On Thu, 24 Nov 2016 10:32:12 +0100 Michal Marek <mmarek@xxxxxxxx> wrote: > On 2016-11-24 08:53, Nicholas Piggin wrote: > > On Thu, 24 Nov 2016 08:36:39 +0100 > > Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > > >> On Thu, Nov 24, 2016 at 06:20:26PM +1100, Nicholas Piggin wrote: > >>> But still, modversions is pretty complicated for what it gives us. It sends > >>> preprocessed C into a C parser that makes CRCs using type definitions of > >>> exported symbols, then turns those CRCs into a linker script which which is > >>> used to link the .o file with. What we get in return is a quite limited and > >>> symbol "versioning" system. > >>> > >>> What if we ripped all that out and just attached an explicit version to > >>> each export, and incompatible changes require an increment? > >> > >> How would that work for structures? Would that be required for every > >> EXPORT_SYMBOL* somehow? > > > > Yeah just have EXPORT_SYMBOL take another parameter which attaches a version > > number and use that as the value for the __crc_ symbol versions rather than > > a calculated CRC. > > The problem is that with every kernel release, the structures change in > a way that you would have to bump the version of virtually every export. > > At which point, there would be little difference between > CONFIG_MODVERSION on and off (without CONFIG_MODVERSION, we compare the > kernel version strings when loading modules). I'm not sure about that. If they are truly incompatible changes and MODVERSIONS does not pick up a different CRC, then it's even worse if incompatible modules are missed so often. Thanks, Nick -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
