Fix netmap emulated mode for FreeBSD 11 versions

[Vincenzo Maffione]

Hi Luiz,

  I attached the patch, to be applied to the source code contained in this
image:
ftp://ftp.freebsd.org/pub/FreeBSD/snapshots/amd64/amd64/ISO-IMAGES/11.0/FreeBSD-11.0-STABLE-amd64-20170105-r311441-disc1.iso.xz

The patch is simply a backport from -head of some modifications involving
the emulated netmap mode.
I tried the minimize the changes to only (1) fix the crash and (2) fix
another synchronization problem.

I did different tests on em and vtnet interfaces, and the thing seems to
work.

Thanks,
  Vincenzo

2017-01-19 14:24 GMT+01:00 Luiz Otavio O Souza <lists.br at gmail.com>:

> On 19 January 2017 at 09:11, Vincenzo Maffione wrote:
> > Hi,
> >
> >   A change in mb_free_ext() introduced in FreeBSD 11 versions broke the
> > transmission support for netmap in emulated mode. This means immediate
> > kernel crashes for netmap users in non-native (emulated) mode.
> >
> > This problem has been fixed in FreeBSD-12-CURRENT, which contains a
> recent
> > version of Netmap. However, FreeBSD 11 versions (release, stable) are
> still
> > affected, as they contain old Netmap versions.
> > Is it possible to push the fix (provided by me) to the relevant
> > release/stable branches? What is the procedure (I'm not familiar with the
> > FreeBSD release engineering process)?
>
> Hi Vincenzo,
>
> Yeah, I saw that trying netmap on ARM (running with emulated drivers)
> and I can confirm that it is fixed on -head.
>
> Please, send me the fix and I'll get it committed on stable/11 (this
> is a common situation and the fix can be committed directly into the
> affected branch).
>
> Thanks!
> Luiz
>



-- 
Vincenzo Maffione
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