On Mon, Dec 14, 2015 at 4:24 PM, Thierry Reding <thierry.reding@xxxxxxxxx> wrote: > On Mon, Dec 14, 2015 at 09:19:30AM +0100, Geert Uytterhoeven wrote: >> Hi Paul, >> >> On Sun, Dec 13, 2015 at 2:41 AM, Paul Gortmaker >> <paul.gortmaker@xxxxxxxxxxxxx> wrote: >> > This series of commits is a slice of a larger project to ensure >> > people don't have dead code for module removal in non-modular >> > drivers. Overall there was roughly 5k lines of dead code in the >> > kernel due to this. So far we've fixed several areas, like tty, >> > x86, net, etc. and we continue to work on other areas. >> > >> > There are several reasons to not use module_init for code that can >> > never be built as a module, but the big ones are: >> > >> > (1) it is easy to accidentally code up unused module_exit and remove code >> > (2) it can be misleading when reading the source, thinking it can be >> > modular when the Makefile and/or Kconfig prohibit it >> > (3) it requires the include of the module.h header file which in turn >> > includes nearly everything else. >> > >> > Here we convert some module_init() calls into device_initcall() and delete >> > any module_exit and remove code that gets orphaned in the process, for >> > an overall net code reduction, which is always welcome. >> > >> > The use of device_initcall ensures that the init function ordering >> > remains unchanged, but one could argue that PCI host code might be more >> > appropriate to be handled under subsys_initcall. Fortunately we can >> > revisit making this extra change at a later date if desired; it does >> > not need to happen now, and we reduce the risk of introducing >> > regressions at this point in time by separating the two changes. >> > >> > Over half of the drivers changed here already explicitly disallowed any >> > unbind operations. For the rest we make them the same, since there is >> > not really any sensible use case to unbind any built-in bus support that >> > I can think of. >> >> Personally, I think all of these should become tristate, so distro kernels >> don't have to build in PCI(e) support for all SoCs. multi_v7_defconfig kernels >> are becoming too big. >> >> That does not preclude making these modules un-unloadable, though. > > Most of these can't be made tristate as-is, because they use symbols > that aren't exported. Many of those symbols can easily be exported, so > its just a matter of getting the respective patches merged. I disagree > with making the modules non-unloadable, though. I have a local branch > with changes necessary to unload the host controller driver and it > works just fine. > PCIe host driver that use fixup (DECLARE_PCI_FIXUP_*) can't use tristate. Fixup region is in kernel region and this region if not updated when loading a module. Regards Ley Foon -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
