[PATCH v6 0/6] userfaultfd: convert userfaultfd functions to use folios

[PATCH v6 0/6] userfaultfd: convert userfaultfd functions to use folios

[Peng Zhang]

From: ZhangPeng <zhangpeng362@huawei.com>

This patch series converts several userfaultfd functions to use folios.

Change log:

v5->v6:
- Remove VM_BUG_ON_FOLIO from mfill_atomic_pte_copy() per Mike Kravetz.
  (patch 1)
- Keep flush_dcache_page() in copy_folio_from_user() to not change the
  behavior of the function, suggested by Vishal Moola. (patch 3)
- Rename copy_user_folio() to copy_user_large_folio(), suggested by Mike
  Kravetz. (patch 5)
- Add RB from Mike Kravetz. (patch 1-4,6)

v4->v5:
- Update commit description and change page_kaddr to kaddr, suggested by
  Matthew Wilcox. (patch 1,6)
- Remove pages_per_huge_page from copy_user_folio(), suggested by
  Matthew Wilcox. (patch 5)
- Add RB from Sidhartha Kumar. (patch 1,3,4)

v3->v4:
- Rebase onto mm-unstable per Andrew Morton. Update commit description
  because some function names are changed. (patch 1,4,6)

v2->v3:
- Split patch 2 into three patches, suggested by Mike Kravetz. (patch
  2-4)
- Add a new patch to convert copy_user_huge_page to copy_user_folio,
  suggested by Mike Kravetz. (patch 5)
- Fix two uninitialized bugs, thanks to Dan Carpenter. (patch 6)
- Do some indenting cleanups.

v1->v2:
Modified patch 2, suggested by Matthew Wilcox:
- Rename copy_large_folio_from_user() to copy_folio_from_user().
- Delete the inner_folio.
- kmap() and kmap_atomic() are converted to kmap_local_page(). Use
  pagefault_disable() to ensure that a deadlock will not occur.
- flush_dcache_folio() is placed outside the loop.

ZhangPeng (6):
  userfaultfd: convert mfill_atomic_pte_copy() to use a folio
  userfaultfd: use kmap_local_page() in copy_huge_page_from_user()
  userfaultfd: convert copy_huge_page_from_user() to
    copy_folio_from_user()
  userfaultfd: convert mfill_atomic_hugetlb() to use a folio
  mm: convert copy_user_huge_page() to copy_user_large_folio()
  userfaultfd: convert mfill_atomic() to use a folio

 include/linux/hugetlb.h  |  4 +-
 include/linux/mm.h       | 14 +++----
 include/linux/shmem_fs.h |  4 +-
 mm/hugetlb.c             | 40 +++++++++---------
 mm/memory.c              | 61 +++++++++++++---------------
 mm/shmem.c               | 16 ++++----
 mm/userfaultfd.c         | 88 ++++++++++++++++++++--------------------
 7 files changed, 109 insertions(+), 118 deletions(-)

-- 
2.25.1

[PATCH v6 1/6] userfaultfd: convert mfill_atomic_pte_copy() to use a folio

[Peng Zhang]

From: ZhangPeng <zhangpeng362@huawei.com>

Call vma_alloc_folio() directly instead of alloc_page_vma() and convert
page_kaddr to kaddr in mfill_atomic_pte_copy(). Removes several calls to
compound_head().

Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
---
 mm/userfaultfd.c | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 7f1b5f8b712c..313bc683c2b6 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -135,17 +135,18 @@ static int mfill_atomic_pte_copy(pmd_t *dst_pmd,
 				 uffd_flags_t flags,
 				 struct page **pagep)
 {
-	void *page_kaddr;
+	void *kaddr;
 	int ret;
-	struct page *page;
+	struct folio *folio;
 
 	if (!*pagep) {
 		ret = -ENOMEM;
-		page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, dst_vma, dst_addr);
-		if (!page)
+		folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, dst_vma,
+					dst_addr, false);
+		if (!folio)
 			goto out;
 
-		page_kaddr = kmap_local_page(page);
+		kaddr = kmap_local_folio(folio, 0);
 		/*
 		 * The read mmap_lock is held here.  Despite the
 		 * mmap_lock being read recursive a deadlock is still
@@ -162,45 +163,44 @@ static int mfill_atomic_pte_copy(pmd_t *dst_pmd,
 		 * and retry the copy outside the mmap_lock.
 		 */
 		pagefault_disable();
-		ret = copy_from_user(page_kaddr,
-				     (const void __user *) src_addr,
+		ret = copy_from_user(kaddr, (const void __user *) src_addr,
 				     PAGE_SIZE);
 		pagefault_enable();
-		kunmap_local(page_kaddr);
+		kunmap_local(kaddr);
 
