static void xennet_maybe_wake_tx(struct net_device *dev)
{
struct netfront_info *np = netdev_priv(dev);
if (unlikely(netif_queue_stopped(dev)) &&
netfront_tx_slot_available(np) &&
likely(netif_running(dev)))
netif_wake_queue(dev);
}
static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
unsigned short id;
struct netfront_info *np = netdev_priv(dev);
struct xen_netif_tx_request *tx;
struct xen_netif_extra_info *extra;
char *data = skb->data;
RING_IDX i;
grant_ref_t ref;
unsigned long mfn;
int notify;
int frags = skb_shinfo(skb)->nr_frags;
unsigned int offset = offset_in_page(data);
unsigned int len = skb_headlen(skb);
frags += (offset + len + PAGE_SIZE - 1) / PAGE_SIZE;
if (unlikely(frags > MAX_SKB_FRAGS + 1)) {
printk(KERN_ALERT "xennet: skb rides the rocket: %d frags\n",
frags);
dump_stack();
goto drop;
}
spin_lock_irq(&np->tx_lock);
if (unlikely(!netif_carrier_ok(dev) ||
(frags > 1 && !xennet_can_sg(dev)) ||
netif_needs_gso(dev, skb))) {
spin_unlock_irq(&np->tx_lock);
goto drop;
}
i = np->tx.req_prod_pvt;
id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
np->tx_skbs[id].skb = skb;
tx = RING_GET_REQUEST(&np->tx, i);
tx->id = id;
ref = gnttab_claim_grant_reference(&np->gref_tx_head);
BUG_ON((signed short)ref < 0);
mfn = virt_to_mfn(data);
gnttab_grant_foreign_access_ref(
ref, np->xbdev->otherend_id, mfn, GNTMAP_readonly);
tx->gref = np->grant_tx_ref[id] = ref;
tx->offset = offset;
tx->size = len;
extra = NULL;
tx->flags = 0;
if (skb->ip_summed == CHECKSUM_PARTIAL)
/* local packet? */
tx->flags |= NETTXF_csum_blank | NETTXF_data_validated;
else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
/* remote but checksummed. */
tx->flags |= NETTXF_data_validated;
if (skb_shinfo(skb)->gso_size) {
struct xen_netif_extra_info *gso;
gso = (struct xen_netif_extra_info *)
RING_GET_REQUEST(&np->tx, ++i);
if (extra)
extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE;
else
tx->flags |= NETTXF_extra_info;
gso->u.gso.size = skb_shinfo(skb)->gso_size;
gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
gso->u.gso.pad = 0;
gso->u.gso.features = 0;
gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
gso->flags = 0;
extra = gso;
}
np->tx.req_prod_pvt = i + 1;
xennet_make_frags(skb, dev, tx);
tx->size = skb->len;
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->tx, notify);
if (notify)
notify_remote_via_irq(np->netdev->irq);
dev->stats.tx_bytes += skb->len;
dev->stats.tx_packets++;
/* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
xennet_tx_buf_gc(dev);
if (!netfront_tx_slot_available(np))
netif_stop_queue(dev);
spin_unlock_irq(&np->tx_lock);
return 0;
drop:
dev->stats.tx_dropped++;
dev_kfree_skb(skb);
return 0;
}
static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
unsigned short id;
struct netfront_info *np = netdev_priv(dev);
struct netfront_stats *stats = this_cpu_ptr(np->stats);
struct xen_netif_tx_request *tx;
struct xen_netif_extra_info *extra;
char *data = skb->data;
RING_IDX i;
grant_ref_t ref;
unsigned long mfn;
int notify;
int slots;
unsigned int offset = offset_in_page(data);
unsigned int len = skb_headlen(skb);
unsigned long flags;
/* If skb->len is too big for wire format, drop skb and alert
* user about misconfiguration.
*/
if (unlikely(skb->len > XEN_NETIF_MAX_TX_SIZE)) {
net_alert_ratelimited(
"xennet: skb->len = %u, too big for wire format\n",
skb->len);
goto drop;
}
slots = DIV_ROUND_UP(offset + len, PAGE_SIZE) +
xennet_count_skb_frag_slots(skb);
if (unlikely(slots > MAX_SKB_FRAGS + 1)) {
net_alert_ratelimited(
"xennet: skb rides the rocket: %d slots\n", slots);
goto drop;
}
spin_lock_irqsave(&np->tx_lock, flags);
if (unlikely(!netif_carrier_ok(dev) ||
(slots > 1 && !xennet_can_sg(dev)) ||
netif_needs_gso(skb, netif_skb_features(skb)))) {
spin_unlock_irqrestore(&np->tx_lock, flags);
goto drop;
}
i = np->tx.req_prod_pvt;
id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
np->tx_skbs[id].skb = skb;
tx = RING_GET_REQUEST(&np->tx, i);
tx->id = id;
ref = gnttab_claim_grant_reference(&np->gref_tx_head);
BUG_ON((signed short)ref < 0);
mfn = virt_to_mfn(data);
gnttab_grant_foreign_access_ref(
ref, np->xbdev->otherend_id, mfn, GNTMAP_readonly);
tx->gref = np->grant_tx_ref[id] = ref;
tx->offset = offset;
tx->size = len;
extra = NULL;
tx->flags = 0;
if (skb->ip_summed == CHECKSUM_PARTIAL)
/* local packet? */
tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated;
else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
/* remote but checksummed. */
tx->flags |= XEN_NETTXF_data_validated;
if (skb_shinfo(skb)->gso_size) {
struct xen_netif_extra_info *gso;
gso = (struct xen_netif_extra_info *)
RING_GET_REQUEST(&np->tx, ++i);
if (extra)
extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE;
else
tx->flags |= XEN_NETTXF_extra_info;
gso->u.gso.size = skb_shinfo(skb)->gso_size;
gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
gso->u.gso.pad = 0;
gso->u.gso.features = 0;
gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
gso->flags = 0;
extra = gso;
}
np->tx.req_prod_pvt = i + 1;
xennet_make_frags(skb, dev, tx);
tx->size = skb->len;
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->tx, notify);
if (notify)
notify_remote_via_irq(np->netdev->irq);
u64_stats_update_begin(&stats->syncp);
stats->tx_bytes += skb->len;
stats->tx_packets++;
u64_stats_update_end(&stats->syncp);
/* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
xennet_tx_buf_gc(dev);
if (!netfront_tx_slot_available(np))
netif_stop_queue(dev);
spin_unlock_irqrestore(&np->tx_lock, flags);
return NETDEV_TX_OK;
drop:
dev->stats.tx_dropped++;
dev_kfree_skb(skb);
return NETDEV_TX_OK;
}