Re: [PATCH net-next v5 2/3] netdev-genl: Add an XSK attribute to queues

Stanislav Fomichev
2025-02-09T01:43:50Z

On 02/08, Joe Damato wrote:
> Expose a new per-queue nest attribute, xsk, which will be present for
> queues that are being used for AF_XDP. If the queue is not being used for
> AF_XDP, the nest will not be present.
>
> In the future, this attribute can be extended to include more data about
> XSK as it is needed.
>
> Signed-off-by: Joe Damato <jdamato@fastly.com>
> Suggested-by: Jakub Kicinski <kuba@kernel.org>
> ---
> v5:
> - Removed unused variable, ret, from netdev_nl_queue_fill_one.
>
> v4:
> - Updated netdev_nl_queue_fill_one to use the empty nest helper added
> in patch 1.
>
> v2:
> - Patch adjusted to include an attribute, xsk, which is an empty nest
> and exposed for queues which have a pool.
>
> Documentation/netlink/specs/netdev.yaml | 13 ++++++++++++-
> include/uapi/linux/netdev.h | 6 ++++++
> net/core/netdev-genl.c | 11 +++++++++++
> tools/include/uapi/linux/netdev.h | 6 ++++++
> 4 files changed, 35 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
> index 288923e965ae..85402a2e289c 100644
> --- a/Documentation/netlink/specs/netdev.yaml
> +++ b/Documentation/netlink/specs/netdev.yaml
> @@ -276,6 +276,9 @@ attribute-sets:
> doc: The timeout, in nanoseconds, of how long to suspend irq
> processing, if event polling finds events
> type: uint
> + -
> + name: xsk-info
> + attributes: []
> -
> name: queue
> attributes:
> @@ -294,6 +297,9 @@ attribute-sets:
> -
> name: type
> doc: Queue type as rx, tx. Each queue type defines a separate ID space.
> + XDP TX queues allocated in the kernel are not linked to NAPIs and
> + thus not listed. AF_XDP queues will have more information set in
> + the xsk attribute.
> type: u32
> enum: queue-type
> -
> @@ -309,7 +315,11 @@ attribute-sets:
> doc: io_uring memory provider information.
> type: nest
> nested-attributes: io-uring-provider-info
> -
> + -
> + name: xsk
> + doc: XSK information for this queue, if any.
> + type: nest
> + nested-attributes: xsk-info
> -
> name: qstats
> doc: |
> @@ -652,6 +662,7 @@ operations:
> - ifindex
> - dmabuf
> - io-uring
> + - xsk
> dump:
> request:
> attributes:
> diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h
> index 6c6ee183802d..4e82f3871473 100644
> --- a/include/uapi/linux/netdev.h
> +++ b/include/uapi/linux/netdev.h
> @@ -136,6 +136,11 @@ enum {
> NETDEV_A_NAPI_MAX = (__NETDEV_A_NAPI_MAX - 1)
> };
>
> +enum {
> + __NETDEV_A_XSK_INFO_MAX,
> + NETDEV_A_XSK_INFO_MAX = (__NETDEV_A_XSK_INFO_MAX - 1)
> +};
> +
> enum {
> NETDEV_A_QUEUE_ID = 1,
> NETDEV_A_QUEUE_IFINDEX,
> @@ -143,6 +148,7 @@ enum {
> NETDEV_A_QUEUE_NAPI_ID,
> NETDEV_A_QUEUE_DMABUF,
> NETDEV_A_QUEUE_IO_URING,
> + NETDEV_A_QUEUE_XSK,
>
> __NETDEV_A_QUEUE_MAX,
> NETDEV_A_QUEUE_MAX = (__NETDEV_A_QUEUE_MAX - 1)
> diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
> index 0dcd4faefd8d..b5a93a449af9 100644
> --- a/net/core/netdev-genl.c
> +++ b/net/core/netdev-genl.c
> @@ -400,11 +400,22 @@ netdev_nl_queue_fill_one(struct sk_buff *rsp, struct net_device *netdev,
> if (params->mp_ops &&
> params->mp_ops->nl_fill(params->mp_priv, rsp, rxq))
> goto nla_put_failure;
> +
> + if (rxq->pool)
> + if (nla_put_empty_nest(rsp, NETDEV_A_QUEUE_XSK))
> + goto nla_put_failure;

Needs to be guarded by ifdef CONFIG_XDP_SOCKETS?

net/core/netdev-genl.c: In function ‘netdev_nl_queue_fill_one’:
net/core/netdev-genl.c:404:24: error: ‘struct netdev_rx_queue’ has no member named ‘pool’
404 | if (rxq->pool)
| ^~
net/core/netdev-genl.c:414:24: error: ‘struct netdev_queue’ has no member named ‘pool’
414 | if (txq->pool)
| ^~

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