style guide recommendations when including UAPI files?

[rpjday at crashcourse.ca]

   is there a strong (or even weak) style recommendation when including
kernel header files under include/uapi in terms of explicitly including
the "uapi" path component?

   i'm fully aware of the standard that most kernel code should include
the "standard" kernel headers, such as:

   #include <linux/mii.h>

where those headers are, of course, free to turn around and include
the corresponding UAPI content; the above header file does indeed do
just that:

   #include <linux/if.h>
   #include <uapi/linux/mii.h>

however, in that very example, you can see the include of "linux/if.h"
where there is, in fact, no header file include/linux/if.h, only
include/uapi/linux/if.h.

   i can see from the top-level Makefile that that include will
eventually pick up the UAPI version of the if.h header file:

   # Use USERINCLUDE when you must reference the UAPI directories only.
   USERINCLUDE    := \
                 -I$(srctree)/arch/$(SRCARCH)/include/uapi \
                 -I$(objtree)/arch/$(SRCARCH)/include/generated/uapi \
                 -I$(srctree)/include/uapi \
                 -I$(objtree)/include/generated/uapi \
                 -include $(srctree)/include/linux/kconfig.h

   # Use LINUXINCLUDE when you must reference the include/ directory.
   # Needed to be compatible with the O= option
   LINUXINCLUDE    := \
                 -I$(srctree)/arch/$(SRCARCH)/include \
                 -I$(objtree)/arch/$(SRCARCH)/include/generated \
                 $(if $(KBUILD_SRC), -I$(srctree)/include) \
                 -I$(objtree)/include \
                 $(USERINCLUDE)

the point is, is that acceptable style? when i'm perusing kernel
code and i see a reference to a header file <linux/if.h>, i
simply assume it's a standard header file under include/, and
i expect header files under the UAPI directory will explicitly
say so in the include directive.

   thoughts?

rday