+ mm-implement-for_each_valid_pfn-for-config_flatmem.patch added to mm-new branch

+ mm-implement-for_each_valid_pfn-for-config_flatmem.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm: implement for_each_valid_pfn() for CONFIG_FLATMEM
has been added to the -mm mm-new branch.  Its filename is
     mm-implement-for_each_valid_pfn-for-config_flatmem.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-implement-for_each_valid_pfn-for-config_flatmem.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: David Woodhouse <dwmw@amazon.co.uk>
Subject: mm: implement for_each_valid_pfn() for CONFIG_FLATMEM
Date: Wed, 23 Apr 2025 14:33:38 +0100

In the FLATMEM case, the default pfn_valid() just checks that the PFN is
within the range [ ARCH_PFN_OFFSET ..  ARCH_PFN_OFFSET + max_mapnr ).

The for_each_valid_pfn() function can therefore be a simple for() loop
using those as min/max respectively.

Link: https://lkml.kernel.org/r/20250423133821.789413-3-dwmw2@infradead.org
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Ruihan Li <lrh2000@pku.edu.cn>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/asm-generic/memory_model.h |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

--- a/include/asm-generic/memory_model.h~mm-implement-for_each_valid_pfn-for-config_flatmem
+++ a/include/asm-generic/memory_model.h
@@ -30,7 +30,15 @@ static inline int pfn_valid(unsigned lon
 	return pfn >= pfn_offset && (pfn - pfn_offset) < max_mapnr;
 }
 #define pfn_valid pfn_valid
-#endif
+
+#ifndef for_each_valid_pfn
+#define for_each_valid_pfn(pfn, start_pfn, end_pfn)			 \
+	for ((pfn) = max_t(unsigned long, (start_pfn), ARCH_PFN_OFFSET); \
+	     (pfn) < min_t(unsigned long, (end_pfn),			 \
+			   ARCH_PFN_OFFSET + max_mapnr);		 \
+	     (pfn)++)
+#endif /* for_each_valid_pfn */
+#endif /* valid_pfn */
 
 #elif defined(CONFIG_SPARSEMEM_VMEMMAP)
 
_

Patches currently in -mm which might be from dwmw@amazon.co.uk are

mm-introduce-for_each_valid_pfn-and-use-it-from-reserve_bootmem_region.patch
mm-implement-for_each_valid_pfn-for-config_flatmem.patch
mm-implement-for_each_valid_pfn-for-config_sparsemem.patch
mm-pm-use-for_each_valid_pfn-in-kernel-power-snapshotc.patch
mm-x86-use-for_each_valid_pfn-from-__ioremap_check_ram.patch
mm-use-for_each_valid_pfn-in-memory_hotplug.patch
mm-mm_init-use-for_each_valid_pfn-in-init_unavailable_range.patch