Re: [patch net-next v4 8/9] devlink: add a command to set notification filter and use it for multicasts

Przemek Kitszel
2023-11-27T12:30:29Z

On 11/23/23 19:15, Jiri Pirko wrote:
> From: Jiri Pirko <jiri@nvidia.com>
>
> Currently the user listening on a socket for devlink notifications
> gets always all messages for all existing instances, even if he is
> interested only in one of those. That may cause unnecessary overhead
> on setups with thousands of instances present.
>
> User is currently able to narrow down the devlink objects replies
> to dump commands by specifying select attributes.
>
> Allow similar approach for notifications. Introduce a new devlink
> NOTIFY_FILTER_SET which the user passes the select attributes. Store
> these per-socket and use them for filtering messages
> during multicast send.
>
> Signed-off-by: Jiri Pirko <jiri@nvidia.com>
> ---
> v3->v4:
> - rebased on top of genl_sk_priv_*() introduction
> ---
> Documentation/netlink/specs/devlink.yaml | 10 ++++
> include/uapi/linux/devlink.h | 2 +
> net/devlink/devl_internal.h | 34 ++++++++++-
> net/devlink/netlink.c | 73 ++++++++++++++++++++++++
> net/devlink/netlink_gen.c | 15 ++++-
> net/devlink/netlink_gen.h | 4 +-
> tools/net/ynl/generated/devlink-user.c | 31 ++++++++++
> tools/net/ynl/generated/devlink-user.h | 47 +++++++++++++++
> 8 files changed, 212 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/netlink/specs/devlink.yaml b/Documentation/netlink/specs/devlink.yaml
> index 43067e1f63aa..6bad1d3454b7 100644
> --- a/Documentation/netlink/specs/devlink.yaml
> +++ b/Documentation/netlink/specs/devlink.yaml
> @@ -2055,3 +2055,13 @@ operations:
> - bus-name
> - dev-name
> - selftests
> +
> + -
> + name: notify-filter-set
> + doc: Set notification messages socket filter.
> + attribute-set: devlink
> + do:
> + request:
> + attributes:
> + - bus-name
> + - dev-name
> diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
> index b3c8383d342d..130cae0d3e20 100644
> --- a/include/uapi/linux/devlink.h
> +++ b/include/uapi/linux/devlink.h
> @@ -139,6 +139,8 @@ enum devlink_command {
> DEVLINK_CMD_SELFTESTS_GET, /* can dump */
> DEVLINK_CMD_SELFTESTS_RUN,
>
> + DEVLINK_CMD_NOTIFY_FILTER_SET,
> +
> /* add new commands above here */
> __DEVLINK_CMD_MAX,
> DEVLINK_CMD_MAX = __DEVLINK_CMD_MAX - 1
> diff --git a/net/devlink/devl_internal.h b/net/devlink/devl_internal.h
> index 84dc9628d3f2..82e0fb3bbebf 100644
> --- a/net/devlink/devl_internal.h
> +++ b/net/devlink/devl_internal.h
> @@ -191,11 +191,41 @@ static inline bool devlink_nl_notify_need(struct devlink *devlink)
> DEVLINK_MCGRP_CONFIG);
> }
>
> +struct devlink_obj_desc {
> + struct rcu_head rcu;
> + const char *bus_name;
> + const char *dev_name;
> + long data[];

could you please remove that data pointer?,
you are not using desc as flex pointer as of now

> +};
> +
> +static inline void devlink_nl_obj_desc_init(struct devlink_obj_desc *desc,

given next patch of the series with port index, you could rename this
function to devlink_nl_obj_desc_names_set(), and move 0-init outside.

> + struct devlink *devlink)
> +{
> + memset(desc, 0, sizeof(*desc));
> + desc->bus_name = devlink->dev->bus->name;
> + desc->dev_name = dev_name(devlink->dev);
> +}
> +
> +int devlink_nl_notify_filter(struct sock *dsk, struct sk_buff *skb, void *data);
> +
> +static inline void devlink_nl_notify_send_desc(struct devlink *devlink,
> + struct sk_buff *msg,
> + struct devlink_obj_desc *desc)
> +{
> + genlmsg_multicast_netns_filtered(&devlink_nl_family,
> + devlink_net(devlink),
> + msg, 0, DEVLINK_MCGRP_CONFIG,
> + GFP_KERNEL,
> + devlink_nl_notify_filter, desc);
> +}
> +
> static inline void devlink_nl_notify_send(struct devlink *devlink,
> struct sk_buff *msg)
> {
> - genlmsg_multicast_netns(&devlink_nl_family, devlink_net(devlink),
> - msg, 0, DEVLINK_MCGRP_CONFIG, GFP_KERNEL);
> + struct devlink_obj_desc desc;

`= {};` would wipe out the need for memset().

> +
> + devlink_nl_obj_desc_init(&desc, devlink);
> + devlink_nl_notify_send_desc(devlink, msg, &desc);
> }
>
> /* Notify */

[snip]