Re: [PATCH 1/3] x86/mm: do not attempt to convert _PAGE_GNTTAB to a boolean

[Jan Beulich <jbeulich@xxxxxxxx>]

On 05.05.2020 16:11, Roger Pau Monné wrote:
> On Tue, May 05, 2020 at 03:47:43PM +0200, Jan Beulich wrote:
>> On 05.05.2020 11:24, Roger Pau Monne wrote:
>>> Remove the conversion of _PAGE_GNTTAB to a boolean, since the and
>>> operation performed afterwards will already return false if the value
>>> of the macro is 0.
>>
>> I'm sorry, but no. The expression was put there on purpose by
>> 0932210ac095 ("x86: Address "Bitwise-and with zero
>> CONSTANT_EXPRESSION_RESULT" Coverity issues"), and the
>> description there is clearly telling us that this wants to stay
>> unless Coverity changed in the meantime. Otherwise I'm afraid
>> a more elaborate solution will be needed to please both.
> 
> Clang is fine with changing this to _PAGE_GNTTAB != 0. Would you be
> OK with this approach?

I'd be okay with it, but then I guess I'd prefer ...

>> Or a
>> more simplistic one, like using "#if _PAGE_GNTTAB" around the
>> construct.
> 
> Yes, that's the other solution I had in mind.

.... this one. Let's see if Andrew has a clear opinion either
way - it was him to address the original Coverity issue after
all.

Jan