On Thu, Mar 25, 2021 at 11:23:06AM -0700, Linus Torvalds wrote: > On Thu, Mar 25, 2021 at 9:34 AM Lee Jones <[email protected]> wrote: > > > > - Unconstify editable placeholder structures > > Hmm. This does show a real issue with that gpio driver. > > It does garbage things: > > static int intel_quark_gpio_setup(struct pci_dev *pdev, struct mfd_cell > *cell) > { > struct dwapb_platform_data *pdata; > struct resource *res = (struct resource *)cell->resources; > > where that cast is exactly because "cell->resources" _is_ const, and > the driver violates that. > > This horrible mis-use of a const pointer is why the original patch > that got reverted didn't cause build-time warnings. > > Honestly, I think the right thing to do is to get rid of that cast, and do > > struct resource *res = intel_quark_mfd_cells; > > instead, so that you clearly edit somethign that isn't const, and so > that the compiler would have warned about the whole constification in > the first place. > > This broken pattern shows up for both intel_quark_i2c_setup() and > intel_quark_gpio_setup(). > > I've pulled this, but I really want this kind of "take a const pointer > and violate it" crap removed. It is *only* correct if you know exactly > which pointer it is, and then you should just have used that original > pointer in the first place (ie use that intel_quark_mfd_cells[] > directly like suggested above).
Thanks for pointing this out! I'll take it in my TODO list. Hmm... I missed the above b/c I have seen the pattern of supplying non-const data structures via .driver_data field and thought that here is something similar without looking into the actual approach. -- With Best Regards, Andy Shevchenko
