From: Johannes Berg <johannes@sipsolutions.net>
To: David Ahern <dsa@cumulusnetworks.com>,
David Miller <davem@davemloft.net>
Cc: eric.dumazet@gmail.com, roopa@cumulusnetworks.com,
netdev@vger.kernel.org, jhs@mojatatu.com, tgraf@suug.ch,
nicolas.dichtel@6wind.com, egrumbach@gmail.com
Subject: Re: [PATCH net-next v5] rtnetlink: add new RTM_GETSTATS message to dump link stats
Date: Wed, 20 Apr 2016 09:32:20 +0200 [thread overview]
Message-ID: <1461137540.2176.5.camel@sipsolutions.net> (raw)
In-Reply-To: <5716E123.8040002@cumulusnetworks.com> (sfid-20160420_035344_487995_3E03AD21)
On Tue, 2016-04-19 at 19:53 -0600, David Ahern wrote:
>
> The kernel can set a flag in the response that it acknowledges the
> new attribute/flag. I did that for filtering neigh dumps --
> 21fdd092acc7.
>
Hm, that works, but I think it requires writing extra code, which I was
kinda trying to avoid. With the patch that Emmanuel wrote, we can
restrict the changes to just nla_parse().
Anyway, I think we just have to document the behaviour very precisely,
and userspace can make its own decisions.
Essentially, apps will have a number of choices:
1) Use the new attribute flag only with commands known to have been
added after the kernel support was added.
2) Use the new attribute flag with some required attribute for
existing commands, so that older kernel will not find the required
attribute and will reject the operation entirely.
May or may not fall back to trying the operation again without the
flag.
3) Simply use the new flag and do unexpected things on kernels not
supporting the rejection mechanism - not much worse than today in
many cases.
I guess we'll write a proper commit message and send the patch.
johannes
next prev parent reply other threads:[~2016-04-20 7:32 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-18 21:10 [PATCH net-next v5] rtnetlink: add new RTM_GETSTATS message to dump link stats Roopa Prabhu
2016-04-18 21:35 ` Eric Dumazet
2016-04-19 0:57 ` David Miller
2016-04-19 1:48 ` David Miller
2016-04-19 2:22 ` Eric Dumazet
2016-04-19 2:40 ` Roopa Prabhu
2016-04-19 3:49 ` David Miller
2016-04-19 3:52 ` David Miller
2016-04-19 10:09 ` Johannes Berg
2016-04-19 10:48 ` Emmanuel Grumbach
2016-04-19 18:23 ` David Miller
2016-04-19 19:41 ` Johannes Berg
2016-04-20 1:53 ` David Ahern
2016-04-20 7:32 ` Johannes Berg [this message]
2016-04-20 12:48 ` Jiri Benc
2016-04-20 13:17 ` Johannes Berg
2016-04-20 13:34 ` Jiri Benc
2016-04-20 20:13 ` Johannes Berg
2016-04-19 2:30 ` roopa
2016-04-19 3:41 ` David Miller
2016-04-19 4:17 ` Eric Dumazet
2016-04-19 4:32 ` Eric Dumazet
2016-04-19 5:03 ` David Miller
2016-04-19 18:31 ` David Miller
2016-04-19 18:45 ` Eric Dumazet
2016-04-19 18:47 ` Eric Dumazet
2016-04-19 19:08 ` Nicolas Dichtel
2016-04-19 23:50 ` David Miller
2016-04-20 3:54 ` Roopa Prabhu
2016-04-20 8:57 ` [PATCH net-next 0/4] libnl: enhance API to ease 64bit alignment for attribute Nicolas Dichtel
2016-04-20 8:57 ` [PATCH net-next 1/4] netlink: fix test alignment in nla_align_64bit() Nicolas Dichtel
2016-04-20 9:33 ` Eric Dumazet
2016-04-20 9:44 ` Nicolas Dichtel
2016-04-20 9:57 ` Eric Dumazet
2016-04-20 10:14 ` Nicolas Dichtel
2016-04-20 14:31 ` [PATCH net-next] net: fix HAVE_EFFICIENT_UNALIGNED_ACCESS typos Eric Dumazet
2016-04-20 15:03 ` David Miller
2016-04-20 8:57 ` [PATCH net-next 2/4] libnl: add more helpers to align attribute on 64-bit Nicolas Dichtel
2016-04-20 8:57 ` [PATCH net-next 3/4] ipmr: align RTA_MFC_STATS " Nicolas Dichtel
2016-04-20 8:57 ` [PATCH net-next 4/4] ip6mr: " Nicolas Dichtel
2016-04-21 16:58 ` [PATCH net-next v2 0/4] libnl: enhance API to ease 64bit alignment for attribute Nicolas Dichtel
2016-04-21 16:58 ` [PATCH net-next v2 1/4] libnl: add more helpers to align attributes on 64-bit Nicolas Dichtel
2016-04-21 16:58 ` [PATCH net-next v2 2/4] rtnl: use the new API to align IFLA_STATS* Nicolas Dichtel
2016-04-21 16:58 ` [PATCH net-next v2 3/4] ipmr: align RTA_MFC_STATS on 64-bit Nicolas Dichtel
2016-04-21 16:58 ` [PATCH net-next v2 4/4] ip6mr: " Nicolas Dichtel
2016-04-21 18:28 ` [PATCH net-next v2 0/4] libnl: enhance API to ease 64bit alignment for attribute David Miller
2016-04-21 22:00 ` Nicolas Dichtel
2016-04-22 5:31 ` David Miller
2016-04-19 19:05 ` [PATCH net-next v5] rtnetlink: add new RTM_GETSTATS message to dump link stats Roopa Prabhu
2016-04-19 22:49 ` David Miller
2016-04-20 3:53 ` Roopa Prabhu
2016-04-19 4:43 ` Roopa Prabhu
2016-04-19 7:45 ` Nicolas Dichtel
2016-04-19 16:00 ` David Miller
2016-04-19 8:26 ` Nicolas Dichtel
2016-04-19 19:55 ` Paul Moore
2016-04-19 20:40 ` Roopa Prabhu
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