[PATCH v3 3/6] userfaultfd: convert copy_huge_page_from_user() to copy_folio_from_user()

[Peng Zhang]

From: ZhangPeng <zhangpeng362@xxxxxxxxxx>

Replace copy_huge_page_from_user() with copy_folio_from_user().
copy_folio_from_user() does the same as copy_huge_page_from_user(), but
takes in a folio instead of a page. Convert page_kaddr to kaddr in
copy_folio_from_user() to do indenting cleanup.

Signed-off-by: ZhangPeng <zhangpeng362@xxxxxxxxxx>
---
 include/linux/mm.h |  7 +++----
 mm/hugetlb.c       |  5 ++---
 mm/memory.c        | 26 ++++++++++++--------------
 mm/userfaultfd.c   |  6 ++----
 4 files changed, 19 insertions(+), 25 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1f79667824eb..69dfadee23e8 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3546,10 +3546,9 @@ extern void copy_user_huge_page(struct page *dst, struct page *src,
 				unsigned long addr_hint,
 				struct vm_area_struct *vma,
 				unsigned int pages_per_huge_page);
-extern long copy_huge_page_from_user(struct page *dst_page,
-				const void __user *usr_src,
-				unsigned int pages_per_huge_page,
-				bool allow_pagefault);
+long copy_folio_from_user(struct folio *dst_folio,
+			   const void __user *usr_src,
+			   bool allow_pagefault);
 
 /**
  * vma_is_special_huge - Are transhuge page-table entries considered special?
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 07abcb6eb203..29ac064f69d6 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6201,9 +6201,8 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
 			goto out;
 		}
 
-		ret = copy_huge_page_from_user(&folio->page,
-						(const void __user *) src_addr,
-						pages_per_huge_page(h), false);
+		ret = copy_folio_from_user(folio, (const void __user *) src_addr,
+					   false);
 
 		/* fallback to copy_from_user outside mmap_lock */
 		if (unlikely(ret)) {
diff --git a/mm/memory.c b/mm/memory.c
index 062bd215bea8..faf79742e0b6 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5769,35 +5769,33 @@ void copy_user_huge_page(struct page *dst, struct page *src,
 	process_huge_page(addr_hint, pages_per_huge_page, copy_subpage, &arg);
 }
 
-long copy_huge_page_from_user(struct page *dst_page,
-				const void __user *usr_src,
-				unsigned int pages_per_huge_page,
-				bool allow_pagefault)
+long copy_folio_from_user(struct folio *dst_folio,
+			   const void __user *usr_src,
+			   bool allow_pagefault)
 {
-	void *page_kaddr;
+	void *kaddr;
 	unsigned long i, rc = 0;
-	unsigned long ret_val = pages_per_huge_page * PAGE_SIZE;
+	unsigned int nr_pages = folio_nr_pages(dst_folio);
+	unsigned long ret_val = nr_pages * PAGE_SIZE;
 	struct page *subpage;
 
-	for (i = 0; i < pages_per_huge_page; i++) {
-		subpage = nth_page(dst_page, i);
-		page_kaddr = kmap_local_page(subpage);
+	for (i = 0; i < nr_pages; i++) {
+		subpage = folio_page(dst_folio, i);
+		kaddr = kmap_local_page(subpage);
 		if (!allow_pagefault)
 			pagefault_disable();
-		rc = copy_from_user(page_kaddr,
-				usr_src + i * PAGE_SIZE, PAGE_SIZE);
+		rc = copy_from_user(kaddr, usr_src + i * PAGE_SIZE, PAGE_SIZE);
 		if (!allow_pagefault)
 			pagefault_enable();
-		kunmap_local(page_kaddr);
+		kunmap_local(kaddr);
 
 		ret_val -= (PAGE_SIZE - rc);
 		if (rc)
 			break;
 
-		flush_dcache_page(subpage);
-
 		cond_resched();
 	}
+	flush_dcache_folio(dst_folio);
 	return ret_val;
 }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 263191c37fb5..7b660bc07d71 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -425,10 +425,8 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm,
 			mmap_read_unlock(dst_mm);
 			BUG_ON(!page);
 
-			err = copy_huge_page_from_user(page,
-						(const void __user *)src_addr,
-						vma_hpagesize / PAGE_SIZE,
-						true);
+			err = copy_folio_from_user(page_folio(page),
+						   (const void __user *)src_addr, true);
 			if (unlikely(err)) {
 				err = -EFAULT;
 				goto out;
-- 
2.25.1