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net/mlx5e: Use a slow path rule instead if vxlan neighbour isn't avai…
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…lable

When adding a vxlan tc rule, and a neighbour isn't available, we
don't insert any rule to hardware. Once we enable offloading flows
with multiple priorities, a packet that should have matched this rule
will continue in hardware pipeline and might match a wrong one.

This is unlike in tc software path where it will be matched and
forwarded to the vxlan device (which will cause a ARP lookup
eventually) and stop processing further tc filters.

To address that, when when a neighbour isn't available (EAGAIN from
attach_encap), or gets deleted, change the original action to be a
forward to slow path instead. Neighbour update will restore the original
action once the neighbour becomes available. This will be done atomically
so at any given time we will have a the correct match.

Signed-off-by: Paul Blakey <paulb@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
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Paul Blakey authored and Saeed Mahameed committed Oct 17, 2018
1 parent c92a0b9 commit 5dbe906
Showing 1 changed file with 82 additions and 22 deletions.
104 changes: 82 additions & 22 deletions drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -74,6 +74,7 @@ enum {
MLX5E_TC_FLOW_OFFLOADED = BIT(MLX5E_TC_FLOW_BASE + 2),
MLX5E_TC_FLOW_HAIRPIN = BIT(MLX5E_TC_FLOW_BASE + 3),
MLX5E_TC_FLOW_HAIRPIN_RSS = BIT(MLX5E_TC_FLOW_BASE + 4),
MLX5E_TC_FLOW_SLOW = BIT(MLX5E_TC_FLOW_BASE + 5),
};

#define MLX5E_TC_MAX_SPLITS 1
Expand All @@ -82,7 +83,7 @@ struct mlx5e_tc_flow {
struct rhash_head node;
struct mlx5e_priv *priv;
u64 cookie;
u8 flags;
u16 flags;
struct mlx5_flow_handle *rule[MLX5E_TC_MAX_SPLITS + 1];
struct list_head encap; /* flows sharing the same encap ID */
struct list_head mod_hdr; /* flows sharing the same mod hdr ID */
Expand Down Expand Up @@ -860,6 +861,36 @@ mlx5e_tc_unoffload_fdb_rules(struct mlx5_eswitch *esw,
mlx5_eswitch_del_offloaded_rule(esw, flow->rule[0], attr);
}

static struct mlx5_flow_handle *
mlx5e_tc_offload_to_slow_path(struct mlx5_eswitch *esw,
struct mlx5e_tc_flow *flow,
struct mlx5_flow_spec *spec,
struct mlx5_esw_flow_attr *slow_attr)
{
struct mlx5_flow_handle *rule;

memcpy(slow_attr, flow->esw_attr, sizeof(*slow_attr));
slow_attr->action = MLX5_FLOW_CONTEXT_ACTION_FWD_DEST,
slow_attr->mirror_count = 0,
slow_attr->dest_chain = FDB_SLOW_PATH_CHAIN,

rule = mlx5e_tc_offload_fdb_rules(esw, flow, spec, slow_attr);
if (!IS_ERR(rule))
flow->flags |= MLX5E_TC_FLOW_SLOW;

return rule;
}

static void
mlx5e_tc_unoffload_from_slow_path(struct mlx5_eswitch *esw,
struct mlx5e_tc_flow *flow,
struct mlx5_esw_flow_attr *slow_attr)
{
memcpy(slow_attr, flow->esw_attr, sizeof(*slow_attr));
mlx5e_tc_unoffload_fdb_rules(esw, flow, slow_attr);
flow->flags &= ~MLX5E_TC_FLOW_SLOW;
}

static int
mlx5e_tc_add_fdb_flow(struct mlx5e_priv *priv,
struct mlx5e_tc_flow_parse_attr *parse_attr,
Expand Down Expand Up @@ -917,15 +948,21 @@ mlx5e_tc_add_fdb_flow(struct mlx5e_priv *priv,
/* we get here if (1) there's no error or when
* (2) there's an encap action and we're on -EAGAIN (no valid neigh)
*/
if (encap_err != -EAGAIN) {
if (encap_err == -EAGAIN) {
/* continue with goto slow path rule instead */
struct mlx5_esw_flow_attr slow_attr;

flow->rule[0] = mlx5e_tc_offload_to_slow_path(esw, flow, &parse_attr->spec, &slow_attr);
} else {
flow->rule[0] = mlx5e_tc_offload_fdb_rules(esw, flow, &parse_attr->spec, attr);
if (IS_ERR(flow->rule[0])) {
err = PTR_ERR(flow->rule[0]);
goto err_add_rule;
}
}

return encap_err;
if (IS_ERR(flow->rule[0])) {
err = PTR_ERR(flow->rule[0]);
goto err_add_rule;
}

return 0;

err_add_rule:
mlx5_fc_destroy(esw->dev, counter);
Expand All @@ -946,9 +983,14 @@ static void mlx5e_tc_del_fdb_flow(struct mlx5e_priv *priv,
{
struct mlx5_eswitch *esw = priv->mdev->priv.eswitch;
struct mlx5_esw_flow_attr *attr = flow->esw_attr;
struct mlx5_esw_flow_attr slow_attr;

if (flow->flags & MLX5E_TC_FLOW_OFFLOADED)
mlx5e_tc_unoffload_fdb_rules(esw, flow, flow->esw_attr);
if (flow->flags & MLX5E_TC_FLOW_OFFLOADED) {
if (flow->flags & MLX5E_TC_FLOW_SLOW)
mlx5e_tc_unoffload_from_slow_path(esw, flow, &slow_attr);
else
mlx5e_tc_unoffload_fdb_rules(esw, flow, attr);
}

mlx5_eswitch_del_vlan_action(esw, attr);

