Merge tag 'renesas-soc-for-v3.13' of git://git.kernel.org/pub/scm/linux/kernel/git...

[firefly-linux-kernel-4.4.55.git] / drivers / net / xen-netback / netback.c

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 956130c70036d2d3d297e8d101bc68017f19c9d6..f3e591c611ded744ec0b6ea2cefe9b7dd3d568c7 100644 (file)
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -212,6 +212,49 @@ static bool start_new_rx_buffer(int offset, unsigned long size, int head)
        return false;
 }
 
+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
@@ -219,48 +262,39 @@ static bool start_new_rx_buffer(int offset, unsigned long size, int head)
  */
 unsigned int xenvif_count_skb_slots(struct xenvif *vif, struct sk_buff *skb)
 {
+       struct xenvif_count_slot_state state;
        unsigned int count;
-       int i, copy_off;
+       unsigned char *data;
+       unsigned i;
 
-       count = DIV_ROUND_UP(skb_headlen(skb), PAGE_SIZE);
+       state.head = true;
+       state.copy_off = 0;
 
-       copy_off = skb_headlen(skb) % PAGE_SIZE;
+       /* 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++;
 
-       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;
-               unsigned long bytes;
-
-               offset &= ~PAGE_MASK;
-
-               while (size > 0) {
-                       BUG_ON(offset >= PAGE_SIZE);
-                       BUG_ON(copy_off > MAX_BUFFER_OFFSET);
-
-                       bytes = PAGE_SIZE - offset;
-
-                       if (bytes > size)
-                               bytes = size;
+       data = skb->data;
+       while (data < skb_tail_pointer(skb)) {
+               unsigned long offset = offset_in_page(data);
+               unsigned long size = PAGE_SIZE - offset;
 
-                       if (start_new_rx_buffer(copy_off, bytes, 0)) {
-                               count++;
-                               copy_off = 0;
-                       }
+               if (data + size > skb_tail_pointer(skb))
+                       size = skb_tail_pointer(skb) - data;
 
-                       if (copy_off + bytes > MAX_BUFFER_OFFSET)
-                               bytes = MAX_BUFFER_OFFSET - copy_off;
+               count += xenvif_count_frag_slots(vif, offset, size, &state);
 
-                       copy_off += bytes;
+               data += size;
+       }
 
-                       offset += bytes;
-                       size -= bytes;
+       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;
 
-                       if (offset == PAGE_SIZE)
-                               offset = 0;
-               }
+               count += xenvif_count_frag_slots(vif, offset, size, &state);
        }
        return count;
 }