On Sun, Feb 16, 2025 at 06:04:53PM +0100, Magnus Lindholm wrote:
> Function pte_swp_exclusive() checks if _PAGE_SWP_EXCLUSIVE bit is set in
> PTE but returns lower 32-bits only. Shift bits right by 32 to return upper
> 32-bits of PTE which contain the _PAGE_SWP_EXCLUSIVE bit. On alpha this is
> bit 39 but on most other architectures this bit already resides somewhere
> in the first 32-bits and hence a shift is not necessary on those archs.
Just make it return bool and be done with that - all users are either
if (pte_swp_exclusive(...)) or if (!pte_swp_exclusive(...)) or assignments
to bool variable.
No need to shift anything - compiler probably will figure out that
if ((int)((x & (1UL<<39)>>32)))
is equivalent to
if (x & (1UL<<39))
but why bother with such convolutions in the first place?
Seriously, just make it
bool pte_swp_exclusive(pte_t pte)
{
return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
}
and that's it - conversion from arithmetical types to bool will do the right thing.
