From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
To: "David Hildenbrand (Arm)" <david@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
"Liam R. Howlett" <liam@infradead.org>,
Vlastimil Babka <vbabka@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>,
Ying Huang <huang.ying.caritas@gmail.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
Barry Song <baohua@kernel.org>,
Ryan Roberts <ryan.roberts@arm.com>,
Chuanhua Han <hanchuanhua@oppo.com>,
Kiryl Shutsemau <kas@kernel.org>, Kyle Zeng <kylebot@openai.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH] mm: fix address wraparound when scanning large folio PTEs
Date: Wed, 14 Oct 2026 15:56:02 +0100 [thread overview]
Message-ID: <as-XYuUJdeHD3W9p@gremlin> (raw)
In-Reply-To: <06930044-4bcb-4478-8a6f-2dd3cf6d290e@kernel.org>
On Wed, Oct 14, 2026 at 03:45:41PM +0200, David Hildenbrand (Arm) wrote:
> It's the following thing that adds confusion:
>
> include/asm-generic/pgtable-nopmd.h:#define pmd_addr_end(addr, end)
> (end)
Ah ugh :) of course.
> What I am saying is that I don't agree with adding another two const variables
> with names that are less intuitive than just saying the computation. Let me try
> to improve the comment:
>
> /* Avoid address wraparounds by not adding/subtracting beyond limits. */
The variables are a (possibly) neat way of self-documenting that, but then
possibly adds complexity by having yet another variable :)
A comment works for me, though the confusing bit I guess is knowing which bit
exactly might overflow.
So maybe saying 'avoid wraparounds of <variable that can wraparound>' and a
brief bit about how would help?
--
Cheers, Lorenzo
next prev parent reply other threads:[~2026-10-14 14:56 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-13 12:30 [PATCH] mm: fix address wraparound when scanning large folio PTEs David Hildenbrand (Arm)
2026-10-13 12:57 ` Kiryl Shutsemau
2026-10-13 13:17 ` Barry Song
2026-10-14 8:03 ` David Hildenbrand (Arm)
2026-10-14 8:04 ` David Hildenbrand (Arm)
2026-10-13 14:11 ` Lorenzo Stoakes (ARM)
2026-10-14 8:12 ` David Hildenbrand (Arm)
2026-10-14 13:27 ` Lorenzo Stoakes (ARM)
2026-10-14 13:45 ` David Hildenbrand (Arm)
2026-10-14 13:49 ` David Hildenbrand (Arm)
2026-10-14 14:57 ` Lorenzo Stoakes (ARM)
2026-10-14 14:56 ` Lorenzo Stoakes (ARM) [this message]
2026-10-14 6:02 ` Baolin Wang
2026-10-14 8:02 ` David Hildenbrand (Arm)
2026-10-14 16:30 ` Lance Yang
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