+ treewide-remove-pageprivate-and-pg_private-from-comments-and-docs.patch added to mm-unstable branch

+ treewide-remove-pageprivate-and-pg_private-from-comments-and-docs.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: treewide: remove PagePrivate() and PG_private from comments and docs
has been added to the -mm mm-unstable branch.  Its filename is
     treewide-remove-pageprivate-and-pg_private-from-comments-and-docs.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/treewide-remove-pageprivate-and-pg_private-from-comments-and-docs.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

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and is updated there most days

------------------------------------------------------
From: Zi Yan <ziy@nvidia.com>
Subject: treewide: remove PagePrivate() and PG_private from comments and docs
Date: Sun, 20 Sep 2026 22:28:12 -0400

PG_private and PagePrivate() are no longer used. Adjust related comments
and documentations to refer to page/folio->private instead.

hugetlbfs_reserv.rst is outdated and left unchanged. It should be
rewritten.

Assisted-by: LLM
Link: https://lore.kernel.org/20260920-remove-pg_private-v5-16-bb68b6a21869@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Alex Markuze <amarkuze@redhat.com>
Cc: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: Trond Myklebust <trondmy@kernel.org>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Zhihao Cheng <chengzhihao1@huawei.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: "Liam R. Howlett" <liam@infradead.org>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
---

 Documentation/admin-guide/kdump/vmcoreinfo.rst |    2 +-
 Documentation/filesystems/vfs.rst              |    6 +++---
 fs/nfs/file.c                                  |    4 ++--
 fs/ubifs/file.c                                |    8 ++++----
 include/linux/mm.h                             |   15 ++++++++-------
 include/linux/mm_types.h                       |    4 ++--
 6 files changed, 20 insertions(+), 19 deletions(-)

--- a/Documentation/admin-guide/kdump/vmcoreinfo.rst~treewide-remove-pageprivate-and-pg_private-from-comments-and-docs
+++ a/Documentation/admin-guide/kdump/vmcoreinfo.rst
@@ -325,7 +325,7 @@ NR_FREE_PAGES
 On linux-2.6.21 or later, the number of free pages is in
 vm_stat[NR_FREE_PAGES]. Used to get the number of free pages.
 
-PG_lru|PG_private|PG_swapcache|PG_swapbacked|PG_hwpoison|PG_head_mask
+PG_lru|PG_swapcache|PG_swapbacked|PG_hwpoison|PG_head_mask
 --------------------------------------------------------------------------
 
 Page attributes. These flags are used to filter various unnecessary for
--- a/Documentation/filesystems/vfs.rst~treewide-remove-pageprivate-and-pg_private-from-comments-and-docs
+++ a/Documentation/filesystems/vfs.rst
@@ -649,8 +649,8 @@ Writeback.
 
 The first can be used independently to the others.  The VM can try to
 release clean pages in order to reuse them.  To do this it can call
-->release_folio on clean folios with the private
-flag set.  Clean pages without PagePrivate and with no external references
+->release_folio on clean folios with folio->private set. Clean pages
+without folio->private set and with no external references
 will be released without notice being given to the address_space.
 
 To achieve this functionality, pages need to be placed on an LRU with
@@ -674,7 +674,7 @@ filemap_fdatawait_range, to wait for all
 
 An address_space handler may attach extra information to a page,
 typically using the 'private' field in the 'struct page'.  If such
-information is attached, the PG_Private flag should be set.  This will
+information is attached, non-NULL 'private' field will
 cause various VM routines to make extra calls into the address_space
 handler to deal with that data.
 
