netdev - Re: [PATCH net v1 1/1] ethtool: fix clearing of WoL flags

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Date: Thu, 19 Oct 2023 11:05:10 +0200
From: Michal Kubecek <mkubecek@...e.cz>
To: Oleksij Rempel <o.rempel@...gutronix.de>
Cc: Kory Maincent <kory.maincent@...tlin.com>,
	"David S. Miller" <davem@...emloft.net>,
	Andrew Lunn <andrew@...n.ch>, Eric Dumazet <edumazet@...gle.com>,
	Florian Fainelli <f.fainelli@...il.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Vladimir Oltean <olteanv@...il.com>, kernel@...gutronix.de,
	linux-kernel@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: [PATCH net v1 1/1] ethtool: fix clearing of WoL flags

On Thu, Oct 19, 2023 at 09:09:04AM +0200, Oleksij Rempel wrote:
> With current kernel it is possible to set flags, but not possible to remove
> existing WoL flags. For example:
> ~$ ethtool lan2
> ...
>         Supports Wake-on: pg
>         Wake-on: d
> ...
> ~$ ethtool -s lan2 wol gp
> ~$ ethtool lan2
> ...
>         Wake-on: pg
> ...
> ~$ ethtool -s lan2 wol d
> ~$ ethtool lan2
> ...
>         Wake-on: pg
> ...
> 
> This patch makes it work as expected
> 
> Signed-off-by: Oleksij Rempel <o.rempel@...gutronix.de>
> ---
>  net/ethtool/wol.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/net/ethtool/wol.c b/net/ethtool/wol.c
> index 0ed56c9ac1bc..fcefc1bbfa2e 100644
> --- a/net/ethtool/wol.c
> +++ b/net/ethtool/wol.c
> @@ -108,15 +108,16 @@ ethnl_set_wol(struct ethnl_req_info *req_info, struct genl_info *info)
>  	struct net_device *dev = req_info->dev;
>  	struct nlattr **tb = info->attrs;
>  	bool mod = false;
> +	u32 wolopts = 0;
>  	int ret;
>  
>  	dev->ethtool_ops->get_wol(dev, &wol);
> -	ret = ethnl_update_bitset32(&wol.wolopts, WOL_MODE_COUNT,
> +	ret = ethnl_update_bitset32(&wolopts, WOL_MODE_COUNT,
>  				    tb[ETHTOOL_A_WOL_MODES], wol_mode_names,
>  				    info->extack, &mod);
>  	if (ret < 0)
>  		return ret;
> -	if (wol.wolopts & ~wol.supported) {
> +	if (wolopts & ~wol.supported) {
>  		NL_SET_ERR_MSG_ATTR(info->extack, tb[ETHTOOL_A_WOL_MODES],
>  				    "cannot enable unsupported WoL mode");
>  		return -EINVAL;
> @@ -132,8 +133,9 @@ ethnl_set_wol(struct ethnl_req_info *req_info, struct genl_info *info)
>  				    tb[ETHTOOL_A_WOL_SOPASS], &mod);
>  	}
>  
> -	if (!mod)
> +	if (!mod && wolopts == wol.wolopts)
>  		return 0;
> +	wol.wolopts = wolopts;
>  	ret = dev->ethtool_ops->set_wol(dev, &wol);
>  	if (ret)
>  		return ret;
> -- 
> 2.39.2

This doesn't look right, AFAICS with this patch, the resulting WoL flags
would not depend on current values at all, i.e. it would certainly break
non-absolute commands like

  ethtool -s eth0 wol +g
  ethtool -s eth0 wol -u+g
  ethtool -s etho wol 32/34

How recent was the kernel where you encountered the issue? I suspect the
issue might be related to recent 108a36d07c01 ("ethtool: Fix mod state
of verbose no_mask bitset"), I'll look into it closer.

Michal

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