The patch titled
Subject: mm: make compound_head const-preserving
has been removed from the -mm tree. Its filename was
mm-make-compound_head-const-preserving.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm: make compound_head const-preserving
If you pass a const pointer to compound_head(), you get a const pointer
back; if you pass a mutable pointer, you get a mutable pointer back. Also
remove an unnecessary forward definition of struct page; we're about to
dereference page->compound_head, so it must already have been defined.
Link: https://lkml.kernel.org/r/20210416231531.2521383-5-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>
Reviewed-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Reviewed-by: William Kucharski <william.kucharski@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/page-flags.h | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
--- a/include/linux/page-flags.h~mm-make-compound_head-const-preserving
+++ a/include/linux/page-flags.h
@@ -177,17 +177,17 @@ enum pageflags {
#ifndef __GENERATING_BOUNDS_H
-struct page; /* forward declaration */
-
-static inline struct page *compound_head(struct page *page)
+static inline unsigned long _compound_head(const struct page *page)
{
unsigned long head = READ_ONCE(page->compound_head);
if (unlikely(head & 1))
- return (struct page *) (head - 1);
- return page;
+ return head - 1;
+ return (unsigned long)page;
}
+#define compound_head(page) ((typeof(page))_compound_head(page))
+
static __always_inline int PageTail(struct page *page)
{
return READ_ONCE(page->compound_head) & 1;
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-mark-idle-page-tracking-as-broken.patch
