mm/page_table_check: use unsigned long for page counters and cleanup

For consistency, use "unsigned long" for all page counters.

Also, reduce code duplication by calling __page_table_check_*_clear()
from __page_table_check_*_set() functions.

Link: https://lkml.kernel.org/r/20220131203249.2832273-3-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Wei Xu <weixugc@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Paul Turner <pjt@google.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Author: soleen

mm/page_table_check.c

@@ -86,8 +86,8 @@ static void page_table_check_clear(struct mm_struct *mm, unsigned long addr,
 {
 	struct page_ext *page_ext;
 	struct page *page;
+	unsigned long i;
 	bool anon;
-	int i;
 
 	if (!pfn_valid(pfn))
 		return;
@@ -121,8 +121,8 @@ static void page_table_check_set(struct mm_struct *mm, unsigned long addr,
 {
 	struct page_ext *page_ext;
 	struct page *page;
+	unsigned long i;
 	bool anon;
-	int i;
 
 	if (!pfn_valid(pfn))
 		return;
@@ -152,10 +152,10 @@ static void page_table_check_set(struct mm_struct *mm, unsigned long addr,
 void __page_table_check_zero(struct page *page, unsigned int order)
 {
 	struct page_ext *page_ext = lookup_page_ext(page);
-	int i;
+	unsigned long i;
 
 	BUG_ON(!page_ext);
-	for (i = 0; i < (1 << order); i++) {
+	for (i = 0; i < (1ul << order); i++) {
 		struct page_table_check *ptc = get_page_table_check(page_ext);
 
 		BUG_ON(atomic_read(&ptc->anon_map_count));
@@ -206,17 +206,10 @@ EXPORT_SYMBOL(__page_table_check_pud_clear);
 void __page_table_check_pte_set(struct mm_struct *mm, unsigned long addr,
 				pte_t *ptep, pte_t pte)
 {
-	pte_t old_pte;
-
 	if (&init_mm == mm)
 		return;
 
-	old_pte = *ptep;
-	if (pte_user_accessible_page(old_pte)) {
-		page_table_check_clear(mm, addr, pte_pfn(old_pte),
-				       PAGE_SIZE >> PAGE_SHIFT);
-	}
-
+	__page_table_check_pte_clear(mm, addr, *ptep);
 	if (pte_user_accessible_page(pte)) {
 		page_table_check_set(mm, addr, pte_pfn(pte),
 				     PAGE_SIZE >> PAGE_SHIFT,
@@ -228,17 +221,10 @@ EXPORT_SYMBOL(__page_table_check_pte_set);
 void __page_table_check_pmd_set(struct mm_struct *mm, unsigned long addr,
 				pmd_t *pmdp, pmd_t pmd)
 {
-	pmd_t old_pmd;
-
 	if (&init_mm == mm)
 		return;
 
-	old_pmd = *pmdp;
-	if (pmd_user_accessible_page(old_pmd)) {
-		page_table_check_clear(mm, addr, pmd_pfn(old_pmd),
-				       PMD_PAGE_SIZE >> PAGE_SHIFT);
-	}
-
+	__page_table_check_pmd_clear(mm, addr, *pmdp);
 	if (pmd_user_accessible_page(pmd)) {
 		page_table_check_set(mm, addr, pmd_pfn(pmd),
 				     PMD_PAGE_SIZE >> PAGE_SHIFT,
@@ -250,17 +236,10 @@ EXPORT_SYMBOL(__page_table_check_pmd_set);
 void __page_table_check_pud_set(struct mm_struct *mm, unsigned long addr,
 				pud_t *pudp, pud_t pud)
 {
-	pud_t old_pud;
-
 	if (&init_mm == mm)
 		return;
 
-	old_pud = *pudp;
-	if (pud_user_accessible_page(old_pud)) {
-		page_table_check_clear(mm, addr, pud_pfn(old_pud),
-				       PUD_PAGE_SIZE >> PAGE_SHIFT);
-	}
-
+	__page_table_check_pud_clear(mm, addr, *pudp);
 	if (pud_user_accessible_page(pud)) {
 		page_table_check_set(mm, addr, pud_pfn(pud),
 				     PUD_PAGE_SIZE >> PAGE_SHIFT,