[RFC PATCH bpf-next 4/8] i40e: handle the XDP_REDIRECT_XSK action

[Ciara Loftus <ciara.loftus@xxxxxxxxx>]

If the BPF program returns XDP_REDIRECT_XSK, obtain the pointer to the
socket from the netdev_rx_queue struct and call the newly exposed xsk_rcv
function to push the XDP descriptor to the Rx ring. Then use xsk_flush to
flush the socket.

Signed-off-by: Ciara Loftus <ciara.loftus@xxxxxxxxx>
---
 drivers/net/ethernet/intel/i40e/i40e_txrx.c   | 13 +++++++++++-
 .../ethernet/intel/i40e/i40e_txrx_common.h    |  1 +
 drivers/net/ethernet/intel/i40e/i40e_xsk.c    | 21 +++++++++++++------
 3 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index 10a83e5385c7..b6a883a8d088 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -4,6 +4,7 @@
 #include <linux/prefetch.h>
 #include <linux/bpf_trace.h>
 #include <net/xdp.h>
+#include <net/xdp_sock_drv.h>
 #include "i40e.h"
 #include "i40e_trace.h"
 #include "i40e_prototype.h"
@@ -2296,6 +2297,7 @@ static int i40e_run_xdp(struct i40e_ring *rx_ring, struct xdp_buff *xdp)
 	int err, result = I40E_XDP_PASS;
 	struct i40e_ring *xdp_ring;
 	struct bpf_prog *xdp_prog;
+	struct xdp_sock *xs;
 	u32 act;
 
 	xdp_prog = READ_ONCE(rx_ring->xdp_prog);
@@ -2315,6 +2317,12 @@ static int i40e_run_xdp(struct i40e_ring *rx_ring, struct xdp_buff *xdp)
 		if (result == I40E_XDP_CONSUMED)
 			goto out_failure;
 		break;
+	case XDP_REDIRECT_XSK:
+		xs = xsk_get_redirect_xsk(&rx_ring->netdev->_rx[xdp->rxq->queue_index]);
+		err = xsk_rcv(xs, xdp);
+		if (err)
+			goto out_failure;
+		return I40E_XDP_REDIR_XSK;
 	case XDP_REDIRECT:
 		err = xdp_do_redirect(rx_ring->netdev, xdp, xdp_prog);
 		if (err)
@@ -2401,6 +2409,9 @@ void i40e_update_rx_stats(struct i40e_ring *rx_ring,
  **/
 void i40e_finalize_xdp_rx(struct i40e_ring *rx_ring, unsigned int xdp_res)
 {
+	if (xdp_res & I40E_XDP_REDIR_XSK)
+		xsk_flush(xsk_get_redirect_xsk(&rx_ring->netdev->_rx[rx_ring->queue_index]));
+
 	if (xdp_res & I40E_XDP_REDIR)
 		xdp_do_flush_map();
 
@@ -2516,7 +2527,7 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget)
 		}
 
 		if (xdp_res) {
-			if (xdp_res & (I40E_XDP_TX | I40E_XDP_REDIR)) {
+			if (xdp_res & (I40E_XDP_TX | I40E_XDP_REDIR | I40E_XDP_REDIR_XSK)) {
 				xdp_xmit |= xdp_res;
 				i40e_rx_buffer_flip(rx_ring, rx_buffer, size);
 			} else {
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h b/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h
index 19da3b22160f..17e521a71201 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h
@@ -20,6 +20,7 @@ void i40e_release_rx_desc(struct i40e_ring *rx_ring, u32 val);
 #define I40E_XDP_CONSUMED	BIT(0)
 #define I40E_XDP_TX		BIT(1)
 #define I40E_XDP_REDIR		BIT(2)
+#define I40E_XDP_REDIR_XSK	BIT(3)
 
 /*
  * build_ctob - Builds the Tx descriptor (cmd, offset and type) qword
diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
index ea06e957393e..31b794672ea5 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
@@ -144,13 +144,14 @@ int i40e_xsk_pool_setup(struct i40e_vsi *vsi, struct xsk_buff_pool *pool,
  * @rx_ring: Rx ring
  * @xdp: xdp_buff used as input to the XDP program
  *
- * Returns any of I40E_XDP_{PASS, CONSUMED, TX, REDIR}
+ * Returns any of I40E_XDP_{PASS, CONSUMED, TX, REDIR, REDIR_XSK}
  **/
 static int i40e_run_xdp_zc(struct i40e_ring *rx_ring, struct xdp_buff *xdp)
 {
 	int err, result = I40E_XDP_PASS;
 	struct i40e_ring *xdp_ring;
 	struct bpf_prog *xdp_prog;
+	struct xdp_sock *xs;
 	u32 act;
 
 	/* NB! xdp_prog will always be !NULL, due to the fact that
@@ -159,14 +160,21 @@ static int i40e_run_xdp_zc(struct i40e_ring *rx_ring, struct xdp_buff *xdp)
 	xdp_prog = READ_ONCE(rx_ring->xdp_prog);
 	act = bpf_prog_run_xdp(xdp_prog, xdp);
 
-	if (likely(act == XDP_REDIRECT)) {
-		err = xdp_do_redirect(rx_ring->netdev, xdp, xdp_prog);
+	if (likely(act == XDP_REDIRECT_XSK)) {
+		xs = xsk_get_redirect_xsk(&rx_ring->netdev->_rx[xdp->rxq->queue_index]);
+		err = xsk_rcv(xs, xdp);
 		if (err)
 			goto out_failure;
-		return I40E_XDP_REDIR;
+		return I40E_XDP_REDIR_XSK;
 	}
 
 	switch (act) {
+	case XDP_REDIRECT:
+		err = xdp_do_redirect(rx_ring->netdev, xdp, xdp_prog);
+		if (err)
+			goto out_failure;
+		result = I40E_XDP_REDIR;
+		break;
 	case XDP_PASS:
 		break;
 	case XDP_TX:
@@ -275,7 +283,8 @@ static void i40e_handle_xdp_result_zc(struct i40e_ring *rx_ring,
 	*rx_packets = 1;
 	*rx_bytes = size;
 
-	if (likely(xdp_res == I40E_XDP_REDIR) || xdp_res == I40E_XDP_TX)
+	if (likely(xdp_res == I40E_XDP_REDIR_XSK) || xdp_res == I40E_XDP_REDIR ||
+	    xdp_res == I40E_XDP_TX)
 		return;
 
 	if (xdp_res == I40E_XDP_CONSUMED) {
@@ -371,7 +380,7 @@ int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget)
 					  &rx_bytes, size, xdp_res);
 		total_rx_packets += rx_packets;
 		total_rx_bytes += rx_bytes;
-		xdp_xmit |= xdp_res & (I40E_XDP_TX | I40E_XDP_REDIR);
+		xdp_xmit |= xdp_res & (I40E_XDP_TX | I40E_XDP_REDIR | I40E_XDP_REDIR_XSK);
 		next_to_clean = (next_to_clean + 1) & count_mask;
 	}
 
-- 
2.17.1