From: Lorenzo Bianconi <lorenzo@kernel.org>
Date: Fri, 17 Jul 2020 00:16:29 +0200
Subject: xdp: introduce xdp_get_shared_info_from_{buff, frame} utility
 routines
Patch-mainline: v5.9-rc1
Git-commit: 2f0bc54ba9a85032f2402faf0fccab513848300a
References: bsc#1177028

Introduce xdp_get_shared_info_from_{buff,frame} utility routines to get
skb_shared_info from xdp buffer/frame pointer.
xdp_get_shared_info_from_{buff,frame} will be used to implement xdp
multi-buffer support

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Gary Lin <glin@suse.com>
---
 include/net/xdp.h |   15 +++++++++++++++
 1 file changed, 15 insertions(+)

--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -85,6 +85,12 @@ struct xdp_buff {
 	((xdp)->data_hard_start + (xdp)->frame_sz -	\
 	 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
 
+static inline struct skb_shared_info *
+xdp_get_shared_info_from_buff(struct xdp_buff *xdp)
+{
+	return (struct skb_shared_info *)xdp_data_hard_end(xdp);
+}
+
 struct xdp_frame {
 	void *data;
 	u16 len;
@@ -98,6 +104,15 @@ struct xdp_frame {
 	struct net_device *dev_rx; /* used by cpumap */
 };
 
+static inline struct skb_shared_info *
+xdp_get_shared_info_from_frame(struct xdp_frame *frame)
+{
+	void *data_hard_start = frame->data - frame->headroom - sizeof(*frame);
+
+	return (struct skb_shared_info *)(data_hard_start + frame->frame_sz -
+				SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
+}
+
 /* Clear kernel pointers in xdp_frame */
 static inline void xdp_scrub_frame(struct xdp_frame *frame)
 {