The network protocol used to communicate with the host is the remote ndis (rndis)
protocol. We need to decorate each outgoing packet with a rndis header and
additional rndis state (rndis per-packet state). To manage this state, we
currently allocate memory in the transmit path. Eliminate this allocation by
requesting additional head room in the skb.
Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
---
drivers/net/hyperv/hyperv_net.h | 3 +-
drivers/net/hyperv/netvsc.c | 10 ++++--
drivers/net/hyperv/netvsc_drv.c | 67 +++++++++++++++++++++++++++----------
drivers/net/hyperv/rndis_filter.c | 2 +
4 files changed, 60 insertions(+), 22 deletions(-)
diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 384f057..309adee 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -128,6 +128,7 @@ struct ndis_tcp_ip_checksum_info;
struct hv_netvsc_packet {
/* Bookkeeping stuff */
u32 status;
+ bool part_of_skb;
struct hv_device *device;
bool is_data_pkt;
@@ -150,7 +151,7 @@ struct hv_netvsc_packet {
/* Points to the send/receive buffer where the ethernet frame is */
void *data;
u32 page_buf_cnt;
- struct hv_page_buffer page_buf[0];
+ struct hv_page_buffer *page_buf;
};
struct netvsc_device_info {
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index ecbd813..f699236 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -866,11 +866,15 @@ int netvsc_send(struct hv_device *device,
netvsc_copy_to_send_buf(net_device,
section_index, msd_len,
packet);
- skb = (struct sk_buff *)
- (unsigned long)packet->send_completion_tid;
+ if (!packet->part_of_skb) {
+ skb = (struct sk_buff *)
+ (unsigned long)
+ packet->send_completion_tid;
+
+ packet->send_completion_tid = 0;
+ }
packet->page_buf_cnt = 0;
- packet->send_completion_tid = 0;
packet->send_buf_index = section_index;
packet->total_data_buflen += msd_len;
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 75beb89..f9db6bc 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -235,7 +235,8 @@ static void netvsc_xmit_completion(void *context)
struct sk_buff *skb = (struct sk_buff *)
(unsigned long)packet->send_completion_tid;
- kfree(packet);
+ if (!packet->part_of_skb)
+ kfree(packet);
if (skb)
dev_kfree_skb_any(skb);
@@ -383,6 +384,9 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
u32 net_trans_info;
u32 hash;
u32 skb_length = skb->len;
+ u32 head_room = skb_headroom(skb);
+ u32 pkt_sz;
+ struct hv_page_buffer page_buf[MAX_PAGE_BUFFER_COUNT];
/* We will atmost need two pages to describe the rndis
@@ -397,24 +401,32 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
return NETDEV_TX_OK;
}
- /* Allocate a netvsc packet based on # of frags. */
- packet = kzalloc(sizeof(struct hv_netvsc_packet) +
- (num_data_pgs * sizeof(struct hv_page_buffer)) +
- sizeof(struct rndis_message) +
- NDIS_VLAN_PPI_SIZE + NDIS_CSUM_PPI_SIZE +
- NDIS_LSO_PPI_SIZE + NDIS_HASH_PPI_SIZE, GFP_ATOMIC);
- if (!packet) {
- /* out of memory, drop packet */
- netdev_err(net, "unable to allocate hv_netvsc_packet\n");
-
- dev_kfree_skb(skb);
- net->stats.tx_dropped++;
- return NETDEV_TX_OK;
+ pkt_sz = sizeof(struct hv_netvsc_packet) +
+ sizeof(struct rndis_message) +
+ NDIS_VLAN_PPI_SIZE + NDIS_CSUM_PPI_SIZE +
+ NDIS_LSO_PPI_SIZE + NDIS_HASH_PPI_SIZE;
+
+ if (head_room < pkt_sz) {
+ packet = kmalloc(pkt_sz, GFP_ATOMIC);
