netdev - Re: [PATCH net-next] ipv4: do not abuse GFP_ATOMIC in inet_netconf_notify

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Message-ID: <577F5C20.4050201@6wind.com>
Date:	Fri, 8 Jul 2016 09:54:08 +0200
From:	Nicolas Dichtel <nicolas.dichtel@...nd.com>
To:	Eric Dumazet <eric.dumazet@...il.com>,
	Masashi Honma <masashi.honma@...il.com>,
	David Miller <davem@...emloft.net>
Cc:	netdev@...r.kernel.org
Subject: Re: [PATCH net-next] ipv4: do not abuse GFP_ATOMIC in
 inet_netconf_notify_devconf()

Le 08/07/2016 05:18, Eric Dumazet a écrit :
> From: Eric Dumazet <edumazet@...gle.com>
> 
> inet_forward_change() runs with RTNL held.
> We are allowed to sleep if required.
> 
> If we use __in_dev_get_rtnl() instead of __in_dev_get_rcu(),
> we no longer have to use GFP_ATOMIC allocations in
> inet_netconf_notify_devconf(), meaning we are less likely to miss
> notifications under memory pressure, and wont touch precious memory
> reserves either and risk dropping incoming packets.
> 
> inet_netconf_get_devconf() can also use GFP_KERNEL allocation.
> 
> Fixes: edc9e748934c ("rtnl/ipv4: use netconf msg to advertise forwarding status")
> Fixes: 9e5511106f99 ("rtnl/ipv4: add support of RTM_GETNETCONF")
> Signed-off-by: Eric Dumazet <edumazet@...gle.com>
> Cc: Nicolas Dichtel <nicolas.dichtel@...nd.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@...nd.com>

Nice catch, thank you!