From: Matthew Wilcox (Oracle) <willy@infradead.org>
Date: Fri, 7 May 2021 15:17:34 +0000 (-0400)
Subject: mm: Add folio_raw_mapping()
X-Git-Tag: v6.6.17~9013^2~38
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=646010009d3541b8cb4f803dcb4b8d0da2f22579;p=platform%2Fkernel%2Flinux-rpi.git

mm: Add folio_raw_mapping()

Convert __page_rmapping to folio_raw_mapping and move it to mm/internal.h.
It's only a couple of instructions (load and mask), so it's definitely
going to be cheaper to inline it than call it.  Leave page_rmapping
out of line.  Change page_anon_vma() to not call folio_raw_mapping() --
it's more efficient to do the subtraction than the mask.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---

diff --git a/mm/internal.h b/mm/internal.h
index 1a84484..187a032 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -34,6 +34,13 @@
 
 void page_writeback_init(void);
 
+static inline void *folio_raw_mapping(struct folio *folio)
+{
+	unsigned long mapping = (unsigned long)folio->mapping;
+
+	return (void *)(mapping & ~PAGE_MAPPING_FLAGS);
+}
+
 vm_fault_t do_swap_page(struct vm_fault *vmf);
 void folio_rotate_reclaimable(struct folio *folio);
 
diff --git a/mm/util.c b/mm/util.c
index e322a42..96a5e71 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -654,21 +654,10 @@ void *kvrealloc(const void *p, size_t oldsize, size_t newsize, gfp_t flags)
 }
 EXPORT_SYMBOL(kvrealloc);
 
-static inline void *__page_rmapping(struct page *page)
-{
-	unsigned long mapping;
-
-	mapping = (unsigned long)page->mapping;
-	mapping &= ~PAGE_MAPPING_FLAGS;
-
-	return (void *)mapping;
-}
-
 /* Neutral page->mapping pointer to address_space or anon_vma or other */
 void *page_rmapping(struct page *page)
 {
-	page = compound_head(page);
-	return __page_rmapping(page);
+	return folio_raw_mapping(page_folio(page));
 }
 
 /**
@@ -699,13 +688,12 @@ EXPORT_SYMBOL(folio_mapped);
 
 struct anon_vma *page_anon_vma(struct page *page)
 {
-	unsigned long mapping;
+	struct folio *folio = page_folio(page);
+	unsigned long mapping = (unsigned long)folio->mapping;
 
-	page = compound_head(page);
-	mapping = (unsigned long)page->mapping;
 	if ((mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON)
 		return NULL;
-	return __page_rmapping(page);
+	return (void *)(mapping - PAGE_MAPPING_ANON);
 }
 
 /**