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Date: Wed, 21 Aug 2019 23:28:42 +0000
From: Saeed Mahameed <saeedm@...lanox.com>
To: "David S. Miller" <davem@...emloft.net>
CC: "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
Vlad Buslov <vladbu@...lanox.com>,
Jianbo Liu <jianbol@...lanox.com>,
Roi Dayan <roid@...lanox.com>,
Saeed Mahameed <saeedm@...lanox.com>
Subject: [net-next 05/11] net/mlx5e: Protect neigh hash encap list with
spinlock and rcu
From: Vlad Buslov <vladbu@...lanox.com>
Rcu-ify mlx5e_neigh_hash_entry->encap_list by changing operations on encap
list to their rcu counterparts and extending encap structure with rcu_head
to free the encap instances after rcu grace period. Use rcu read lock when
traversing encap list. Implement helper mlx5e_get_next_valid_encap()
function that is used by mlx5e_tc_update_neigh_used_value() to safely
iterate over valid entries of nhe->encap_list.
Signed-off-by: Vlad Buslov <vladbu@...lanox.com>
Reviewed-by: Jianbo Liu <jianbol@...lanox.com>
Reviewed-by: Roi Dayan <roid@...lanox.com>
Signed-off-by: Saeed Mahameed <saeedm@...lanox.com>
---
.../net/ethernet/mellanox/mlx5/core/en_rep.c | 10 ++-
.../net/ethernet/mellanox/mlx5/core/en_rep.h | 3 +
.../net/ethernet/mellanox/mlx5/core/en_tc.c | 64 ++++++++++++++++---
3 files changed, 66 insertions(+), 11 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
index 218772d5c062..f26edf458152 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
@@ -1064,6 +1064,7 @@ static int mlx5e_rep_neigh_entry_create(struct mlx5e_priv *priv,
(*nhe)->priv = priv;
memcpy(&(*nhe)->m_neigh, &e->m_neigh, sizeof(e->m_neigh));
INIT_WORK(&(*nhe)->neigh_update_work, mlx5e_rep_neigh_update);
+ spin_lock_init(&(*nhe)->encap_list_lock);
INIT_LIST_HEAD(&(*nhe)->encap_list);
refcount_set(&(*nhe)->refcnt, 1);
@@ -1103,7 +1104,10 @@ int mlx5e_rep_encap_entry_attach(struct mlx5e_priv *priv,
}
e->nhe = nhe;
- list_add(&e->encap_list, &nhe->encap_list);
+ spin_lock(&nhe->encap_list_lock);
+ list_add_rcu(&e->encap_list, &nhe->encap_list);
+ spin_unlock(&nhe->encap_list_lock);
+
mutex_unlock(&rpriv->neigh_update.encap_lock);
return 0;
@@ -1119,7 +1123,9 @@ void mlx5e_rep_encap_entry_detach(struct mlx5e_priv *priv,
if (!e->nhe)
return;
- list_del(&e->encap_list);
+ spin_lock(&e->nhe->encap_list_lock);
+ list_del_rcu(&e->encap_list);
+ spin_unlock(&e->nhe->encap_list_lock);
mlx5e_rep_neigh_entry_release(e->nhe);
e->nhe = NULL;
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.h b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.h
index 8fa27832bd81..a0ae5069d8c3 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.h
@@ -119,6 +119,8 @@ struct mlx5e_neigh_hash_entry {
*/
struct list_head neigh_list;
+ /* protects encap list */
+ spinlock_t encap_list_lock;
/* encap list sharing the same neigh */
struct list_head encap_list;
@@ -173,6 +175,7 @@ struct mlx5e_encap_entry {
refcount_t refcnt;
struct completion res_ready;
int compl_result;
+ struct rcu_head rcu;
};
struct mlx5e_rep_sq {
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index 3917834b48ff..a4d11274be30 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -1412,11 +1412,56 @@ static struct mlx5_fc *mlx5e_tc_get_counter(struct mlx5e_tc_flow *flow)
return flow->nic_attr->counter;
}
+static struct mlx5e_encap_entry *
+mlx5e_get_next_valid_encap(struct mlx5e_neigh_hash_entry *nhe,
+ struct mlx5e_encap_entry *e)
+{
+ struct mlx5e_encap_entry *next = NULL;
+
+retry:
+ rcu_read_lock();
+
+ /* find encap with non-zero reference counter value */
+ for (next = e ?
+ list_next_or_null_rcu(&nhe->encap_list,
+ &e->encap_list,
+ struct mlx5e_encap_entry,
+ encap_list) :
+ list_first_or_null_rcu(&nhe->encap_list,
+ struct mlx5e_encap_entry,
+ encap_list);
+ next;
+ next = list_next_or_null_rcu(&nhe->encap_list,
+ &next->encap_list,
+ struct mlx5e_encap_entry,
+ encap_list))
+ if (mlx5e_encap_take(next))
+ break;
+
+ rcu_read_unlock();
+
+ /* release starting encap */
+ if (e)
+ mlx5e_encap_put(netdev_priv(e->out_dev), e);
+ if (!next)
+ return next;
+
+ /* wait for encap to be fully initialized */
+ wait_for_completion(&next->res_ready);
+ /* continue searching if encap entry is not in valid state after completion */
+ if (!(next->flags & MLX5_ENCAP_ENTRY_VALID)) {
+ e = next;
+ goto retry;
+ }
+
+ return next;
+}
+
void mlx5e_tc_update_neigh_used_value(struct mlx5e_neigh_hash_entry *nhe)
{
struct mlx5e_neigh *m_neigh = &nhe->m_neigh;
+ struct mlx5e_encap_entry *e = NULL;
struct mlx5e_tc_flow *flow;
- struct mlx5e_encap_entry *e;
struct mlx5_fc *counter;
struct neigh_table *tbl;
bool neigh_used = false;
@@ -1432,13 +1477,12 @@ void mlx5e_tc_update_neigh_used_value(struct mlx5e_neigh_hash_entry *nhe)
else
return;
- list_for_each_entry(e, &nhe->encap_list, encap_list) {
+ /* mlx5e_get_next_valid_encap() releases previous encap before returning
+ * next one.
+ */
+ while ((e = mlx5e_get_next_valid_encap(nhe, e)) != NULL) {
struct encap_flow_item *efi, *tmp;
- if (!(e->flags & MLX5_ENCAP_ENTRY_VALID) ||
- !mlx5e_encap_take(e))
- continue;
-
list_for_each_entry_safe(efi, tmp, &e->flows, list) {
flow = container_of(efi, struct mlx5e_tc_flow,
encaps[efi->index]);
@@ -1458,9 +1502,11 @@ void mlx5e_tc_update_neigh_used_value(struct mlx5e_neigh_hash_entry *nhe)
mlx5e_flow_put(netdev_priv(e->out_dev), flow);
}
- mlx5e_encap_put(netdev_priv(e->out_dev), e);
- if (neigh_used)
+ if (neigh_used) {
+ /* release current encap before breaking the loop */
+ mlx5e_encap_put(netdev_priv(e->out_dev), e);
break;
+ }
}
if (neigh_used) {
@@ -1490,7 +1536,7 @@ static void mlx5e_encap_dealloc(struct mlx5e_priv *priv, struct mlx5e_encap_entr
}
kfree(e->encap_header);
- kfree(e);
+ kfree_rcu(e, rcu);
}
void mlx5e_encap_put(struct mlx5e_priv *priv, struct mlx5e_encap_entry *e)
--
2.21.0
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