Thread (5 messages) 5 messages, 2 authors, 7d ago

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

From: Sang-Heon Jeon <hidden>
Date: 2026-07-07 13:24:22
Also in: linux-efi, linux-mm, linux-sh, lkml

Hi Mike,

On Tue, Jul 7, 2026 at 3:17 PM Mike Rapoport [off-list ref] wrote:
Hi Sang-Heon,

On Tue, Jul 07, 2026 at 01:37:48AM +0900, Sang-Heon Jeon wrote:
quoted
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.
Makes sense to me.

But most early boot callers of memblock_reserve() don't check the
return value, so I thought we already rely on its internal behavior
anyway. So the few remaining checks just looked a bit inconsistent to
me.

Would you still prefer to keep these checks? If so, I'm fine with
dropping this patch series. It's not a big deal :)

Thank you for taking the time to review this series.
--
Sincerely yours,
Mike.
Best Regards,
Sang-Heon Jeon
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