linux-kernel - Re: [PATCH 17/31] gpu: nova-core: Hopper/Blackwell: calculate reserved FB heap size

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Message-ID: <4e36e160bfa53240987f65ba36cae8e6fe4d6e6c.camel@nvidia.com>
Date: Wed, 3 Dec 2025 20:48:15 +0000
From: Timur Tabi <ttabi@...dia.com>
To: "dakr@...nel.org" <dakr@...nel.org>, John Hubbard <jhubbard@...dia.com>
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Subject: Re: [PATCH 17/31] gpu: nova-core: Hopper/Blackwell: calculate
 reserved FB heap size

On Tue, 2025-12-02 at 21:59 -0800, John Hubbard wrote:
> +#[inline(always)]
> +pub(crate) const fn const_align_up<const ALIGN: usize>(value: usize) -> usize {
> +    build_assert!(ALIGN.is_power_of_two());
> +    (value + (ALIGN - 1)) & !(ALIGN - 1)
> +}

So this is just like the issue I'm having with .next_multiple_of() in my patch #10.  

Shouldn't you have a check to make sure that value + (ALIGN - 1) doesn't overflow?  Since I need to
align up to the nearest const power of two, I could use this function instead of align_up() and
avoid testing for an error condition.