[PATCH net-next 1/8] pkt_cls: add new tc cls helper to check offload flag and chain index

[Jakub Kicinski]

Very few (mlxsw) upstream drivers seem to allow offload of chains
other than 0.  Save driver developers typing and add a helper for
checking both if ethtool's TC offload flag is on and if chain is 0.
This helper will set the extack appropriately in both error cases.

Signed-off-by: Jakub Kicinski <jakub.kicin...@netronome.com>
Reviewed-by: Simon Horman <simon.hor...@netronome.com>
---
 drivers/net/ethernet/netronome/nfp/bpf/main.c |  4 +---
 drivers/net/netdevsim/bpf.c                   |  5 +----
 include/net/pkt_cls.h                         | 12 ++++++++++++
 3 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/main.c 
b/drivers/net/ethernet/netronome/nfp/bpf/main.c
index b3206855535a..322027792fe8 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/main.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/main.c
@@ -130,7 +130,7 @@ static int nfp_bpf_setup_tc_block_cb(enum tc_setup_type 
type,
                                   "only offload of BPF classifiers supported");
                return -EOPNOTSUPP;
        }
-       if (!tc_can_offload_extack(nn->dp.netdev, cls_bpf->common.extack))
+       if (!tc_cls_can_offload_and_chain0(nn->dp.netdev, &cls_bpf->common))
                return -EOPNOTSUPP;
        if (!nfp_net_ebpf_capable(nn)) {
                NL_SET_ERR_MSG_MOD(cls_bpf->common.extack,
@@ -142,8 +142,6 @@ static int nfp_bpf_setup_tc_block_cb(enum tc_setup_type 
type,
                                   "only ETH_P_ALL supported as filter 
protocol");
                return -EOPNOTSUPP;
        }
-       if (cls_bpf->common.chain_index)
-               return -EOPNOTSUPP;
 
        /* Only support TC direct action */
        if (!cls_bpf->exts_integrated ||
diff --git a/drivers/net/netdevsim/bpf.c b/drivers/net/netdevsim/bpf.c
index 8166f121bbcc..de73c1ff0939 100644
--- a/drivers/net/netdevsim/bpf.c
+++ b/drivers/net/netdevsim/bpf.c
@@ -135,7 +135,7 @@ int nsim_bpf_setup_tc_block_cb(enum tc_setup_type type,
                return -EOPNOTSUPP;
        }
 
-       if (!tc_can_offload_extack(ns->netdev, cls_bpf->common.extack))
+       if (!tc_cls_can_offload_and_chain0(ns->netdev, &cls_bpf->common))
                return -EOPNOTSUPP;
 
        if (cls_bpf->common.protocol != htons(ETH_P_ALL)) {
@@ -144,9 +144,6 @@ int nsim_bpf_setup_tc_block_cb(enum tc_setup_type type,
                return -EOPNOTSUPP;
        }
 
-       if (cls_bpf->common.chain_index)
-               return -EOPNOTSUPP;
-
        if (!ns->bpf_tc_accept) {
                NSIM_EA(cls_bpf->common.extack,
                        "netdevsim configured to reject BPF TC offload");
diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h
index 1a41513cec7f..4db08d7dd22c 100644
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -656,6 +656,18 @@ static inline bool tc_can_offload_extack(const struct 
net_device *dev,
        return can;
 }
 
+static inline bool
+tc_cls_can_offload_and_chain0(const struct net_device *dev,
+                             struct tc_cls_common_offload *common)
+{
+       if (common->chain_index) {
+               NL_SET_ERR_MSG(common->extack,
+                              "Driver supports only offload of chain 0");
+               return false;
+       }
+       return tc_can_offload_extack(dev, common->extack);
+}
+
 static inline bool tc_skip_hw(u32 flags)
 {
        return (flags & TCA_CLS_FLAGS_SKIP_HW) ? true : false;
-- 
2.15.1