xdp: bpf_xdp_metadata use EOPNOTSUPP for no driver support

When driver doesn't implement a bpf_xdp_metadata kfunc the fallback
implementation returns EOPNOTSUPP, which indicate device driver doesn't
implement this kfunc.

Currently many drivers also return EOPNOTSUPP when the hint isn't
available, which is ambiguous from an API point of view. Instead
change drivers to return ENODATA in these cases.

There can be natural cases why a driver doesn't provide any hardware
info for a specific hint, even on a frame to frame basis (e.g. PTP).
Lets keep these cases as separate return codes.

When describing the return values, adjust the function kernel-doc layout
to get proper rendering for the return values.

Fixes: ab46182d0dcb ("net/mlx4_en: Support RX XDP metadata")
Fixes: bc8d405b1ba9 ("net/mlx5e: Support RX XDP metadata")
Fixes: 306531f0249f ("veth: Support RX XDP metadata")
Fixes: 3d76a4d3d4e5 ("bpf: XDP metadata RX kfuncs")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://lore.kernel.org/r/167940675120.2718408.8176058626864184420.stgit@firesoul
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

3 files changed, 6 insertions, 6 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
index 0869d4fff17b..4b5e459b6d49 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
@@ -674,7 +674,7 @@ int mlx4_en_xdp_rx_timestamp(const struct xdp_md *ctx, u64 *timestamp)
 	struct mlx4_en_xdp_buff *_ctx = (void *)ctx;
 
 	if (unlikely(_ctx->ring->hwtstamp_rx_filter != HWTSTAMP_FILTER_ALL))
-		return -EOPNOTSUPP;
+		return -ENODATA;
 
 	*timestamp = mlx4_en_get_hwtstamp(_ctx->mdev,
 					  mlx4_en_get_cqe_ts(_ctx->cqe));
@@ -686,7 +686,7 @@ int mlx4_en_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash)
 	struct mlx4_en_xdp_buff *_ctx = (void *)ctx;
 
 	if (unlikely(!(_ctx->dev->features & NETIF_F_RXHASH)))
-		return -EOPNOTSUPP;
+		return -ENODATA;
 
 	*hash = be32_to_cpu(_ctx->cqe->immed_rss_invalid);
 	return 0;
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
index bcd6370de440..c5dae48b7932 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
@@ -162,7 +162,7 @@ static int mlx5e_xdp_rx_timestamp(const struct xdp_md *ctx, u64 *timestamp)
 	const struct mlx5e_xdp_buff *_ctx = (void *)ctx;
 
 	if (unlikely(!mlx5e_rx_hw_stamp(_ctx->rq->tstamp)))
-		return -EOPNOTSUPP;
+		return -ENODATA;
 
 	*timestamp =  mlx5e_cqe_ts_to_ns(_ctx->rq->ptp_cyc2time,
 					 _ctx->rq->clock, get_cqe_ts(_ctx->cqe));
@@ -174,7 +174,7 @@ static int mlx5e_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash)
 	const struct mlx5e_xdp_buff *_ctx = (void *)ctx;
 
 	if (unlikely(!(_ctx->xdp.rxq->dev->features & NETIF_F_RXHASH)))
-		return -EOPNOTSUPP;
+		return -ENODATA;
 
 	*hash = be32_to_cpu(_ctx->cqe->rss_hash_result);
 	return 0;
diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 1bb54de7124d..046461ee42ea 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -1610,7 +1610,7 @@ static int veth_xdp_rx_timestamp(const struct xdp_md *ctx, u64 *timestamp)
 	struct veth_xdp_buff *_ctx = (void *)ctx;
 
 	if (!_ctx->skb)
-		return -EOPNOTSUPP;
+		return -ENODATA;
 
 	*timestamp = skb_hwtstamps(_ctx->skb)->hwtstamp;
 	return 0;
@@ -1621,7 +1621,7 @@ static int veth_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash)
 	struct veth_xdp_buff *_ctx = (void *)ctx;
 
 	if (!_ctx->skb)
-		return -EOPNOTSUPP;
+		return -ENODATA;
 
 	*hash = skb_get_hash(_ctx->skb);
 	return 0;