Re: [PATCH 1/2] Correct function definition for C++
From: Joakim Tjernlund
Date: Wed Feb 22 2017 - 09:01:17 EST
On Wed, 2017-02-22 at 14:03 +0100, greg@xxxxxxxxx wrote:
> On Wed, Feb 22, 2017 at 07:50:46AM +0000, Joakim Tjernlund wrote:
> > On Wed, 2017-02-22 at 08:10 +0100, Greg KH wrote:
> > > On Tue, Feb 21, 2017 at 04:24:04PM +0100, Joakim Tjernlund wrote:
> > > > C++ does does not like the extra extern before asmlinkage, remove it.
> > > >
> > > > Signed-off-by: Joakim Tjernlund <joakim.tjernlund@xxxxxxxxxxxx>
> > > > ---
> > > > include/linux/printk.h | 4 ++--
> > > > 1 file changed, 2 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/include/linux/printk.h b/include/linux/printk.h
> > > > index 3472cc6..be823f5 100644
> > > > --- a/include/linux/printk.h
> > > > +++ b/include/linux/printk.h
> > >
> > >
> > > Why are you building this file with a C++ compiler?
> > virtualbox uses C++ and includes various kernel headers and the build
> > fails, virtualbox guest additions has not build for quite some time now and
> > this is one of the problems.
> Virtualbox is a horrid pile of crap. You can quote me on that. We
> don't care about out-of-tree drivers, the authors should work to get
> them merged properly if they do care.
Sure, I believe you :)
But in this case it is not the kernel modules that fails, it is their
guest additions/xf86 video driver. Seem like that these need to include some
kernel herders there too.
> Kernel code should be C, not C++, and if you do want to use C++, then
> you are on your own, sorry.
But there are already a lot of C++ adjustments!? Just grepping for __cplusplus shows
plenty of hits and what is the point of asmlinkage then:
#define CPP_ASMLINKAGE extern "C"
#define asmlinkage CPP_ASMLINKAGE
I read all of this that C++ code should be able to at least include kernel headers
without fatal errors.
You don't agree? In that case all __cplusplus/asmlinkage should be removed?
> > > Also, this is not the correct way to submit patches for inclusion in the
> > > stable kernel tree. Please read Documentation/stable_kernel_rules.txt
> > > for how to do this properly.
> > Sorry, I was in a hurry(lazy:) so I just included stable directly as
> > I know it needs to be fixed in 4.9 as well.
> But that's not how to get a patch into the stable tree :(
Right, my mistake. No need to be sorry, I got what I deserved :)
> greg k-h