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Date: Thu, 14 Dec 2023 18:11:28 -0800
From: Jakub Kicinski <kuba@kernel.org>
To: Aurelien Aptel <aaptel@nvidia.com>
Cc: linux-nvme@lists.infradead.org, netdev@vger.kernel.org,
 sagi@grimberg.me, hch@lst.de, kbusch@kernel.org, axboe@fb.com,
 chaitanyak@nvidia.com, davem@davemloft.net, aurelien.aptel@gmail.com,
 smalin@nvidia.com, malin1024@gmail.com, ogerlitz@nvidia.com,
 yorayz@nvidia.com, borisp@nvidia.com, galshalom@nvidia.com,
 mgurtovoy@nvidia.com, edumazet@google.com, pabeni@redhat.com,
 john.fastabend@gmail.com, daniel@iogearbox.net
Subject: Re: [PATCH v21 04/20] net/tls,core: export get_netdev_for_sock
Message-ID: <20231214181128.63793cdc@kernel.org>
In-Reply-To: <20231214132623.119227-5-aaptel@nvidia.com>
References: <20231214132623.119227-1-aaptel@nvidia.com>
	<20231214132623.119227-5-aaptel@nvidia.com>
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On Thu, 14 Dec 2023 13:26:07 +0000 Aurelien Aptel wrote:
> -struct net_device *netdev_sk_get_lowest_dev(struct net_device *dev,
> -					    struct sock *sk)
> +struct net_device *get_netdev_for_sock(struct sock *sk)
>  {
> -	struct net_device *lower;
> +	struct dst_entry *dst = sk_dst_get(sk);
> +	struct net_device *dev, *lower;
>  
> -	lower = netdev_sk_get_lower_dev(dev, sk);
> -	while (lower) {
> +	if (unlikely(!dst))
> +		return NULL;
> +	dev = dst->dev;
> +	while ((lower = netdev_sk_get_lower_dev(dev, sk)))
>  		dev = lower;
> -		lower = netdev_sk_get_lower_dev(dev, sk);
> -	}
> -
> +	dev_hold(dev);
> +	dst_release(dst);
>  	return dev;
>  }
> -EXPORT_SYMBOL(netdev_sk_get_lowest_dev);
> +EXPORT_SYMBOL_GPL(get_netdev_for_sock);

Since the use of this helper is now spreading we should
switch it to netdev_hold and have the caller pass in a
netdevice_tracker.