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Date: Thu, 27 Jul 2023 08:45:19 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: Leon Romanovsky <leon@kernel.org>
Cc: davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com,
 pabeni@redhat.com, sd@queasysnail.net
Subject: Re: [PATCH net-next v2 1/2] net: store netdevs in an xarray
Message-ID: <20230727084519.7ec951dd@kernel.org>
In-Reply-To: <20230727130824.GA2652767@unreal>
References: <20230726185530.2247698-1-kuba@kernel.org>
	<20230726185530.2247698-2-kuba@kernel.org>
	<20230727130824.GA2652767@unreal>
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On Thu, 27 Jul 2023 16:08:24 +0300 Leon Romanovsky wrote:
> > +	if (!ifindex)
> > +		err = xa_alloc_cyclic(&net->dev_by_index, &ifindex, NULL,
> > +				      xa_limit_31b, &net->ifindex, GFP_KERNEL);
> > +	else
> > +		err = xa_insert(&net->dev_by_index, ifindex, NULL, GFP_KERNEL);
> > +	if (err < 0)
> > +		return err;
> > +
> > +	return ifindex;  
> 
> ifindex is now u32, but you return it as int. In potential, you can
> return valid ifindex which will be treated as error.
> 
> You should ensure that ifindex doesn't have signed bit on.

I'm feeding xa_alloc_cyclic() xa_limit_31b, which should take care 
of that, no?