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

Jiri Pirko
2023-11-28T08:26:15Z

Mon, Nov 27, 2023 at 04:40:22PM CET, przemyslaw.kitszel@intel.com wrote:
>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[];
>> +};
>> +
>> +static inline void devlink_nl_obj_desc_init(struct devlink_obj_desc *desc,
>> + 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;
>> +
>> + devlink_nl_obj_desc_init(&desc, devlink);
>> + devlink_nl_notify_send_desc(devlink, msg, &desc);
>> }
>> /* Notify */
>> diff --git a/net/devlink/netlink.c b/net/devlink/netlink.c
>> index fa9afe3e6d9b..33a8e51dea68 100644
>> --- a/net/devlink/netlink.c
>> +++ b/net/devlink/netlink.c
>> @@ -17,6 +17,79 @@ static const struct genl_multicast_group devlink_nl_mcgrps[] = {
>> [DEVLINK_MCGRP_CONFIG] = { .name = DEVLINK_GENL_MCGRP_CONFIG_NAME },
>> };
>> +int devlink_nl_notify_filter_set_doit(struct sk_buff *skb,
>> + struct genl_info *info)
>> +{
>> + struct nlattr **attrs = info->attrs;
>> + struct devlink_obj_desc *flt;
>> + size_t data_offset = 0;
>> + size_t data_size = 0;
>> + char *pos;
>> +
>> + if (attrs[DEVLINK_ATTR_BUS_NAME])
>> + data_size += nla_len(attrs[DEVLINK_ATTR_BUS_NAME]) + 1;
>> + if (attrs[DEVLINK_ATTR_DEV_NAME])
>> + data_size += nla_len(attrs[DEVLINK_ATTR_DEV_NAME]) + 1;
>> +
>> + flt = kzalloc(sizeof(*flt) + data_size, GFP_KERNEL);
>
>instead of arithmetic here, you could use struct_size()
>
>> + if (!flt)
>> + return -ENOMEM;
>> +
>> + pos = (char *) flt->data;
>> + if (attrs[DEVLINK_ATTR_BUS_NAME]) {
>> + data_offset += nla_strscpy(pos,
>> + attrs[DEVLINK_ATTR_BUS_NAME],
>> + data_size) + 1;
>> + flt->bus_name = pos;
>> + pos += data_offset;
>> + }
>> + if (attrs[DEVLINK_ATTR_DEV_NAME]) {
>> + nla_strscpy(pos, attrs[DEVLINK_ATTR_DEV_NAME],
>> + data_size - data_offset);
>> + flt->dev_name = pos;
>> + }
>> +
>> + /* Don't attach empty filter. */
>> + if (!flt->bus_name && !flt->dev_name) {
>> + kfree(flt);
>> + flt = NULL;
>> + }
>> +
>
>(Thanks for pointing out to this place in the other sub-thread)
>
>[here1] Assume that @flt is fine here.
>
>> + flt = genl_sk_priv_store(NETLINK_CB(skb).sk, &devlink_nl_family, flt);
>> + if (IS_ERR(flt))
>> + return PTR_ERR(flt);
>
>and now you got an error from genl_sk_priv_store(),
>which means that you leak old flt as of [here1].
>I am correct? (sorry it's kinda late :/)

You are correct. Thanks. Looks like I'll be rewriting this entirely
anyway.

