header at front. */
>       if (vi->mergeable_rx_bufs)
> -             sg_set_buf(vi->tx_sg, &hdr->mhdr, sizeof hdr->mhdr);
> +             sg_set_buf(tx_sg, &hdr->mhdr, sizeof hdr->mhdr);
>       else
> -             sg_set_buf(vi->tx_sg, &hdr->hdr, sizeof hdr->hdr);
> +             sg_set_buf(tx_sg, &hdr->hdr, sizeof hdr->hdr);
>  
> -     hdr->num_sg = skb_to_sgvec(skb, vi->tx_sg + 1, 0, skb->len) + 1;
> -     return virtqueue_add_buf(vi->svq, vi->tx_sg, hdr->num_sg,
> +     hdr->num_sg = skb_to_sgvec(skb, tx_sg + 1, 0, skb->len) + 1;
> +     return virtqueue_add_buf(svq, tx_sg, hdr->num_sg,
>                                       0, skb);
>  }
>  
> @@ -598,31 +642,34 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, 
> struct net_device *dev)
>  {
>       struct virtnet_info *vi = netdev_priv(dev);
>       int capacity;
> +     int qnum = skb_get_queue_mapping(skb);
> +     struct virtqueue *svq = vi->sq[qnum]->svq;
>  
>       /* Free up any pending old buffers before queueing new ones. */
> -     free_old_xmit_skbs(vi);
> +     free_old_xmit_skbs(vi, svq);
>  
>       /* Try to transmit */
> -     capacity = xmit_skb(vi, skb);
> +     capacity = xmit_skb(vi, skb, svq, vi->sq[qnum]->tx_sg);
>  
>       /* This can happen with OOM and indirect buffers. */
>       if (unlikely(capacity < 0)) {
>               if (net_ratelimit()) {
>                       if (likely(capacity == -ENOMEM)) {
>                               dev_warn(&dev->dev,
> -                                      "TX queue failure: out of memory\n");
> +                                      "TXQ (%d) failure: out of memory\n",
> +                                      qnum);
>                       } else {
>                               dev->stats.tx_fifo_errors++;
>                               dev_warn(&dev->dev,
> -                                      "Unexpected TX queue failure: %d\n",
> -                                      capacity);
> +                                      "Unexpected TXQ (%d) failure: %d\n",
> +                                      qnum, capacity);
>                       }
>               }
>               dev->stats.tx_dropped++;
>               kfree_skb(skb);
>               return NETDEV_TX_OK;
>       }
> -     virtqueue_kick(vi->svq);
> +     virtqueue_kick(svq);
>  
>       /* Don't wait up for transmitted skbs to be freed. */
>       skb_orphan(skb);
> @@ -631,13 +678,13 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, 
> struct net_device *dev)
>       /* Apparently nice girls don't return TX_BUSY; stop the queue
>        * before it gets out of hand.  Naturally, this wastes entries. */
>       if (capacity < 2+MAX_SKB_FRAGS) {
> -             netif_stop_queue(dev);
> -             if (unlikely(!virtqueue_enable_cb_delayed(vi->svq))) {
> +             netif_stop_subqueue(dev, qnum);
> +             if (unlikely(!virtqueue_enable_cb_delayed(svq))) {
>                       /* More just got used, free them then recheck. */
> -                     capacity += free_old_xmit_skbs(vi);
> +                     capacity += free_old_xmit_skbs(vi, svq);
>                       if (capacity >= 2+MAX_SKB_FRAGS) {
> -                             netif_start_queue(dev);
> -                             virtqueue_disable_cb(vi->svq);
> +                             netif_start_subqueue(dev, qnum);
> +                             virtqueue_disable_cb(svq);
>                       }
>               }
>       }
> @@ -700,8 +747,10 @@ static struct rtnl_link_stats64 *virtnet_stats(struct 
> net_device *dev,
>  static void virtnet_netpoll(struct net_device *dev)
>  {
>       struct virtnet_info *vi = netdev_priv(dev);
> +     int i;
>  
> -     napi_schedule(&vi->napi);
> +     for (i = 0; i < vi->numtxqs; i++)
> +             napi_schedule(&vi->rq[i]->napi);
>  }
>  #endif
>  
> @@ -709,7 +758,7 @@ static int virtnet_open(struct net_device *dev)
>  {
>       struct virtnet_info *vi = netdev_priv(dev);
>  
> -     virtnet_napi_enable(vi);
> +     virtnet_napi_enable_all_queues(vi);
>       return 0;
>  }
>  
> @@ -761,8 +810,10 @@ static bool virtnet_send_command(struct virtnet_info 
> *vi, u8 class, u8 cmd,
>  static int virtnet_close(struct net_device *dev)
>  {
