From: Patrick McHardy <kaber@trash•net>
To: David Miller <davem@davemloft•net>
Cc: nhorman@tuxdriver•com, zbr@ioremap•net, netdev@vger•kernel.org,
kuznet@ms2•inr.ac.ru, pekkas@netcore•fi, jmorris@namei•org,
yoshfuji@linux-ipv6•org
Subject: Re: [Patch 4/5] Network Drop Monitor: Adding drop monitor implementation & Netlink protocol
Date: Wed, 04 Mar 2009 11:06:41 +0100 [thread overview]
Message-ID: <49AE52B1.3020200@trash.net> (raw)
In-Reply-To: <20090303.141612.160287111.davem@davemloft.net>
David Miller wrote:
> From: Neil Horman <nhorman@tuxdriver•com>
> Date: Tue, 3 Mar 2009 14:21:07 -0500
>
>> On Tue, Mar 03, 2009 at 09:19:09PM +0300, Evgeniy Polyakov wrote:
>>>> +struct net_dm_config_msg {
>>>> + size_t entries;
>>>> + struct net_dm_config_entry options[0];
>>>> +};
>>> Isn't size_t have different size on different platforms?
>>>
>> Probably, but we're only sending this data over netlink sockets, so despite the
>> platform, I don't really see this as an issue. About the only place for concern
>> I think are cases like x86_64 and ppc64, in the event you have a 64 bit kernel
>> and 32 bit user space, and in those the app can be adjusted to compensate for
>> this. I suppose I can fixate the size if its a real concern, but I don't think
>> it really is.
>
> Neil, that is _THE_ concern. You have to use portable types that
> will be both sized and aligned identically on both 32-bit and
> 64-bit variants of a given platform.
>
> This means size_t is absolutely not usable.
>
> We really don't have a clean way to add compat layer translators
> for netlink, so you have to get this right from the beginning.
It should also be noted that netlink attributes only provide 4 byte
alignment. Not sure what the current status of handling unaligned
accesses on all architectures is, but something that might have to
be taken into consideration.
next prev parent reply other threads:[~2009-03-04 10:06 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-03 17:04 [Patch 4/5] Network Drop Monitor: Adding drop monitor implementation & Netlink protocol Neil Horman
2009-03-03 18:19 ` Evgeniy Polyakov
2009-03-03 19:21 ` Neil Horman
2009-03-03 22:14 ` David Miller
2009-03-03 22:16 ` David Miller
2009-03-04 10:06 ` Patrick McHardy [this message]
2009-03-04 11:00 ` David Miller
2009-04-02 9:39 ` Herbert Xu
2009-04-02 9:50 ` David Miller
2009-04-02 9:52 ` David Miller
2009-04-02 9:59 ` Herbert Xu
2009-04-02 14:42 ` Patrick McHardy
2009-04-02 14:45 ` Herbert Xu
2009-04-02 14:57 ` Patrick McHardy
2009-04-02 14:59 ` Herbert Xu
2009-04-02 15:06 ` Patrick McHardy
2009-04-02 15:09 ` Herbert Xu
2009-04-02 15:14 ` Patrick McHardy
2009-04-02 15:30 ` Herbert Xu
2009-04-05 9:59 ` David Miller
2009-04-06 13:21 ` Patrick McHardy
2009-06-10 8:08 ` David Miller
2009-06-10 10:35 ` Patrick McHardy
2009-04-05 9:57 ` David Miller
2009-04-05 9:56 ` David Miller
2009-04-05 9:54 ` David Miller
2009-03-04 11:44 ` Neil Horman
2009-03-05 19:27 ` Neil Horman
2009-03-11 16:17 ` David Miller
2009-03-11 19:51 ` Neil Horman
2009-03-13 19:10 ` David Miller
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