 		/* fallback to copy_from_user outside mmap_lock */
 		if (unlikely(ret)) {
 			ret = -ENOENT;
-			*pagep = page;
+			*pagep = &folio->page;
 			/* don't free the page */
 			goto out;
 		}
 
-		flush_dcache_page(page);
+		flush_dcache_folio(folio);
 	} else {
-		page = *pagep;
+		folio = page_folio(*pagep);
 		*pagep = NULL;
 	}
 
 	/*
-	 * The memory barrier inside __SetPageUptodate makes sure that
+	 * The memory barrier inside __folio_mark_uptodate makes sure that
 	 * preceding stores to the page contents become visible before
 	 * the set_pte_at() write.
 	 */
-	__SetPageUptodate(page);
+	__folio_mark_uptodate(folio);
 
 	ret = -ENOMEM;
-	if (mem_cgroup_charge(page_folio(page), dst_vma->vm_mm, GFP_KERNEL))
+	if (mem_cgroup_charge(folio, dst_vma->vm_mm, GFP_KERNEL))
 		goto out_release;
 
 	ret = mfill_atomic_install_pte(dst_pmd, dst_vma, dst_addr,
-				       page, true, flags);
+				       &folio->page, true, flags);
 	if (ret)
 		goto out_release;
 out:
 	return ret;
 out_release:
-	put_page(page);
+	folio_put(folio);
 	goto out;
 }
 
-- 
2.25.1

[PATCH v6 2/6] userfaultfd: use kmap_local_page() in copy_huge_page_from_user()

[Peng Zhang]

From: ZhangPeng <zhangpeng362@huawei.com>

kmap() and kmap_atomic() are being deprecated in favor of
kmap_local_page() which is appropriate for any thread local context.[1]

Let's replace the kmap() and kmap_atomic() with kmap_local_page() in
copy_huge_page_from_user(). When allow_pagefault is false, disable page
faults to prevent potential deadlock.[2]

[1] https://lore.kernel.org/all/20220813220034.806698-1-ira.weiny@intel.com/
[2] https://lkml.kernel.org/r/20221025220136.2366143-1-ira.weiny@intel.com

Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
---
 mm/memory.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 387226d6094d..808f354bce65 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5880,16 +5880,14 @@ long copy_huge_page_from_user(struct page *dst_page,
 
 	for (i = 0; i < pages_per_huge_page; i++) {
 		subpage = nth_page(dst_page, i);
-		if (allow_pagefault)
-			page_kaddr = kmap(subpage);
-		else
-			page_kaddr = kmap_atomic(subpage);
+		page_kaddr = kmap_local_page(subpage);
+		if (!allow_pagefault)
+			pagefault_disable();
 		rc = copy_from_user(page_kaddr,
 				usr_src + i * PAGE_SIZE, PAGE_SIZE);
-		if (allow_pagefault)
-			kunmap(subpage);
-		else
-			kunmap_atomic(page_kaddr);
+		if (!allow_pagefault)
+			pagefault_enable();
+		kunmap_local(page_kaddr);
 
 		ret_val -= (PAGE_SIZE - rc);
 		if (rc)
-- 
2.25.1

[PATCH v6 3/6] userfaultfd: convert copy_huge_page_from_user() to copy_folio_from_user()

[Peng Zhang]

From: ZhangPeng <zhangpeng362@huawei.com>

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@huawei.com>
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
---
 include/linux/mm.h |  7 +++----
 mm/hugetlb.c       |  5 ++---
 mm/memory.c        | 23 +++++++++++------------
 mm/userfaultfd.c   |  6 ++----
 4 files changed, 18 insertions(+), 23 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 243bfba378c5..a978413b40a4 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3698,10 +3698,9 @@ 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 7e4a80769c9e..aade1b513474 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6217,9 +6217,8 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
 			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 808f354bce65..021cab989703 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5868,26 +5868,25 @@ 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)
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 313bc683c2b6..1e7dba6c4c5f 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -421,10 +421,8 @@ static __always_inline ssize_t mfill_atomic_hugetlb(
 			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

