Re: [PATCH] xen/netfront: handle compound page fragments on transmit

On Wed, 2012-11-21 at 02:52 +0000, ANNIE LI wrote:

On 2012-11-20 19:40, Ian Campbell wrote:

quoted

An SKB paged fragment can consist of a compound page with order>  0.
However the netchannel protocol deals only in PAGE_SIZE frames.

Handle this in xennet_make_frags by iterating over the frames which
make up the page.

This is the netfront equivalent to 6a8ed462f16b for netback.

Signed-off-by: Ian Campbell<redacted>
Cc: netdev@vger.kernel.org
Cc: xen-devel@lists.xen.org
Cc: Eric Dumazet<redacted>
Cc: Konrad Rzeszutek Wilk<konrad@kernel.org>
Cc: ANNIE LI<redacted>
Cc: Sander Eikelenboom<redacted>
Cc: Stefan Bader<redacted>
---
  drivers/net/xen-netfront.c |   58 +++++++++++++++++++++++++++++++++----------
  1 files changed, 44 insertions(+), 14 deletions(-)

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index caa0110..a12b99a 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c

@@ -452,24 +452,54 @@ static void xennet_make_frags(struct sk_buff *skb, struct net_device *dev,
  	/* Grant backend access to each skb fragment page. */
  	for (i = 0; i<  frags; i++) {
  		skb_frag_t *frag = skb_shinfo(skb)->frags + i;
+		struct page *page = skb_frag_page(frag);
+		unsigned long size = skb_frag_size(frag);
+		unsigned long offset = frag->page_offset;

There are following definitions at the beginning of xennet_make_frags,

         unsigned int offset = offset_in_page(data);
         unsigned int len = skb_headlen(skb);

So they are, well spotted.

Is it better to reuse those definitions, and not define new size and 
offset again in this for loop? And unsigned int is enough here, right?

Yes to both.

[...]
Over 80 characters?

[...]

Over 80 characters?

Both fixed, thanks for your review.

Ian.