From: David Woodhouse <dwmw@amazon.co.uk>
Date: Wed, 2 Apr 2025 17:23:01 +0000 (+0100)
Subject: mm: Implement for_each_valid_pfn() for CONFIG_FLATMEM
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=d68fe39883dfea92e1163f9fb8f59cc44f460fa1;p=users%2Fdwmw2%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.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
---

diff --git a/include/asm-generic/memory_model.h b/include/asm-generic/memory_model.h
index a3b5029aebbdc..93fcd7e8c4111 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 /* pfn_valid */
 
 #elif defined(CONFIG_SPARSEMEM_VMEMMAP)