On 07/09/2021 14.35, Lorenzo Bianconi wrote:

quoted

Introduce xdp_frags_tsize field in skb_shared_info data structure
to store xdp_buff/xdp_frame truesize (xdp_frags_tsize will be used
in xdp multi-buff support). In order to not increase skb_shared_info
size we will use a hole due to skb_shared_info alignment.
Introduce xdp_frags_size field in skb_shared_info data structure
reusing gso_type field in order to store xdp_buff/xdp_frame paged size.
xdp_frags_size will be used in xdp multi-buff support.

Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
  include/linux/skbuff.h | 6 +++++-
  1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 6bdb0db3e825..1abeba7ef82e 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h

@@ -522,13 +522,17 @@ struct skb_shared_info {
  	unsigned short	gso_segs;
  	struct sk_buff	*frag_list;
  	struct skb_shared_hwtstamps hwtstamps;
-	unsigned int	gso_type;
+	union {
+		unsigned int	gso_type;
+		unsigned int	xdp_frags_size;
+	};
  	u32		tskey;
  	/*
  	 * Warning : all fields before dataref are cleared in __alloc_skb()
  	 */
  	atomic_t	dataref;
+	unsigned int	xdp_frags_tsize;

I wonder if we could call this variable: xdp_frags_truesize.

As while reviewing patches I had to focus my eyes extra hard to tell the
variables xdp_frags_size and xdp_frags_tsize from each-other.

sure, I will fix it in v14.

Regards,
Lorenzo

--Jesper