Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa...

[karo-tx-linux.git] / drivers / net / hyperv / netvsc_drv.c

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 63c98bbbc596dbe11cc74ba71c384da02c5d763b..0d78727f1a14dd9c4ae301f053769437cbe4eb3b 100644 (file)
--- 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;