Messages in this thread | | | From | Dan Williams <> | Date | Wed, 6 Jan 2021 12:59:35 -0800 | Subject | Re: [PATCH] x86: fix movdir64b() sparse warning |
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On Wed, Jan 6, 2021 at 12:40 PM Dave Jiang <dave.jiang@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 '*'."
With clarified changelog for both you can add:
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
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