--- a/fs/nfs/file.c~treewide-remove-pageprivate-and-pg_private-from-comments-and-docs
+++ a/fs/nfs/file.c
@@ -484,7 +484,7 @@ static int nfs_write_end(const struct ki
  * Partially or wholly invalidate a page
  * - Release the private state associated with a page if undergoing complete
  *   page invalidation
- * - Called if either PG_private or PG_fscache is set on the page
+ * - Called if either folio->private or PG_fscache is set on the page
  * - Caller holds page lock
  */
 static void nfs_invalidate_folio(struct folio *folio, size_t offset,
@@ -555,7 +555,7 @@ static void nfs_check_dirty_writeback(st
  * Attempt to clear the private state associated with a page when an error
  * occurs that requires the cached contents of an inode to be written back or
  * destroyed
- * - Called if either PG_private or fscache is set on the page
+ * - Called if either page->private or fscache is set on the page
  * - Caller holds page lock
  * - Return 0 if successful, -error otherwise
  */
--- a/fs/ubifs/file.c~treewide-remove-pageprivate-and-pg_private-from-comments-and-docs
+++ a/fs/ubifs/file.c
@@ -12,14 +12,14 @@
  * This file implements VFS file and inode operations for regular files, device
  * nodes and symlinks as well as address space operations.
  *
- * UBIFS uses 2 page flags: @PG_private and @PG_checked. @PG_private is set if
+ * UBIFS uses folio->private and page flag @PG_checked. folio->private is set if
  * the page is dirty and is used for optimization purposes - dirty pages are
- * not budgeted so the flag shows that 'ubifs_write_end()' should not release
+ * not budgeted so it shows that 'ubifs_write_end()' should not release
  * the budget for this page. The @PG_checked flag is set if full budgeting is
  * required for the page e.g., when it corresponds to a file hole or it is
  * beyond the file size. The budgeting is done in 'ubifs_write_begin()', because
  * it is OK to fail in this function, and the budget is released in
- * 'ubifs_write_end()'. So the @PG_private and @PG_checked flags carry
+ * 'ubifs_write_end()'. So the folio->private and the @PG_checked flag carry
  * information about how the page was budgeted, to make it possible to release
  * the budget properly.
  *
@@ -1509,7 +1509,7 @@ static vm_fault_t ubifs_vm_page_mkwrite(
 	 *
 	 * At the moment we do not know whether the folio is dirty or not, so we
 	 * assume that it is not and budget for a new folio. We could look at
-	 * the @PG_private flag and figure this out, but we may race with write
+	 * folio->private and figure this out, but we may race with write
 	 * back and the folio state may change by the time we lock it, so this
 	 * would need additional care. We do not bother with this at the
 	 * moment, although it might be good idea to do. Instead, we allocate
--- a/include/linux/mm.h~treewide-remove-pageprivate-and-pg_private-from-comments-and-docs
+++ a/include/linux/mm.h
@@ -2048,20 +2048,21 @@ vm_fault_t finish_fault(struct vm_fault
  *
  * A pagecache page contains an opaque `private' member, which belongs to the
  * page's address_space. Usually, this is the address of a circular list of
- * the page's disk buffers. PG_private must be set to tell the VM to call
- * into the filesystem to release these pages.
+ * the page's disk buffers. It tells the VM to call into the filesystem to
+ * release these pages.
  *
  * A folio may belong to an inode's memory mapping. In this case,
  * folio->mapping points to the inode, and folio->index is the file
  * offset of the folio, in units of PAGE_SIZE.
  *
- * If pagecache pages are not associated with an inode, they are said to be
- * anonymous pages. These may become associated with the swapcache, and in that
- * case PG_swapcache is set, and page->private is an offset into the swapcache.
+ * If pagecache folios are not associated with an inode, they are said to be
+ * anonymous folios. These may become associated with the swapcache, and in that
+ * case PG_swapcache is set, and folio->private is an offset into the swapcache.
  *
  * In either case (swapcache or inode backed), the pagecache itself holds one
- * reference to the page. Setting PG_private should also increment the
- * refcount. The each user mapping also has a reference to the page.
+ * reference to the folio. Attaching filesystem private data via
+ * folio_attach_private() also increments the refcount. Each user mapping also
+ * has a reference to the folio.
  *
  * The pagecache pages are stored in a per-mapping radix tree, which is
  * rooted at mapping->i_pages, and indexed by offset.
--- a/include/linux/mm_types.h~treewide-remove-pageprivate-and-pg_private-from-comments-and-docs
+++ a/include/linux/mm_types.h
@@ -108,7 +108,7 @@ struct page {
 			};
 			/**
 			 * @private: Mapping-private opaque data.
-			 * Usually used for buffer_heads if PagePrivate.
+			 * Usually used for buffer_heads.
 			 * Used for swp_entry_t if swapcache flag set.
 			 * Indicates order in the buddy system if PageBuddy
 			 * or on pcp_llist.
@@ -675,7 +675,7 @@ static inline void ptdesc_pmd_pts_init(s
 #define STRUCT_PAGE_MAX_SHIFT	(order_base_2(sizeof(struct page)))
 
 /*
- * page_private can be used on tail pages.  However, PagePrivate is only
+ * page_private can be used on tail pages.  However, it is only
  * checked by the VM on the head page.  So page_private on the tail pages
  * should be used for data that's ancillary to the head page (eg attaching
  * buffer heads to tail pages after attaching buffer heads to the head page)
_

Patches currently in -mm which might be from ziy@nvidia.com are

mm-zsmalloc-replace-pg_private-with-pointer-comparison.patch
perf-ring_buffer-stop-using-pg_private-as-aux-page-high-order-marker.patch
xen-grant-table-stop-setting-pg_private-on-pages-for-grant-mapping.patch
fscrypt-stop-setting-pg_private-on-bounce-page.patch
mm-hugetlb-use-direct-assignment-instead-of-folio_change_private.patch
f2fs-stop-using-pg_private.patch
f2fs-convert-the-private-flag-helpers-to-folio-only.patch
erofs-mm-pagemap-add-readahead_folio_last-to-avoid-folio-private.patch
erofs-use-folio_attach-detach_private-instead-of-direct-assignment.patch
mm-page-flags-check-page-folio-private-instead-of-pg_private.patch
treewide-remove-folio_set-clear_private-usage.patch
ceph-replace-pageprivate-with-page_private.patch
treewide-remove-pageprivate-and-pg_private-from-comments-and-docs.patch
mm-page-flags-remove-pg_private.patch
usb-gadgetfs-do-not-warn-about-excessively-large-memory-allocations.patch