Re: [PATCH v6 1/4] sgl_alloc_order: remove 4 GiB limit, sgl_free() warning

[Bodo Stroesser]

On 19.01.21 19:03, Jason Gunthorpe wrote:
> On Tue, Jan 19, 2021 at 06:24:49PM +0100, Bodo Stroesser wrote:
> > I had a second look into math.h, but I don't find any reason why round_up
> > could overflow. Can you give a hint please?
>
> #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
>                                                      ^^^^^
>
> That +1 can overflow

But that would be a unsigned long long overflow. I considered this to
not be relevant.

> It looks like it would not be so bad to implement some
> check_round_up_overflow() if people prefer
>
> Jason