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Message-ID: <YVw/MluEOlQjQRr7@shredder>
Date: Tue, 5 Oct 2021 15:04:02 +0300
From: Ido Schimmel <idosch@...sch.org>
To: Jakub Kicinski <kuba@...nel.org>
Cc: netdev@...r.kernel.org, davem@...emloft.net, andrew@...n.ch,
mkubecek@...e.cz, pali@...nel.org, jacob.e.keller@...el.com,
jiri@...dia.com, vadimp@...dia.com, mlxsw@...dia.com,
Ido Schimmel <idosch@...dia.com>
Subject: Re: [PATCH net-next 1/6] ethtool: Add ability to control transceiver
modules' power mode
On Tue, Oct 05, 2021 at 09:57:25AM +0300, Ido Schimmel wrote:
> On Mon, Oct 04, 2021 at 06:01:35PM -0700, Jakub Kicinski wrote:
> > On Sun, 3 Oct 2021 10:32:14 +0300 Ido Schimmel wrote:
> > > From: Ido Schimmel <idosch@...dia.com>
> > >
> > > Add a pair of new ethtool messages, 'ETHTOOL_MSG_MODULE_SET' and
> > > 'ETHTOOL_MSG_MODULE_GET', that can be used to control transceiver
> > > modules parameters and retrieve their status.
> >
> > Acked-by: Jakub Kicinski <kuba@...nel.org>
>
> Thanks!
>
> >
> > Couple of take it or leave it comments again, if you prefer to leave as
> > is that's fine.
>
> I'll make whatever changes we conclude are necessary. See below.
>
> >
> > > +enum ethtool_module_power_mode_policy {
> > > + ETHTOOL_MODULE_POWER_MODE_POLICY_HIGH,
> > > + ETHTOOL_MODULE_POWER_MODE_POLICY_AUTO,
> > > +};
> >
> > I see you left this starting from 0, and we still need a valid bit,
> > granted just internal to the core.
>
> I was under the impression that we were only talking about the power
> mode itself (which can be invalid if a module is unplugged), but not the
> policy [1]. I did change that like we discussed.
>
> [1] https://lore.kernel.org/netdev/YSYmFEDWJIu6eDvR@shredder/
>
> >
> > Would we not need a driver-facing valid bit later on when we extend
> > the module API to control more params?
>
> To keep the driver-facing API simple I want to have different ethtool
> operations for different parameters (like rtnetlink and ndos). So, if a
> driver does not support a parameter, the operation will not be
> implemented and the attributes will not be dumped.
>
> > Can't there be drivers which implement power but don't support the
> > mode policy?
>
> I don't really see how. The policy is a host attribute (not module)
> determining how the host configures the power mode of the module. It
> always exists, but can be fixed.
>
> Do you still think we should make the change below?
>
> diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
> index 1b126e8b5269..a2223b685451 100644
> --- a/include/uapi/linux/ethtool.h
> +++ b/include/uapi/linux/ethtool.h
> @@ -721,7 +721,7 @@ enum ethtool_stringset {
> * administratively down.
> */
> enum ethtool_module_power_mode_policy {
> - ETHTOOL_MODULE_POWER_MODE_POLICY_HIGH,
> + ETHTOOL_MODULE_POWER_MODE_POLICY_HIGH = 1,
> ETHTOOL_MODULE_POWER_MODE_POLICY_AUTO,
> };
I read your reply again about "still need a valid bit, granted just
internal to the core". My confusion was that I thought only the valid
bit in the driver-facing API bothered you, but you actually wanted me to
remove all of them.
How about the below (compile tested)?
diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
index 1b126e8b5269..a2223b685451 100644
--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h
@@ -721,7 +721,7 @@ enum ethtool_stringset {
* administratively down.
*/
enum ethtool_module_power_mode_policy {
- ETHTOOL_MODULE_POWER_MODE_POLICY_HIGH,
+ ETHTOOL_MODULE_POWER_MODE_POLICY_HIGH = 1,
ETHTOOL_MODULE_POWER_MODE_POLICY_AUTO,
};
diff --git a/net/ethtool/module.c b/net/ethtool/module.c
index 254ac84f9728..5d430b2bb20a 100644
--- a/net/ethtool/module.c
+++ b/net/ethtool/module.c
@@ -13,7 +13,6 @@ struct module_req_info {
struct module_reply_data {
struct ethnl_reply_data base;
struct ethtool_module_power_mode_params power;
- u8 power_valid:1;
};
#define MODULE_REPDATA(__reply_base) \
@@ -30,18 +29,11 @@ static int module_get_power_mode(struct net_device *dev,
struct netlink_ext_ack *extack)
{
const struct ethtool_ops *ops = dev->ethtool_ops;
- int ret;
if (!ops->get_module_power_mode)
return 0;
- ret = ops->get_module_power_mode(dev, &data->power, extack);
- if (ret < 0)
- return ret;
-
- data->power_valid = true;
-
- return 0;
+ return ops->get_module_power_mode(dev, &data->power, extack);
}
static int module_prepare_data(const struct ethnl_req_info *req_base,
@@ -72,10 +64,10 @@ static int module_reply_size(const struct ethnl_req_info *req_base,
struct module_reply_data *data = MODULE_REPDATA(reply_base);
int len = 0;
- if (data->power_valid)
+ if (data->power.policy)
len += nla_total_size(sizeof(u8)); /* _MODULE_POWER_MODE_POLICY */
- if (data->power_valid && data->power.mode)
+ if (data->power.mode)
len += nla_total_size(sizeof(u8)); /* _MODULE_POWER_MODE */
return len;
@@ -87,12 +79,12 @@ static int module_fill_reply(struct sk_buff *skb,
{
const struct module_reply_data *data = MODULE_REPDATA(reply_base);
- if (data->power_valid &&
+ if (data->power.policy &&
nla_put_u8(skb, ETHTOOL_A_MODULE_POWER_MODE_POLICY,
data->power.policy))
return -EMSGSIZE;
- if (data->power_valid && data->power.mode &&
+ if (data->power.mode &&
nla_put_u8(skb, ETHTOOL_A_MODULE_POWER_MODE, data->power.mode))
return -EMSGSIZE;
@@ -116,7 +108,8 @@ const struct ethnl_request_ops ethnl_module_request_ops = {
const struct nla_policy ethnl_module_set_policy[ETHTOOL_A_MODULE_POWER_MODE_POLICY + 1] = {
[ETHTOOL_A_MODULE_HEADER] = NLA_POLICY_NESTED(ethnl_header_policy),
[ETHTOOL_A_MODULE_POWER_MODE_POLICY] =
- NLA_POLICY_MAX(NLA_U8, ETHTOOL_MODULE_POWER_MODE_POLICY_AUTO),
+ NLA_POLICY_RANGE(NLA_U8, ETHTOOL_MODULE_POWER_MODE_HIGH,
+ ETHTOOL_MODULE_POWER_MODE_POLICY_AUTO),
};
static int module_set_power_mode(struct net_device *dev, struct nlattr **tb,
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