[PATCH RFC 13/14] treewide: adjust comments on PagePrivate and PG_private

[Zi Yan]

PG_private is going to be deleted. Adjust related comments to refer to
page/folio->private instead.

Assisted-by: Claude:claude-opus-4-8
Assisted-by: Codex:gpt-5
Signed-off-by: Zi Yan <ziy at nvidia.com>
To: Ilya Dryomov <idryomov at gmail.com>
To: Alex Markuze <amarkuze at redhat.com>
To: Viacheslav Dubeyko <slava at dubeyko.com>
To: Trond Myklebust <trondmy at kernel.org>
To: Anna Schumaker <anna at kernel.org>
To: Richard Weinberger <richard at nod.at>
To: Andrew Morton <akpm at linux-foundation.org>
To: David Hildenbrand <david at kernel.org>
Cc: Zhihao Cheng <chengzhihao1 at huawei.com>
Cc: Lorenzo Stoakes <ljs at kernel.org>
Cc: "Liam R. Howlett" <liam at infradead.org>
Cc: Vlastimil Babka <vbabka at kernel.org>
Cc: Mike Rapoport <rppt at kernel.org>
Cc: Suren Baghdasaryan <surenb at google.com>
Cc: Michal Hocko <mhocko at suse.com>
Cc: ceph-devel at vger.kernel.org
Cc: linux-kernel at vger.kernel.org
Cc: linux-nfs at vger.kernel.org
Cc: linux-mtd at lists.infradead.org
Cc: linux-mm at kvack.org
---
 fs/ceph/addr.c           | 4 ++--
 fs/nfs/file.c            | 4 ++--
 fs/ubifs/file.c          | 6 +++---
 include/linux/mm.h       | 6 +++---
 include/linux/mm_types.h | 4 ++--
 5 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 92074db8732ac..a4a463a9cef0a 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -122,8 +122,8 @@ static bool ceph_dirty_folio(struct address_space *mapping, struct folio *folio)
 	spin_unlock(&ci->i_ceph_lock);
 
 	/*
-	 * Reference snap context in folio->private.  Also set
-	 * PagePrivate so that we get invalidate_folio callback.
+	 * Reference snap context in folio->private. folio_attach_private()
+	 * triggers invalidate_folio callback.
 	 */
 	VM_WARN_ON_FOLIO(folio->private, folio);
 	folio_attach_private(folio, snapc);
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 851d93a099889..fa3389d766d52 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -485,7 +485,7 @@ static int nfs_write_end(const struct kiocb *iocb,
  * 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,
@@ -556,7 +556,7 @@ static void nfs_check_dirty_writeback(struct folio *folio,
  * 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
  */
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index e73c28b12f97f..61d6a56b8c8a4 100644
--- a/fs/ubifs/file.c
+++ b/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
  * 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 @PG_checked flags 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(struct vm_fault *vmf)
 	 *
 	 * 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
diff --git a/include/linux/mm.h b/include/linux/mm.h
index a93eaf7aae545..fc33cc1914273 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2073,8 +2073,8 @@ vm_fault_t finish_fault(struct vm_fault *vmf);
  *
  * 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
@@ -2085,7 +2085,7 @@ vm_fault_t finish_fault(struct vm_fault *vmf);
  * case PG_swapcache is set, and page->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
+ * reference to the page. Setting page->private should also increment the
  * refcount. The each user mapping also has a reference to the page.
  *
  * The pagecache pages are stored in a per-mapping radix tree, which is
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index b5d4cd3b067bf..f15290dde16d3 100644
--- a/include/linux/mm_types.h
+++ b/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(struct ptdesc *ptdesc)
 #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)

-- 
2.53.0