Messages in this thread |  | | Date | Mon, 8 Jun 2015 19:27:12 +0300 | Subject | Re: [PATCH v3 5/6] arch: introduce memremap_cache() and memremap_wt() | From | Andy Shevchenko <> |
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On Thu, Jun 4, 2015 at 12:34 AM, Dan Williams <dan.j.williams@intel.com> wrote: > Existing users of ioremap_cache() are mapping memory that is known in > advance to not have i/o side effects. These users are forced to cast > away the __iomem annotation, or otherwise neglect to fix the sparse > errors thrown when dereferencing pointers to this memory. Provide > memremap_*() as a non __iomem annotated ioremap_*(). > > The ARCH_HAS_MEMREMAP kconfig symbol is introduced for archs to assert > that it is safe to recast / reuse the return value from ioremap as a > normal pointer to memory. In other words, archs that mandate specific > accessors for __iomem are not memremap() capable and drivers that care, > like pmem, can add a dependency to disable themselves on these archs.
One minor comment. Otherwise looks good for me.
[]
> --- a/kernel/resource.c > +++ b/kernel/resource.c
> @@ -528,6 +528,45 @@ int region_is_ram(resource_size_t start, unsigned long size) > return ret; > } > > +#ifdef CONFIG_ARCH_HAS_MEMREMAP > +/* > + * memremap() is "ioremap" for cases where it is known that the resource > + * being mapped does not have i/o side effects and the __iomem > + * annotation is not applicable. > + */ > +static bool memremap_valid(resource_size_t offset, size_t size) > +{ > + if (region_is_ram(offset, size) != 0) { > + WARN_ONCE(1, "memremap attempted on ram %pa size: %zd\n",
%zu
> + &offset, size); > + return false; > + } > + return true; > +}
-- With Best Regards, Andy Shevchenko
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