-struct xenvif_count_slot_state {
- unsigned long copy_off;
- bool head;
-};
-
-unsigned int xenvif_count_frag_slots(struct xenvif *vif,
- unsigned long offset, unsigned long size,
- struct xenvif_count_slot_state *state)
-{
- unsigned count = 0;
-
- offset &= ~PAGE_MASK;
-
- while (size > 0) {
- unsigned long bytes;
-
- bytes = PAGE_SIZE - offset;
-
- if (bytes > size)
- bytes = size;
-
- if (start_new_rx_buffer(state->copy_off, bytes, state->head)) {
- count++;
- state->copy_off = 0;
- }
-
- if (state->copy_off + bytes > MAX_BUFFER_OFFSET)
- bytes = MAX_BUFFER_OFFSET - state->copy_off;
-
- state->copy_off += bytes;
-
- offset += bytes;
- size -= bytes;
-
- if (offset == PAGE_SIZE)
- offset = 0;
-
- state->head = false;
- }
-
- return count;
-}
-
-/*
- * Figure out how many ring slots we're going to need to send @skb to
- * the guest. This function is essentially a dry run of
- * xenvif_gop_frag_copy.
- */
-unsigned int xenvif_count_skb_slots(struct xenvif *vif, struct sk_buff *skb)
-{
- struct xenvif_count_slot_state state;
- unsigned int count;
- unsigned char *data;
- unsigned i;
-
- state.head = true;
- state.copy_off = 0;
-
- /* Slot for the first (partial) page of data. */
- count = 1;
-
- /* Need a slot for the GSO prefix for GSO extra data? */
- if (skb_shinfo(skb)->gso_size)
- count++;
-
- data = skb->data;
- while (data < skb_tail_pointer(skb)) {
- unsigned long offset = offset_in_page(data);
- unsigned long size = PAGE_SIZE - offset;
-
- if (data + size > skb_tail_pointer(skb))
- size = skb_tail_pointer(skb) - data;
-
- count += xenvif_count_frag_slots(vif, offset, size, &state);
-
- data += size;
- }
-
- for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
- unsigned long size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
- unsigned long offset = skb_shinfo(skb)->frags[i].page_offset;
-
- count += xenvif_count_frag_slots(vif, offset, size, &state);
- }
- return count;
-}
-