Hi Ingo, On Wed, Jul 22, 2015 at 10:38:45AM +0200, Ingo Molnar wrote: > > * Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote: > > > > > > Let me know if these are OK or if there are any questions. > > > > > > > > > > [0] http://lkml.kernel.org/r/20150625204703.GC4898@xxxxxxx > > > > > [1] http://lkml.kernel.org/r/20150707095012.GQ7021@xxxxxxxxxxxxx > > > > > > > > Ingo, > > > > > > > > Just a friendly reminder. Let me know if there are any issues or questions. > > > > > > It would be nice to get an Acked-by from Bjorn for the PCI API bits. > > > > I think the actual code of pci_ioremap_wc() and pci_ioremap_wc_bar() is fine > > (although I might have named it pci_ioremap_bar_wc() for consistency). > > > > I declined to merge or ack them myself because they're obvious extensions of > > pci_ioremap() and pci_ioremap_bar(), and I would prefer that they be exported > > the same way, i.e., with EXPORT_SYMBOL(), not EXPORT_SYMBOL_GPL(). > > Huh? AFAICS pci_ioremap_bar() has been a _GPL export for a long time: > ... > (ioremap_wc() is EXPORT_SYMBOL() mostly by accident, it's the odd one out.) You're right, I was mistaken about pci_ioremap_bar(). But I'm not convinced yet that ioremap_wc() is the odd one out. All the interfaces I found, with the exception of ioremap_uc() on x86 and pci_ioremap_bar(), are EXPORT_SYMBOL(), even the _wc and _wt flavors. > Also, FWIIW: I personally got essentially zero feedback and help from proprietary > binary kernel module vendors in the past couple of years as x86 maintainer, > despite a fair chunk of kernel crashes reported on distro kernels occuring in > them... > > Based on that very negative experience, when we introduce something as complex and > as critical as new caching APIs, the last thing I want is to have obscure bugs in > binary modules I cannot fix in any reasonable fashion. So even if the parent APIs > of new APIs weren't already _GPL exports (as in this case), I'd export them as > _GPL in this case. > > > I think using EXPORT_SYMBOL_GPL to express individual political aims rather than > > as a hint about what might be derived work makes us look like zealots, and > > that's not my style. > > As far as I'm concerned it's a pure technological choice: I don't want to export > certain types of hard to fix and critical functionality to drivers that I cannot > then fix. That's a good argument that I hadn't heard before (or possibly it was there and I missed it). It would be stronger still if we could change the parent APIs similarly. If a proprietary driver can't use pci_ioremap_wc() because it's exported _GPL, it's trivial to use ioremap_wc() directly. Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
