userfaultfd: convert mfill_atomic_hugetlb() to use a folio

Convert hugetlb_mfill_atomic_pte() to take in a folio pointer instead of
a page pointer.

Convert mfill_atomic_hugetlb() to use a folio.

Link: https://lkml.kernel.org/r/20230410133932.32288-5-zhangpeng362@huawei.comSigned-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/hugetlb.h

@@ -163,7 +163,7 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
 			     unsigned long dst_addr,
 			     unsigned long src_addr,
 			     uffd_flags_t flags,
-			     struct page **pagep);
+			     struct folio **foliop);
 #endif /* CONFIG_USERFAULTFD */
 bool hugetlb_reserve_pages(struct inode *inode, long from, long to,
 						struct vm_area_struct *vma,
@@ -397,7 +397,7 @@ static inline int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
 					   unsigned long dst_addr,
 					   unsigned long src_addr,
 					   uffd_flags_t flags,
-					   struct page **pagep)
+					   struct folio **foliop)
 {
 	BUG();
 	return 0;

mm/hugetlb.c

@@ -6178,7 +6178,7 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
 			     unsigned long dst_addr,
 			     unsigned long src_addr,
 			     uffd_flags_t flags,
-			     struct page **pagep)
+			     struct folio **foliop)
 {
 	struct mm_struct *dst_mm = dst_vma->vm_mm;
 	bool is_continue = uffd_flags_mode_is(flags, MFILL_ATOMIC_CONTINUE);
@@ -6201,8 +6201,8 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
 		if (IS_ERR(folio))
 			goto out;
 		folio_in_pagecache = true;
-	} else if (!*pagep) {
-		/* If a page already exists, then it's UFFDIO_COPY for
+	} else if (!*foliop) {
+		/* If a folio already exists, then it's UFFDIO_COPY for
 		 * a non-missing case. Return -EEXIST.
 		 */
 		if (vm_shared &&
@@ -6237,33 +6237,33 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
 				ret = -ENOMEM;
 				goto out;
 			}
-			*pagep = &folio->page;
-			/* Set the outparam pagep and return to the caller to
+			*foliop = folio;
+			/* Set the outparam foliop and return to the caller to
 			 * copy the contents outside the lock. Don't free the
-			 * page.
+			 * folio.
 			 */
 			goto out;
 		}
 	} else {
 		if (vm_shared &&
 		    hugetlbfs_pagecache_present(h, dst_vma, dst_addr)) {
-			put_page(*pagep);
+			folio_put(*foliop);
 			ret = -EEXIST;
-			*pagep = NULL;
+			*foliop = NULL;
 			goto out;
 		}
 
 		folio = alloc_hugetlb_folio(dst_vma, dst_addr, 0);
 		if (IS_ERR(folio)) {
-			put_page(*pagep);
+			folio_put(*foliop);
 			ret = -ENOMEM;
-			*pagep = NULL;
+			*foliop = NULL;
 			goto out;
 		}
-		copy_user_huge_page(&folio->page, *pagep, dst_addr, dst_vma,
+		copy_user_huge_page(&folio->page, &(*foliop)->page, dst_addr, dst_vma,
 				    pages_per_huge_page(h));
-		put_page(*pagep);
-		*pagep = NULL;
+		folio_put(*foliop);
+		*foliop = NULL;
 	}
 
 	/*

mm/userfaultfd.c

@@ -321,7 +321,7 @@ static __always_inline ssize_t mfill_atomic_hugetlb(
 	pte_t *dst_pte;
 	unsigned long src_addr, dst_addr;
 	long copied;
-	struct page *page;
+	struct folio *folio;
 	unsigned long vma_hpagesize;
 	pgoff_t idx;
 	u32 hash;
@@ -341,7 +341,7 @@ static __always_inline ssize_t mfill_atomic_hugetlb(
 	src_addr = src_start;
 	dst_addr = dst_start;
 	copied = 0;
-	page = NULL;
+	folio = NULL;
 	vma_hpagesize = vma_kernel_pagesize(dst_vma);
 
 	/*
@@ -410,7 +410,7 @@ static __always_inline ssize_t mfill_atomic_hugetlb(
 		}
 
 		err = hugetlb_mfill_atomic_pte(dst_pte, dst_vma, dst_addr,
-					       src_addr, flags, &page);
+					       src_addr, flags, &folio);
 
 		hugetlb_vma_unlock_read(dst_vma);
 		mutex_unlock(&hugetlb_fault_mutex_table[hash]);
@@ -419,9 +419,9 @@ static __always_inline ssize_t mfill_atomic_hugetlb(
 
 		if (unlikely(err == -ENOENT)) {
 			mmap_read_unlock(dst_mm);
-			BUG_ON(!page);
+			BUG_ON(!folio);
 
-			err = copy_folio_from_user(page_folio(page),
+			err = copy_folio_from_user(folio,
 						   (const void __user *)src_addr, true);
 			if (unlikely(err)) {
 				err = -EFAULT;
@@ -432,7 +432,7 @@ static __always_inline ssize_t mfill_atomic_hugetlb(
 			dst_vma = NULL;
 			goto retry;
 		} else
-			BUG_ON(page);
+			BUG_ON(folio);
 
 		if (!err) {
 			dst_addr += vma_hpagesize;
@@ -449,8 +449,8 @@ static __always_inline ssize_t mfill_atomic_hugetlb(
 out_unlock:
 	mmap_read_unlock(dst_mm);
 out:
-	if (page)
-		put_page(page);
+	if (folio)
+		folio_put(folio);
 	BUG_ON(copied < 0);
 	BUG_ON(err > 0);
 	BUG_ON(!copied && !err);