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Date: Mon, 30 Oct 2017 18:03:01 +0100
From: Jiri Pirko <jiri@...nulli.us>
To: Steve Lin <steven.lin1@...adcom.com>
Cc: netdev@...r.kernel.org, jiri@...lanox.com, davem@...emloft.net,
michael.chan@...adcom.com, linville@...driver.com,
gospo@...adcom.com, yuvalm@...lanox.com
Subject: Re: [PATCH net-next v5 01/10] devlink: Add permanent config
parameter get/set operations
Mon, Oct 30, 2017 at 03:46:07PM CET, steven.lin1@...adcom.com wrote:
>Add support for permanent config parameter get/set commands. Used
>for persistent device configuration parameters.
>
>Signed-off-by: Steve Lin <steven.lin1@...adcom.com>
>Acked-by: Andy Gospodarek <gospo@...adcom.com>
In general, I don't like how you use netlink. Please see the rest of
this code. We should do things in the common way. More info inlined.
[...]
>
>+/* Permanent config parameters */
>+enum devlink_perm_config_param {
>+ __DEVLINK_PERM_CONFIG_MAX,
>+ DEVLINK_PERM_CONFIG_MAX = __DEVLINK_PERM_CONFIG_MAX - 1
>+};
>+
>+/* Permanent config types */
>+enum devlink_perm_config_type {
>+ DEVLINK_PERM_CONFIG_TYPE_UNSPEC,
You should not need this. Type should be always specified.
>+ DEVLINK_PERM_CONFIG_TYPE_U8,
>+ DEVLINK_PERM_CONFIG_TYPE_U16,
>+ DEVLINK_PERM_CONFIG_TYPE_U32,
>+};
This definitelly should not be in uapi header.
>+
>+/* Permanent config value */
>+union devlink_perm_config_value {
>+ __u8 value8;
>+ __u16 value16;
>+ __u32 value32;
>+};
This definitelly should not be in uapi header.
>+
> #endif /* _UAPI_LINUX_DEVLINK_H_ */
[...]
>+static int devlink_nl_config_get_fill(struct sk_buff *msg,
>+ struct devlink *devlink,
>+ enum devlink_command cmd,
>+ struct genl_info *info)
>+{
>+ struct nlattr *tb[DEVLINK_ATTR_MAX + 1];
>+ enum devlink_perm_config_param param;
>+ enum devlink_perm_config_type type;
>+ struct nlattr *cfgparam_attr;
>+ struct nlattr *attr;
>+ void *hdr;
>+ int err;
>+ int rem;
>+
>+ hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
>+ &devlink_nl_family, 0, cmd);
>+ if (!hdr)
>+ return -EMSGSIZE;
>+
>+ err = devlink_nl_put_handle(msg, devlink);
>+ if (err)
>+ goto nla_put_failure;
>+
>+ if (!info->attrs[DEVLINK_ATTR_PERM_CONFIGS]) {
>+ err = -EINVAL;
>+ goto nla_put_failure;
>+ }
>+
>+ cfgparam_attr = nla_nest_start(msg, DEVLINK_ATTR_PERM_CONFIGS);
>+
>+ nla_for_each_nested(attr, info->attrs[DEVLINK_ATTR_PERM_CONFIGS],
Okay. So I have to know what is in kernel in order to get the value.
We need a dump operation. In fact, why can't we just have dump operation?
>+ rem) {
>+ err = nla_parse_nested(tb, DEVLINK_ATTR_MAX, attr,
>+ devlink_nl_policy, NULL);
>+ if (err)
>+ goto nla_nest_failure;
>+ if (!tb[DEVLINK_ATTR_PERM_CONFIG_PARAMETER] ||
>+ !tb[DEVLINK_ATTR_PERM_CONFIG_TYPE])
>+ continue;
>+
>+ param = nla_get_u32(tb[DEVLINK_ATTR_PERM_CONFIG_PARAMETER]);
>+ type = nla_get_u8(tb[DEVLINK_ATTR_PERM_CONFIG_TYPE]);
So to get parameter, I have to specify a type? What if I specify wrong
type? That is wrong. The type should be read attr for get.
You should have a param -> type table and always use that.
>+ if (param > DEVLINK_PERM_CONFIG_MAX ||
>+ type > NLA_TYPE_MAX) {
>+ continue;
>+ }
>+ /* Note if single_param_get fails, that param won't be in
>+ * response msg, so caller will know which param(s) failed to
>+ * get.
