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Date: Mon, 3 Jun 2024 16:55:43 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: Stefan Schmidt <stefan@datenfreihafen.org>
Cc: Yunshui Jiang <jiangyunshui@kylinos.cn>, linux-kernel@vger.kernel.org,
 netdev@vger.kernel.org, linux-wpan@vger.kernel.org, alex.aring@gmail.com,
 miquel.raynal@bootlin.com, davem@davemloft.net
Subject: Re: [PATCH] net: mac802154: Fix racy device stats updates by
 DEV_STATS_INC() and DEV_STATS_ADD()
Message-ID: <20240603165543.46c7d3b4@kernel.org>
In-Reply-To: <41e4b0e3-ecc0-43ca-a6cd-4a6beb0ceb8f@datenfreihafen.org>
References: <20240531080739.2608969-1-jiangyunshui@kylinos.cn>
	<41e4b0e3-ecc0-43ca-a6cd-4a6beb0ceb8f@datenfreihafen.org>
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On Mon, 3 Jun 2024 11:33:28 +0200 Stefan Schmidt wrote:
> Hello.
> 
> On 31.05.24 10:07, Yunshui Jiang wrote:
> > mac802154 devices update their dev->stats fields locklessly. Therefore
> > these counters should be updated atomically. Adopt SMP safe DEV_STATS_INC()
> > and DEV_STATS_ADD() to achieve this.
> > 
> > Signed-off-by: Yunshui Jiang <jiangyunshui@kylinos.cn>
> > ---
> >   net/mac802154/tx.c | 8 ++++----
> >   1 file changed, 4 insertions(+), 4 deletions(-)
> > 
> > diff --git a/net/mac802154/tx.c b/net/mac802154/tx.c
> > index 2a6f1ed763c9..6fbed5bb5c3e 100644
> > --- a/net/mac802154/tx.c
> > +++ b/net/mac802154/tx.c
> > @@ -34,8 +34,8 @@ void ieee802154_xmit_sync_worker(struct work_struct *work)
> >   	if (res)
> >   		goto err_tx;
> >   
> > -	dev->stats.tx_packets++;
> > -	dev->stats.tx_bytes += skb->len;
> > +	DEV_STATS_INC(dev, tx_packets);
> > +	DEV_STATS_ADD(dev, tx_bytes, skb->len);
> >   
> >   	ieee802154_xmit_complete(&local->hw, skb, false);
> >   
> > @@ -90,8 +90,8 @@ ieee802154_tx(struct ieee802154_local *local, struct sk_buff *skb)
> >   		if (ret)
> >   			goto err_wake_netif_queue;
> >   
> > -		dev->stats.tx_packets++;
> > -		dev->stats.tx_bytes += len;
> > +		DEV_STATS_INC(dev, tx_packets);
> > +		DEV_STATS_ADD(dev, tx_bytes, len);
> >   	} else {
> >   		local->tx_skb = skb;
> >   		queue_work(local->workqueue, &local->sync_tx_work);  
> 
> This patch has been applied to the wpan tree and will be
> part of the next pull request to net. Thanks!

Hi! I haven't looked in detail, but FWIW

$ git grep LLTX net/mac802154/
$

and similar patch from this author has been rejected:

https://lore.kernel.org/all/CANn89iLPYoOjMxNjBVHY7GwPFBGuxwRoM9gZZ-fWUUYFYjM1Uw@mail.gmail.com/