>       struct virtnet_info *vi = netdev_priv(dev);
> +     int i;
>  
> -     napi_disable(&vi->napi);
> +     for (i = 0; i < vi->numtxqs; i++)
> +             napi_disable(&vi->rq[i]->napi);
>  
>       return 0;
>  }
> @@ -919,10 +970,10 @@ static void virtnet_update_status(struct virtnet_info 
> *vi)
>  
>       if (vi->status & VIRTIO_NET_S_LINK_UP) {
>               netif_carrier_on(vi->dev);
> -             netif_wake_queue(vi->dev);
> +             netif_tx_wake_all_queues(vi->dev);
>       } else {
>               netif_carrier_off(vi->dev);
> -             netif_stop_queue(vi->dev);
> +             netif_tx_stop_all_queues(vi->dev);
>       }
>  }
>  
> @@ -933,18 +984,222 @@ static void virtnet_config_changed(struct 
> virtio_device *vdev)
>       virtnet_update_status(vi);
>  }
>  
> +static void free_receive_bufs(struct virtnet_info *vi)
> +{
> +     int i;
> +
> +     for (i = 0; i < vi->numtxqs; i++) {
> +             BUG_ON(vi->rq[i] == NULL);
> +             while (vi->rq[i]->pages)
> +                     __free_pages(get_a_page(vi->rq[i], GFP_KERNEL), 0);
> +     }
> +}
> +
> +/* Free memory allocated for send and receive queues */
> +static void free_rq_sq(struct virtnet_info *vi)
> +{
> +     int i;
> +
> +     if (vi->rq) {
> +             for (i = 0; i < vi->numtxqs; i++)
> +                     kfree(vi->rq[i]);
> +             kfree(vi->rq);
> +     }
> +
> +     if (vi->sq) {
> +             for (i = 0; i < vi->numtxqs; i++)
> +                     kfree(vi->sq[i]);
> +             kfree(vi->sq);
> +     }
> +}
> +
> +static void free_unused_bufs(struct virtnet_info *vi)
> +{
> +     void *buf;
> +     int i;
> +
> +     for (i = 0; i < vi->numtxqs; i++) {
> +             struct virtqueue *svq = vi->sq[i]->svq;
> +
> +             while (1) {
> +                     buf = virtqueue_detach_unused_buf(svq);
> +                     if (!buf)
> +                             break;
> +                     dev_kfree_skb(buf);
> +             }
> +     }
> +
> +     for (i = 0; i < vi->numtxqs; i++) {
> +             struct virtqueue *rvq = vi->rq[i]->rvq;
> +
> +             while (1) {
> +                     buf = virtqueue_detach_unused_buf(rvq);
> +                     if (!buf)
> +                             break;
> +                     if (vi->mergeable_rx_bufs || vi->big_packets)
> +                             give_pages(vi->rq[i], buf);
> +                     else
> +                             dev_kfree_skb(buf);
> +                     --vi->rq[i]->num;
> +             }
> +             BUG_ON(vi->rq[i]->num != 0);
> +     }
> +}
> +
> +#define MAX_DEVICE_NAME              16
> +static int initialize_vqs(struct virtnet_info *vi, int numtxqs)
> +{
> +     vq_callback_t **callbacks;
> +     struct virtqueue **vqs;
> +     int i, err = -ENOMEM;
> +     int totalvqs;
> +     char **names;
> +
> +     /* Allocate receive queues */
> +     vi->rq = kcalloc(numtxqs, sizeof(*vi->rq), GFP_KERNEL);
> +     if (!vi->rq)
> +             goto out;
> +     for (i = 0; i < numtxqs; i++) {
> +             vi->rq[i] = kzalloc(sizeof(*vi->rq[i]), GFP_KERNEL);
> +             if (!vi->rq[i])
> +                     goto out;
> +     }
> +
> +     /* Allocate send queues */
> +     vi->sq = kcalloc(numtxqs, sizeof(*vi->sq), GFP_KERNEL);
> +     if (!vi->sq)
> +             goto out;
> +     for (i = 0; i < numtxqs; i++) {
> +             vi->sq[i] = kzalloc(sizeof(*vi->sq[i]), GFP_KERNEL);
> +             if (!vi->sq[i])
> +                     goto out;
> +     }
> +
> +     /* setup initial receive and send queue parameters */
> +     for (i = 0; i < numtxqs; i++) {
> +             vi->rq[i]->vi = vi;
> +             vi->rq[i]->pages = NULL;
> +             INIT_DELAYED_WORK(&vi->rq[i]->refill, refill_work);
> +             netif_napi_add(vi->dev, &vi->rq[i]->napi, virtnet_poll,
> +                            napi_weight);
> +
> +             sg_init_table(vi->rq[i]->rx_sg, ARRAY_SIZE(vi->rq[i]->rx_sg));
> +             sg_init_table(vi->sq[i]->tx_sg, ARRAY_SIZE(vi->sq[i]->tx_sg));
> +     }
> +
> +     /*
> +      * We expect 1 RX virtqueue followed by 1 TX virtqueues, followed
> +      * by the same 'numtxqs-1' times, and optionally one control virtqueue.
