mm/memory_hotplug: factor out altmap freeing checks

Use a small helper to centralize altmap freeing after verifying that all
vmemmap pages were released.  This keeps the check consistent between the
normal teardown path and the memory hotplug error paths.

Link: https://lore.kernel.org/20260511084307.1827127-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Suggested-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Donet Tom <donettom@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 462d8dcd636dc9dd1a4a3683a1c9c24aaa89c897..af5489f03771b91da9ee27c6aebc72b18b23ecf9 100644 (file)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1403,6 +1403,12 @@ bool mhp_supports_memmap_on_memory(void)
 }
 EXPORT_SYMBOL_GPL(mhp_supports_memmap_on_memory);
 
+static void altmap_free(struct vmem_altmap *altmap)
+{
+       WARN_ONCE(altmap->alloc, "Altmap not fully unmapped");
+       kfree(altmap);
+}
+
 static void remove_memory_blocks_and_altmaps(u64 start, u64 size)
 {
        unsigned long memblock_size = memory_block_size_bytes();
@@ -1427,12 +1433,8 @@ static void remove_memory_blocks_and_altmaps(u64 start, u64 size)
                put_device(&mem->dev);
 
                remove_memory_block_devices(cur_start, memblock_size);
-
                arch_remove_memory(cur_start, memblock_size, altmap, NULL);
-
-               /* Verify that all vmemmap pages have actually been freed. */
-               WARN(altmap->alloc, "Altmap not fully unmapped");
-               kfree(altmap);
+               altmap_free(altmap);
        }
 }
 
@@ -1463,7 +1465,7 @@ static int create_altmaps_and_memory_blocks(int nid, struct memory_group *group,
                /* call arch's memory hotadd */
                ret = arch_add_memory(nid, cur_start, memblock_size, &params);
                if (ret < 0) {
-                       kfree(params.altmap);
+                       altmap_free(params.altmap);
                        goto out;
                }
 
@@ -1472,7 +1474,7 @@ static int create_altmaps_and_memory_blocks(int nid, struct memory_group *group,
                                                  params.altmap, group);
                if (ret) {
                        arch_remove_memory(cur_start, memblock_size, params.altmap, NULL);
-                       kfree(params.altmap);
+                       altmap_free(params.altmap);
                        goto out;
                }
        }