5.4-stable review patch. If anyone has any objections, please let me know.
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From: Jakub Kicinski kuba@kernel.org
[ Upstream commit 6f5dacf88a32b3fd8b52c8ea781bf188c42aaa95 ]
This reverts commit ceddedc969f0532b7c62ca971ee50d519d2bc0cb.
Commit in question breaks the mapping of PGs to pools for some SKUs. Specifically multi-host NICs seem to be shipped with a custom buffer configuration which maps the lossy PG to pool 4. But the bad commit overrides this with pool 0 which does not have sufficient buffer space reserved. Resulting in ~40% packet loss. The commit also breaks BMC / OOB connection completely (100% packet loss).
Revert, similarly to commit 3fbfe251cc9f ("Revert "net/mlx5e: Update and set Xon/Xoff upon port speed set""). The breakage is exactly the same, the only difference is that quoted commit would break the NIC immediately on boot, and the currently reverted commit only when MTU is changed.
Note: "good" kernels do not restore the configuration, so downgrade isn't enough to recover machines. A NIC power cycle seems to be necessary to return to a healthy state (or overriding the relevant registers using a custom patch).
Fixes: ceddedc969f0 ("net/mlx5e: Update and set Xon/Xoff upon MTU set") Signed-off-by: Jakub Kicinski kuba@kernel.org Reviewed-by: Tariq Toukan tariqt@nvidia.com Link: https://patch.msgid.link/20250929181529.1848157-1-kuba@kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.h | 12 ---------- drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 17 --------------- 2 files changed, 1 insertion(+), 28 deletions(-)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.h @@ -64,23 +64,11 @@ struct mlx5e_port_buffer { struct mlx5e_bufferx_reg buffer[MLX5E_MAX_BUFFER]; };
-#ifdef CONFIG_MLX5_CORE_EN_DCB int mlx5e_port_manual_buffer_config(struct mlx5e_priv *priv, u32 change, unsigned int mtu, struct ieee_pfc *pfc, u32 *buffer_size, u8 *prio2buffer); -#else -static inline int -mlx5e_port_manual_buffer_config(struct mlx5e_priv *priv, - u32 change, unsigned int mtu, - void *pfc, - u32 *buffer_size, - u8 *prio2buffer) -{ - return 0; -} -#endif
int mlx5e_port_query_buffer(struct mlx5e_priv *priv, struct mlx5e_port_buffer *port_buffer); --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c @@ -42,7 +42,6 @@ #include "eswitch.h" #include "en.h" #include "en/txrx.h" -#include "en/port_buffer.h" #include "en_tc.h" #include "en_rep.h" #include "en_accel/ipsec.h" @@ -2895,11 +2894,9 @@ int mlx5e_set_dev_port_mtu(struct mlx5e_ struct mlx5e_params *params = &priv->channels.params; struct net_device *netdev = priv->netdev; struct mlx5_core_dev *mdev = priv->mdev; - u16 mtu, prev_mtu; + u16 mtu; int err;
- mlx5e_query_mtu(mdev, params, &prev_mtu); - err = mlx5e_set_mtu(mdev, params, params->sw_mtu); if (err) return err; @@ -2909,18 +2906,6 @@ int mlx5e_set_dev_port_mtu(struct mlx5e_ netdev_warn(netdev, "%s: VPort MTU %d is different than netdev mtu %d\n", __func__, mtu, params->sw_mtu);
- if (mtu != prev_mtu && MLX5_BUFFER_SUPPORTED(mdev)) { - err = mlx5e_port_manual_buffer_config(priv, 0, mtu, - NULL, NULL, NULL); - if (err) { - netdev_warn(netdev, "%s: Failed to set Xon/Xoff values with MTU %d (err %d), setting back to previous MTU %d\n", - __func__, mtu, err, prev_mtu); - - mlx5e_set_mtu(mdev, params, prev_mtu); - return err; - } - } - params->sw_mtu = mtu; return 0; }