> +      */
> +     totalvqs = numtxqs * 2 +
> +                virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ);
> +
> +     /* Allocate space for find_vqs parameters */
> +     vqs = kmalloc(totalvqs * sizeof(*vqs), GFP_KERNEL);
> +     callbacks = kmalloc(totalvqs * sizeof(*callbacks), GFP_KERNEL);
> +     names = kzalloc(totalvqs * sizeof(*names), GFP_KERNEL);
> +     if (!vqs || !callbacks || !names)
> +             goto free_params;
> +
> +#if 1
> +     /* Allocate/initialize parameters for recv/send virtqueues */
> +     for (i = 0; i < numtxqs * 2; i++) {
> +             names[i] = kmalloc(MAX_DEVICE_NAME * sizeof(*names[i]),
> +                                GFP_KERNEL);
> +             if (!names[i])
> +                     goto free_params;
> +
> +             if (!(i & 1)) {         /* RX */
> +                     callbacks[i] = skb_recv_done;
> +                     sprintf(names[i], "input.%d", i / 2);
> +             } else {
> +                     callbacks[i] = skb_xmit_done;
> +                     sprintf(names[i], "output.%d", i / 2);
> +             }
> +     }
> +
> +     /* Parameters for control virtqueue, if any */
> +     if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) {
> +             callbacks[i] = NULL;
> +             names[i] = "control";
> +     }
> +#else
> +     /* Allocate/initialize parameters for recv virtqueues */
> +     for (i = 0; i < numtxqs * 2; i += 2) {
> +             callbacks[i] = skb_recv_done;
> +             names[i] = kmalloc(MAX_DEVICE_NAME * sizeof(*names[i]),
> +                                GFP_KERNEL);
> +             if (!names[i])
> +                     goto free_params;
> +             sprintf(names[i], "input.%d", i / 2);
> +     }
> +
> +     /* Allocate/initialize parameters for send virtqueues */
> +     for (i = 1; i < numtxqs * 2; i += 2) {
> +             callbacks[i] = skb_xmit_done;
> +             names[i] = kmalloc(MAX_DEVICE_NAME * sizeof(*names[i]),
> +                                GFP_KERNEL);
> +             if (!names[i])
> +                     goto free_params;
> +             sprintf(names[i], "output.%d", i / 2);
> +     }
> +
> +     /* Parameters for control virtqueue, if any */
> +     if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) {
> +             callbacks[i - 1] = NULL;
> +             names[i - 1] = "control";
> +     }
> +#endif
> +
> +     err = vi->vdev->config->find_vqs(vi->vdev, totalvqs, vqs, callbacks,
> +                                      (const char **)names);
> +     if (err)
> +             goto free_params;
> +
> +     /* Assign the allocated vqs alternatively for RX/TX */
> +     for (i = 0; i < numtxqs * 2; i += 2) {
> +             vi->rq[i/2]->rvq = vqs[i];
> +             vi->sq[i/2]->svq = vqs[i + 1];
> +     }
> +
> +     if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ))
> +             vi->cvq = vqs[i];
> +
> +free_params:
> +     if (names) {
> +             for (i = 0; i < numtxqs * 2; i++)
> +                     kfree(names[i]);
> +             kfree(names);
> +     }
> +
> +     kfree(callbacks);
> +     kfree(vqs);
> +
> +out:
> +     if (err)
> +             free_rq_sq(vi);
> +
> +     return err;
> +}
> +
>  static int virtnet_probe(struct virtio_device *vdev)
>  {
> -     int err;
> +     int i, err;
> +     u16 numtxqs;
> +     u16 num_queue_pairs = 2;
>       struct net_device *dev;
>       struct virtnet_info *vi;
> -     struct virtqueue *vqs[3];
> -     vq_callback_t *callbacks[] = { skb_recv_done, skb_xmit_done, NULL};
> -     const char *names[] = { "input", "output", "control" };
> -     int nvqs;
> +
