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path: root/drivers/net/hyperv/netvsc_drv.c
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Diffstat (limited to 'drivers/net/hyperv/netvsc_drv.c')
-rw-r--r--drivers/net/hyperv/netvsc_drv.c43
1 files changed, 33 insertions, 10 deletions
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 63c98bbbc596..0d78727f1a14 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -315,14 +315,34 @@ static u32 init_page_array(void *hdr, u32 len, struct sk_buff *skb,
return slots_used;
}
-/* Estimate number of page buffers neede to transmit
- * Need at most 2 for RNDIS header plus skb body and fragments.
- */
-static unsigned int netvsc_get_slots(const struct sk_buff *skb)
+static int count_skb_frag_slots(struct sk_buff *skb)
+{
+ int i, frags = skb_shinfo(skb)->nr_frags;
+ int pages = 0;
+
+ for (i = 0; i < frags; i++) {
+ skb_frag_t *frag = skb_shinfo(skb)->frags + i;
+ unsigned long size = skb_frag_size(frag);
+ unsigned long offset = frag->page_offset;
+
+ /* Skip unused frames from start of page */
+ offset &= ~PAGE_MASK;
+ pages += PFN_UP(offset + size);
+ }
+ return pages;
+}
+
+static int netvsc_get_slots(struct sk_buff *skb)
{
- return PFN_UP(offset_in_page(skb->data) + skb_headlen(skb))
- + skb_shinfo(skb)->nr_frags
- + 2;
+ char *data = skb->data;
+ unsigned int offset = offset_in_page(data);
+ unsigned int len = skb_headlen(skb);
+ int slots;
+ int frag_slots;
+
+ slots = DIV_ROUND_UP(offset + len, PAGE_SIZE);
+ frag_slots = count_skb_frag_slots(skb);
+ return slots + frag_slots;
}
static u32 net_checksum_info(struct sk_buff *skb)
@@ -360,18 +380,21 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
struct hv_page_buffer page_buf[MAX_PAGE_BUFFER_COUNT];
struct hv_page_buffer *pb = page_buf;
- /* We can only transmit MAX_PAGE_BUFFER_COUNT number
+ /* We will atmost need two pages to describe the rndis
+ * header. We can only transmit MAX_PAGE_BUFFER_COUNT number
* of pages in a single packet. If skb is scattered around
* more pages we try linearizing it.
*/
- num_data_pgs = netvsc_get_slots(skb);
+
+ num_data_pgs = netvsc_get_slots(skb) + 2;
+
if (unlikely(num_data_pgs > MAX_PAGE_BUFFER_COUNT)) {
++net_device_ctx->eth_stats.tx_scattered;
if (skb_linearize(skb))
goto no_memory;
- num_data_pgs = netvsc_get_slots(skb);
+ num_data_pgs = netvsc_get_slots(skb) + 2;
if (num_data_pgs > MAX_PAGE_BUFFER_COUNT) {
++net_device_ctx->eth_stats.tx_too_big;
goto drop;