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    Subject[net-next RFC PATCH 7/7] virtio-net changes
    From
    Date
    From: Krishna Kumar <krkumar2@in.ibm.com>

    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 <krkumar2@in.ibm.com>
    Signed-off-by: Jason Wang <jasowang@redhat.com>
    ---
    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


    \
     
     \ /
      Last update: 2011-08-12 04:01    [W:0.088 / U:92.972 seconds]
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