Re: [Qemu-devel] [PATCH v2] net: add mmsghdr struct check for L2TPV3

["Anton Ivanov (antivano)" <antivano@cisco.com>]

On 01/07/14 15:35, Stefan Hajnoczi wrote:
> On Tue, Jul 1, 2014 at 2:58 PM,  <arei.gonglei@huawei.com> wrote:
>> From: Gonglei <arei.gonglei@huawei.com>
>>
>> because mmsghdr struct is introduced on Linux kernel 3.3+.
>> add check for mmsghdr struct, it only gets built on hosts that
>> support mmsghdr.

Incorrect.

mmsghdr itself is Linux 2.6.32 and so is recvmmsg. Sendmmsg which will
be introduced in the next version of the patch is 3.0. None of them is 3.3+

Please see release notes for either kernel version.

2.6.32 is now 5 years old it is about time to update to relevant headers
on whatever embedded platform you are using to try to build on.

As far as general purpose linuxes, the relevant libc headers are present
in Ubuntul LTS 12.x and onwards, Debian 7.x, Fedora, and all other major
distros. I do not have a RHEL handy to check, but looking at release
notes that the kernel supporting recmmsg is in 6.0 in the first place
and so are the headers for glibc from certain point onwards.

What appears in 3.3+ is kernel support for l2tpv3 tunnels which is what
would allow a linux host to interop.

A.

>>
>> Reported-by: chenliang <chenliang88@huawei.com>
>> Signed-off-by: Gonglei <arei.gonglei@huawei.com>
>> ---
>> v2->v1:
>>    delete $l2tpv3 variable initialization and
>>    'if' false check suggested by PMM.
>> ---
>>  configure         | 16 ++++++++++++++++
>>  net/Makefile.objs |  2 +-
>>  net/net.c         |  4 ++--
>>  3 files changed, 19 insertions(+), 3 deletions(-)
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>