> +     /* Find if host supports MULTIQUEUE */
> +     err = virtio_config_val(vdev, VIRTIO_NET_F_MULTIQUEUE,
> +                             offsetof(struct virtio_net_config,
> +                             num_queue_pairs), &num_queue_pairs);
> +     numtxqs = num_queue_pairs / 2;
> +     if (!numtxqs)
> +             numtxqs = 1;
>  
>       /* Allocate ourselves a network device with room for our info */
> -     dev = alloc_etherdev(sizeof(struct virtnet_info));
> +     dev = alloc_etherdev_mq(sizeof(struct virtnet_info), numtxqs);
>       if (!dev)
>               return -ENOMEM;
>  
> @@ -991,19 +1246,14 @@ static int virtnet_probe(struct virtio_device *vdev)
>  
>       /* Set up our device-specific information */
>       vi = netdev_priv(dev);
> -     netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight);
>       vi->dev = dev;
>       vi->vdev = vdev;
>       vdev->priv = vi;
> -     vi->pages = NULL;
>       vi->stats = alloc_percpu(struct virtnet_stats);
>       err = -ENOMEM;
>       if (vi->stats == NULL)
>               goto free;
> -
> -     INIT_DELAYED_WORK(&vi->refill, refill_work);
> -     sg_init_table(vi->rx_sg, ARRAY_SIZE(vi->rx_sg));
> -     sg_init_table(vi->tx_sg, ARRAY_SIZE(vi->tx_sg));
> +     vi->numtxqs = numtxqs;
>  
>       /* If we can receive ANY GSO packets, we must allocate large ones. */
>       if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
> @@ -1014,23 +1264,14 @@ static int virtnet_probe(struct virtio_device *vdev)
>       if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
>               vi->mergeable_rx_bufs = true;
>  
> -     /* We expect two virtqueues, receive then send,
> -      * and optionally control. */
> -     nvqs = virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ? 3 : 2;
> -
> -     err = vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names);
> +     /* Initialize our rx/tx queue parameters, and invoke find_vqs */
> +     err = initialize_vqs(vi, numtxqs);
>       if (err)
>               goto free_stats;
>  
> -     vi->rvq = vqs[0];
> -     vi->svq = vqs[1];
> -
> -     if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) {
> -             vi->cvq = vqs[2];
> -
> -             if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
> -                     dev->features |= NETIF_F_HW_VLAN_FILTER;
> -     }
> +     if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) &&
> +         virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
> +             dev->features |= NETIF_F_HW_VLAN_FILTER;
>  
>       err = register_netdev(dev);
>       if (err) {
> @@ -1039,14 +1280,21 @@ static int virtnet_probe(struct virtio_device *vdev)
>       }
>  
>       /* Last of all, set up some receive buffers. */
> -     try_fill_recv(vi, GFP_KERNEL);
> -
> -     /* If we didn't even get one input buffer, we're useless. */
> -     if (vi->num == 0) {
> -             err = -ENOMEM;
> -             goto unregister;
> +     for (i = 0; i < numtxqs; i++) {
> +             try_fill_recv(vi->rq[i], GFP_KERNEL);
> +
> +             /* If we didn't even get one input buffer, we're useless. */
> +             if (vi->rq[i]->num == 0) {
> +                     if (i)
> +                             free_unused_bufs(vi);
> +                     err = -ENOMEM;
> +                     goto free_recv_bufs;
> +             }
>       }
>  
> +     dev_info(&dev->dev, "(virtio-net) Allocated %d RX & TX vq's\n",
> +              numtxqs);
> +
>       /* Assume link up if device can't report link status,
>          otherwise get link status from config. */
>       if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> @@ -1057,61 +1305,51 @@ static int virtnet_probe(struct virtio_device *vdev)
