[PATCH] mm: fix accounting of memmap pages for early sections

[Sumanth Korikkar <sumanthk@linux.ibm.com>]

memmap pages  can be allocated either from the memblock (boot) allocator
during early boot or from the buddy allocator.

When these memmap pages are removed via arch_remove_memory(), the
deallocation path depends on their source:

* For pages from the buddy allocator, depopulate_section_memmap() is
  called, which also decrements the count of nr_memmap_pages.

* For pages from the boot allocator, free_map_bootmem() is called. But
  it currently does not adjust the nr_memmap_boot_pages.

To fix this inconsistency, update free_map_bootmem() to also decrement
the nr_memmap_boot_pages count by invoking memmap_boot_pages_add(),
mirroring how free_vmemmap_page() handles this for boot-allocated pages.

This ensures correct tracking of memmap pages regardless of allocation
source.

Cc: stable@vger.kernel.org
Fixes: 15995a352474 ("mm: report per-page metadata information")
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
---
 mm/sparse.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/sparse.c b/mm/sparse.c
index 3c012cf83cc2..d7c128015397 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -688,6 +688,7 @@ static void free_map_bootmem(struct page *memmap)
 	unsigned long start = (unsigned long)memmap;
 	unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION);
 
+	memmap_boot_pages_add(-1L * (DIV_ROUND_UP(end - start, PAGE_SIZE)));
 	vmemmap_free(start, end, NULL);
 }
 
-- 
2.48.1