i40e: setup xdp_rxq_info

The i40e driver has a special "FDIR" RX-ring (I40E_VSI_FDIR) which is
a sideband channel for configuring/updating the flow director tables.
This (i40e_vsi_)type does not invoke XDP-ebpf code.

As suggested by Björn (V2): Instead of marking this I40E_VSI_FDIR RX-ring
a special case, reverse the logic and only select RX-rings of type
I40E_VSI_MAIN to register xdp_rxq_info's for.

Driver hook points for xdp_rxq_info:
 * reg  : i40e_setup_rx_descriptors (via i40e_vsi_setup_rx_resources)
 * unreg: i40e_free_rx_resources    (via i40e_vsi_free_rx_resources)

Tested on actual hardware with samples/bpf program.

V2: Fixed bug in i40e_set_ringparam (memset zero) + match on I40E_VSI_MAIN.
V4: Update patch desc that got out-of-sync with code.

Cc: intel-wired-lan@lists.osuosl.org
Cc: Björn Töpel <bjorn.topel@intel.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

3 files changed, 21 insertions, 2 deletions

diff --git a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
index 5f6cf7212d4f..cfd788b4fd7a 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
@@ -1585,6 +1585,8 @@ static int i40e_set_ringparam(struct net_device *netdev,
                          */
                         rx_rings[i].desc = NULL;
                         rx_rings[i].rx_bi = NULL;
+                        /* Clear cloned XDP RX-queue info before setup call */
+                        memset(&rx_rings[i].xdp_rxq, 0, sizeof(rx_rings[i].xdp_rxq));
                         /* this is to allow wr32 to have something to write to
                          * during early allocation of Rx buffers
                          */
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index 4566d66ffc7c..2a8a85e3ae8f 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -27,6 +27,7 @@
 #include <linux/prefetch.h>
 #include <net/busy_poll.h>
 #include <linux/bpf_trace.h>
+#include <net/xdp.h>
 #include "i40e.h"
 #include "i40e_trace.h"
 #include "i40e_prototype.h"
@@ -1236,6 +1237,8 @@ void i40e_clean_rx_ring(struct i40e_ring *rx_ring)
 void i40e_free_rx_resources(struct i40e_ring *rx_ring)
 {
         i40e_clean_rx_ring(rx_ring);
+        if (rx_ring->vsi->type == I40E_VSI_MAIN)
+                xdp_rxq_info_unreg(&rx_ring->xdp_rxq);
         rx_ring->xdp_prog = NULL;
         kfree(rx_ring->rx_bi);
         rx_ring->rx_bi = NULL;
@@ -1256,6 +1259,7 @@ void i40e_free_rx_resources(struct i40e_ring *rx_ring)
 int i40e_setup_rx_descriptors(struct i40e_ring *rx_ring)
 {
         struct device *dev = rx_ring->dev;
+        int err = -ENOMEM;
         int bi_size;
 
         /* warn if we are about to overwrite the pointer */
@@ -1283,13 +1287,21 @@ int i40e_setup_rx_descriptors(struct i40e_ring *rx_ring)
         rx_ring->next_to_clean = 0;
         rx_ring->next_to_use = 0;
 
+        /* XDP RX-queue info only needed for RX rings exposed to XDP */
+        if (rx_ring->vsi->type == I40E_VSI_MAIN) {
+                err = xdp_rxq_info_reg(&rx_ring->xdp_rxq, rx_ring->netdev,
+                                       rx_ring->queue_index);
+                if (err < 0)
+                        goto err;
+        }
+
         rx_ring->xdp_prog = rx_ring->vsi->xdp_prog;
 
         return 0;
 err:
         kfree(rx_ring->rx_bi);
         rx_ring->rx_bi = NULL;
-        return -ENOMEM;
+        return err;
 }
 
 /**
@@ -2068,11 +2080,13 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget)
         struct sk_buff *skb = rx_ring->skb;
         u16 cleaned_count = I40E_DESC_UNUSED(rx_ring);
         bool failure = false, xdp_xmit = false;
+        struct xdp_buff xdp;
+
+        xdp.rxq = &rx_ring->xdp_rxq;
 
         while (likely(total_rx_packets < (unsigned int)budget)) {
                 struct i40e_rx_buffer *rx_buffer;
                 union i40e_rx_desc *rx_desc;
-                struct xdp_buff xdp;
                 unsigned int size;
                 u16 vlan_tag;
                 u8 rx_ptype;
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.h b/drivers/net/ethernet/intel/i40e/i40e_txrx.h
index fbae1182e2ea..2d08760fc4ce 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.h
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.h
@@ -27,6 +27,8 @@
 #ifndef _I40E_TXRX_H_
 #define _I40E_TXRX_H_
 
+#include <net/xdp.h>
+
 /* Interrupt Throttling and Rate Limiting Goodies */
 
 #define I40E_MAX_ITR               0x0FF0  /* reg uses 2 usec resolution */
@@ -428,6 +430,7 @@ struct i40e_ring {
                                          */
 
         struct i40e_channel *ch;
+        struct xdp_rxq_info xdp_rxq;
 } ____cacheline_internodealigned_in_smp;
 
 static inline bool ring_uses_build_skb(struct i40e_ring *ring)