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Date: Mon, 31 Jul 2023 09:03:05 -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, Stephen Hemminger <stephen@networkplumber.org>
Subject: Re: [PATCH net-next] net: make sure we never create ifindex = 0
Message-ID: <20230731090305.0c5fe7a1@kernel.org>
In-Reply-To: <20230730133219.GG94048@unreal>
References: <20230729015623.17373-1-kuba@kernel.org>
	<20230730133219.GG94048@unreal>
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On Sun, 30 Jul 2023 16:32:19 +0300 Leon Romanovsky wrote:
> > @@ -11271,7 +11272,6 @@ static int __net_init netdev_init(struct net *net)
> >  	if (net->dev_index_head == NULL)
> >  		goto err_idx;
> >  
> > -	net->ifindex = 1;
> >  	xa_init_flags(&net->dev_by_index, XA_FLAGS_ALLOC);  
> 
> You don't need to change xa_limit_31b, just change XA_FLAGS_ALLOC to be XA_FLAGS_ALLOC1
> and allocations will start from 1.

Because obviously there is a magic flag for this...