linux-kernel - [RFC v2 06/10] mm: rename init_page_count() -> page_ref

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Date:   Wed, 17 Nov 2021 01:20:55 +0000
From:   Pasha Tatashin <pasha.tatashin@...een.com>
To:     pasha.tatashin@...een.com, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, linux-m68k@...ts.linux-m68k.org,
        anshuman.khandual@....com, willy@...radead.org,
        akpm@...ux-foundation.org, william.kucharski@...cle.com,
        mike.kravetz@...cle.com, vbabka@...e.cz, geert@...ux-m68k.org,
        schmitzmic@...il.com, rostedt@...dmis.org, mingo@...hat.com,
        hannes@...xchg.org, guro@...com, songmuchun@...edance.com,
        weixugc@...gle.com, gthelen@...gle.com, rientjes@...gle.com,
        pjt@...gle.com
Subject: [RFC v2 06/10] mm: rename init_page_count() -> page_ref_init()

Now, that set_page_count() is not called from outside anymore and about
to be removed, init_page_count() is the only function that is going to
be used to unconditionally set _refcount, however it is restricted to set
it only to 1.

Make init_page_count() aligned with the other page_ref_*
functions by renaming it.

Signed-off-by: Pasha Tatashin <pasha.tatashin@...een.com>
Acked-by: Geert Uytterhoeven <geert@...ux-m68k.org>
---
 arch/m68k/mm/motorola.c  |  2 +-
 include/linux/mm.h       |  2 +-
 include/linux/page_ref.h | 10 +++++++---
 mm/page_alloc.c          |  2 +-
 4 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/m68k/mm/motorola.c b/arch/m68k/mm/motorola.c
index 2b05bb2bac00..e81ecafedff3 100644
--- a/arch/m68k/mm/motorola.c
+++ b/arch/m68k/mm/motorola.c
@@ -133,7 +133,7 @@ void __init init_pointer_table(void *table, int type)
 
 	/* unreserve the page so it's possible to free that page */
 	__ClearPageReserved(PD_PAGE(dp));
-	init_page_count(PD_PAGE(dp));
+	page_ref_init(PD_PAGE(dp));
 
 	return;
 }
diff --git a/include/linux/mm.h b/include/linux/mm.h
index a7e4a9e7d807..736bf16e7104 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2506,7 +2506,7 @@ extern void reserve_bootmem_region(phys_addr_t start, phys_addr_t end);
 static inline void free_reserved_page(struct page *page)
 {
 	ClearPageReserved(page);
-	init_page_count(page);
+	page_ref_init(page);
 	__free_page(page);
 	adjust_managed_page_count(page, 1);
 }
diff --git a/include/linux/page_ref.h b/include/linux/page_ref.h
index 27880aca2e2f..ff946d753df8 100644
--- a/include/linux/page_ref.h
+++ b/include/linux/page_ref.h
@@ -107,10 +107,14 @@ static inline void folio_set_count(struct folio *folio, int v)
 }
 
 /*
- * Setup the page count before being freed into the page allocator for
- * the first time (boot or memory hotplug)
+ * Setup the page refcount to one before being freed into the page allocator.
+ * The memory might not be initialized and therefore there cannot be any
+ * assumptions about the current value of page->_refcount. This call should be
+ * done during boot when memory is being initialized, during memory hotplug
+ * when new memory is added, or when a previous reserved memory is unreserved
+ * this is the first time kernel take control of the given memory.
  */
-static inline void init_page_count(struct page *page)
+static inline void page_ref_init(struct page *page)
 {
 	set_page_count(page, 1);
 }
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 217c0c9fa25b..fc828dfde4fc 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1555,7 +1555,7 @@ static void __meminit __init_single_page(struct page *page, unsigned long pfn,
 {
 	mm_zero_struct_page(page);
 	set_page_links(page, zone, nid, pfn);
-	init_page_count(page);
+	page_ref_init(page);
 	page_mapcount_reset(page);
 	page_cpupid_reset_last(page);
 	page_kasan_tag_reset(page);
-- 
2.34.0.rc1.387.gb447b232ab-goog