[PATCH] mm/memblock: drop redundant 'struct page *' argument from memblock_free_pages()

[PATCH] mm/memblock: drop redundant 'struct page *' argument from memblock_free_pages()

[shengminghu512]

From: Shengming Hu <hu.shengming@zte.com.cn>

memblock_free_pages() currently takes both a struct page * and the
corresponding PFN. The page pointer is always derived from the PFN at
call sites (pfn_to_page(pfn)), making the parameter redundant and also
allowing accidental mismatches between the two arguments.

Simplify the interface by removing the struct page * argument and
deriving the page locally from the PFN, after the deferred struct page
initialization check. This keeps the behavior unchanged while making
the helper harder to misuse.

Signed-off-by: Shengming Hu <hu.shengming@zte.com.cn>
---
 mm/internal.h                     | 3 +--
 mm/memblock.c                     | 4 ++--
 mm/mm_init.c                      | 7 +++++--
 tools/testing/memblock/internal.h | 3 +--
 4 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/mm/internal.h b/mm/internal.h
index e430da900..5f93ee145 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -742,8 +742,7 @@ static inline void clear_zone_contiguous(struct zone *zone)
 extern int __isolate_free_page(struct page *page, unsigned int order);
 extern void __putback_isolated_page(struct page *page, unsigned int order,
 				    int mt);
-extern void memblock_free_pages(struct page *page, unsigned long pfn,
-					unsigned int order);
+extern void memblock_free_pages(unsigned long pfn, unsigned int order);
 extern void __free_pages_core(struct page *page, unsigned int order,
 		enum meminit_context context);
 
diff --git a/mm/memblock.c b/mm/memblock.c
index 905d06b16..6e11f81c4 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1771,7 +1771,7 @@ void __init memblock_free_late(phys_addr_t base, phys_addr_t size)
 	end = PFN_DOWN(base + size);
 
 	for (; cursor < end; cursor++) {
-		memblock_free_pages(pfn_to_page(cursor), cursor, 0);
+		memblock_free_pages(cursor, 0);
 		totalram_pages_inc();
 	}
 }
@@ -2216,7 +2216,7 @@ static void __init __free_pages_memory(unsigned long start, unsigned long end)
 		while (start + (1UL << order) > end)
 			order--;
 
-		memblock_free_pages(pfn_to_page(start), start, order);
+		memblock_free_pages(start, order);
 
 		start += (1UL << order);
 	}
diff --git a/mm/mm_init.c b/mm/mm_init.c
index fc2a6f1e5..8e95d65cf 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -2480,9 +2480,10 @@ void *__init alloc_large_system_hash(const char *tablename,
 	return table;
 }
 
-void __init memblock_free_pages(struct page *page, unsigned long pfn,
-							unsigned int order)
+void __init memblock_free_pages(unsigned long pfn, unsigned int order)
 {
+	struct page *page;
+
 	if (IS_ENABLED(CONFIG_DEFERRED_STRUCT_PAGE_INIT)) {
 		int nid = early_pfn_to_nid(pfn);
 
@@ -2490,6 +2491,8 @@ void __init memblock_free_pages(struct page *page, unsigned long pfn,
 			return;
 	}
 
+	page = pfn_to_page(pfn);
+
 	if (!kmsan_memblock_free_pages(page, order)) {
 		/* KMSAN will take care of these pages. */
 		return;
diff --git a/tools/testing/memblock/internal.h b/tools/testing/memblock/internal.h
index 0ab4b53bb..009b97bbd 100644
--- a/tools/testing/memblock/internal.h
+++ b/tools/testing/memblock/internal.h
@@ -15,8 +15,7 @@ bool mirrored_kernelcore = false;
 
 struct page {};
 
-void memblock_free_pages(struct page *page, unsigned long pfn,
-			 unsigned int order)
+void memblock_free_pages(unsigned long pfn, unsigned int order)
 {
 }
 
-- 
2.25.1

Re: [PATCH] mm/memblock: drop redundant 'struct page *' argument from memblock_free_pages()

[Mike Rapoport]

On Sun, Dec 28, 2025 at 07:38:50PM +0800, shengminghu512 wrote:
> From: Shengming Hu <hu.shengming@zte.com.cn>
> 
> memblock_free_pages() currently takes both a struct page * and the
> corresponding PFN. The page pointer is always derived from the PFN at
> call sites (pfn_to_page(pfn)), making the parameter redundant and also
> allowing accidental mismatches between the two arguments.
> 
> Simplify the interface by removing the struct page * argument and
> deriving the page locally from the PFN, after the deferred struct page
> initialization check. This keeps the behavior unchanged while making
> the helper harder to misuse.
> 
> Signed-off-by: Shengming Hu <hu.shengming@zte.com.cn>
> ---
>  mm/internal.h                     | 3 +--
>  mm/memblock.c                     | 4 ++--
>  mm/mm_init.c                      | 7 +++++--
>  tools/testing/memblock/internal.h | 3 +--
>  4 files changed, 9 insertions(+), 8 deletions(-)
> 
> --- a/mm/mm_init.c
> +++ b/mm/mm_init.c
> @@ -2480,9 +2480,10 @@ void *__init alloc_large_system_hash(const char *tablename,
>  	return table;
>  }
>  
> -void __init memblock_free_pages(struct page *page, unsigned long pfn,
> -							unsigned int order)
> +void __init memblock_free_pages(unsigned long pfn, unsigned int order)
>  {
> +	struct page *page;

page can be initialized here, the compiler should figure out how to avoid
extra instructions.

> +
>  	if (IS_ENABLED(CONFIG_DEFERRED_STRUCT_PAGE_INIT)) {
>  		int nid = early_pfn_to_nid(pfn);
>  
> @@ -2490,6 +2491,8 @@ void __init memblock_free_pages(struct page *page, unsigned long pfn,
>  			return;
>  	}
>  
> +	page = pfn_to_page(pfn);
> +
>  	if (!kmsan_memblock_free_pages(page, order)) {
>  		/* KMSAN will take care of these pages. */
>  		return;

-- 
Sincerely yours,
Mike.