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

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Date:   Thu, 19 Oct 2023 11:12:28 +0200
From:   Oleksij Rempel <o.rempel@...gutronix.de>
To:     Michal Kubecek <mkubecek@...e.cz>
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 11:05:10AM +0200, Michal Kubecek wrote:
> 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

Wow, I have learned something new :)

> How recent was the kernel where you encountered the issue?

It is latest net-next.

> 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.

Thx!

Regards,
Oleksij
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