[PATCH net-next 1/6] sfc: support encapsulation of xdp_frames in efx_tx_buffer.

[Charles McLachlan]

Add a field to efx_tx_buffer so that we can track xdp_frames. Add a
flag so that buffers that contain xdp_frames can be identified and
passed to xdp_return_frame.

Signed-off-by: Charles McLachlan <cmclach...@solarflare.com>
---
 drivers/net/ethernet/sfc/net_driver.h | 10 ++++++++--
 drivers/net/ethernet/sfc/tx.c         |  2 ++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/sfc/net_driver.h 
b/drivers/net/ethernet/sfc/net_driver.h
index 284a1b047ac2..7394d901e021 100644
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -27,6 +27,7 @@
 #include <linux/i2c.h>
 #include <linux/mtd/mtd.h>
 #include <net/busy_poll.h>
+#include <net/xdp.h>
 
 #include "enum.h"
 #include "bitfield.h"
@@ -136,7 +137,8 @@ struct efx_special_buffer {
  * struct efx_tx_buffer - buffer state for a TX descriptor
  * @skb: When @flags & %EFX_TX_BUF_SKB, the associated socket buffer to be
  *     freed when descriptor completes
- * @option: When @flags & %EFX_TX_BUF_OPTION, a NIC-specific option descriptor.
+ * @xdpf: When @flags & %EFX_TX_BUF_XDP, the XDP frame information; its @data
+ *     member is the associated buffer to drop a page reference on.
  * @dma_addr: DMA address of the fragment.
  * @flags: Flags for allocation and DMA mapping type
  * @len: Length of this fragment.
@@ -146,7 +148,10 @@ struct efx_special_buffer {
  * Only valid if @unmap_len != 0.
  */
 struct efx_tx_buffer {
-       const struct sk_buff *skb;
+       union {
+               const struct sk_buff *skb;
+               struct xdp_frame *xdpf;
+       };
        union {
                efx_qword_t option;
                dma_addr_t dma_addr;
@@ -160,6 +165,7 @@ struct efx_tx_buffer {
 #define EFX_TX_BUF_SKB         2       /* buffer is last part of skb */
 #define EFX_TX_BUF_MAP_SINGLE  8       /* buffer was mapped with 
dma_map_single() */
 #define EFX_TX_BUF_OPTION      0x10    /* empty buffer for option descriptor */
+#define EFX_TX_BUF_XDP         0x20    /* buffer was sent with XDP */
 
 /**
  * struct efx_tx_queue - An Efx TX queue
diff --git a/drivers/net/ethernet/sfc/tx.c b/drivers/net/ethernet/sfc/tx.c
index 65e81ec1b314..9905e8952a45 100644
--- a/drivers/net/ethernet/sfc/tx.c
+++ b/drivers/net/ethernet/sfc/tx.c
@@ -95,6 +95,8 @@ static void efx_dequeue_buffer(struct efx_tx_queue *tx_queue,
                netif_vdbg(tx_queue->efx, tx_done, tx_queue->efx->net_dev,
                           "TX queue %d transmission id %x complete\n",
                           tx_queue->queue, tx_queue->read_count);
+       } else if (buffer->flags & EFX_TX_BUF_XDP) {
+               xdp_return_frame(buffer->xdpf);
        }
 
        buffer->len = 0;