release/5.2.37/mlxsw-core-Add-support-for-using-SKB-control-buffer.patch

From 1db8c9217928b36555c247bcf91a4c648fe9ad2f Mon Sep 17 00:00:00 2001
From: Petr Machata <petrm@mellanox.com>
Date: Sun, 30 Jun 2019 09:04:52 +0300
Subject: [PATCH] mlxsw: core: Add support for using SKB control buffer

commit d7cd206dbfb25efc5f06ea3c595074a51d48d00a upstream.

The SKB control buffer is useful (and used) for bookkeeping of information
related to that SKB. Add helpers so that the mlxsw driver(s) can safely use
the buffer as well. The structure is currently empty, individual users will
add members to it as necessary.

Note that SKB allocation functions already clear the buffer, so the cleanup
is only necessary when ndo_start_xmit is called.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/net/ethernet/mellanox/mlxsw/core.h b/drivers/net/ethernet/mellanox/mlxsw/core.h
index e3832cb5bdda..685ed82b123f 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/core.h
+++ b/drivers/net/ethernet/mellanox/mlxsw/core.h
@@ -409,4 +409,13 @@ enum mlxsw_devlink_param_id {
 	MLXSW_DEVLINK_PARAM_ID_ACL_REGION_REHASH_INTERVAL,
 };
 
+struct mlxsw_skb_cb {
+};
+
+static inline struct mlxsw_skb_cb *mlxsw_skb_cb(struct sk_buff *skb)
+{
+	BUILD_BUG_ON(sizeof(mlxsw_skb_cb) > sizeof(skb->cb));
+	return (struct mlxsw_skb_cb *) skb->cb;
+}
+
 #endif
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
index d51442e63aba..e1a9ce611387 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
@@ -738,6 +738,8 @@ static netdev_tx_t mlxsw_sp_port_xmit(struct sk_buff *skb,
 	u64 len;
 	int err;
 
+	memset(skb->cb, 0, sizeof(struct mlxsw_skb_cb));
+
 	if (mlxsw_core_skb_transmit_busy(mlxsw_sp->core, &tx_info))
 		return NETDEV_TX_BUSY;
 
diff --git a/drivers/net/ethernet/mellanox/mlxsw/switchx2.c b/drivers/net/ethernet/mellanox/mlxsw/switchx2.c
index fc4f19167262..bdab96f5bc70 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/switchx2.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/switchx2.c
@@ -299,6 +299,8 @@ static netdev_tx_t mlxsw_sx_port_xmit(struct sk_buff *skb,
 	u64 len;
 	int err;
 
+	memset(skb->cb, 0, sizeof(struct mlxsw_skb_cb));
+
 	if (mlxsw_core_skb_transmit_busy(mlxsw_sx->core, &tx_info))
 		return NETDEV_TX_BUSY;
 
-- 
2.7.4