[PATCH v2 1/4] mm: memory: convert clear_huge_page() to folio_zero_user()

[Kefeng Wang <wangkefeng.wang@huawei.com>]

Replace clear_huge_page() with folio_zero_user(), and take a folio
instead of a page. Directly get number of pages by folio_nr_pages()
to remove pages_per_huge_page argument, furthermore, move the address
alignment from folio_zero_user() to the callers since the alignment
is only needed when we don't know which address will be accessed.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 fs/hugetlbfs/inode.c |  2 +-
 include/linux/mm.h   |  4 +---
 mm/huge_memory.c     |  4 ++--
 mm/hugetlb.c         |  3 +--
 mm/memory.c          | 34 ++++++++++++++++------------------
 5 files changed, 21 insertions(+), 26 deletions(-)

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 1107e5aa8343..ecad73a4f713 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -892,7 +892,7 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
 			error = PTR_ERR(folio);
 			goto out;
 		}
-		clear_huge_page(&folio->page, addr, pages_per_huge_page(h));
+		folio_zero_user(folio, ALIGN_DOWN(addr, hpage_size));
 		__folio_mark_uptodate(folio);
 		error = hugetlb_add_to_page_cache(folio, mapping, index);
 		if (unlikely(error)) {
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 106bb0310352..ecbca6281a4e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -4071,9 +4071,7 @@ enum mf_action_page_type {
 };
 
 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
-extern void clear_huge_page(struct page *page,
-			    unsigned long addr_hint,
-			    unsigned int pages_per_huge_page);
+void folio_zero_user(struct folio *folio, unsigned long addr_hint);
 int copy_user_large_folio(struct folio *dst, struct folio *src,
 			  unsigned long addr_hint,
 			  struct vm_area_struct *vma);
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index f409ea9fcc18..85b852861610 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -943,10 +943,10 @@ static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf,
 		goto release;
 	}
 
-	clear_huge_page(page, vmf->address, HPAGE_PMD_NR);
+	folio_zero_user(folio, vmf->address);
 	/*
 	 * The memory barrier inside __folio_mark_uptodate makes sure that
-	 * clear_huge_page writes become visible before the set_pmd_at()
+	 * folio_zero_user writes become visible before the set_pmd_at()
 	 * write.
 	 */
 	__folio_mark_uptodate(folio);
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 3518321f6598..58d8703a1065 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6296,8 +6296,7 @@ static vm_fault_t hugetlb_no_page(struct address_space *mapping,
 				ret = 0;
 			goto out;
 		}
-		clear_huge_page(&folio->page, vmf->real_address,
-				pages_per_huge_page(h));
+		folio_zero_user(folio, vmf->real_address);
 		__folio_mark_uptodate(folio);
 		new_folio = true;
 
diff --git a/mm/memory.c b/mm/memory.c
index 54d7d2acdf39..bc5d446d9174 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4477,7 +4477,7 @@ static struct folio *alloc_anon_folio(struct vm_fault *vmf)
 				goto next;
 			}
 			folio_throttle_swaprate(folio, gfp);
-			clear_huge_page(&folio->page, vmf->address, 1 << order);
+			folio_zero_user(folio, vmf->address);
 			return folio;
 		}
 next:
@@ -6420,41 +6420,39 @@ static inline int process_huge_page(
 	return 0;
 }
 
-static void clear_gigantic_page(struct page *page,
-				unsigned long addr,
+static void clear_gigantic_page(struct folio *folio, unsigned long addr,
 				unsigned int pages_per_huge_page)
 {
 	int i;
-	struct page *p;
 
 	might_sleep();
 	for (i = 0; i < pages_per_huge_page; i++) {
-		p = nth_page(page, i);
 		cond_resched();
-		clear_user_highpage(p, addr + i * PAGE_SIZE);
+		clear_user_highpage(folio_page(folio, i), addr + i * PAGE_SIZE);
 	}
 }
 
 static int clear_subpage(unsigned long addr, int idx, void *arg)
 {
-	struct page *page = arg;
+	struct folio *folio = arg;
 
-	clear_user_highpage(nth_page(page, idx), addr);
+	clear_user_highpage(folio_page(folio, idx), addr);
 	return 0;
 }
 
-void clear_huge_page(struct page *page,
-		     unsigned long addr_hint, unsigned int pages_per_huge_page)
+/**
+ * folio_zero_user - Zero a folio which will be mapped to userspace.
+ * @folio: The folio to zero.
+ * @addr_hint: The address will be accessed or the base address if uncelar.
+ */
+void folio_zero_user(struct folio *folio, unsigned long addr_hint)
 {
-	unsigned long addr = addr_hint &
-		~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1);
+	unsigned int nr_pages = folio_nr_pages(folio);
 
-	if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
-		clear_gigantic_page(page, addr, pages_per_huge_page);
-		return;
-	}
-
-	process_huge_page(addr_hint, pages_per_huge_page, clear_subpage, page);
+	if (unlikely(nr_pages > MAX_ORDER_NR_PAGES))
+		clear_gigantic_page(folio, addr_hint, nr_pages);
+	else
+		process_huge_page(addr_hint, nr_pages, clear_subpage, folio);
 }
 
 static int copy_user_gigantic_page(struct folio *dst, struct folio *src,
-- 
2.27.0