Re: [PATCH v2 2/2] tools/virtio: fix build caused by virtio_ring changes

Michael S. Tsirkin
2023-04-10T19:44:58Z

On Mon, Apr 10, 2023 at 08:40:34PM +0200, Greg Kroah-Hartman wrote:
> On Mon, Apr 10, 2023 at 08:00:33AM -0400, Michael S. Tsirkin wrote:
> > On Mon, Apr 10, 2023 at 08:28:45PM +0900, Shunsuke Mie wrote:
> > > Fix the build dependency for virtio_test. The virtio_ring that is used from
> > > the test requires container_of_const(). Change to use container_of.h kernel
> > > header directly and adapt related codes.
> > >
> > > Signed-off-by: Shunsuke Mie <mie@igel.co.jp>
> >
> > This is only for next right? That's where container_of_const
> > things are I think ...
>
> container_of_const() is in 6.2.

Absolutely but the patch switching virtio to that is not there.

>
> >
> > > ---
> > > tools/include/linux/types.h | 1 -
> > > tools/virtio/linux/compiler.h | 2 ++
> > > tools/virtio/linux/kernel.h | 5 +----
> > > tools/virtio/linux/module.h | 1 -
> > > tools/virtio/linux/uaccess.h | 11 ++---------
> > > 5 files changed, 5 insertions(+), 15 deletions(-)
> > >
> > > diff --git a/tools/include/linux/types.h b/tools/include/linux/types.h
> > > index 051fdeaf2670..f1896b70a8e5 100644
> > > --- a/tools/include/linux/types.h
> > > +++ b/tools/include/linux/types.h
> > > @@ -49,7 +49,6 @@ typedef __s8 s8;
> > > #endif
> > >
> > > #define __force
> > > -#define __user
>
> Why is this needed?
>
> > > #define __must_check
> > > #define __cold
> > >
> > > diff --git a/tools/virtio/linux/compiler.h b/tools/virtio/linux/compiler.h
> > > index 2c51bccb97bb..1f3a15b954b9 100644
> > > --- a/tools/virtio/linux/compiler.h
> > > +++ b/tools/virtio/linux/compiler.h
> > > @@ -2,6 +2,8 @@
> > > #ifndef LINUX_COMPILER_H
> > > #define LINUX_COMPILER_H
> > >
> > > +#include "../../../include/linux/compiler_types.h"
>
> While I understand your need to not want to duplicate code, what in the
> world is this doing? Why not use the in-kernel compiler.h instead? Why
> are you copying loads of .h files into tools/virtio/? What is this for
> and why not just use the real files so you don't have to even attempt to
> try to keep things in sync (hint, they will always be out of sync.)

Because it's doing a very weird hack: building some kernel
code into a userspace binary, used for just for testing.
This is all not part of kernel build intentionally, no
one is supposed to use this binary in production, but
it was helpful in finding bugs in virtio core in the past
so I keep it around.

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MST