>               netif_carrier_on(dev);
>       }
>  
> -     pr_debug("virtnet: registered device %s\n", dev->name);
> +     pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
> +              dev->name, numtxqs);
>       return 0;
>  
> -unregister:
> +free_recv_bufs:
> +     free_receive_bufs(vi);
>       unregister_netdev(dev);
> -     cancel_delayed_work_sync(&vi->refill);
> +
>  free_vqs:
> +     for (i = 0; i < numtxqs; i++)
> +             cancel_delayed_work_sync(&vi->rq[i]->refill);
>       vdev->config->del_vqs(vdev);
> +     free_rq_sq(vi);
> +
>  free_stats:
>       free_percpu(vi->stats);
> +
>  free:
>       free_netdev(dev);
>       return err;
>  }
>  
> -static void free_unused_bufs(struct virtnet_info *vi)
> -{
> -     void *buf;
> -     while (1) {
> -             buf = virtqueue_detach_unused_buf(vi->svq);
> -             if (!buf)
> -                     break;
> -             dev_kfree_skb(buf);
> -     }
> -     while (1) {
> -             buf = virtqueue_detach_unused_buf(vi->rvq);
> -             if (!buf)
> -                     break;
> -             if (vi->mergeable_rx_bufs || vi->big_packets)
> -                     give_pages(vi, buf);
> -             else
> -                     dev_kfree_skb(buf);
> -             --vi->num;
> -     }
> -     BUG_ON(vi->num != 0);
> -}
> -
>  static void __devexit virtnet_remove(struct virtio_device *vdev)
>  {
>       struct virtnet_info *vi = vdev->priv;
> +     int i;
>  
>       /* Stop all the virtqueues. */
>       vdev->config->reset(vdev);
>  
> 
>       unregister_netdev(vi->dev);
> -     cancel_delayed_work_sync(&vi->refill);
> +
> +     for (i = 0; i < vi->numtxqs; i++)
> +             cancel_delayed_work_sync(&vi->rq[i]->refill);
>  
>       /* Free unused buffers in both send and recv, if any. */
>       free_unused_bufs(vi);
>  
>       vdev->config->del_vqs(vi->vdev);
>  
> -     while (vi->pages)
> -             __free_pages(get_a_page(vi, GFP_KERNEL), 0);
> +     free_receive_bufs(vi);
> +
> +     /* Free memory for send and receive queues */
> +     free_rq_sq(vi);
>  
>       free_percpu(vi->stats);
>       free_netdev(vi->dev);
> @@ -1129,7 +1367,7 @@ static unsigned int features[] = {
>       VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
>       VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
>       VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
> -     VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
> +     VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN, VIRTIO_NET_F_MULTIQUEUE,
>  };
>  
>  static struct virtio_driver virtio_net_driver = {
> diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
> index 970d5a2..fa85ac3 100644
> --- a/include/linux/virtio_net.h
> +++ b/include/linux/virtio_net.h
> @@ -49,6 +49,7 @@
>  #define VIRTIO_NET_F_CTRL_RX 18      /* Control channel RX mode support */
>  #define VIRTIO_NET_F_CTRL_VLAN       19      /* Control channel VLAN 
> filtering */
>  #define VIRTIO_NET_F_CTRL_RX_EXTRA 20        /* Extra RX mode control 
> support */
> +#define VIRTIO_NET_F_MULTIQUEUE      21      /* Device supports multiple 
> TXQ/RXQ */
>  
>  #define VIRTIO_NET_S_LINK_UP 1       /* Link is up */
>  
> @@ -57,6 +58,8 @@ struct virtio_net_config {
>       __u8 mac[6];
>       /* See VIRTIO_NET_F_STATUS and VIRTIO_NET_S_* above */
>       __u16 status;
> +     /* total number of RX/TX queues */
> +     __u16 num_queue_pairs;
>  } __attribute__((packed));
>  
>  /* This is the first element of the scatter-gather list.  If you don't
> 
> 

-- 

Sasha.




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