>+ */
>+ devlink_nl_single_param_get(msg, devlink, param, type);
>+ }
>+
>+ nla_nest_end(msg, cfgparam_attr);
>+
>+ genlmsg_end(msg, hdr);
>+ return 0;
>+
>+nla_nest_failure:
>+ nla_nest_cancel(msg, cfgparam_attr);
>+nla_put_failure:
You should make this multipart aware. If config parameters won't fit
into a single skb, you have to allocate another one. See devlink_dpipe_tables_fill
as an example how to do it. It is important to have this from the
beginning as the userspace knows to expect multipart message.
>+ genlmsg_cancel(msg, hdr);
>+ return err;
>+}
>+
>+static int devlink_nl_cmd_perm_config_get_doit(struct sk_buff *skb,
>+ struct genl_info *info)
>+{
>+ struct devlink *devlink = info->user_ptr[0];
>+ struct sk_buff *msg;
>+ int err;
>+
>+ if (!devlink->ops || !devlink->ops->perm_config_get)
>+ return -EOPNOTSUPP;
>+
>+ msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
>+ if (!msg)
>+ return -ENOMEM;
>+
>+ err = devlink_nl_config_get_fill(msg, devlink,
>+ DEVLINK_CMD_PERM_CONFIG_GET, info);
>+
>+ if (err) {
>+ nlmsg_free(msg);
>+ return err;
>+ }
>+
>+ return genlmsg_reply(msg, info);
>+}
>+
>+static int devlink_nl_single_param_set(struct sk_buff *msg,
>+ struct devlink *devlink,
>+ enum devlink_perm_config_param param,
>+ enum devlink_perm_config_type type,
>+ union devlink_perm_config_value *value)
>+{
>+ const struct devlink_ops *ops = devlink->ops;
>+ struct nlattr *cfgparam_attr;
>+ bool need_restart;
>+ int err;
>+
>+ /* Now set parameter */
>+ err = ops->perm_config_set(devlink, param, type, value, &need_restart);
>+ if (err)
>+ return err;
>+
>+ cfgparam_attr = nla_nest_start(msg, DEVLINK_ATTR_PERM_CONFIG);
>+ /* Update restart reqd - if any param needs restart, should be set */
>+ if (need_restart) {
You should propagate this out so the caller would fill it to the
message. This is a global thing, not per-param, shoult not be nested.
>+ err = nla_put_flag(msg,
>+ DEVLINK_ATTR_PERM_CONFIG_RESTART_REQUIRED);
>+ if (err)
>+ goto nest_fail;
>+ }
>+
>+ /* Since set was successful, write attr back to msg */
>+ err = nla_put_u32(msg, DEVLINK_ATTR_PERM_CONFIG_PARAMETER, param);
>+ if (err)
>+ goto nest_fail;
>+
>+ nla_nest_end(msg, cfgparam_attr);
>+
>+ return 0;
>+
>+nest_fail:
>+ nla_nest_cancel(msg, cfgparam_attr);
>+ return err;
>+}
>+
>+static int devlink_nl_cmd_perm_config_set_doit(struct sk_buff *skb,
>+ struct genl_info *info)
>+{
>+ struct devlink *devlink = info->user_ptr[0];
>+ struct nlattr *tb[DEVLINK_ATTR_MAX + 1];
>+ union devlink_perm_config_value value;
>+ enum devlink_perm_config_param param;
>+ enum devlink_perm_config_type type;
>+ struct nlattr *cfgparam_attr;
>+ struct sk_buff *msg;
>+ struct nlattr *attr;
>+ void *hdr;
>+ int rem;
>+ int err;
>+
>+ if (!devlink->ops || !devlink->ops->perm_config_get ||
>+ !devlink->ops->perm_config_set)
>+ return -EOPNOTSUPP;
>+
>+ msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
>+ if (!msg)
>+ return -ENOMEM;
>+
>+ hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
>+ &devlink_nl_family, 0, DEVLINK_CMD_PERM_CONFIG_SET);
>+ if (!hdr) {
