mm/debug_vm_pgtable: use struct pgtable_debug_args in migration and thp tests

This uses struct pgtable_debug_args in the migration and thp test
functions.  It's notable that the pre-allocated page is used in
swap_migration_tests() as set_pte_at() is used there.

Link: https://lkml.kernel.org/r/20210809092631.1888748-7-gshan@redhat.comSigned-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu>	[powerpc 8xx]
Tested-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>	[s390]
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chunyu Hu <chuhu@redhat.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/debug_vm_pgtable.c

@@ -845,7 +845,7 @@ static void __init pmd_swap_tests(struct pgtable_debug_args *args)
 static void __init pmd_swap_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_ARCH_ENABLE_THP_MIGRATION */
 
-static void __init swap_migration_tests(void)
+static void __init swap_migration_tests(struct pgtable_debug_args *args)
 {
 	struct page *page;
 	swp_entry_t swp;
@@ -853,19 +853,18 @@ static void __init swap_migration_tests(void)
 	if (!IS_ENABLED(CONFIG_MIGRATION))
 		return;
 
-	pr_debug("Validating swap migration\n");
 	/*
 	 * swap_migration_tests() requires a dedicated page as it needs to
 	 * be locked before creating a migration entry from it. Locking the
 	 * page that actually maps kernel text ('start_kernel') can be real
-	 * problematic. Lets allocate a dedicated page explicitly for this
-	 * purpose that will be freed subsequently.
+	 * problematic. Lets use the allocated page explicitly for this
+	 * purpose.
 	 */
-	page = alloc_page(GFP_KERNEL);
-	if (!page) {
-		pr_err("page allocation failed\n");
+	page = (args->pte_pfn != ULONG_MAX) ? pfn_to_page(args->pte_pfn) : NULL;
+	if (!page)
 		return;
-	}
+
+	pr_debug("Validating swap migration\n");
 
 	/*
 	 * make_migration_entry() expects given page to be
@@ -884,7 +883,6 @@ static void __init swap_migration_tests(void)
 	WARN_ON(!is_migration_entry(swp));
 	WARN_ON(is_writable_migration_entry(swp));
 	__ClearPageLocked(page);
-	__free_page(page);
 }
 
 #ifdef CONFIG_HUGETLB_PAGE
@@ -916,7 +914,7 @@ static void __init hugetlb_basic_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_HUGETLB_PAGE */
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-static void __init pmd_thp_tests(unsigned long pfn, pgprot_t prot)
+static void __init pmd_thp_tests(struct pgtable_debug_args *args)
 {
 	pmd_t pmd;
 
@@ -935,7 +933,7 @@ static void __init pmd_thp_tests(unsigned long pfn, pgprot_t prot)
 	 * needs to return true. pmd_present() should be true whenever
 	 * pmd_trans_huge() returns true.
 	 */
-	pmd = pfn_pmd(pfn, prot);
+	pmd = pfn_pmd(args->fixed_pmd_pfn, args->page_prot);
 	WARN_ON(!pmd_trans_huge(pmd_mkhuge(pmd)));
 
 #ifndef __HAVE_ARCH_PMDP_INVALIDATE
@@ -945,7 +943,7 @@ static void __init pmd_thp_tests(unsigned long pfn, pgprot_t prot)
 }
 
 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
-static void __init pud_thp_tests(unsigned long pfn, pgprot_t prot)
+static void __init pud_thp_tests(struct pgtable_debug_args *args)
 {
 	pud_t pud;
 
@@ -953,7 +951,7 @@ static void __init pud_thp_tests(unsigned long pfn, pgprot_t prot)
 		return;
 
 	pr_debug("Validating PUD based THP\n");
-	pud = pfn_pud(pfn, prot);
+	pud = pfn_pud(args->fixed_pud_pfn, args->page_prot);
 	WARN_ON(!pud_trans_huge(pud_mkhuge(pud)));
 
 	/*
@@ -965,11 +963,11 @@ static void __init pud_thp_tests(unsigned long pfn, pgprot_t prot)
 	 */
 }
 #else  /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
-static void __init pud_thp_tests(unsigned long pfn, pgprot_t prot) { }
+static void __init pud_thp_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 #else  /* !CONFIG_TRANSPARENT_HUGEPAGE */
-static void __init pmd_thp_tests(unsigned long pfn, pgprot_t prot) { }
-static void __init pud_thp_tests(unsigned long pfn, pgprot_t prot) { }
+static void __init pmd_thp_tests(struct pgtable_debug_args *args) { }
+static void __init pud_thp_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 static unsigned long __init get_random_vaddr(void)
@@ -1335,10 +1333,10 @@ static int __init debug_vm_pgtable(void)
 	pte_swap_tests(&args);
 	pmd_swap_tests(&args);
 
-	swap_migration_tests();
+	swap_migration_tests(&args);
 
-	pmd_thp_tests(pmd_aligned, prot);
-	pud_thp_tests(pud_aligned, prot);
+	pmd_thp_tests(&args);
+	pud_thp_tests(&args);
 
 	hugetlb_basic_tests(&args);