mm/sparse: drop set_section_nid() from sparse_add_section()

CONFIG_MEMORY_HOTPLUG is CONFIG_SPARSEMEM_VMEMMAP-only.  And
CONFIG_SPARSEMEM_VMEMMAP implies that NODE_NOT_IN_PAGE_FLAGS cannot be
set: see include/linux/page-flags-layout.h

	...
	#elif defined(CONFIG_SPARSEMEM_VMEMMAP)
	#error "Vmemmap: No space for nodes field in page flags"
	...

Which implies that the node is always stored in page flags and
NODE_NOT_IN_PAGE_FLAGS cannot be set.  Therefore, set_section_nid() is a
NOP on CONFIG_SPARSEMEM_VMEMMAP.

So let's remove the set_section_nid() call to prepare for moving
CONFIG_MEMORY_HOTPLUG to mm/sparse-vmemmap.c

Link: https://lkml.kernel.org/r/20260320-sparsemem_cleanups-v2-12-096addc8800d@kernel.org
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/sparse.c b/mm/sparse.c
index c96ac5e70c222d84fa8dbd86b6825f00b0d2fb46..5c9cad390282af67fd0f92c28f2ec458d479589a 100644 (file)
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -765,7 +765,6 @@ int __meminit sparse_add_section(int nid, unsigned long start_pfn,
        page_init_poison(memmap, sizeof(struct page) * nr_pages);
 
        ms = __nr_to_section(section_nr);
-       set_section_nid(section_nr, nid);
        __section_mark_present(ms, section_nr);
 
        /* Align memmap to section boundary in the subsection case */