Re: [PATCH v2 0/5] treewide: remove unreachable memblock_reserve() return value checks in early boot

Mike Rapoport <[email protected]> Tue, 7 Jul 2026 09:17:08 +0300
Newsgroups org.kernel.vger.linux-efi,org.kernel.vger.linux-kernel,org.kernel.vger.linux-sh,org.kvack.linux-mm,org.ozlabs.lists.linuxppc-dev
Message-ID <[email protected]>
Hi Sang-Heon,

On Tue, Jul 07, 2026 at 01:37:48AM +0900, Sang-Heon Jeon wrote:
> memblock_reserve() can only return an error after memblock_allow_resize()
> has been called. Before that it either succeeds or panics, never returning
> an error.
> 
> Before memblock_allow_resize() is called, the return value checks of
> memblock_reserve() are unreachable and can be removed.

I'd rather keep these checks.

Removing them relies on internal details of memblock_reserve() implementation
and the existing event sequence. If the code would move around relying on
panic in memblock_reserve() may not be correct.

And the few bytes and cycles the change saves do not worth the churn.

-- 
Sincerely yours,
Mike.