arm64/hugetlb: Define __hugetlb_valid_size()

arch_hugetlb_valid_size() can be just factored out to create another helper
to be used in arch_hugetlb_migration_supported() as well. This just defines
__hugetlb_valid_size() for that purpose.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/1645073557-6150-1-git-send-email-anshuman.khandual@arm.comSigned-off-by: Will Deacon <will@kernel.org>

arch/arm64/mm/hugetlbpage.c

@@ -56,24 +56,33 @@ void __init arm64_hugetlb_cma_reserve(void)
 }
 #endif /* CONFIG_CMA */
 
-#ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION
-bool arch_hugetlb_migration_supported(struct hstate *h)
+static bool __hugetlb_valid_size(unsigned long size)
 {
-	size_t pagesize = huge_page_size(h);
-
-	switch (pagesize) {
+	switch (size) {
 #ifndef __PAGETABLE_PMD_FOLDED
 	case PUD_SIZE:
 		return pud_sect_supported();
 #endif
-	case PMD_SIZE:
 	case CONT_PMD_SIZE:
+	case PMD_SIZE:
 	case CONT_PTE_SIZE:
 		return true;
 	}
+
+	return false;
+}
+
+#ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION
+bool arch_hugetlb_migration_supported(struct hstate *h)
+{
+	size_t pagesize = huge_page_size(h);
+
+	if (!__hugetlb_valid_size(pagesize)) {
 		pr_warn("%s: unrecognized huge page size 0x%lx\n",
 			__func__, pagesize);
 		return false;
+	}
+	return true;
 }
 #endif
 
@@ -506,16 +515,5 @@ arch_initcall(hugetlbpage_init);
 
 bool __init arch_hugetlb_valid_size(unsigned long size)
 {
-	switch (size) {
-#ifndef __PAGETABLE_PMD_FOLDED
-	case PUD_SIZE:
-		return pud_sect_supported();
-#endif
-	case CONT_PMD_SIZE:
-	case PMD_SIZE:
-	case CONT_PTE_SIZE:
-		return true;
-	}
-
-	return false;
+	return __hugetlb_valid_size(size);
 }