net/mlx5: Avoid using xso.real_dev unnecessarily

[ Upstream commit d79444e ]

xso.real_dev is the active device of an offloaded xfrm state and is
managed by bonding. As such, it's subject to change when states are
migrated to a new device. Using it in places other than
offloading/unoffloading the states is risky.

This commit saves the device into the driver-specific struct
mlx5e_ipsec_sa_entry and switches mlx5e_ipsec_init_macs() and
mlx5e_ipsec_netevent_event() to make use of it.

Additionally, mlx5e_xfrm_update_stats() used xso.real_dev to validate
that correct net locks are held. But in a bonding config, the net of the
master device is the same as the underlying devices, and the net is
already a local var, so use that instead.

The only remaining references to xso.real_dev are now in the
.xdo_dev_state_add() / .xdo_dev_state_delete() path.

Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Cosmin Ratiu

drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec.c

@@ -266,8 +266,7 @@ static void mlx5e_ipsec_init_macs(struct mlx5e_ipsec_sa_entry *sa_entry,
 				  struct mlx5_accel_esp_xfrm_attrs *attrs)
 {
 	struct mlx5_core_dev *mdev = mlx5e_ipsec_sa2dev(sa_entry);
-	struct xfrm_state *x = sa_entry->x;
-	struct net_device *netdev;
+	struct net_device *netdev = sa_entry->dev;
 	struct neighbour *n;
 	u8 addr[ETH_ALEN];
 	const void *pkey;
@@ -277,8 +276,6 @@ static void mlx5e_ipsec_init_macs(struct mlx5e_ipsec_sa_entry *sa_entry,
 	    attrs->type != XFRM_DEV_OFFLOAD_PACKET)
 		return;
 
-	netdev = x->xso.real_dev;
-
 	mlx5_query_mac_address(mdev, addr);
 	switch (attrs->dir) {
 	case XFRM_DEV_OFFLOAD_IN:
@@ -707,6 +704,7 @@ static int mlx5e_xfrm_add_state(struct xfrm_state *x,
 		return -ENOMEM;
 
 	sa_entry->x = x;
+	sa_entry->dev = netdev;
 	sa_entry->ipsec = ipsec;
 	/* Check if this SA is originated from acquire flow temporary SA */
 	if (x->xso.flags & XFRM_DEV_OFFLOAD_FLAG_ACQ)
@@ -849,8 +847,6 @@ static int mlx5e_ipsec_netevent_event(struct notifier_block *nb,
 	struct mlx5e_ipsec_sa_entry *sa_entry;
 	struct mlx5e_ipsec *ipsec;
 	struct neighbour *n = ptr;
-	struct net_device *netdev;
-	struct xfrm_state *x;
 	unsigned long idx;
 
 	if (event != NETEVENT_NEIGH_UPDATE || !(n->nud_state & NUD_VALID))
@@ -870,11 +866,9 @@ static int mlx5e_ipsec_netevent_event(struct notifier_block *nb,
 				continue;
 		}
 
-		x = sa_entry->x;
-		netdev = x->xso.real_dev;
 		data = sa_entry->work->data;
 
-		neigh_ha_snapshot(data->addr, n, netdev);
+		neigh_ha_snapshot(data->addr, n, sa_entry->dev);
 		queue_work(ipsec->wq, &sa_entry->work->work);
 	}
 
@@ -1005,8 +999,8 @@ static void mlx5e_xfrm_update_stats(struct xfrm_state *x)
 	size_t headers;
 
 	lockdep_assert(lockdep_is_held(&x->lock) ||
-		       lockdep_is_held(&dev_net(x->xso.real_dev)->xfrm.xfrm_cfg_mutex) ||
-		       lockdep_is_held(&dev_net(x->xso.real_dev)->xfrm.xfrm_state_lock));
+		       lockdep_is_held(&net->xfrm.xfrm_cfg_mutex) ||
+		       lockdep_is_held(&net->xfrm.xfrm_state_lock));
 
 	if (x->xso.flags & XFRM_DEV_OFFLOAD_FLAG_ACQ)
 		return;

drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec.h

@@ -260,6 +260,7 @@ struct mlx5e_ipsec_limits {
 struct mlx5e_ipsec_sa_entry {
 	struct mlx5e_ipsec_esn_state esn_state;
 	struct xfrm_state *x;
+	struct net_device *dev;
 	struct mlx5e_ipsec *ipsec;
 	struct mlx5_accel_esp_xfrm_attrs attrs;
 	void (*set_iv_op)(struct sk_buff *skb, struct xfrm_state *x,