[PATCH v7 bpf-next 2/9] net: refactor xdp_convert_buff_to_frame

Lorenzo Bianconi
2020-07-14T13:57:11Z

From: David Ahern <dsahern@kernel.org>

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>
Acked-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>
---
include/net/xdp.h | 35 ++++++++++++++++++++++-------------
1 file changed, 22 insertions(+), 13 deletions(-)

diff --git a/include/net/xdp.h b/include/net/xdp.h
index 609f819ed08b..5b383c450858 100644
--- 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;

--
2.26.2