From: Lorenzo Bianconi <lorenzo@kernel.org>
Date: Fri, 21 Jan 2022 11:09:54 +0100
Subject: bpf: introduce bpf_xdp_get_buff_len helper
Patch-mainline: v5.18-rc1
Git-commit: 0165cc817075cf701e4289838f1d925ff1911b3e
References: jsc#PED-373

Introduce bpf_xdp_get_buff_len helper in order to return the xdp buffer
total size (linear and paged area)

SUSE: This patch is stripped down to only include xdp_get_buff_len().
      All BPF parts are removed.

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/aac9ac3504c84026cf66a3c71b7c5ae89bc991be.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 include/net/xdp.h |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -145,6 +145,20 @@ xdp_get_shared_info_from_buff(struct xdp
 	return (struct skb_shared_info *)xdp_data_hard_end(xdp);
 }
 
+static __always_inline unsigned int xdp_get_buff_len(struct xdp_buff *xdp)
+{
+	unsigned int len = xdp->data_end - xdp->data;
+	struct skb_shared_info *sinfo;
+
+	if (likely(!xdp_buff_has_frags(xdp)))
+		goto out;
+
+	sinfo = xdp_get_shared_info_from_buff(xdp);
+	len += sinfo->xdp_frags_size;
+out:
+	return len;
+}
+
 struct xdp_frame {
 	void *data;
 	u16 len;