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xdp: bpf_xdp_metadata use EOPNOTSUPP for no driver support

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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: ab46182d0d ("net/mlx4_en: Support RX XDP metadata")
Fixes: bc8d405b1b ("net/mlx5e: Support RX XDP metadata")
Fixes: 306531f024 ("veth: Support RX XDP metadata")
Fixes: 3d76a4d3d4 ("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>
This commit is contained in:
Jesper Dangaard Brouer 2023-03-21 14:52:31 +01:00 committed by Alexei Starovoitov
parent 10ec8ca8ec
commit 915efd8a44
5 changed files with 19 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
Documentation/networking/xdp-rx-metadata.rst
View File

@ -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::

4
drivers/net/ethernet/mellanox/mlx4/en_rx.c
View File

@ -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;

4
drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
View File

@ -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;

4
drivers/net/veth.c
View File

@ -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;

10
net/core/xdp.c
View File

@ -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)
{