>
>> + else if (flt)
>> + kfree_rcu(flt, rcu);
>> +
>> + return 0;
>> +}
>> +
>> +static bool devlink_obj_desc_match(const struct devlink_obj_desc *desc,
>> + const struct devlink_obj_desc *flt)
>> +{
>> + if (desc->bus_name && flt->bus_name &&
>> + strcmp(desc->bus_name, flt->bus_name))
>> + return false;
>> + if (desc->dev_name && flt->dev_name &&
>> + strcmp(desc->dev_name, flt->dev_name))
>> + return false;
>> + return true;
>> +}
>> +
>> +int devlink_nl_notify_filter(struct sock *dsk, struct sk_buff *skb, void *data)
>> +{
>> + struct devlink_obj_desc *desc = data;
>> + struct devlink_obj_desc *flt;
>> + int ret = 0;
>> +
>> + rcu_read_lock();
>> + flt = genl_sk_priv_get(dsk, &devlink_nl_family);
>> + if (flt)
>> + ret = !devlink_obj_desc_match(desc, flt);
>> + rcu_read_unlock();
>> + return ret;
>> +}
>> +
>> int devlink_nl_put_nested_handle(struct sk_buff *msg, struct net *net,
>> struct devlink *devlink, int attrtype)
>> {
>> diff --git a/net/devlink/netlink_gen.c b/net/devlink/netlink_gen.c
>> index 95f9b4350ab7..1cb0e05305d2 100644
>> --- a/net/devlink/netlink_gen.c
>> +++ b/net/devlink/netlink_gen.c
>> @@ -560,8 +560,14 @@ static const struct nla_policy devlink_selftests_run_nl_policy[DEVLINK_ATTR_SELF
>> [DEVLINK_ATTR_SELFTESTS] = NLA_POLICY_NESTED(devlink_dl_selftest_id_nl_policy),
>> };
>> +/* DEVLINK_CMD_NOTIFY_FILTER_SET - do */
>> +static const struct nla_policy devlink_notify_filter_set_nl_policy[DEVLINK_ATTR_DEV_NAME + 1] = {
>> + [DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING, },
>> + [DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING, },
>> +};
>> +
>> /* Ops table for devlink */
>> -const struct genl_split_ops devlink_nl_ops[73] = {
>> +const struct genl_split_ops devlink_nl_ops[74] = {
>> {
>> .cmd = DEVLINK_CMD_GET,
>> .validate = GENL_DONT_VALIDATE_STRICT,
>> @@ -1233,4 +1239,11 @@ const struct genl_split_ops devlink_nl_ops[73] = {
>> .maxattr = DEVLINK_ATTR_SELFTESTS,
>> .flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
>> },
>> + {
>> + .cmd = DEVLINK_CMD_NOTIFY_FILTER_SET,
>> + .doit = devlink_nl_notify_filter_set_doit,
>> + .policy = devlink_notify_filter_set_nl_policy,
>> + .maxattr = DEVLINK_ATTR_DEV_NAME,
>> + .flags = GENL_CMD_CAP_DO,
>> + },
>> };
>> diff --git a/net/devlink/netlink_gen.h b/net/devlink/netlink_gen.h
>> index 02f3c0bfae0e..8f2bd50ddf5e 100644
>> --- a/net/devlink/netlink_gen.h
>> +++ b/net/devlink/netlink_gen.h
>> @@ -16,7 +16,7 @@ extern const struct nla_policy devlink_dl_port_function_nl_policy[DEVLINK_PORT_F
>> extern const struct nla_policy devlink_dl_selftest_id_nl_policy[DEVLINK_ATTR_SELFTEST_ID_FLASH + 1];
>> /* Ops table for devlink */
>> -extern const struct genl_split_ops devlink_nl_ops[73];
>> +extern const struct genl_split_ops devlink_nl_ops[74];
>> int devlink_nl_pre_doit(const struct genl_split_ops *ops, struct sk_buff *skb,
>> struct genl_info *info);
>> @@ -142,5 +142,7 @@ int devlink_nl_selftests_get_doit(struct sk_buff *skb, struct genl_info *info);
>> int devlink_nl_selftests_get_dumpit(struct sk_buff *skb,
>> struct netlink_callback *cb);
>> int devlink_nl_selftests_run_doit(struct sk_buff *skb, struct genl_info *info);
>> +int devlink_nl_notify_filter_set_doit(struct sk_buff *skb,
>> + struct genl_info *info);
>> #endif /* _LINUX_DEVLINK_GEN_H */