Expand All @@ -968,7 +1010,7 @@ void mlx5e_tc_encap_flows_add(struct mlx5e_priv *priv,
struct mlx5e_encap_entry *e)
{
struct mlx5_eswitch *esw = priv->mdev->priv.eswitch;
struct mlx5_esw_flow_attr *esw_attr;
struct mlx5_esw_flow_attr slow_attr, *esw_attr;
struct mlx5_flow_handle *rule;
struct mlx5_flow_spec *spec;
struct mlx5e_tc_flow *flow;
Expand All @@ -991,13 +1033,17 @@ void mlx5e_tc_encap_flows_add(struct mlx5e_priv *priv,
esw_attr->encap_id = e->encap_id;
spec = &esw_attr->parse_attr->spec;

/* update from slow path rule to encap rule */
rule = mlx5e_tc_offload_fdb_rules(esw, flow, spec, esw_attr);
if (IS_ERR(rule)) {
err = PTR_ERR(rule);
mlx5_core_warn(priv->mdev, "Failed to update cached encapsulation flow, %d\n",
err);
continue;
}

mlx5e_tc_unoffload_from_slow_path(esw, flow, &slow_attr);
flow->flags |= MLX5E_TC_FLOW_OFFLOADED; /* was unset when slow path rule removed */
flow->rule[0] = rule;
}
}
Expand All @@ -1006,11 +1052,28 @@ void mlx5e_tc_encap_flows_del(struct mlx5e_priv *priv,
struct mlx5e_encap_entry *e)
{
struct mlx5_eswitch *esw = priv->mdev->priv.eswitch;
struct mlx5_esw_flow_attr slow_attr;
struct mlx5_flow_handle *rule;
struct mlx5_flow_spec *spec;
struct mlx5e_tc_flow *flow;
int err;

list_for_each_entry(flow, &e->flows, encap) {
if (flow->flags & MLX5E_TC_FLOW_OFFLOADED)
mlx5e_tc_unoffload_fdb_rules(esw, flow, flow->esw_attr);
spec = &flow->esw_attr->parse_attr->spec;

/* update from encap rule to slow path rule */
rule = mlx5e_tc_offload_to_slow_path(esw, flow, spec, &slow_attr);

if (IS_ERR(rule)) {
err = PTR_ERR(rule);
mlx5_core_warn(priv->mdev, "Failed to update slow path (encap) flow, %d\n",
err);
continue;
}

mlx5e_tc_unoffload_fdb_rules(esw, flow, flow->esw_attr);
flow->flags |= MLX5E_TC_FLOW_OFFLOADED; /* was unset when fast path rule removed */
flow->rule[0] = rule;
}

if (e->flags & MLX5_ENCAP_ENTRY_VALID) {
Expand Down Expand Up @@ -2888,9 +2951,9 @@ static int parse_tc_fdb_actions(struct mlx5e_priv *priv, struct tcf_exts *exts,
return 0;
}

static void get_flags(int flags, u8 *flow_flags)
static void get_flags(int flags, u16 *flow_flags)
{
u8 __flow_flags = 0;
u16 __flow_flags = 0;

if (flags & MLX5E_TC_INGRESS)
__flow_flags |= MLX5E_TC_FLOW_INGRESS;
Expand Down Expand Up @@ -2921,7 +2984,7 @@ static struct rhashtable *get_tc_ht(struct mlx5e_priv *priv)

static int
mlx5e_alloc_flow(struct mlx5e_priv *priv, int attr_size,
struct tc_cls_flower_offload *f, u8 flow_flags,
struct tc_cls_flower_offload *f, u16 flow_flags,
struct mlx5e_tc_flow_parse_attr **__parse_attr,
struct mlx5e_tc_flow **__flow)
{
Expand Down Expand Up @@ -2958,7 +3021,7 @@ mlx5e_alloc_flow(struct mlx5e_priv *priv, int attr_size,
static int
mlx5e_add_fdb_flow(struct mlx5e_priv *priv,
struct tc_cls_flower_offload *f,
u8 flow_flags,
u16 flow_flags,
struct mlx5e_tc_flow **__flow)
{
struct netlink_ext_ack *extack = f->common.extack;
Expand All @@ -2978,12 +3041,9 @@ mlx5e_add_fdb_flow(struct mlx5e_priv *priv,
goto err_free;

err = mlx5e_tc_add_fdb_flow(priv, parse_attr, flow, extack);
if (err && err != -EAGAIN)
if (err)
goto err_free;

if (!err)
flow->flags |= MLX5E_TC_FLOW_OFFLOADED;

if (!(flow->esw_attr->action &
MLX5_FLOW_CONTEXT_ACTION_PACKET_REFORMAT))
kvfree(parse_attr);
Expand All @@ -3002,7 +3062,7 @@ mlx5e_add_fdb_flow(struct mlx5e_priv *priv,
static int
mlx5e_add_nic_flow(struct mlx5e_priv *priv,
struct tc_cls_flower_offload *f,
u8 flow_flags,
u16 flow_flags,
struct mlx5e_tc_flow **__flow)
{
struct netlink_ext_ack *extack = f->common.extack;
Expand Down Expand Up @@ -3045,7 +3105,7 @@ mlx5e_tc_add_flow(struct mlx5e_priv *priv,
struct mlx5e_tc_flow **flow)
{
struct mlx5_eswitch *esw = priv->mdev->priv.eswitch;
u8 flow_flags;
u16 flow_flags;
int err;

get_flags(flags, &flow_flags);
Expand Down

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