From 3f4b13b06062a03530df98310fcd9e189b2cddfa Mon Sep 17 00:00:00 2001
From: "David Hildenbrand (Arm)" <david@kernel.org>
Date: Mon, 21 Sep 2026 21:59:04 +0200
Subject: [PATCH] fs/proc/page: clarify comment in get_max_dump_pfn()

pfn_to_online_page() will only succeed on some PFNs within the same
section, not necessarily all.  Let's make that clearer.

While at it, rephrase it to "Allow inspection of".

Link: https://lore.kernel.org/20260921-b4-sparsemem_cleanups-v2-12-54d81d65e125@kernel.org
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Qi Zheng <qi.zheng@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Barry Song <baohua@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
---
 fs/proc/page.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/fs/proc/page.c b/fs/proc/page.c
index f90e1030825e..6aa99e42ec22 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -31,10 +31,9 @@ static inline unsigned long get_max_dump_pfn(void)
 {
 #ifdef CONFIG_SPARSEMEM
 	/*
-	 * The memmap of early sections is completely populated and marked
-	 * online even if max_pfn does not fall on a section boundary -
-	 * pfn_to_online_page() will succeed on all pages. Allow inspecting
-	 * these memmaps.
+	 * If max_pfn does not fall on a section boundary, pfn_to_online_page()
+	 * can succeed on PFNs beyond max_pfn within the same section. Allow
+	 * inspection of these memmaps.
 	 */
 	return round_up(max_pfn, PAGES_PER_SECTION);
 #else