+ if (!packet) {
+ /* out of memory, drop packet */
+ netdev_err(net, "unable to alloc hv_netvsc_packet\n");
+ dev_kfree_skb(skb);
+ net->stats.tx_dropped++;
+ return NETDEV_TX_OK;
+ }
+ packet->part_of_skb = false;
+ } else {
+ /* Use the headroom for building up the packet */
+ packet = (struct hv_netvsc_packet *)skb->head;
+ packet->part_of_skb = true;
}
+ packet->status = 0;
packet->xmit_more = skb->xmit_more;
packet->vlan_tci = skb->vlan_tci;
+ packet->page_buf = page_buf;
packet->q_idx = skb_get_queue_mapping(skb);
@@ -422,8 +434,13 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
packet->total_data_buflen = skb->len;
packet->rndis_msg = (struct rndis_message *)((unsigned long)packet +
- sizeof(struct hv_netvsc_packet) +
- (num_data_pgs * sizeof(struct hv_page_buffer)));
+ sizeof(struct hv_netvsc_packet));
+
+ memset(packet->rndis_msg, 0, sizeof(struct rndis_message) +
+ NDIS_VLAN_PPI_SIZE +
+ NDIS_CSUM_PPI_SIZE +
+ NDIS_LSO_PPI_SIZE +
+ NDIS_HASH_PPI_SIZE);
/* Set the completion routine */
packet->send_completion = netvsc_xmit_completion;
@@ -555,7 +572,7 @@ do_send:
rndis_msg->msg_len += rndis_msg_size;
packet->total_data_buflen = rndis_msg->msg_len;
packet->page_buf_cnt = init_page_array(rndis_msg, rndis_msg_size,
- skb, &packet->page_buf[0]);
+ skb, &page_buf[0]);
ret = netvsc_send(net_device_ctx->device_ctx, packet);
@@ -564,7 +581,8 @@ drop:
net->stats.tx_bytes += skb_length;
net->stats.tx_packets++;
} else {
- kfree(packet);
+ if (!packet->part_of_skb)
+ kfree(packet);
if (ret != -EAGAIN) {
dev_kfree_skb_any(skb);
net->stats.tx_dropped++;
@@ -846,12 +864,18 @@ static int netvsc_probe(struct hv_device *dev,
struct netvsc_device_info device_info;
struct netvsc_device *nvdev;
int ret;
+ u32 max_needed_headroom;
net = alloc_etherdev_mq(sizeof(struct net_device_context),
num_online_cpus());
if (!net)
return -ENOMEM;
+ max_needed_headroom = sizeof(struct hv_netvsc_packet) +
+ sizeof(struct rndis_message) +
+ NDIS_VLAN_PPI_SIZE + NDIS_CSUM_PPI_SIZE +
+ NDIS_LSO_PPI_SIZE + NDIS_HASH_PPI_SIZE;
+
netif_carrier_off(net);
net_device_ctx = netdev_priv(net);
@@ -870,6 +894,13 @@ static int netvsc_probe(struct hv_device *dev,
net->ethtool_ops = ðtool_ops;
SET_NETDEV_DEV(net, &dev->device);
+ /*
+ * Request additional head room in the skb.
+ * We will use this space to build the rndis
+ * heaser and other state we need to maintain.
+ */
+ net->needed_headroom = max_needed_headroom;
+
/* Notify the netvsc driver of the new device */
device_info.ring_size = ring_size;
ret = rndis_filter_device_add(dev, &device_info);
diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
index fdfab1f..a160437 100644
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -210,6 +210,7 @@ static int rndis_filter_send_request(struct rndis_device *dev,
{
int ret;
struct hv_netvsc_packet *packet;
+ struct hv_page_buffer page_buf[2];
/* Setup the packet to send it */
packet = &req->pkt;
@@ -217,6 +218,7 @@ static int rndis_filter_send_request(struct rndis_device *dev,
packet->is_data_pkt = false;
packet->total_data_buflen = req->request_msg.msg_len;
packet->page_buf_cnt = 1;
+ packet->page_buf = page_buf;
packet->page_buf[0].pfn = virt_to_phys(&req->request_msg) >>
PAGE_SHIFT;
--
1.7.4.1
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