mm: rename page->index to page->__folio_index

All users of page->index have been converted to not refer to it any more. 
Update a few pieces of documentation that were missed and prevent new
users from appearing (or at least make them easy to grep for).

Link: https://lkml.kernel.org/r/20250514181508.3019795-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

5 files changed, 10 insertions, 10 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 09d005848f0d..bc244a2edc93 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -142,7 +142,7 @@ static void page_cache_delete(struct address_space *mapping,
 	xas_init_marks(&xas);
 
 	folio->mapping = NULL;
-	/* Leave page->index set: truncation lookup relies upon it */
+	/* Leave folio->index set: truncation lookup relies upon it */
 	mapping->nrpages -= nr;
 }
 
@@ -949,7 +949,7 @@ unlock:
 	return 0;
 error:
 	folio->mapping = NULL;
-	/* Leave page->index set: truncation relies upon it */
+	/* Leave folio->index set: truncation relies upon it */
 	folio_put_refs(folio, nr);
 	return xas_error(&xas);
 }
diff --git a/mm/memory.c b/mm/memory.c
index 5cb48f262ab0..37d8738f5e12 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4668,8 +4668,8 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
 
 		/*
 		 * KSM sometimes has to copy on read faults, for example, if
-		 * page->index of !PageKSM() pages would be nonlinear inside the
-		 * anon VMA -- PageKSM() is lost on actual swapout.
+		 * folio->index of non-ksm folios would be nonlinear inside the
+		 * anon VMA -- the ksm flag is lost on actual swapout.
 		 */
 		folio = ksm_might_need_to_copy(folio, vma, vmf->address);
 		if (unlikely(!folio)) {
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 9ff44b64d3d6..e8641aa1043e 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2565,11 +2565,11 @@ struct folio *writeback_iter(struct address_space *mapping,
 	if (!folio) {
 		/*
 		 * To avoid deadlocks between range_cyclic writeback and callers
-		 * that hold pages in PageWriteback to aggregate I/O until
+		 * that hold folios in writeback to aggregate I/O until
 		 * the writeback iteration finishes, we do not loop back to the
-		 * start of the file.  Doing so causes a page lock/page
+		 * start of the file.  Doing so causes a folio lock/folio
 		 * writeback access order inversion - we should only ever lock
-		 * multiple pages in ascending page->index order, and looping
+		 * multiple folios in ascending folio->index order, and looping
 		 * back to the start of the file violates that rule and causes
 		 * deadlocks.
 		 */
diff --git a/mm/truncate.c b/mm/truncate.c
index 5d98054094d1..3c1bcdc3a3e9 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -421,7 +421,7 @@ void truncate_inode_pages_range(struct address_space *mapping,
 		for (i = 0; i < folio_batch_count(&fbatch); i++) {
 			struct folio *folio = fbatch.folios[i];
 
-			/* We rely upon deletion not changing page->index */
+			/* We rely upon deletion not changing folio->index */
 
 			if (xa_is_value(folio))
 				continue;
diff --git a/mm/zpdesc.h b/mm/zpdesc.h
index 57e7a4d6c6ca..d3df316e5bb7 100644
--- a/mm/zpdesc.h
+++ b/mm/zpdesc.h
@@ -54,8 +54,8 @@ struct zpdesc {
 ZPDESC_MATCH(flags, flags);
 ZPDESC_MATCH(lru, lru);
 ZPDESC_MATCH(mapping, movable_ops);
-ZPDESC_MATCH(index, next);
-ZPDESC_MATCH(index, handle);
+ZPDESC_MATCH(__folio_index, next);
+ZPDESC_MATCH(__folio_index, handle);
 ZPDESC_MATCH(private, zspage);
 ZPDESC_MATCH(page_type, first_obj_offset);
 ZPDESC_MATCH(_refcount, _refcount);