On 21-01-06 12:59:35, Dan Williams wrote: > On Wed, Jan 6, 2021 at 12:40 PM Dave Jiang <dave.ji...@intel.com> wrote: > > > > Add missing __iomem anotation to address sparse warning. > > s/anotation/annotation/ > > > > > "sparse warnings: (new ones prefixed by >>)" > > drivers/dma/idxd/submit.c: note: in included file (through > > include/linux/io.h, include/linux/pci.h): > > >> arch/x86/include/asm/io.h:422:27: sparse: sparse: incorrect type in > > >> argument 1 (different address spaces) @@ expected void *dst @@ > > >> got void [noderef] __iomem *dst @@ > > arch/x86/include/asm/io.h:422:27: sparse: expected void *dst > > arch/x86/include/asm/io.h:422:27: sparse: got void [noderef] __iomem > > *dst > > The sparse spew is somewhat interesting, but what would be more > helpful is explain the why. I.e. that existing and future users expect > to be passing an __iomem annotated pointer to this routine because... > <reasons go here>. Otherwise someone (reviewer / future git blame > user) might reasonably ask, "well, why is the driver passing an > __iomem annotated pointer in the first instance?". > > To Ben's point you might also duplicate part of the comment from > movdir64b and say: > > "Recall, from the comment in movdir64b @__dst must be supplied as an > lvalue because this tells the compiler what the object is (its size) > the instruction accesses. I.e., not the pointers but what they point > to, thus the deref'ing '*'."
Thanks for pasting this, I missed that. It still doesn't make sense to me why the compiler needs to know this. I guess it makes sense to the rest of you. > > With clarified changelog for both you can add: > > Reviewed-by: Dan Williams <dan.j.willi...@intel.com>
