Re: [PATCH v5 2/6] arch: unify ioremap prototypes and macro aliases

[Dan Williams <dan.j.williams@intel.com>]

On Mon, Jun 22, 2015 at 9:10 AM, Christoph Hellwig <hch@lst.de> wrote:
> On Mon, Jun 22, 2015 at 04:24:27AM -0400, Dan Williams wrote:
>> Some archs define the first parameter to ioremap() as unsigned long,
>> while the balance define it as resource_size_t.  Unify on
>> resource_size_t to enable passing ioremap function pointers.  Also, some
>> archs use function-like macros for defining ioremap aliases, but
>> asm-generic/io.h expects object-like macros, unify on the latter.
>>
>> Move all handling of ioremap aliasing (i.e. ioremap_wt => ioremap) to
>> include/linux/io.h.  Add a check to include/linux/io.h to warn at
>> compile time if an arch violates expectations.
>>
>> Kill ARCH_HAS_IOREMAP_WC and ARCH_HAS_IOREMAP_WT in favor of just
>> testing for ioremap_wc, and ioremap_wt being defined.  This arrangement
>> allows drivers to know when ioremap_<foo> are being re-directed to plain
>> ioremap.
>>
>> Reported-by: kbuild test robot <fengguang.wu@intel.com>
>> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
>
> Hmm, this is quite a bit of churn, and doesn't make the interface lot
> more obvious.
>
> I guess it's enough to get the pmem related bits going

Is that an acked-by for this cycle with a request to go deeper for 4.3?

> but I'd really
> prefer defining the ioremap* prototype in linux/io.h and requiring
> and out of line implementation in the architectures, it's not like
> it's a fast path.  And to avoid the ifdef mess make it something like:
>
> void __iomem *ioremap_flags(resource_size_t offset, unsigned long size,
>                         unsigned long prot_val, unsigned flags);

Yes, I do like this even better.

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