Re: [PATCH v2] bitops: Avoid integer overflow in GENMASK(_ULL)

[Andrew Morton]

On Thu,  3 Aug 2017 14:20:20 -0700 Matthias Kaehlcke <mka@xxxxxxxxxxxx> wrote:

> GENMASK(_ULL) performs a left-shift of ~0UL(L), which technically
> results in an integer overflow. clang raises a warning if the overflow
> occurs in a preprocessor expression.

That's just irritaing.

> Clear the low-order bits through
> a substraction instead of the left-shift to avoid the overflow.

There's no change in .text size for a few files I tested so guess we
can live with it.