On Wednesday 10 August 2011, Michal Marek wrote: > On 7.8.2011 23:00, Linus Torvalds wrote: > > There is value in having <asm-generic/xyz.h> for helper headers that > > are not complete in themselves. And for that case, we really do want > > to have the ability for header files to just do > > > > #include <asm-generic/bitops/le.h> There are very few of these files, and there is no reason for them to be named asm/* or arm-generic/*. How about moving those incomplete files into a different directory to separate the problem space? We can e.g. move asm-generic/bitops/ to linux/bitops/ > > So I would suggest we just start a new directory, something like > > include/default, and add it as the last entry to the search path. Then > > we start populating it with <asm/xyz.h> files, and start removing the > > silly 'generic-y' workaround. Let's just use the search-path instead. > > But we would still have to generate the wrapper for userspace headers, > we can't rely on any -I/usr/include/default in userspace. So > Makefile.headersinst would still need some special handling for these > headers. Right. We have to deal with at least three cases here: 1. An architecture does not provide its own asm/foo.h, and we want the generic version to transparently be used. 2. Another architecture has an asm/foo.h that contains a few arch specific definitions plus an include of the generic file. 3. There is a generic file that is used as a helper from a file with a different name (e.g. bitops/find.h, libata-portmap.h, atomic-long.h, ...). Simply renaming "asm-generic" to "asm" or "default/asm" with an appropriate include path would take care of the first kind, but not of the second. This is also easy to handle for headers exported to user space, where we can simply copy the generic header instead of an arch specific one when that does not exist. The second case is still easily handled in many cases, except for the 34 generic header files that do get exported to user space (see include/asm-generic/Kbuild). The best I can think of is to move them to linux/include/asm-generic/asm/ and install them to /usr/include/asm-generic/asm/ to avoid opening up another namespace for user space headers. Any file including them would then have to be changed to "#include <asm-generic/asm/foo.h>". I hope that the work that David Howells is trying to push for the separation between internal and ABI headers will help a bit to simplify this. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