[PATCH v6 4/6] userfaultfd: convert mfill_atomic_hugetlb() to use a folio

[Peng Zhang]

From: ZhangPeng <zhangpeng362@huawei.com>

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

Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
---
 include/linux/hugetlb.h |  4 ++--
 mm/hugetlb.c            | 26 +++++++++++++-------------
 mm/userfaultfd.c        | 16 ++++++++--------
 3 files changed, 23 insertions(+), 23 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 2a758bcd6719..28703fe22386 100644
--- a/include/linux/hugetlb.h
+++ b/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;
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index aade1b513474..c88f856ec2e2 100644
--- a/mm/hugetlb.c
+++ b/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;
 	}
 
 	/*
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 1e7dba6c4c5f..2f263afb823d 100644
--- a/mm/userfaultfd.c
+++ b/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);
-- 
2.25.1

[PATCH v6 5/6] mm: convert copy_user_huge_page() to copy_user_large_folio()

[Peng Zhang]

From: ZhangPeng <zhangpeng362@huawei.com>

Replace copy_user_huge_page() with copy_user_large_folio().
copy_user_large_folio() does the same as copy_user_huge_page(), but
takes in folios instead of pages. Remove pages_per_huge_page from
copy_user_large_folio(), because we can get that from
folio_nr_pages(dst).
Convert copy_user_gigantic_page() to take in folios.

Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
---
 include/linux/mm.h |  7 +++----
 mm/hugetlb.c       | 11 +++++------
 mm/memory.c        | 28 ++++++++++++++--------------
 3 files changed, 22 insertions(+), 24 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index a978413b40a4..c8f05c3e1acb 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3694,10 +3694,9 @@ extern const struct attribute_group memory_failure_attr_group;
 extern void clear_huge_page(struct page *page,
 			    unsigned long addr_hint,
 			    unsigned int pages_per_huge_page);
-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);
+void copy_user_large_folio(struct folio *dst, struct folio *src,
+			   unsigned long addr_hint,
+			   struct vm_area_struct *vma);
 long copy_folio_from_user(struct folio *dst_folio,
 			   const void __user *usr_src,
 			   bool allow_pagefault);
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index c88f856ec2e2..f16b25b1a6b9 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5097,8 +5097,9 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
 					ret = PTR_ERR(new_folio);
 					break;
 				}
-				copy_user_huge_page(&new_folio->page, ptepage, addr, dst_vma,
-						    npages);
+				copy_user_large_folio(new_folio,
+						      page_folio(ptepage),
+						      addr, dst_vma);
 				put_page(ptepage);
 
 				/* Install the new hugetlb folio if src pte stable */
@@ -5616,8 +5617,7 @@ static vm_fault_t hugetlb_wp(struct mm_struct *mm, struct vm_area_struct *vma,
 		goto out_release_all;
 	}
 
-	copy_user_huge_page(&new_folio->page, old_page, address, vma,
-			    pages_per_huge_page(h));
+	copy_user_large_folio(new_folio, page_folio(old_page), address, vma);
 	__folio_mark_uptodate(new_folio);
 
 	mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm, haddr,
@@ -6260,8 +6260,7 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
 			*foliop = NULL;
 			goto out;
 		}
-		copy_user_huge_page(&folio->page, &(*foliop)->page, dst_addr, dst_vma,
-				    pages_per_huge_page(h));
+		copy_user_large_folio(folio, *foliop, dst_addr, dst_vma);
 		folio_put(*foliop);
 		*foliop = NULL;
 	}
diff --git a/mm/memory.c b/mm/memory.c
index 021cab989703..f315c2198098 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5815,21 +5815,21 @@ void clear_huge_page(struct page *page,
 	process_huge_page(addr_hint, pages_per_huge_page, clear_subpage, page);
 }
 
-static void copy_user_gigantic_page(struct page *dst, struct page *src,
-				    unsigned long addr,
-				    struct vm_area_struct *vma,
-				    unsigned int pages_per_huge_page)
+static void copy_user_gigantic_page(struct folio *dst, struct folio *src,
+				     unsigned long addr,
+				     struct vm_area_struct *vma,
+				     unsigned int pages_per_huge_page)
 {
 	int i;
-	struct page *dst_base = dst;
-	struct page *src_base = src;
+	struct page *dst_page;
+	struct page *src_page;
 
 	for (i = 0; i < pages_per_huge_page; i++) {
-		dst = nth_page(dst_base, i);
-		src = nth_page(src_base, i);
+		dst_page = folio_page(dst, i);
+		src_page = folio_page(src, i);
 
 		cond_resched();
-		copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma);
+		copy_user_highpage(dst_page, src_page, addr + i*PAGE_SIZE, vma);
 	}
 }
 
