Re: [PATCH RESEND] tracing: Make tracing work when debugfs is not compiled or initialized.

Steven Rostedt
2015-11-04T20:32:43Z

On Wed, 4 Nov 2015 10:54:42 -0800
Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:

> On Wed, Nov 04, 2015 at 10:03:39AM -0500, Steven Rostedt wrote:
> > On Wed, 4 Nov 2015 09:11:18 +0800
> > Jiaxing Wang <hello.wjx@gmail.com> wrote:
> >
> > > Currently tracing_init_dentry() returns -ENODEV when debugfs is not
> > > initialized, which causes tracefs not populated with tracing files and
> > > directories, so we will get an empty directory even after we manually
> > > mount tracefs.
> > >
> > > We can make tracing_init_dentry() return NULL as long as tracefs
> > > is initialized and get a populated tracefs.
> > >
> > > We also need to make global_trace.dir not NULL in order to pass the checks
> > > in tracing_get_dentry() and add_tracer_options().
> > >
> > > Also added stub debugfs_create_automount() for when debugfs is not
> > > configured in.
>
> The debugfs change should be split out into a separate patch, which I'll
> be glad to take through my tree, it isn't dependant on the tracing
> code at all.
>

I guess the tracing code is dependent on that change. As the tracing
code will then be compiled without the select DEBUGFS, and will fail to
compile if that change is not there.

That said. I think it's best to split it up, and have the debugfs
change go through your tree, and the other part go through mine without
the remove of the "select DEBUGFS". After both are in mainline, then we
can remove the select statement.

-- Steve