Commit 915efd8a authored by Jesper Dangaard Brouer's avatar Jesper Dangaard Brouer Committed by Alexei Starovoitov
Browse files

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: ab46182d ("net/mlx4_en: Support RX XDP metadata")
Fixes: bc8d405b ("net/mlx5e: Support RX XDP metadata")
Fixes: 306531f0 ("veth: Support RX XDP metadata")
Fixes: 3d76a4d3 ("bpf: XDP metadata RX kfuncs")
Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Acked-by: default avatarStanislav Fomichev <sdf@google.com>
Acked-by: default avatarToke Høiland-Jørgensen <toke@redhat.com>
Acked-by: default avatarTariq Toukan <tariqt@nvidia.com>
Link: https://lore.kernel.org/r/167940675120.2718408.8176058626864184420.stgit@firesoul


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 10ec8ca8

Documentation/networking/xdp-rx-metadata.rst

+5 −2
Original line number Diff line number Diff line
@@ -23,10 +23,13 @@ metadata is supported, this set will grow: 
An XDP program can use these kfuncs to read the metadata into stack

variables for its own consumption. Or, to pass the metadata on to other

consumers, an XDP program can store it into the metadata area carried

ahead of the packet.

ahead of the packet. Not all packets will necessary have the requested

metadata available in which case the driver returns ``-ENODATA``.



Not all kfuncs have to be implemented by the device driver; when not

implemented, the default ones that return ``-EOPNOTSUPP`` will be used.

implemented, the default ones that return ``-EOPNOTSUPP`` will be used

to indicate the device driver have not implemented this kfunc.





Within an XDP frame, the metadata layout (accessed via ``xdp_buff``) is

as follows::

drivers/net/ethernet/mellanox/mlx4/en_rx.c

+2 −2
Original line number Diff line number Diff line
@@ -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;

drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c

+2 −2
Original line number Diff line number Diff line
@@ -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;

drivers/net/veth.c

+2 −2
Original line number Diff line number Diff line
@@ -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;

net/core/xdp.c

+8 −2
Original line number Diff line number Diff line
@@ -720,7 +720,10 @@ __diag_ignore_all("-Wmissing-prototypes", 
 * @ctx: XDP context pointer.

 * @timestamp: Return value pointer.

 *

 * Returns 0 on success or ``-errno`` on error.

 * Return:

 * * Returns 0 on success or ``-errno`` on error.

 * * ``-EOPNOTSUPP`` : means device driver does not implement kfunc

 * * ``-ENODATA``    : means no RX-timestamp available for this frame

 */

__bpf_kfunc int bpf_xdp_metadata_rx_timestamp(const struct xdp_md *ctx, u64 *timestamp)

{
@@ -732,7 +735,10 @@ __bpf_kfunc int bpf_xdp_metadata_rx_timestamp(const struct xdp_md *ctx, u64 *tim 
 * @ctx: XDP context pointer.

 * @hash: Return value pointer.

 *

 * Returns 0 on success or ``-errno`` on error.

 * Return:

 * * Returns 0 on success or ``-errno`` on error.

 * * ``-EOPNOTSUPP`` : means device driver doesn't implement kfunc

 * * ``-ENODATA``    : means no RX-hash available for this frame

 */

__bpf_kfunc int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, u32 *hash)

{