@@ -5847,15 +5847,15 @@ static void copy_subpage(unsigned long addr, int idx, void *arg)
 			   addr, copy_arg->vma);
 }
 
-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)
+void copy_user_large_folio(struct folio *dst, struct folio *src,
+			   unsigned long addr_hint, struct vm_area_struct *vma)
 {
+	unsigned int pages_per_huge_page = folio_nr_pages(dst);
 	unsigned long addr = addr_hint &
 		~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1);
 	struct copy_subpage_arg arg = {
-		.dst = dst,
-		.src = src,
+		.dst = &dst->page,
+		.src = &src->page,
 		.vma = vma,
 	};
 
-- 
2.25.1

[PATCH v6 6/6] userfaultfd: convert mfill_atomic() to use a folio

[Peng Zhang]

From: ZhangPeng <zhangpeng362@huawei.com>

Convert mfill_atomic_pte_copy(), shmem_mfill_atomic_pte() and
mfill_atomic_pte() to take in a folio pointer.
Convert mfill_atomic() to use a folio. Convert page_kaddr to kaddr in
mfill_atomic().

Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
---
 include/linux/shmem_fs.h |  4 ++--
 mm/shmem.c               | 16 ++++++++--------
 mm/userfaultfd.c         | 40 ++++++++++++++++++++--------------------
 3 files changed, 30 insertions(+), 30 deletions(-)

diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index 3bb8d21edbb3..9e151ba45068 100644
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -158,10 +158,10 @@ extern int shmem_mfill_atomic_pte(pmd_t *dst_pmd,
 				  unsigned long dst_addr,
 				  unsigned long src_addr,
 				  uffd_flags_t flags,
-				  struct page **pagep);
+				  struct folio **foliop);
 #else /* !CONFIG_SHMEM */
 #define shmem_mfill_atomic_pte(dst_pmd, dst_vma, dst_addr, \
-			       src_addr, flags, pagep) ({ BUG(); 0; })
+			       src_addr, flags, foliop) ({ BUG(); 0; })
 #endif /* CONFIG_SHMEM */
 #endif /* CONFIG_USERFAULTFD */
 
diff --git a/mm/shmem.c b/mm/shmem.c
index 6c08f5a75d3a..9218c955f482 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2548,7 +2548,7 @@ int shmem_mfill_atomic_pte(pmd_t *dst_pmd,
 			   unsigned long dst_addr,
 			   unsigned long src_addr,
 			   uffd_flags_t flags,
-			   struct page **pagep)
+			   struct folio **foliop)
 {
 	struct inode *inode = file_inode(dst_vma->vm_file);
 	struct shmem_inode_info *info = SHMEM_I(inode);
@@ -2566,14 +2566,14 @@ int shmem_mfill_atomic_pte(pmd_t *dst_pmd,
 		 * and now we find ourselves with -ENOMEM. Release the page, to
 		 * avoid a BUG_ON in our caller.
 		 */
-		if (unlikely(*pagep)) {
-			put_page(*pagep);
-			*pagep = NULL;
+		if (unlikely(*foliop)) {
+			folio_put(*foliop);
+			*foliop = NULL;
 		}
 		return -ENOMEM;
 	}
 
-	if (!*pagep) {
+	if (!*foliop) {
 		ret = -ENOMEM;
 		folio = shmem_alloc_folio(gfp, info, pgoff);
 		if (!folio)
@@ -2605,7 +2605,7 @@ int shmem_mfill_atomic_pte(pmd_t *dst_pmd,
 
 			/* fallback to copy_from_user outside mmap_lock */
 			if (unlikely(ret)) {
-				*pagep = &folio->page;
+				*foliop = folio;
 				ret = -ENOENT;
 				/* don't free the page */
 				goto out_unacct_blocks;
@@ -2616,9 +2616,9 @@ int shmem_mfill_atomic_pte(pmd_t *dst_pmd,
 			clear_user_highpage(&folio->page, dst_addr);
 		}
 	} else {
-		folio = page_folio(*pagep);
+		folio = *foliop;
 		VM_BUG_ON_FOLIO(folio_test_large(folio), folio);
-		*pagep = NULL;
+		*foliop = NULL;
 	}
 
