Staging: hv: transmit scatter gather support

The transmit management of pages was confusing for handling
fragmented SKB's. (But since NETIF_F_SG was never set, the code was never hit).

The parameter AdditionalRequestPageBufferCount is always one,
(and leads to ugly code), so just inline and add comments.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/hv/RndisFilter.c b/drivers/staging/hv/RndisFilter.c
index 8611396..de4bc80 100644 (file)
--- a/drivers/staging/hv/RndisFilter.c
+++ b/drivers/staging/hv/RndisFilter.c
@@ -624,7 +624,6 @@ int RndisFilterInit(struct netvsc_driver *Driver)
                   sizeof(struct rndis_filter_packet));
 
        Driver->RequestExtSize = sizeof(struct rndis_filter_packet);
-       Driver->AdditionalRequestPageBufferCount = 1; /* For rndis header */
 
        /* Driver->Context = rndisDriver; */
 

diff --git a/drivers/staging/hv/netvsc_drv.c b/drivers/staging/hv/netvsc_drv.c
index b02455c..4124979 100644 (file)
--- a/drivers/staging/hv/netvsc_drv.c
+++ b/drivers/staging/hv/netvsc_drv.c
@@ -144,27 +144,21 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
                (struct netvsc_driver_context *)driver_ctx;
        struct netvsc_driver *net_drv_obj = &net_drv_ctx->drv_obj;
        struct hv_netvsc_packet *packet;
-       int i;
        int ret;
-       int num_frags;
+       unsigned int i, num_pages;
        int retries = 0;
 
        DPRINT_ENTER(NETVSC_DRV);
 
-       /* Support only 1 chain of frags */
-       ASSERT(skb_shinfo(skb)->frag_list == NULL);
-       ASSERT(skb->dev == net);
-
        DPRINT_DBG(NETVSC_DRV, "xmit packet - len %d data_len %d",
                   skb->len, skb->data_len);
 
-       /* Add 1 for skb->data and any additional ones requested */
-       num_frags = skb_shinfo(skb)->nr_frags + 1 +
-                   net_drv_obj->AdditionalRequestPageBufferCount;
+       /* Add 1 for skb->data and additional one for RNDIS */
+       num_pages = skb_shinfo(skb)->nr_frags + 1 + 1;
 
        /* Allocate a netvsc packet based on # of frags. */
        packet = kzalloc(sizeof(struct hv_netvsc_packet) +
-                        (num_frags * sizeof(struct hv_page_buffer)) +
+                        (num_pages * sizeof(struct hv_page_buffer)) +
                         net_drv_obj->RequestExtSize, GFP_ATOMIC);
        if (!packet) {
                DPRINT_ERR(NETVSC_DRV, "unable to allocate hv_netvsc_packet");
@@ -173,36 +167,30 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
 
        packet->Extension = (void *)(unsigned long)packet +
                                sizeof(struct hv_netvsc_packet) +
-                                   (num_frags * sizeof(struct hv_page_buffer));
+                                   (num_pages * sizeof(struct hv_page_buffer));
 
        /* Setup the rndis header */
-       packet->PageBufferCount = num_frags;
+       packet->PageBufferCount = num_pages;
 
        /* TODO: Flush all write buffers/ memory fence ??? */
        /* wmb(); */
 
        /* Initialize it from the skb */
-       ASSERT(skb->data);
        packet->TotalDataBufferLength   = skb->len;
 
-       /*
-        * Start filling in the page buffers starting at
-        * AdditionalRequestPageBufferCount offset
-        */
-       packet->PageBuffers[net_drv_obj->AdditionalRequestPageBufferCount].Pfn = virt_to_phys(skb->data) >> PAGE_SHIFT;
-       packet->PageBuffers[net_drv_obj->AdditionalRequestPageBufferCount].Offset = (unsigned long)skb->data & (PAGE_SIZE - 1);
-       packet->PageBuffers[net_drv_obj->AdditionalRequestPageBufferCount].Length = skb->len - skb->data_len;
-
-       ASSERT((skb->len - skb->data_len) <= PAGE_SIZE);
-
-       for (i = net_drv_obj->AdditionalRequestPageBufferCount + 1;
-            i < num_frags; i++) {
-               packet->PageBuffers[i].Pfn =
-                       page_to_pfn(skb_shinfo(skb)->frags[i-(net_drv_obj->AdditionalRequestPageBufferCount+1)].page);
-               packet->PageBuffers[i].Offset =
-                       skb_shinfo(skb)->frags[i-(net_drv_obj->AdditionalRequestPageBufferCount+1)].page_offset;
-               packet->PageBuffers[i].Length =
-                       skb_shinfo(skb)->frags[i-(net_drv_obj->AdditionalRequestPageBufferCount+1)].size;
+       /* Start filling in the page buffers starting after RNDIS buffer. */
+       packet->PageBuffers[1].Pfn = virt_to_phys(skb->data) >> PAGE_SHIFT;
+       packet->PageBuffers[1].Offset
+               = (unsigned long)skb->data & (PAGE_SIZE - 1);
+       packet->PageBuffers[1].Length = skb_headlen(skb);
+
+       /* Additional fragments are after SKB data */
+       for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+               skb_frag_t *f = &skb_shinfo(skb)->frags[i];
+
+               packet->PageBuffers[i+2].Pfn = page_to_pfn(f->page);
+               packet->PageBuffers[i+2].Offset = f->page_offset;
+               packet->PageBuffers[i+2].Length = f->size;
        }
 
        /* Set the completion routine */
@@ -423,6 +411,9 @@ static int netvsc_probe(struct device *device)
 
        net->netdev_ops = &device_ops;
 
+       /* TODO: Add GSO and Checksum offload */
+       net->features = NETIF_F_SG;
+
        SET_NETDEV_DEV(net, device);
 
        ret = register_netdev(net);