net: Refactor xdp_convert_buff_to_frame

Move the guts of xdp_convert_buff_to_frame to a new helper,
xdp_update_frame_from_buff so it can be reused removing code duplication

Suggested-by: Jesper Dangaard Brouer <brouer@redhat.com>
Co-developed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/90a68c283d7ebeb48924934c9b7ac79492300472.1594734381.git.lorenzo@kernel.org

diff --git a/include/net/xdp.h b/include/net/xdp.h
index 609f819ed08bc0127b061758a6dbc244f1b636f5..5b383c45085867e6fd768fe5beacea9bf519723f 100644 (file)
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -121,39 +121,48 @@ void xdp_convert_frame_to_buff(struct xdp_frame *frame, struct xdp_buff *xdp)
        xdp->frame_sz = frame->frame_sz;
 }
 
-/* Convert xdp_buff to xdp_frame */
 static inline
-struct xdp_frame *xdp_convert_buff_to_frame(struct xdp_buff *xdp)
+int xdp_update_frame_from_buff(struct xdp_buff *xdp,
+                              struct xdp_frame *xdp_frame)
 {
-       struct xdp_frame *xdp_frame;
-       int metasize;
-       int headroom;
-
-       if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL)
-               return xdp_convert_zc_to_xdp_frame(xdp);
+       int metasize, headroom;
 
        /* Assure headroom is available for storing info */
        headroom = xdp->data - xdp->data_hard_start;
        metasize = xdp->data - xdp->data_meta;
        metasize = metasize > 0 ? metasize : 0;
        if (unlikely((headroom - metasize) < sizeof(*xdp_frame)))
-               return NULL;
+               return -ENOSPC;
 
        /* Catch if driver didn't reserve tailroom for skb_shared_info */
        if (unlikely(xdp->data_end > xdp_data_hard_end(xdp))) {
                XDP_WARN("Driver BUG: missing reserved tailroom");
-               return NULL;
+               return -ENOSPC;
        }
 
-       /* Store info in top of packet */
-       xdp_frame = xdp->data_hard_start;
-
        xdp_frame->data = xdp->data;
        xdp_frame->len  = xdp->data_end - xdp->data;
        xdp_frame->headroom = headroom - sizeof(*xdp_frame);
        xdp_frame->metasize = metasize;
        xdp_frame->frame_sz = xdp->frame_sz;
 
+       return 0;
+}
+
+/* Convert xdp_buff to xdp_frame */
+static inline
+struct xdp_frame *xdp_convert_buff_to_frame(struct xdp_buff *xdp)
+{
+       struct xdp_frame *xdp_frame;
+
+       if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL)
+               return xdp_convert_zc_to_xdp_frame(xdp);
+
+       /* Store info in top of packet */
+       xdp_frame = xdp->data_hard_start;
+       if (unlikely(xdp_update_frame_from_buff(xdp, xdp_frame) < 0))
+               return NULL;
+
        /* rxq only valid until napi_schedule ends, convert to xdp_mem_info */
        xdp_frame->mem = xdp->rxq->mem;