Le 07/03/2018 à 18:45, Max Filippov a écrit :
> On Wed, Mar 7, 2018 at 2:08 AM, Laurent Vivier <[email protected]> wrote:
>>> +static inline int guest_range_valid(unsigned long start, unsigned long len)
>>> +{
>>> + if (len)
>>> + return guest_addr_valid(len - 1) && start <= GUEST_ADDR_MAX - len
>>> + 1;
>>> + else
>>> + return guest_addr_valid(start);
>>> +}
>>
>> I think we can consider len == 0 is invalid and use only:
>>
>> return start + (len - 1) <= GUEST_ADDR_MAX;
>
> start + len - 1 may wrap around, that's why I first validate len and then have
> len at the right side of the comparison. I.e. if we drop check for len == 0
> I'd
> still write it as
>
> guest_addr_valid(len - 1) && start <= GUEST_ADDR_MAX - len + 1;
>
Yes, you're right.
it would be clearer to write:
len - 1 <= GUEST_ADDR_MAX && start <= GUEST_ADDR_MAX - len + 1;
but it's only cosmetic.
Thanks,
Laurent
