Staging: hv: add transmit flow control
Keep track of the number of pages sent over transmit and stop before going over. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Acked-by: Hank Janssen <hjanssen@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Stephen Hemminger
Greg Kroah-Hartman
parent
6048718d71
commit
b220f5f925
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@ -43,6 +43,7 @@
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struct net_device_context {
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/* point back to our device context */
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struct vm_device *device_ctx;
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unsigned long avail;
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};
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struct netvsc_driver_context {
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@ -52,8 +53,10 @@ struct netvsc_driver_context {
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struct netvsc_driver drv_obj;
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};
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/* Need at least MAX_SKB_FRAGS (18) + 1
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to handle worst case fragmented packet */
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#define PACKET_PAGES_LOWATER 8
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/* Need this many pages to handle worst case fragmented packet */
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#define PACKET_PAGES_HIWATER (MAX_SKB_FRAGS + 2)
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static int ring_size = roundup_pow_of_two(2*MAX_SKB_FRAGS+1);
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module_param(ring_size, int, S_IRUGO);
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MODULE_PARM_DESC(ring_size, "Ring buffer size (# of pages)");
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@ -122,14 +125,13 @@ static void netvsc_xmit_completion(void *context)
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if (skb) {
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struct net_device *net = skb->dev;
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struct net_device_context *net_device_ctx = netdev_priv(net);
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unsigned int num_pages = skb_shinfo(skb)->nr_frags + 2;
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dev_kfree_skb_any(skb);
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if (netif_queue_stopped(net)) {
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DPRINT_INFO(NETVSC_DRV, "net device (%p) waking up...",
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net);
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netif_wake_queue(net);
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}
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if ((net_device_ctx->avail += num_pages) >= PACKET_PAGES_HIWATER)
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netif_wake_queue(net);
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}
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DPRINT_EXIT(NETVSC_DRV);
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@ -146,7 +148,6 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
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struct hv_netvsc_packet *packet;
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int ret;
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unsigned int i, num_pages;
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int retries = 0;
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DPRINT_ENTER(NETVSC_DRV);
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@ -155,14 +156,20 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
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/* Add 1 for skb->data and additional one for RNDIS */
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num_pages = skb_shinfo(skb)->nr_frags + 1 + 1;
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if (num_pages > net_device_ctx->avail)
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return NETDEV_TX_BUSY;
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/* Allocate a netvsc packet based on # of frags. */
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packet = kzalloc(sizeof(struct hv_netvsc_packet) +
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(num_pages * sizeof(struct hv_page_buffer)) +
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net_drv_obj->RequestExtSize, GFP_ATOMIC);
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if (!packet) {
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/* out of memory, silently drop packet */
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DPRINT_ERR(NETVSC_DRV, "unable to allocate hv_netvsc_packet");
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return -1;
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dev_kfree_skb(skb);
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net->stats.tx_dropped++;
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return NETDEV_TX_OK;
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}
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packet->Extension = (void *)(unsigned long)packet +
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@ -198,52 +205,26 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
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packet->Completion.Send.SendCompletionContext = packet;
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packet->Completion.Send.SendCompletionTid = (unsigned long)skb;
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retry_send:
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ret = net_drv_obj->OnSend(&net_device_ctx->device_ctx->device_obj,
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packet);
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if (ret == 0) {
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ret = NETDEV_TX_OK;
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net->stats.tx_bytes += skb->len;
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net->stats.tx_packets++;
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DPRINT_DBG(NETVSC_DRV, "# of xmits %lu total size %lu",
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net->stats.tx_packets,
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net->stats.tx_bytes);
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if ((net_device_ctx->avail -= num_pages) < PACKET_PAGES_LOWATER)
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netif_stop_queue(net);
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} else {
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retries++;
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if (retries < 4) {
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DPRINT_ERR(NETVSC_DRV, "unable to send..."
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"retrying %d...", retries);
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udelay(100);
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goto retry_send;
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}
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/* no more room or we are shutting down */
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DPRINT_ERR(NETVSC_DRV, "unable to send (%d)..."
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"marking net device (%p) busy", ret, net);
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DPRINT_INFO(NETVSC_DRV, "net device (%p) stopping", net);
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ret = NETDEV_TX_BUSY;
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/* we are shutting down or bus overloaded, just drop packet */
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net->stats.tx_dropped++;
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netif_stop_queue(net);
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/*
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* Null it since the caller will free it instead of the
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* completion routine
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*/
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packet->Completion.Send.SendCompletionTid = 0;
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/*
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* Release the resources since we will not get any send
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* completion
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*/
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netvsc_xmit_completion((void *)packet);
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netvsc_xmit_completion(packet);
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}
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DPRINT_DBG(NETVSC_DRV, "# of xmits %lu total size %lu",
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net->stats.tx_packets,
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net->stats.tx_bytes);
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DPRINT_EXIT(NETVSC_DRV);
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return ret;
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return NETDEV_TX_OK;
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}
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/*
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@ -382,6 +363,7 @@ static int netvsc_probe(struct device *device)
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net_device_ctx = netdev_priv(net);
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net_device_ctx->device_ctx = device_ctx;
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net_device_ctx->avail = ring_size;
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dev_set_drvdata(device, net);
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/* Notify the netvsc driver of the new device */
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