[PATCH 1/3 bpf-next] net: add convert_to_xdp_frame_keep_zc function

[Jonathan Lemon <jonathan.lemon@gmail.com>]

Add a function which converts a ZC xdp_buff to a an xdp_frame, while
keeping the zc backing storage.  This will be used to support TX of
received AF_XDP frames.

Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
---
 include/net/xdp.h | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/include/net/xdp.h b/include/net/xdp.h
index 40c6d3398458..abe5f47ff0a5 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -82,6 +82,7 @@ struct xdp_frame {
 	 */
 	struct xdp_mem_info mem;
 	struct net_device *dev_rx; /* used by cpumap */
+	unsigned long handle;
 };
 
 /* Clear kernel pointers in xdp_frame */
@@ -95,15 +96,12 @@ struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp);
 
 /* Convert xdp_buff to xdp_frame */
 static inline
-struct xdp_frame *convert_to_xdp_frame(struct xdp_buff *xdp)
+struct xdp_frame *__convert_to_xdp_frame(struct xdp_buff *xdp)
 {
 	struct xdp_frame *xdp_frame;
 	int metasize;
 	int headroom;
 
-	if (xdp->rxq->mem.type == MEM_TYPE_ZERO_COPY)
-		return xdp_convert_zc_to_xdp_frame(xdp);
-
 	/* Assure headroom is available for storing info */
 	headroom = xdp->data - xdp->data_hard_start;
 	metasize = xdp->data - xdp->data_meta;
@@ -125,6 +123,20 @@ struct xdp_frame *convert_to_xdp_frame(struct xdp_buff *xdp)
 	return xdp_frame;
 }
 
+static inline
+struct xdp_frame *convert_to_xdp_frame(struct xdp_buff *xdp)
+{
+	if (xdp->rxq->mem.type == MEM_TYPE_ZERO_COPY)
+		return xdp_convert_zc_to_xdp_frame(xdp);
+	return __convert_to_xdp_frame(xdp);
+}
+
+static inline
+struct xdp_frame *convert_to_xdp_frame_keep_zc(struct xdp_buff *xdp)
+{
+	return __convert_to_xdp_frame(xdp);
+}
+
 void xdp_return_frame(struct xdp_frame *xdpf);
 void xdp_return_frame_rx_napi(struct xdp_frame *xdpf);
 void xdp_return_buff(struct xdp_buff *xdp);
-- 
2.17.1