selftests/cgroup: Fix build on older distros

On older distros struct clone_args does not have a cgroup member,
leading to build errors:

  cgroup_util.c: In function 'clone_into_cgroup':
  cgroup_util.c:343:4: error: 'struct clone_args' has no member named 'cgroup'

But the selftests already have a locally defined version of the
structure which is up to date, called __clone_args.

So use __clone_args which fixes the error.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 tools/testing/selftests/cgroup/cgroup_util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)


base-commit: cf7cd542d1b538f6e9e83490bc090dd773f4266d

> On 04-Nov-2020, at 3:35 PM, Michael Ellerman <mpe@ellerman.id.au> wrote:

> 

> On older distros struct clone_args does not have a cgroup member,

> leading to build errors:

> 

>  cgroup_util.c: In function 'clone_into_cgroup':

>  cgroup_util.c:343:4: error: 'struct clone_args' has no member named 'cgroup'

> 

> But the selftests already have a locally defined version of the

> structure which is up to date, called __clone_args.

> 

> So use __clone_args which fixes the error.

> 


Argument passed to sys_clone3() will also require a similar change.

-	pid = sys_clone3(&args, sizeof(struct clone_args));
+	pid = sys_clone3(&args, sizeof(struct __clone_args));

Without this compilation still fails(at least for me) due to following error

cgroup_util.c: In function 'clone_into_cgroup':
cgroup_util.c:346:33: error: invalid application of 'sizeof' to incomplete type 'struct clone_args'
  pid = sys_clone3(&args, sizeof(struct clone_args));

> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

> ---

> tools/testing/selftests/cgroup/cgroup_util.c | 2 +-

> 1 file changed, 1 insertion(+), 1 deletion(-)

> 

> diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c

> index 05853b0b8831..58e30f65df5e 100644

> --- a/tools/testing/selftests/cgroup/cgroup_util.c

> +++ b/tools/testing/selftests/cgroup/cgroup_util.c

> @@ -337,7 +337,7 @@ pid_t clone_into_cgroup(int cgroup_fd)

> #ifdef CLONE_ARGS_SIZE_VER2

> 	pid_t pid;

> 

> -	struct clone_args args = {

> +	struct __clone_args args = {

> 		.flags = CLONE_INTO_CGROUP,

> 		.exit_signal = SIGCHLD,

> 		.cgroup = cgroup_fd,

> 

> base-commit: cf7cd542d1b538f6e9e83490bc090dd773f4266d

> -- 

> 2.25.1

>

On Wed, Nov 04, 2020 at 05:50:40PM +0530, Sachin Sant wrote:
> 
> 
> > On 04-Nov-2020, at 3:35 PM, Michael Ellerman <mpe@ellerman.id.au> wrote:
> > 
> > On older distros struct clone_args does not have a cgroup member,
> > leading to build errors:
> > 
> >  cgroup_util.c: In function 'clone_into_cgroup':
> >  cgroup_util.c:343:4: error: 'struct clone_args' has no member named 'cgroup'
> > 
> > But the selftests already have a locally defined version of the
> > structure which is up to date, called __clone_args.
> > 
> > So use __clone_args which fixes the error.
> > 
> 
> Argument passed to sys_clone3() will also require a similar change.
> 
> -	pid = sys_clone3(&args, sizeof(struct clone_args));
> +	pid = sys_clone3(&args, sizeof(struct __clone_args));
> 
> Without this compilation still fails(at least for me) due to following error
> 
> cgroup_util.c: In function 'clone_into_cgroup':
> cgroup_util.c:346:33: error: invalid application of 'sizeof' to incomplete type 'struct clone_args'
>   pid = sys_clone3(&args, sizeof(struct clone_args));
> 
> > Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
> > ---

Thanks Michael for taking care fo this. Much appreciated. I think with
the fix that Sachin pointed out this should work out fine!

Once that's fixed up:
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>

Thanks!
Christian