From 76c4c463bbc0836c46d84775e7ca5bf6e22e8618 Mon Sep 17 00:00:00 2001
From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
Date: Sun, 11 Jan 2026 10:20:51 +0200
Subject: [PATCH] s390: introduce arch_zone_limits_init()

Move calculations of zone limits to a dedicated arch_zone_limits_init()
function.

Later MM core will use this function as an architecture specific callback
during nodes and zones initialization and thus there won't be a need to
call free_area_init() from every architecture.

Link: https://lkml.kernel.org/r/20260111082105.290734-18-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Pratyush Yadav <pratyush@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 arch/s390/mm/init.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index e4953453d2548..1c11ad84dddbe 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -86,6 +86,12 @@ static void __init setup_zero_pages(void)
 	zero_page_mask = ((PAGE_SIZE << order) - 1) & PAGE_MASK;
 }
 
+void __init arch_zone_limits_init(unsigned long *max_zone_pfns)
+{
+	max_zone_pfns[ZONE_DMA] = virt_to_pfn(MAX_DMA_ADDRESS);
+	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
+}
+
 /*
  * paging_init() sets up the page tables
  */
@@ -97,8 +103,7 @@ void __init paging_init(void)
 	sparse_init();
 	zone_dma_limit = DMA_BIT_MASK(31);
 	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
-	max_zone_pfns[ZONE_DMA] = virt_to_pfn(MAX_DMA_ADDRESS);
-	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
+	arch_zone_limits_init(max_zone_pfns);
 	free_area_init(max_zone_pfns);
 }
 
-- 
2.47.3