[PATCH v2 4/9] mm: move free_reserved_area() to mm/memblock.c

Mike Rapoport
2026-03-23T07:49:35Z

free_reserved_area() is related to memblock as it frees reserved memory
back to the buddy allocator, similar to what memblock_free_late() does.

Move free_reserved_area() to mm/memblock.c to prepare for further
consolidation of the functions that free reserved memory.

No functional changes.

Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---
mm/memblock.c | 37 ++++++++++++++++++++++++++++++-
mm/page_alloc.c | 36 ------------------------------
tools/include/linux/mm.h | 1 +
tools/testing/memblock/internal.h | 34 +++++++++++++++++++++++++---
4 files changed, 68 insertions(+), 40 deletions(-)

diff --git a/mm/memblock.c b/mm/memblock.c
index d4a02f1750e9..c0896efbee97 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -893,6 +893,42 @@ int __init_memblock memblock_remove(phys_addr_t base, phys_addr_t size)
return memblock_remove_range(&memblock.memory, base, size);
}

+unsigned long free_reserved_area(void *start, void *end, int poison, const char *s)
+{
+ void *pos;
+ unsigned long pages = 0;
+
+ start = (void *)PAGE_ALIGN((unsigned long)start);
+ end = (void *)((unsigned long)end & PAGE_MASK);
+ for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
+ struct page *page = virt_to_page(pos);
+ void *direct_map_addr;
+
+ /*
+ * 'direct_map_addr' might be different from 'pos'
+ * because some architectures' virt_to_page()
+ * work with aliases. Getting the direct map
+ * address ensures that we get a _writeable_
+ * alias for the memset().
+ */
+ direct_map_addr = page_address(page);
+ /*
+ * Perform a kasan-unchecked memset() since this memory
+ * has not been initialized.
+ */
+ direct_map_addr = kasan_reset_tag(direct_map_addr);
+ if ((unsigned int)poison <= 0xFF)
+ memset(direct_map_addr, poison, PAGE_SIZE);
+
+ free_reserved_page(page);
+ }
+
+ if (pages && s)
+ pr_info("Freeing %s memory: %ldK\n", s, K(pages));
+
+ return pages;
+}
+
/**
* memblock_free - free boot memory allocation
* @ptr: starting address of the boot memory allocation
@@ -1776,7 +1812,6 @@ void __init memblock_free_late(phys_addr_t base, phys_addr_t size)
totalram_pages_inc();
}
}
-
/*
* Remaining API functions
*/
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2d4b6f1a554e..df3d61253001 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6234,42 +6234,6 @@ void adjust_managed_page_count(struct page *page, long count)
}
EXPORT_SYMBOL(adjust_managed_page_count);

-unsigned long free_reserved_area(void *start, void *end, int poison, const char *s)
-{
- void *pos;
- unsigned long pages = 0;
-
- start = (void *)PAGE_ALIGN((unsigned long)start);
- end = (void *)((unsigned long)end & PAGE_MASK);
- for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
- struct page *page = virt_to_page(pos);
- void *direct_map_addr;
-
- /*
- * 'direct_map_addr' might be different from 'pos'
- * because some architectures' virt_to_page()
- * work with aliases. Getting the direct map
- * address ensures that we get a _writeable_
- * alias for the memset().
- */
- direct_map_addr = page_address(page);
- /*
- * Perform a kasan-unchecked memset() since this memory
- * has not been initialized.
- */
- direct_map_addr = kasan_reset_tag(direct_map_addr);
- if ((unsigned int)poison <= 0xFF)
- memset(direct_map_addr, poison, PAGE_SIZE);
-
- free_reserved_page(page);
- }
-
- if (pages && s)
- pr_info("Freeing %s memory: %ldK\n", s, K(pages));
-
- return pages;
-}
-
void free_reserved_page(struct page *page)
{
clear_page_tag_ref(page);
diff --git a/tools/include/linux/mm.h b/tools/include/linux/mm.h
index 028f3faf46e7..4407d8396108 100644
--- a/tools/include/linux/mm.h
+++ b/tools/include/linux/mm.h
@@ -17,6 +17,7 @@

#define __va(x) ((void *)((unsigned long)(x)))
#define __pa(x) ((unsigned long)(x))
+#define __pa_symbol(x) ((unsigned long)(x))

#define pfn_to_page(pfn) ((void *)((pfn) * PAGE_SIZE))

diff --git a/tools/testing/memblock/internal.h b/tools/testing/memblock/internal.h
index 009b97bbdd22..b72be2968104 100644
--- a/tools/testing/memblock/internal.h
+++ b/tools/testing/memblock/internal.h
@@ -11,9 +11,22 @@ static int memblock_debug = 1;

#define pr_warn_ratelimited(fmt, ...) printf(fmt, ##__VA_ARGS__)

+#define K(x) ((x) << (PAGE_SHIFT-10))
+
bool mirrored_kernelcore = false;

struct page {};
+static inline void *page_address(struct page *page)
+{
+ BUG();
+ return page;
+}
+
+static inline struct page *virt_to_page(void *virt)
+{
+ BUG();
+ return virt;
+}

void memblock_free_pages(unsigned long pfn, unsigned int order)
{
@@ -23,10 +36,25 @@ static inline void accept_memory(phys_addr_t start, unsigned long size)
{
}

-static inline unsigned long free_reserved_area(void *start, void *end,
- int poison, const char *s)
+unsigned long free_reserved_area(void *start, void *end, int poison, const char *s);
+void free_reserved_page(struct page *page);
+
+static inline bool deferred_pages_enabled(void)
+{
+ return false;
+}
+
+#define for_each_valid_pfn(pfn, start_pfn, end_pfn) \
+ for ((pfn) = (start_pfn); (pfn) < (end_pfn); (pfn)++)
+
+static inline void *kasan_reset_tag(const void *addr)
+{
+ return (void *)addr;
+}
+
+static inline bool __is_kernel(unsigned long addr)
{
- return 0;
+ return false;
}

#endif
--
2.53.0