Re: [PATCH v5 1/2] iommu - Enable debugfs exposure of IOMMU driver internals

[Gary R Hook]

On 05/08/2018 01:48 PM, Joe Perches wrote:
> On Tue, 2018-05-08 at 12:08 -0500, Hook, Gary wrote:
> > On 5/7/2018 6:47 PM, kbuild test robot wrote:
> > > All error/warnings (new ones prefixed by >>):
> > >
> > >      In file included from include/linux/intel-iommu.h:32:0,
> > >                       from drivers/gpu/drm/i915/i915_drv.h:41,
> > >                       from drivers/gpu/drm/i915/i915_oa_bxt.c:31:
> > >      include/linux/iommu.h: In function 'iommu_debugfs_new_driver_dir':
> > > > > include/linux/iommu.h:706:8: error: parameter name omitted
> > >
> > >       struct dentry *iommu_debugfs_new_driver_dir(char *) {};
> > >              ^~~~~~
> > >      In file included from include/linux/intel-iommu.h:32:0,
> > >                       from drivers/gpu/drm/i915/i915_drv.h:41,
> > >                       from drivers/gpu/drm/i915/i915_oa_bxt.c:31:
> > > > > include/linux/iommu.h:706:8: warning: control reaches end of non-void function [-Wreturn-type]
> > >
> > >       struct dentry *iommu_debugfs_new_driver_dir(char *) {};
> > >              ^~~~~~
> > >
> > > vim +706 include/linux/iommu.h
> > >
> > >      700	
> > >      701	#ifdef CONFIG_IOMMU_DEBUGFS
> > >      702	void iommu_debugfs_setup(void);
> > >      703	struct dentry *iommu_debugfs_new_driver_dir(char *);
> > >      704	#else
> > >      705	static inline void iommu_debugfs_setup(void) {}
> > >    > 706	struct dentry *iommu_debugfs_new_driver_dir(char *) {};
> > >      707	#endif
> > >      708	
> >
> > I have no problems with adding parameter names. But
> > scripts/checkpatch.pl doesn't seem to check for this, nor require it.
> > Should checkpatch be updated?
>
> I'm pretty sure that's not feasible.

Ugh. This is a definition, not a declaration. My bad. Which is likely 
why I decided to apologize up front.

> And when the compiler tells you you've stuffed up some
> syntactical bit, why should checkpatch duplicate the
> output error message too?

Well, that's the point: neither the 4.8 nor 5.4 compiler complained 
about this. Not as an error, despite the fact that (now that I read what 
is actually here, as opposed to what I think is there) this is wrong. 
Had an error message been emitted, and the make stopped, I would have 
figure this out before embarrassing myself in front of the entire interwebs.

> btw:  That's an unnecessary ; at the end of that non-void
> function and it should probably be something like:

You are correct, sir. I've made a change on this.

> static inline struct dentry *iommu_debugfs_new_driver_dir(char *dir)
> {
> 	return NULL;
> }

Thanks for taking a few moments to comment. Much appreciated.