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Message-ID: <CAG4TOxOOPgAqUtX14V7k-qPCbOm7+5gaHOqBvgWBYQwJkO6v8g@mail.gmail.com>
Date: Thu, 31 Dec 2020 10:51:09 -0800
From: Roland Dreier <roland@...nel.org>
To: Oliver Neukum <oneukum@...e.com>
Cc: Jakub Kicinski <kuba@...nel.org>,
Greg KH <gregkh@...uxfoundation.org>, netdev@...r.kernel.org,
linux-usb@...r.kernel.org
Subject: Re: [PATCH] CDC-NCM: remove "connected" log message
I haven't tried these patches yet but they don't look quite right to
me. inlining the first 0001 patch:
> diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
> index 1447da1d5729..bcd17f6d6de6 100644
> --- a/drivers/net/usb/usbnet.c
> +++ b/drivers/net/usb/usbnet.c
> @@ -944,7 +944,7 @@ EXPORT_SYMBOL_GPL(usbnet_open);
> * they'll probably want to use this base set.
> */
>
> -int usbnet_get_link_ksettings(struct net_device *net,
> +int usbnet_get_link_ksettings_mdio(struct net_device *net,
> struct ethtool_link_ksettings *cmd)
> {
> struct usbnet *dev = netdev_priv(net);
> @@ -956,6 +956,32 @@ int usbnet_get_link_ksettings(struct net_device *net,
>
> return 0;
> }
> +EXPORT_SYMBOL_GPL(usbnet_get_link_ksettings_mdio);
why keep and export the old function when it will have no callers?
> +int usbnet_get_link_ksettings(struct net_device *net,
> + struct ethtool_link_ksettings *cmd)
> +{
> + struct usbnet *dev = netdev_priv(net);
> +
> + /* the assumption that speed is equal on tx and rx
> + * is deeply engrained into the networking layer.
> + * For wireless stuff it is not true.
> + * We assume that rxspeed matters more.
> + */
> + if (dev->rxspeed != SPEED_UNKNOWN)
> + cmd->base.speed = dev->rxspeed / 1000000;
> + else if (dev->txspeed != SPEED_UNKNOWN)
> + cmd->base.speed = dev->txspeed / 1000000;
> + /* if a minidriver does not record speed we try to
> + * fall back on MDIO
> + */
> + else if (!dev->mii.mdio_read)
> + cmd->base.speed = SPEED_UNKNOWN;
> + else
> + mii_ethtool_get_link_ksettings(&dev->mii, cmd);
> +
> + return 0;
This is a change in behavior for every driver that doesn't set rxspeed
/ txspeed - the old get_link function would return EOPNOTSUPP if
mdio_read isn't implemented, now we give SPEED_UNKNOWN with a
successful return code.
> @@ -1661,6 +1687,8 @@ usbnet_probe (struct usb_interface *udev,
const struct usb_device_id *prod)
> dev->intf = udev;
> dev->driver_info = info;
> dev->driver_name = name;
> + dev->rxspeed = -1; /* unknown or handled by MII */
> + dev->txspeed = -1;
Minor nit: if we're going to test these against SPEED_UNKNOWN above,
then I think it's clearer to initialize them to that value via the
same constant.
> diff --git a/include/linux/usb/usbnet.h b/include/linux/usb/usbnet.h
> index 88a7673894d5..f748c758f82a 100644
> --- a/include/linux/usb/usbnet.h
> +++ b/include/linux/usb/usbnet.h
> @@ -267,8 +269,11 @@ extern void usbnet_purge_paused_rxq(struct usbnet *);
>
> extern int usbnet_get_link_ksettings(struct net_device *net,
> struct ethtool_link_ksettings *cmd);
> -extern int usbnet_set_link_ksettings(struct net_device *net,
> +extern int usbnet_set_link_ksettings_mdio(struct net_device *net,
> const struct ethtool_link_ksettings *cmd);
> +/* Legacy - to be used if you really need an error to be returned */
> +extern int usbnet_set_link_ksettings(struct net_device *net,
> + const struct ethtool_link_ksettings *cmd);
> extern u32 usbnet_get_link(struct net_device *net);
> extern u32 usbnet_get_msglevel(struct net_device *);
> extern void usbnet_set_msglevel(struct net_device *, u32);
I think this was meant to be changing get_link, not set_link.
Also I don't understand the "Legacy" comment. Is that referring to
the EOPNOTSUPP change I mentioned above? If so, wouldn't it be better
to preserve the legacy behavior rather than changing the behavior of
every usbnet driver all at once? Like make a new
usbnet_get_link_ksettings_nonmdio and update only cdc_ncm to use it?
- R.
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