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And we intend to continue avoiding them. So the ordering shouldn't matter. More below: > > This way we can directly import the UAPI header file without issue, use the > latest system header file without having to duplicate anything. > > Reviewed-by: Shuah Khan > Signed-off-by: Lorenzo Stoakes > --- > tools/include/linux/pidfd.h | 14 ++++++++++++++ > tools/testing/selftests/pidfd/Makefile | 3 +-- > 2 files changed, 15 insertions(+), 2 deletions(-) > create mode 100644 tools/include/linux/pidfd.h > > diff --git a/tools/include/linux/pidfd.h b/tools/include/linux/pidfd.h > new file mode 100644 > index 000000000000..113c8023072d > --- /dev/null > +++ b/tools/include/linux/pidfd.h > @@ -0,0 +1,14 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > + > +#ifndef _TOOLS_LINUX_PIDFD_H > +#define _TOOLS_LINUX_PIDFD_H > + > +/* > + * Some systems have issues with the linux/fcntl.h import in linux/pidfd.h, so > + * work around this by setting the header guard. > + */ > +#define _LINUX_FCNTL_H > +#include "../../../include/uapi/linux/pidfd.h" > +#undef _LINUX_FCNTL_H Oh shoot, I think you, Shuah and I were referring to different uapi locations, the whole time. And so the basic approach is different after all. Your include path above actually refers to: $(top_srcdir)/include/uapi/linux/fcntl.h ...but what I was intending was to copy a snapshot of that file (or a snapshot from the one generated by "make headers"), to here: $(top_srcdir)/tools/include/uapi/linux/fcntl.h ...and then use $(TOOLS_INCLUDES), which is already in selftests/lib.mk, for that reason: to be available to all of the kselftests: TOOLS_INCLUDES := -isystem $(top_srcdir)/tools/include/uapi The reasoning for this directory is further explained here: tools/include/uapi/README (And I see that selftests/proc has started using $(TOOLS_INCLUDES), that's progress.) And now, it's possible to change fcntl.h in place, instead of using a wrapper. Although either way seems OK to me. (I'm sort of ignoring the details of the actual header file conflict itself, for now.) > + > +#endif /* _TOOLS_LINUX_PIDFD_H */ > diff --git a/tools/testing/selftests/pidfd/Makefile b/tools/testing/selftests/pidfd/Makefile > index d731e3e76d5b..f5038c9dae14 100644 > --- a/tools/testing/selftests/pidfd/Makefile > +++ b/tools/testing/selftests/pidfd/Makefile > @@ -1,8 +1,7 @@ > # SPDX-License-Identifier: GPL-2.0-only > -CFLAGS += -g $(KHDR_INCLUDES) -pthread -Wall > +CFLAGS += -g -isystem $(top_srcdir)/tools/include $(KHDR_INCLUDES) -pthread -Wall Instead, it would look like this, which now mostly matches selftests/mm/Makefile, which is also helpful, because eventually this can be factored into a common piece for all selftests: CFLAGS += -g -isystem $(KHDR_INCLUDES) $(TOOLS_INCLUDES) -pthread -Wall I apologize for just now noticing this! And these kselftests shouldn't require so much fussing around, I know. But once we get this just right, it will work well and last a long time. :) thanks, -- John Hubbard