From: David Woodhouse <dwmw@amazon.co.uk>
Date: Wed, 23 Apr 2025 13:33:38 +0000 (+0100)
Subject: mm: implement for_each_valid_pfn() for CONFIG_FLATMEM
X-Git-Tag: v6.16-rc1~92^2~91
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=928930c2e0a8e1d9252aedb1fa9be83c3669dfd7;p=thirdparty%2Flinux.git

mm: implement for_each_valid_pfn() for CONFIG_FLATMEM

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>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.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>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/include/asm-generic/memory_model.h b/include/asm-generic/memory_model.h
index a3b5029aebbdc..74d0077cc5faa 100644
--- a/include/asm-generic/memory_model.h
+++ b/include/asm-generic/memory_model.h
@@ -30,7 +30,15 @@ static inline int pfn_valid(unsigned long pfn)
 	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)