>> diff --git a/tools/net/ynl/generated/devlink-user.c b/tools/net/ynl/generated/devlink-user.c
>> index bc5065bd99b2..cd5f70eadf5b 100644
>> --- a/tools/net/ynl/generated/devlink-user.c
>> +++ b/tools/net/ynl/generated/devlink-user.c
>> @@ -6830,6 +6830,37 @@ int devlink_selftests_run(struct ynl_sock *ys,
>> return 0;
>> }
>> +/* ============== DEVLINK_CMD_NOTIFY_FILTER_SET ============== */
>> +/* DEVLINK_CMD_NOTIFY_FILTER_SET - do */
>> +void
>> +devlink_notify_filter_set_req_free(struct devlink_notify_filter_set_req *req)
>> +{
>> + free(req->bus_name);
>> + free(req->dev_name);
>> + free(req);
>> +}
>> +
>> +int devlink_notify_filter_set(struct ynl_sock *ys,
>> + struct devlink_notify_filter_set_req *req)
>> +{
>> + struct nlmsghdr *nlh;
>> + int err;
>> +
>> + nlh = ynl_gemsg_start_req(ys, ys->family_id, DEVLINK_CMD_NOTIFY_FILTER_SET, 1);
>> + ys->req_policy = &devlink_nest;
>> +
>> + if (req->_present.bus_name_len)
>> + mnl_attr_put_strz(nlh, DEVLINK_ATTR_BUS_NAME, req->bus_name);
>> + if (req->_present.dev_name_len)
>> + mnl_attr_put_strz(nlh, DEVLINK_ATTR_DEV_NAME, req->dev_name);
>> +
>> + err = ynl_exec(ys, nlh, NULL);
>> + if (err < 0)
>> + return -1;
>> +
>> + return 0;
>> +}
>> +
>> const struct ynl_family ynl_devlink_family = {
>> .name = "devlink",
>> };
>> diff --git a/tools/net/ynl/generated/devlink-user.h b/tools/net/ynl/generated/devlink-user.h
>> index 1db4edc36eaa..e5d79b824a67 100644
>> --- a/tools/net/ynl/generated/devlink-user.h
>> +++ b/tools/net/ynl/generated/devlink-user.h
>> @@ -5252,4 +5252,51 @@ devlink_selftests_run_req_set_selftests_flash(struct devlink_selftests_run_req *
>> int devlink_selftests_run(struct ynl_sock *ys,
>> struct devlink_selftests_run_req *req);
>> +/* ============== DEVLINK_CMD_NOTIFY_FILTER_SET ============== */
>> +/* DEVLINK_CMD_NOTIFY_FILTER_SET - do */
>> +struct devlink_notify_filter_set_req {
>> + struct {
>> + __u32 bus_name_len;
>> + __u32 dev_name_len;
>> + } _present;
>> +
>> + char *bus_name;
>> + char *dev_name;
>> +};
>> +
>> +static inline struct devlink_notify_filter_set_req *
>> +devlink_notify_filter_set_req_alloc(void)
>> +{
>> + return calloc(1, sizeof(struct devlink_notify_filter_set_req));
>> +}
>> +void
>> +devlink_notify_filter_set_req_free(struct devlink_notify_filter_set_req *req);
>> +
>> +static inline void
>> +devlink_notify_filter_set_req_set_bus_name(struct devlink_notify_filter_set_req *req,
>> + const char *bus_name)
>> +{
>> + free(req->bus_name);
>> + req->_present.bus_name_len = strlen(bus_name);
>> + req->bus_name = malloc(req->_present.bus_name_len + 1);
>> + memcpy(req->bus_name, bus_name, req->_present.bus_name_len);
>> + req->bus_name[req->_present.bus_name_len] = 0;
>> +}
>> +static inline void
>> +devlink_notify_filter_set_req_set_dev_name(struct devlink_notify_filter_set_req *req,
>> + const char *dev_name)
>> +{
>> + free(req->dev_name);
>> + req->_present.dev_name_len = strlen(dev_name);
>> + req->dev_name = malloc(req->_present.dev_name_len + 1);
>> + memcpy(req->dev_name, dev_name, req->_present.dev_name_len);
>> + req->dev_name[req->_present.dev_name_len] = 0;
>> +}
>> +
>> +/*
>> + * Set notification messages socket filter.
>> + */
>> +int devlink_notify_filter_set(struct ynl_sock *ys,
>> + struct devlink_notify_filter_set_req *req);
>> +
>> #endif /* _LINUX_DEVLINK_GEN_H */
>