Commit 24fc595e authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

Merge branch 'netdev-genl-add-an-xsk-attribute-to-queues' 

Joe Damato says:

====================
netdev-genl: Add an xsk attribute to queues

This is an attempt to followup on something Jakub asked me about [1],
adding an xsk attribute to queues and more clearly documenting which
queues are linked to NAPIs...

After the RFC [2], Jakub suggested creating an empty nest for queues
which have a pool, so I've adjusted this version to work that way.

The nest can be extended in the future to express attributes about XSK
as needed. Queues which are not used for AF_XDP do not have the xsk
attribute present.

I've run the included test on:
  - my mlx5 machine (via NETIF=)
  - without setting NETIF

And the test seems to pass in both cases.

[1]: https://lore.kernel.org/netdev/20250113143109.60afa59a@kernel.org/
[2]: https://lore.kernel.org/netdev/20250129172431.65773-1-jdamato@fastly.com/
====================

Link: https://patch.msgid.link/20250214211255.14194-1-jdamato@fastly.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parents c935af42 788e52e2

Documentation/netlink/specs/netdev.yaml

+12 −1
Original line number Diff line number Diff line
@@ -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:

include/net/netlink.h

+15 −0
Original line number Diff line number Diff line
@@ -118,6 +118,7 @@ 
 *   nla_nest_start(skb, type)		start a nested attribute

 *   nla_nest_end(skb, nla)		finalize a nested attribute

 *   nla_nest_cancel(skb, nla)		cancel nested attribute construction

 *   nla_put_empty_nest(skb, type)	create an empty nest

 *

 * Attribute Length Calculations:

 *   nla_attr_size(payload)		length of attribute w/o padding
@@ -2240,6 +2241,20 @@ static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start) 
	nlmsg_trim(skb, start);

}



/**

 * nla_put_empty_nest - Create an empty nest

 * @skb: socket buffer the message is stored in

 * @attrtype: attribute type of the container

 *

 * This function is a helper for creating empty nests.

 *

 * Returns: 0 when successful or -EMSGSIZE on failure.

 */

static inline int nla_put_empty_nest(struct sk_buff *skb, int attrtype)

{

	return nla_nest_start(skb, attrtype) ? 0 : -EMSGSIZE;

}



/**

 * __nla_validate_nested - Validate a stream of nested attributes

 * @start: container attribute

include/uapi/linux/netdev.h

+6 −0
Original line number Diff line number Diff line
@@ -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)

net/core/netdev-genl.c

+12 −0
Original line number Diff line number Diff line
@@ -400,11 +400,23 @@ 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;

#ifdef CONFIG_XDP_SOCKETS

		if (rxq->pool)

			if (nla_put_empty_nest(rsp, NETDEV_A_QUEUE_XSK))

				goto nla_put_failure;

#endif



		break;

	case NETDEV_QUEUE_TYPE_TX:

		txq = netdev_get_tx_queue(netdev, q_idx);

		if (nla_put_napi_id(rsp, txq->napi))

			goto nla_put_failure;

#ifdef CONFIG_XDP_SOCKETS

		if (txq->pool)

			if (nla_put_empty_nest(rsp, NETDEV_A_QUEUE_XSK))

				goto nla_put_failure;

#endif

		break;

	}



	genlmsg_end(rsp, hdr);

tools/include/uapi/linux/netdev.h

+6 −0
Original line number Diff line number Diff line
@@ -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)