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.