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From:   Masahiro Yamada <yamada.masahiro@socionext.com>
Date:   Mon, 7 Jan 2019 20:39:19 +0900
Message-ID: <CAK7LNAQtsW5KoOQmOB4uSv2zHM80azmHnEMj=2BunikhJQEpig@mail.gmail.com>
Subject: Re: [PATCH] vfio_pci: Add local source directory as include
To:     Cornelia Huck <cohuck@redhat.com>
Cc:     Michael Ellerman <mpe@ellerman.id.au>,
        Laura Abbott <labbott@redhat.com>,
        Alexey Kardashevskiy <aik@ozlabs.ru>,
        Alex Williamson <alex.williamson@redhat.com>,
        kvm@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Mon, Jan 7, 2019 at 8:09 PM Cornelia Huck <cohuck@redhat.com> wrote:
>
> On Mon, 7 Jan 2019 19:12:10 +0900
> Masahiro Yamada <yamada.masahiro@socionext.com> wrote:
>
> > On Mon, Jan 7, 2019 at 6:18 PM Michael Ellerman <mpe@ellerman.id.au> wrote:
> > >
> > > Laura Abbott <labbott@redhat.com> writes:
> > > > Commit 7f92891778df ("vfio_pci: Add NVIDIA GV100GL [Tesla V100 SXM2]
> > > > subdriver") introduced a trace.h file in the local directory but
> > > > missed adding the local include path, resulting in compilation
> > > > failures with tracepoints:
> > > >
> > > > In file included from drivers/vfio/pci/trace.h:102,
> > > >                  from drivers/vfio/pci/vfio_pci_nvlink2.c:29:
> > > > ./include/trace/define_trace.h:89:42: fatal error: ./trace.h: No such file or directory
> > > >  #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
> > > >
> > > > Fix this by adjusting the include path.
> > > >
> > > > Fixes: 7f92891778df ("vfio_pci: Add NVIDIA GV100GL [Tesla V100 SXM2] subdriver")
> > > > Signed-off-by: Laura Abbott <labbott@redhat.com>
>
> (...)
>
> > > Alex I assume you'll merge this fix via the vfio tree?
> > >
> > > cheers
> > >
> > > > diff --git a/drivers/vfio/pci/Makefile b/drivers/vfio/pci/Makefile
> > > > index 9662c063a6b1..08d4676a8495 100644
> > > > --- a/drivers/vfio/pci/Makefile
> > > > +++ b/drivers/vfio/pci/Makefile
> > > > @@ -1,3 +1,4 @@
> > > > +ccflags-y                               += -I$(src)
> > > >
> > > >  vfio-pci-y := vfio_pci.o vfio_pci_intrs.o vfio_pci_rdwr.o vfio_pci_config.o
> > > >  vfio-pci-$(CONFIG_VFIO_PCI_IGD) += vfio_pci_igd.o
> > > > --
> > > > 2.20.1
> >
> >
> > Hi.
> >
> > If I correctly understand the usage of TRACE_INCLUDE_PATH,
> > the correct fix should be like follows:
> >
> >
> > 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
> >  #undef TRACE_INCLUDE_FILE
> >  #define TRACE_INCLUDE_FILE trace
>
> Going from the comments in samples/trace_events/trace-events-sample.h,
> I think both approaches are possible, and I see both used in various
> places.
>
> Personally, I'd prefer Laura's patch, as it doesn't involve hardcoding
> a path.


ccflags-y += -I$(src)
would add the header search path for all files in drivers/vfio/pci/
whereas only the drivers/vfio/pci/vfio_pci_nvlink2.c needs it.


CFLAGS_vfio_pci_nvlink2.o += -I$(src)
is a bit better.
However, it is not obvious why this extra header search path is needed
until you find vfio_pci_nvlink2.c including trace.h


#define TRACE_INCLUDE_PATH ../../drivers/vfio/pci
clarifies the intention because the related code is all placed in trace.h


From the comment in include/trace/define_trace.h
TRACE_INCLUDE_PATH is relative to include/trace/define_trace.h


-- 
Best Regards
Masahiro Yamada