Re: [vfio:next 33/38] drivers/gpu/drm/i915/i915_pci.c:975:2: warning: missing field 'override_only' initializer

[Jason Gunthorpe <jgg@nvidia.com>]

On Fri, Oct 01, 2021 at 02:04:04PM +0300, Jani Nikula wrote:
> On Fri, 27 Aug 2021, Jason Gunthorpe <jgg@nvidia.com> wrote:
> > On Fri, Aug 27, 2021 at 03:12:36PM +0000, kernel test robot wrote:
> >> tree:   https://github.com/awilliam/linux-vfio.git next
> >> head:   ea870730d83fc13a5fa2bd0e175176d7ac8a400a
> >> commit: 343b7258687ecfbb363bfda8833a7cf641aac524 [33/38] PCI: Add 'override_only' field to struct pci_device_id
> >> config: i386-randconfig-a004-20210827 (attached as .config)
> >> compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 1076082a0d97bd5c16a25ee7cf3dbb6ee4b5a9fe)
> >> reproduce (this is a W=1 build):
> >>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> >>         chmod +x ~/bin/make.cross
> >>         # https://github.com/awilliam/linux-vfio/commit/343b7258687ecfbb363bfda8833a7cf641aac524
> >>         git remote add vfio https://github.com/awilliam/linux-vfio.git
> >>         git fetch --no-tags vfio next
> >>         git checkout 343b7258687ecfbb363bfda8833a7cf641aac524
> >>         # save the attached .config to linux build tree
> >>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=i386 
> >> 
> >> If you fix the issue, kindly add following tag as appropriate
> >> Reported-by: kernel test robot <lkp@intel.com>
> >
> > Ugh, this is due to this code:
> >
> > #define INTEL_VGA_DEVICE(id, info) {		\
> > 	0x8086,	id,				\
> > 	~0, ~0,					\
> > 	0x030000, 0xff0000,			\
> > 	(unsigned long) info }
> >
> > #define INTEL_QUANTA_VGA_DEVICE(info) {		\
> > 	0x8086,	0x16a,				\
> > 	0x152d,	0x8990,				\
> > 	0x030000, 0xff0000,			\
> > 	(unsigned long) info }
> >
> >
> > Which really should be using the normal pattern for defining these
> > structs:
> >
> > #define PCI_DEVICE_CLASS(dev_class,dev_class_mask) \
> >         .class = (dev_class), .class_mask = (dev_class_mask), \
> >         .vendor = PCI_ANY_ID, .device = PCI_ANY_ID, \
> >         .subvendor = PCI_ANY_ID, .subdevice = PCI_ANY_ID
> >
> > The warning is also not a real issue, just clang being overzealous.
> 
> Stumbled upon this old report, sorry for the delayed response.
> 
> The reason it's not using designated initializers is that the same file
> gets synced to some userspace projects (at least libdrm and
> igt-gpu-tools) which use the macros to initialize slightly different
> structs. For example, igt uses struct pci_id_match from libpciaccess-dev
> (/usr/include/pciaccess.h) and can't easily adapt to different member
> names.

Do it like this:


#ifdef __KERNEL__
#define INTEL_VGA_DEVICE(..)
#endif


And userspace does

#define INTEL_VGA_DEVICE(..)
#include <foo.h>

> Anyway, we've got
> 
> subdir-ccflags-y += $(call cc-disable-warning, missing-field-initializers)
> subdir-ccflags-y += $(call cc-disable-warning, initializer-overrides)
> 
> in drivers/gpu/drm/i915/Makefile, so I wonder why they're not respected.

Disabling kernel warnings because some userspace wants to copy a
kernel header is horrific, don't do that.

Jason