Commit 61086f39 authored by Vlad Buslov's avatar Vlad Buslov Committed by Saeed Mahameed
Browse files

net/mlx5e: Protect encap hash table with mutex 



To remove dependency on rtnl lock, protect encap hash table from concurrent
modifications with new "encap_tbl_lock" mutex. Use the mutex to protect
internal encap entry state from concurrent modification. This is necessary
because a flow can be attached to multiple encap entries simultaneously,
which significantly complicates using finer grained per-entry lock.

Signed-off-by: default avatarVlad Buslov <vladbu@mellanox.com>
Reviewed-by: default avatarRoi Dayan <roid@mellanox.com>
Signed-off-by: default avatarSaeed Mahameed <saeedm@mellanox.com>
parent 948993f2

drivers/net/ethernet/mellanox/mlx5/core/en_tc.c

+33 −10
Original line number Diff line number Diff line
@@ -1478,33 +1478,51 @@ void mlx5e_tc_update_neigh_used_value(struct mlx5e_neigh_hash_entry *nhe) 
	}

}



void mlx5e_encap_put(struct mlx5e_priv *priv, struct mlx5e_encap_entry *e)

static void mlx5e_encap_dealloc(struct mlx5e_priv *priv, struct mlx5e_encap_entry *e)

{

	if (!refcount_dec_and_test(&e->refcnt))

		return;



	WARN_ON(!list_empty(&e->flows));

	mlx5e_rep_encap_entry_detach(netdev_priv(e->out_dev), e);



	if (e->flags & MLX5_ENCAP_ENTRY_VALID)

		mlx5_packet_reformat_dealloc(priv->mdev, e->encap_id);



	hash_del_rcu(&e->encap_hlist);

	kfree(e->encap_header);

	kfree(e);

}



void mlx5e_encap_put(struct mlx5e_priv *priv, struct mlx5e_encap_entry *e)

{

	struct mlx5_eswitch *esw = priv->mdev->priv.eswitch;



	if (!refcount_dec_and_mutex_lock(&e->refcnt, &esw->offloads.encap_tbl_lock))

		return;

	hash_del_rcu(&e->encap_hlist);

	mutex_unlock(&esw->offloads.encap_tbl_lock);



	mlx5e_encap_dealloc(priv, e);

}



static void mlx5e_detach_encap(struct mlx5e_priv *priv,

			       struct mlx5e_tc_flow *flow, int out_index)

{

	struct mlx5e_encap_entry *e = flow->encaps[out_index].e;

	struct mlx5_eswitch *esw = priv->mdev->priv.eswitch;



	/* flow wasn't fully initialized */

	if (!flow->encaps[out_index].e)

	if (!e)

		return;



	mutex_lock(&esw->offloads.encap_tbl_lock);

	list_del(&flow->encaps[out_index].list);



	mlx5e_encap_put(priv, flow->encaps[out_index].e);

	flow->encaps[out_index].e = NULL;

	if (!refcount_dec_and_test(&e->refcnt)) {

		mutex_unlock(&esw->offloads.encap_tbl_lock);

		return;

	}

	hash_del_rcu(&e->encap_hlist);

	mutex_unlock(&esw->offloads.encap_tbl_lock);



	mlx5e_encap_dealloc(priv, e);

}



static void __mlx5e_tc_del_fdb_peer_flow(struct mlx5e_tc_flow *flow)
@@ -2882,6 +2900,7 @@ static int mlx5e_attach_encap(struct mlx5e_priv *priv, 


	hash_key = hash_encap_info(&key);



	mutex_lock(&esw->offloads.encap_tbl_lock);

	e = mlx5e_encap_get(priv, &key, hash_key);



	/* must verify if encap is valid or not */
@@ -2889,8 +2908,10 @@ static int mlx5e_attach_encap(struct mlx5e_priv *priv, 
		goto attach_flow;



	e = kzalloc(sizeof(*e), GFP_KERNEL);

	if (!e)

		return -ENOMEM;

	if (!e) {

		err = -ENOMEM;

		goto out_err;

	}



	refcount_set(&e->refcnt, 1);

	e->tun_info = tun_info;
@@ -2922,10 +2943,12 @@ attach_flow: 
	} else {

		*encap_valid = false;

	}

	mutex_unlock(&esw->offloads.encap_tbl_lock);



	return err;



out_err:

	mutex_unlock(&esw->offloads.encap_tbl_lock);

	kfree(e);

	return err;

}

drivers/net/ethernet/mellanox/mlx5/core/eswitch.c

+2 −0
Original line number Diff line number Diff line
@@ -1999,6 +1999,7 @@ int mlx5_eswitch_init(struct mlx5_core_dev *dev) 
	if (err)

		goto abort;



	mutex_init(&esw->offloads.encap_tbl_lock);

	hash_init(esw->offloads.encap_tbl);

	mutex_init(&esw->offloads.mod_hdr.lock);

	hash_init(esw->offloads.mod_hdr.hlist);
@@ -2039,6 +2040,7 @@ void mlx5_eswitch_cleanup(struct mlx5_eswitch *esw) 
	destroy_workqueue(esw->work_queue);

	esw_offloads_cleanup_reps(esw);

	mutex_destroy(&esw->offloads.mod_hdr.lock);

	mutex_destroy(&esw->offloads.encap_tbl_lock);

	kfree(esw->vports);

	kfree(esw);

}

drivers/net/ethernet/mellanox/mlx5/core/eswitch.h

+1 −0
Original line number Diff line number Diff line
@@ -181,6 +181,7 @@ struct mlx5_esw_offload { 
	struct mlx5_eswitch_rep *vport_reps;

	struct list_head peer_flows;

	struct mutex peer_mutex;

	struct mutex encap_tbl_lock; /* protects encap_tbl */

	DECLARE_HASHTABLE(encap_tbl, 8);

	struct mod_hdr_tbl mod_hdr;

	DECLARE_HASHTABLE(termtbl_tbl, 8);

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