+static u32 fill_pg_buf(struct page *page, u32 offset, u32 len,
+ struct hv_page_buffer *pb)
+{
+ int j = 0;
+
+ /* Deal with compund pages by ignoring unused part
+ * of the page.
+ */
+ page += (offset >> PAGE_SHIFT);
+ offset &= ~PAGE_MASK;
+
+ while (len > 0) {
+ unsigned long bytes;
+
+ bytes = PAGE_SIZE - offset;
+ if (bytes > len)
+ bytes = len;
+ pb[j].pfn = page_to_pfn(page);
+ pb[j].offset = offset;
+ pb[j].len = bytes;
+
+ offset += bytes;
+ len -= bytes;
+
+ if (offset == PAGE_SIZE && len) {
+ page++;
+ offset = 0;
+ j++;
+ }
+ }
+
+ return j + 1;
+}
+
+static u32 init_page_array(void *hdr, u32 len, struct sk_buff *skb,
+ struct hv_page_buffer *pb)
+{
+ u32 slots_used = 0;
+ char *data = skb->data;
+ int frags = skb_shinfo(skb)->nr_frags;
+ int i;
+
+ /* The packet is laid out thus:
+ * 1. hdr
+ * 2. skb linear data
+ * 3. skb fragment data
+ */
+ if (hdr != NULL)
+ slots_used += fill_pg_buf(virt_to_page(hdr),
+ offset_in_page(hdr),
+ len, &pb[slots_used]);
+
+ slots_used += fill_pg_buf(virt_to_page(data),
+ offset_in_page(data),
+ skb_headlen(skb), &pb[slots_used]);
+
+ for (i = 0; i < frags; i++) {
+ skb_frag_t *frag = skb_shinfo(skb)->frags + i;
+
+ slots_used += fill_pg_buf(skb_frag_page(frag),
+ frag->page_offset,
+ skb_frag_size(frag), &pb[slots_used]);
+ }
+ return slots_used;
+}
+
+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)
+{
+ 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 get_net_transport_info(struct sk_buff *skb, u32 *trans_off)
+{
+ u32 ret_val = TRANSPORT_INFO_NOT_IP;
+
+ if ((eth_hdr(skb)->h_proto != htons(ETH_P_IP)) &&
+ (eth_hdr(skb)->h_proto != htons(ETH_P_IPV6))) {
+ goto not_ip;
+ }
+
+ *trans_off = skb_transport_offset(skb);
+
+ if ((eth_hdr(skb)->h_proto == htons(ETH_P_IP))) {
+ struct iphdr *iphdr = ip_hdr(skb);
+
+ if (iphdr->protocol == IPPROTO_TCP)
+ ret_val = TRANSPORT_INFO_IPV4_TCP;
+ else if (iphdr->protocol == IPPROTO_UDP)
+ ret_val = TRANSPORT_INFO_IPV4_UDP;
+ } else {
+ if (ipv6_hdr(skb)->nexthdr == IPPROTO_TCP)
+ ret_val = TRANSPORT_INFO_IPV6_TCP;
+ else if (ipv6_hdr(skb)->nexthdr == IPPROTO_UDP)
+ ret_val = TRANSPORT_INFO_IPV6_UDP;
+ }
+
+not_ip:
+ return ret_val;
+}
+