[net-next RFC PATCH 7/7] virtio-net changes

From: Jason Wang
Date: Thu Aug 11 2011 - 21:59:29 EST

From: Krishna Kumar <krkumar2@xxxxxxxxxx>

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@xxxxxxxxxx>
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
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

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