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Staging: hv: add transmit flow control

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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 2010-05-04 09:58:56 -07:00 committed by Greg Kroah-Hartman
parent 6048718d71
commit b220f5f925
1 changed files with 28 additions and 46 deletions
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74
drivers/staging/hv/netvsc_drv.c
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@ -43,6 +43,7 @@
struct net_device_context {
/* point back to our device context */
struct vm_device *device_ctx;
unsigned long avail;
};
struct netvsc_driver_context {
@ -52,8 +53,10 @@ struct netvsc_driver_context {
struct netvsc_driver drv_obj;
};
/* Need at least MAX_SKB_FRAGS (18) + 1
to handle worst case fragmented packet */
#define PACKET_PAGES_LOWATER 8
/* Need this many pages to handle worst case fragmented packet */
#define PACKET_PAGES_HIWATER (MAX_SKB_FRAGS + 2)
static int ring_size = roundup_pow_of_two(2*MAX_SKB_FRAGS+1);
module_param(ring_size, int, S_IRUGO);
MODULE_PARM_DESC(ring_size, "Ring buffer size (# of pages)");
@ -122,14 +125,13 @@ static void netvsc_xmit_completion(void *context)
if (skb) {
struct net_device *net = skb->dev;
struct net_device_context *net_device_ctx = netdev_priv(net);
unsigned int num_pages = skb_shinfo(skb)->nr_frags + 2;
dev_kfree_skb_any(skb);
if (netif_queue_stopped(net)) {
DPRINT_INFO(NETVSC_DRV, "net device (%p) waking up...",
net);
netif_wake_queue(net);
}
if ((net_device_ctx->avail += num_pages) >= PACKET_PAGES_HIWATER)
netif_wake_queue(net);
}
DPRINT_EXIT(NETVSC_DRV);
@ -146,7 +148,6 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
struct hv_netvsc_packet *packet;
int ret;
unsigned int i, num_pages;
int retries = 0;
DPRINT_ENTER(NETVSC_DRV);
@ -155,14 +156,20 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
/* Add 1 for skb->data and additional one for RNDIS */
num_pages = skb_shinfo(skb)->nr_frags + 1 + 1;
if (num_pages > net_device_ctx->avail)
return NETDEV_TX_BUSY;
/* Allocate a netvsc packet based on # of frags. */
packet = kzalloc(sizeof(struct hv_netvsc_packet) +
(num_pages * sizeof(struct hv_page_buffer)) +
net_drv_obj->RequestExtSize, GFP_ATOMIC);
if (!packet) {
/* out of memory, silently drop packet */
DPRINT_ERR(NETVSC_DRV, "unable to allocate hv_netvsc_packet");
return -1;
dev_kfree_skb(skb);
net->stats.tx_dropped++;
return NETDEV_TX_OK;
}
packet->Extension = (void *)(unsigned long)packet +
@ -198,52 +205,26 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
packet->Completion.Send.SendCompletionContext = packet;
packet->Completion.Send.SendCompletionTid = (unsigned long)skb;
retry_send:
ret = net_drv_obj->OnSend(&net_device_ctx->device_ctx->device_obj,
packet);
if (ret == 0) {
ret = NETDEV_TX_OK;
net->stats.tx_bytes += skb->len;
net->stats.tx_packets++;
DPRINT_DBG(NETVSC_DRV, "# of xmits %lu total size %lu",
net->stats.tx_packets,
net->stats.tx_bytes);
if ((net_device_ctx->avail -= num_pages) < PACKET_PAGES_LOWATER)
netif_stop_queue(net);
} else {
retries++;
if (retries < 4) {
DPRINT_ERR(NETVSC_DRV, "unable to send..."
"retrying %d...", retries);
udelay(100);
goto retry_send;
}
/* no more room or we are shutting down */
DPRINT_ERR(NETVSC_DRV, "unable to send (%d)..."
"marking net device (%p) busy", ret, net);
DPRINT_INFO(NETVSC_DRV, "net device (%p) stopping", net);
ret = NETDEV_TX_BUSY;
/* we are shutting down or bus overloaded, just drop packet */
net->stats.tx_dropped++;
netif_stop_queue(net);
/*
* Null it since the caller will free it instead of the
* completion routine
*/
packet->Completion.Send.SendCompletionTid = 0;
/*
* Release the resources since we will not get any send
* completion
*/
netvsc_xmit_completion((void *)packet);
netvsc_xmit_completion(packet);
}
DPRINT_DBG(NETVSC_DRV, "# of xmits %lu total size %lu",
net->stats.tx_packets,
net->stats.tx_bytes);
DPRINT_EXIT(NETVSC_DRV);
return ret;
return NETDEV_TX_OK;
}
/*
@ -382,6 +363,7 @@ static int netvsc_probe(struct device *device)
net_device_ctx = netdev_priv(net);
net_device_ctx->device_ctx = device_ctx;
net_device_ctx->avail = ring_size;
dev_set_drvdata(device, net);
/* Notify the netvsc driver of the new device */