Re: [PATCH] vfio_pci: set TRACE_INCLUDE_PATH to fix the build error

[Steven Rostedt]

On Tue, Jan 08, 2019 at 12:08:03PM +0900, Masahiro Yamada wrote:
> ---
> 
>  drivers/vfio/pci/trace.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/vfio/pci/trace.h b/drivers/vfio/pci/trace.h
> index 228ccdb..4d13e51 100644
> --- a/drivers/vfio/pci/trace.h
> +++ b/drivers/vfio/pci/trace.h
> @@ -94,7 +94,7 @@ TRACE_EVENT(vfio_pci_npu2_mmap,
>  #endif /* _TRACE_VFIO_PCI_H */
>  
>  #undef TRACE_INCLUDE_PATH
> -#define TRACE_INCLUDE_PATH .
> +#define TRACE_INCLUDE_PATH ../../drivers/vfio/pci

Note, the reason why I did not show this method in the samples/trace_events/
is that there's one "gotcha" that you need to be careful about. It may not be
an issue here, but please be aware of it.

The words in TRACE_INCLUDE_PATH can be updated by C preprocessor defines. For
example, if for some reason you had:

#define pci special_pci

The above would turn into:

 ../../drivers/vfio/special_pci

and it wont build, and you will be left scratching your head wondering why.

-- Steve

>  #undef TRACE_INCLUDE_FILE
>  #define TRACE_INCLUDE_FILE trace
>  
> -- 
> 2.7.4