Re: [PATCH v3 1/3] resource: Add @flags to region_intersects()

[Linus Torvalds <torvalds@linux-foundation.org>]

On Thu, Dec 3, 2015 at 10:40 AM, Borislav Petkov <bp@alien8.de> wrote:
> On Thu, Dec 03, 2015 at 11:54:19AM -0700, Toshi Kani wrote:
>> Adding a new type for regular memory will require inspecting the codes
>> using IORESOURCE_MEM currently, and modify them to use the new type if
>> their target ranges are regular memory.  There are many references to this
>> type across multiple architectures and drivers, which make this inspection
>> and testing challenging.
>
> What's wrong with adding a new type_flags to struct resource and not
> touching IORESOURCE_* at all?

Bah. Both of these ideas are bogus.

Just add a new flag. The bits are already modifiers that you can
*combine* to show what kind of resource it is, and we already have
things like IORESOURCE_PREFETCH etc, that are in *addition* to the
normal IORESOURCE_MEM bit.

Just add another modifier: IORESOURCE_RAM.

So it would still show up as IORESOURCE_MEM, but it would have
additional information specifying that it's actually RAM.

If somebody does something like

     if (res->flags == IORESOURCE_MEM)

then they are already completely broken and won't work *anyway*. It's
a bitmask, bit a set of values.

             Linus

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