From mboxrd@z Thu Jan  1 00:00:00 1970
From: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Subject: Re: [PATCH v2 net-next] net/core: generic support for disabling
 netdev features down stack
Date: Tue, 3 Nov 2015 11:03:09 +0100
Message-ID: <5638865D.2000804@cumulusnetworks.com>
References: <1446486818-26166-1-git-send-email-jarod@redhat.com>
 <1446519359-21400-1-git-send-email-jarod@redhat.com>
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Cc: "David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jay Vosburgh <j.vosburgh@gmail.com>,
	Veaceslav Falico <vfalico@gmail.com>,
	Andy Gospodarek <gospo@cumulusnetworks.com>,
	Jiri Pirko <jiri@resnulli.us>,
	Nikolay Aleksandrov <razor@blackwall.org>,
	Michal Kubecek <mkubecek@suse.cz>,
	Alexander Duyck <alexander.duyck@gmail.com>,
	netdev@vger.kernel.org
To: Jarod Wilson <jarod@redhat.com>, linux-kernel@vger.kernel.org
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On 11/03/2015 03:55 AM, Jarod Wilson wrote:
[snip]
>  
> +#define for_each_netdev_feature(mask_addr, feature)				\
> +	int bit;								\
> +	for_each_set_bit(bit, (unsigned long *)mask_addr, NETDEV_FEATURE_COUNT)	\
> +		feature = __NETIF_F_BIT(bit);
> +
^
This is broken, it will not work for more than a single feature.

>  /* Features valid for ethtool to change */
>  /* = all defined minus driver/device-class-related */
>  #define NETIF_F_NEVER_CHANGE	(NETIF_F_VLAN_CHALLENGED | \
> @@ -167,6 +172,12 @@ enum {
>   */
>  #define NETIF_F_ALL_FOR_ALL	(NETIF_F_NOCACHE_COPY | NETIF_F_FSO)
>  
> +/*
> + * If upper/master device has these features disabled, they must be disabled
> + * on all lower/slave devices as well.
> + */
> +#define NETIF_F_UPPER_DISABLES	NETIF_F_LRO
> +
[snip]