mlx4: xdp_prog becomes inactive after ethtool '-L' or '-G'

After calling mlx4_en_try_alloc_resources (e.g. by changing the
number of rx-queues with ethtool -L), the existing xdp_prog becomes
inactive.

The bug is that the xdp_prog ptr has not been carried over from
the old rx-queues to the new rx-queues

Fixes: 47a38e155037 ("net/mlx4_en: add support for fast rx drop bpf program")
Cc: Brenden Blanco <bblanco@plumgrid.com>
Cc: Saeed Mahameed <saeedm@mellanox.com>
Cc: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 27 insertions, 7 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c b/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c
index d5a9372ed84d..9aa422691954 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c
@@ -1099,7 +1099,7 @@ static int mlx4_en_set_ringparam(struct net_device *dev,
         memcpy(&new_prof, priv->prof, sizeof(struct mlx4_en_port_profile));
         new_prof.tx_ring_size = tx_size;
         new_prof.rx_ring_size = rx_size;
-        err = mlx4_en_try_alloc_resources(priv, tmp, &new_prof);
+        err = mlx4_en_try_alloc_resources(priv, tmp, &new_prof, true);
         if (err)
                 goto out;
 
@@ -1774,7 +1774,7 @@ static int mlx4_en_set_channels(struct net_device *dev,
         new_prof.tx_ring_num[TX_XDP] = xdp_count;
         new_prof.rx_ring_num = channel->rx_count;
 
-        err = mlx4_en_try_alloc_resources(priv, tmp, &new_prof);
+        err = mlx4_en_try_alloc_resources(priv, tmp, &new_prof, true);
         if (err)
                 goto out;
 
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index 3abcead208d2..3b4961a8e8e4 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -2186,9 +2186,11 @@ static void mlx4_en_update_priv(struct mlx4_en_priv *dst,
 
 int mlx4_en_try_alloc_resources(struct mlx4_en_priv *priv,
                                 struct mlx4_en_priv *tmp,
-                                struct mlx4_en_port_profile *prof)
+                                struct mlx4_en_port_profile *prof,
+                                bool carry_xdp_prog)
 {
-        int t;
+        struct bpf_prog *xdp_prog;
+        int i, t;
 
         mlx4_en_copy_priv(tmp, priv, prof);
 
@@ -2202,6 +2204,23 @@ int mlx4_en_try_alloc_resources(struct mlx4_en_priv *priv,
                 }
                 return -ENOMEM;
         }
+
+        /* All rx_rings has the same xdp_prog.  Pick the first one. */
+        xdp_prog = rcu_dereference_protected(
+                priv->rx_ring[0]->xdp_prog,
+                lockdep_is_held(&priv->mdev->state_lock));
+
+        if (xdp_prog && carry_xdp_prog) {
+                xdp_prog = bpf_prog_add(xdp_prog, tmp->rx_ring_num);
+                if (IS_ERR(xdp_prog)) {
+                        mlx4_en_free_resources(tmp);
+                        return PTR_ERR(xdp_prog);
+                }
+                for (i = 0; i < tmp->rx_ring_num; i++)
+                        rcu_assign_pointer(tmp->rx_ring[i]->xdp_prog,
+                                           xdp_prog);
+        }
+
         return 0;
 }
 
@@ -2751,7 +2770,7 @@ static int mlx4_xdp_set(struct net_device *dev, struct bpf_prog *prog)
                 en_warn(priv, "Reducing the number of TX rings, to not exceed the max total rings number.\n");
         }
 
-        err = mlx4_en_try_alloc_resources(priv, tmp, &new_prof);
+        err = mlx4_en_try_alloc_resources(priv, tmp, &new_prof, false);
         if (err) {
                 if (prog)
                         bpf_prog_sub(prog, priv->rx_ring_num - 1);
@@ -3495,7 +3514,7 @@ int mlx4_en_reset_config(struct net_device *dev,
         memcpy(&new_prof, priv->prof, sizeof(struct mlx4_en_port_profile));
         memcpy(&new_prof.hwtstamp_config, &ts_config, sizeof(ts_config));
 
-        err = mlx4_en_try_alloc_resources(priv, tmp, &new_prof);
+        err = mlx4_en_try_alloc_resources(priv, tmp, &new_prof, true);
         if (err)
                 goto out;
 
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index ba1c6cd0cc79..cec59bc264c9 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -679,7 +679,8 @@ void mlx4_en_set_stats_bitmap(struct mlx4_dev *dev,
 
 int mlx4_en_try_alloc_resources(struct mlx4_en_priv *priv,
                                 struct mlx4_en_priv *tmp,
-                                struct mlx4_en_port_profile *prof);
+                                struct mlx4_en_port_profile *prof,
+                                bool carry_xdp_prog);
 void mlx4_en_safe_replace_resources(struct mlx4_en_priv *priv,
                                     struct mlx4_en_priv *tmp);