Prepare 'struct i40e_xdp_buff' that contains an xdp_buff and a pointer
to i40e_rx_desc in order to pass the RX descriptor to the XDP kfuncs.
Also in ZC path, use XSK_CHECK_PRIV_TYPE() to ensure i40e_xdp_buff
doesn't exceed the offset of cb in xdp_buff_xsk.

No functional changes.

Signed-off-by: Kohei Enju <kohei@enjuk.jp>
---
 drivers/net/ethernet/intel/i40e/i40e_main.c |  2 +-
 drivers/net/ethernet/intel/i40e/i40e_txrx.c |  5 ++++-
 drivers/net/ethernet/intel/i40e/i40e_txrx.h |  7 ++++++-
 drivers/net/ethernet/intel/i40e/i40e_xsk.c  | 12 ++++++++++++
 4 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index 31a42ee18aa0..7966d9cb8009 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -3619,7 +3619,7 @@ static int i40e_configure_rx_ring(struct i40e_ring *ring)
 	}
 
 skip:
-	xdp_init_buff(&ring->xdp, xdp_frame_sz, &ring->xdp_rxq);
+	xdp_init_buff(&ring->xdp_ctx.xdp, xdp_frame_sz, &ring->xdp_rxq);
 
 	rx_ctx.dbuff = DIV_ROUND_UP(ring->rx_buf_len,
 				    BIT_ULL(I40E_RXQ_CTX_DBUFF_SHIFT));
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index 4ffdb007c41a..cfaf724ee7ff 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -2438,10 +2438,11 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget,
 			     unsigned int *rx_cleaned)
 {
 	unsigned int total_rx_bytes = 0, total_rx_packets = 0;
+	struct i40e_xdp_buff *xdp_ctx = &rx_ring->xdp_ctx;
 	u16 cleaned_count = I40E_DESC_UNUSED(rx_ring);
 	u16 clean_threshold = rx_ring->count / 2;
 	unsigned int offset = rx_ring->rx_offset;
-	struct xdp_buff *xdp = &rx_ring->xdp;
+	struct xdp_buff *xdp = &xdp_ctx->xdp;
 	unsigned int xdp_xmit = 0;
 	struct bpf_prog *xdp_prog;
 	bool failure = false;
@@ -2530,6 +2531,8 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget,
 		if (neop)
 			continue;
 
+		xdp_ctx->desc = rx_desc;
+
 		xdp_res = i40e_run_xdp(rx_ring, xdp, xdp_prog);
 
 		if (xdp_res) {
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.h b/drivers/net/ethernet/intel/i40e/i40e_txrx.h
index e630493e9139..6c6ba42ee00c 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.h
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.h
@@ -283,6 +283,11 @@ struct i40e_rx_buffer {
 	__u32 page_count;
 };
 
+struct i40e_xdp_buff {
+	struct xdp_buff xdp;
+	const union i40e_rx_desc *desc;
+};
+
 struct i40e_queue_stats {
 	u64 packets;
 	u64 bytes;
@@ -345,7 +350,7 @@ struct i40e_ring {
 	 * and to resume packet building for this ring in the next call to
 	 * i40e_clean_rx_ring_irq().
 	 */
-	struct xdp_buff xdp;
+	struct i40e_xdp_buff xdp_ctx;
 
 	/* Next descriptor to be processed; next_to_clean is updated only on
 	 * processing EOP descriptor
diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
index 9f47388eaba5..51a05ce4c7ce 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
@@ -246,6 +246,8 @@ bool i40e_alloc_rx_buffers_zc(struct i40e_ring *rx_ring, u16 count)
 	u32 nb_buffs, i;
 	dma_addr_t dma;
 
+	XSK_CHECK_PRIV_TYPE(struct i40e_xdp_buff);
+
 	rx_desc = I40E_RX_DESC(rx_ring, ntu);
 	xdp = i40e_rx_bi(rx_ring, ntu);
 
@@ -396,6 +398,14 @@ static void i40e_handle_xdp_result_zc(struct i40e_ring *rx_ring,
 	WARN_ON_ONCE(1);
 }
 
+static struct i40e_xdp_buff *xsk_buff_to_i40e_ctx(struct xdp_buff *xdp)
+{
+	/* xdp_buff pointer used by ZC code path is allocated as xdp_buff_xsk.
+	 * i40e_xdp_buff private fields overlap with xdp_buff_xsk->cb.
+	 */
+	return (struct i40e_xdp_buff *)xdp;
+}
+
 /**
  * i40e_clean_rx_irq_zc - Consumes Rx packets from the hardware ring
  * @rx_ring: Rx ring
@@ -472,6 +482,8 @@ int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget)
 		if (i40e_is_non_eop(rx_ring, rx_desc))
 			continue;
 
+		xsk_buff_to_i40e_ctx(first)->desc = rx_desc;
+
 		xdp_res = i40e_run_xdp_zc(rx_ring, first, xdp_prog);
 		i40e_handle_xdp_result_zc(rx_ring, first, rx_desc, &rx_packets,
 					  &rx_bytes, xdp_res, &failure);
-- 
2.51.0