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    SubjectRe: [Qemu-devel] [net-next RFC PATCH 7/7] virtio-net changes
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    Date
    On Fri, 2011-08-12 at 09:55 +0800, Jason Wang wrote:
    > 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>
    > ---

    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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