 	VM_BUG_ON(folio_test_locked(folio));
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 2f263afb823d..11cfd82c6726 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -133,13 +133,13 @@ static int mfill_atomic_pte_copy(pmd_t *dst_pmd,
 				 unsigned long dst_addr,
 				 unsigned long src_addr,
 				 uffd_flags_t flags,
-				 struct page **pagep)
+				 struct folio **foliop)
 {
 	void *kaddr;
 	int ret;
 	struct folio *folio;
 
-	if (!*pagep) {
+	if (!*foliop) {
 		ret = -ENOMEM;
 		folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, dst_vma,
 					dst_addr, false);
@@ -171,15 +171,15 @@ static int mfill_atomic_pte_copy(pmd_t *dst_pmd,
 		/* fallback to copy_from_user outside mmap_lock */
 		if (unlikely(ret)) {
 			ret = -ENOENT;
-			*pagep = &folio->page;
+			*foliop = folio;
 			/* don't free the page */
 			goto out;
 		}
 
 		flush_dcache_folio(folio);
 	} else {
-		folio = page_folio(*pagep);
-		*pagep = NULL;
+		folio = *foliop;
+		*foliop = NULL;
 	}
 
 	/*
@@ -470,7 +470,7 @@ static __always_inline ssize_t mfill_atomic_pte(pmd_t *dst_pmd,
 						unsigned long dst_addr,
 						unsigned long src_addr,
 						uffd_flags_t flags,
-						struct page **pagep)
+						struct folio **foliop)
 {
 	ssize_t err;
 
@@ -493,14 +493,14 @@ static __always_inline ssize_t mfill_atomic_pte(pmd_t *dst_pmd,
 		if (uffd_flags_mode_is(flags, MFILL_ATOMIC_COPY))
 			err = mfill_atomic_pte_copy(dst_pmd, dst_vma,
 						    dst_addr, src_addr,
-						    flags, pagep);
+						    flags, foliop);
 		else
 			err = mfill_atomic_pte_zeropage(dst_pmd,
 						 dst_vma, dst_addr);
 	} else {
 		err = shmem_mfill_atomic_pte(dst_pmd, dst_vma,
 					     dst_addr, src_addr,
-					     flags, pagep);
+					     flags, foliop);
 	}
 
 	return err;
@@ -518,7 +518,7 @@ static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm,
 	pmd_t *dst_pmd;
 	unsigned long src_addr, dst_addr;
 	long copied;
-	struct page *page;
+	struct folio *folio;
 
 	/*
 	 * Sanitize the command parameters:
@@ -533,7 +533,7 @@ static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm,
 	src_addr = src_start;
 	dst_addr = dst_start;
 	copied = 0;
-	page = NULL;
+	folio = NULL;
 retry:
 	mmap_read_lock(dst_mm);
 
@@ -629,28 +629,28 @@ static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm,
 		BUG_ON(pmd_trans_huge(*dst_pmd));
 
 		err = mfill_atomic_pte(dst_pmd, dst_vma, dst_addr,
-				       src_addr, flags, &page);
+				       src_addr, flags, &folio);
 		cond_resched();
 
 		if (unlikely(err == -ENOENT)) {
-			void *page_kaddr;
+			void *kaddr;
 
 			mmap_read_unlock(dst_mm);
-			BUG_ON(!page);
+			BUG_ON(!folio);
 
-			page_kaddr = kmap_local_page(page);
-			err = copy_from_user(page_kaddr,
+			kaddr = kmap_local_folio(folio, 0);
+			err = copy_from_user(kaddr,
 					     (const void __user *) src_addr,
 					     PAGE_SIZE);
-			kunmap_local(page_kaddr);
+			kunmap_local(kaddr);
 			if (unlikely(err)) {
 				err = -EFAULT;
 				goto out;
 			}
-			flush_dcache_page(page);
+			flush_dcache_folio(folio);
 			goto retry;
 		} else
-			BUG_ON(page);
+			BUG_ON(folio);
 
 		if (!err) {
 			dst_addr += PAGE_SIZE;
@@ -667,8 +667,8 @@ static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm,
 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);
-- 
2.25.1