>+ err = -EMSGSIZE;
>+ goto nla_msg_failure;
>+ }
>+
>+ err = devlink_nl_put_handle(msg, devlink);
>+ if (err)
>+ goto nla_put_failure;
>+
>+ cfgparam_attr = nla_nest_start(msg, DEVLINK_ATTR_PERM_CONFIGS);
>+
>+ nla_for_each_nested(attr, info->attrs[DEVLINK_ATTR_PERM_CONFIGS], rem) {
>+ err = nla_parse_nested(tb, DEVLINK_ATTR_MAX, attr,
>+ devlink_nl_policy, NULL);
>+ if (err)
>+ goto nla_nest_failure;
>+
>+ if (!tb[DEVLINK_ATTR_PERM_CONFIG_PARAMETER] ||
>+ !tb[DEVLINK_ATTR_PERM_CONFIG_TYPE] ||
>+ !tb[DEVLINK_ATTR_PERM_CONFIG_VALUE])
>+ continue;
>+
>+ param = nla_get_u32(tb[DEVLINK_ATTR_PERM_CONFIG_PARAMETER]);
>+ type = nla_get_u8(tb[DEVLINK_ATTR_PERM_CONFIG_TYPE]);
>+ if (param > DEVLINK_PERM_CONFIG_MAX ||
>+ type > NLA_TYPE_MAX) {
>+ continue;
>+ }
>+
>+ switch (type) {
>+ case DEVLINK_PERM_CONFIG_TYPE_U8:
>+ value.value8 =
>+ nla_get_u8(tb[DEVLINK_ATTR_PERM_CONFIG_VALUE]);
>+ break;
>+ case DEVLINK_PERM_CONFIG_TYPE_U16:
>+ value.value16 =
>+ nla_get_u16(tb[DEVLINK_ATTR_PERM_CONFIG_VALUE]);
>+ break;
>+ case DEVLINK_PERM_CONFIG_TYPE_U32:
>+ value.value32 =
>+ nla_get_u32(tb[DEVLINK_ATTR_PERM_CONFIG_VALUE]);
>+ break;
>+ default:
>+ continue;
>+ }
>+
>+ /* Note if single_param_set fails, that param won't be in
>+ * response msg, so caller will know which param(s) failed to
>+ * set.
No. You should not send the params back on set operation. That is wrong.
You should use extact in order to tell anything useful to the user.
>+ */
>+ devlink_nl_single_param_set(msg, devlink, param, type, &value);
>+ }
>+
>+ nla_nest_end(msg, cfgparam_attr);
>+
>+ genlmsg_end(msg, hdr);
>+ return genlmsg_reply(msg, info);
>+
>+nla_nest_failure:
>+ nla_nest_cancel(msg, cfgparam_attr);
>+nla_put_failure:
>+ genlmsg_cancel(msg, hdr);
>+nla_msg_failure:
>+ return err;
>+}
>+
> int devlink_dpipe_match_put(struct sk_buff *skb,
> struct devlink_dpipe_match *match)
> {
>@@ -2291,6 +2568,8 @@ static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
> [DEVLINK_ATTR_ESWITCH_ENCAP_MODE] = { .type = NLA_U8 },
> [DEVLINK_ATTR_DPIPE_TABLE_NAME] = { .type = NLA_NUL_STRING },
> [DEVLINK_ATTR_DPIPE_TABLE_COUNTERS_ENABLED] = { .type = NLA_U8 },
>+ [DEVLINK_ATTR_PERM_CONFIG_PARAMETER] = { .type = NLA_U32 },
>+ [DEVLINK_ATTR_PERM_CONFIG_TYPE] = { .type = NLA_U8 },
> };
>
> static const struct genl_ops devlink_nl_ops[] = {
>@@ -2451,6 +2730,20 @@ static const struct genl_ops devlink_nl_ops[] = {
> .flags = GENL_ADMIN_PERM,
> .internal_flags = DEVLINK_NL_FLAG_NEED_DEVLINK,
> },
>+ {
>+ .cmd = DEVLINK_CMD_PERM_CONFIG_GET,
>+ .doit = devlink_nl_cmd_perm_config_get_doit,
As I said, you need dumpit.
>+ .policy = devlink_nl_policy,
>+ .flags = GENL_ADMIN_PERM,
>+ .internal_flags = DEVLINK_NL_FLAG_NEED_DEVLINK,
>+ },
>+ {
>+ .cmd = DEVLINK_CMD_PERM_CONFIG_SET,
>+ .doit = devlink_nl_cmd_perm_config_set_doit,
>+ .policy = devlink_nl_policy,
>+ .flags = GENL_ADMIN_PERM,
>+ .internal_flags = DEVLINK_NL_FLAG_NEED_DEVLINK,
>+ },
> };
>
> static struct genl_family devlink_nl_family __ro_after_init = {
>--
>2.7.4
>
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