From: Sang-Heon Jeon <ekffu200098@gmail.com>
Date: Sun, 19 Apr 2026 14:42:25 +0000 (+0900)
Subject: mm/sparse: remove unnecessary NULL check before allocating mem_section
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=e0974347f5bbf5f869d616779684a5ed8337c27b;p=thirdparty%2Flinux.git

mm/sparse: remove unnecessary NULL check before allocating mem_section

Commit 850ed20539a4 ("mm: move array mem_section init code out of
memory_present()") moved mem_section allocation logic into
memblocks_present().

Before that move, memory_present() could be called multiple times, so
unlikely() matched the common case, where most calls found mem_section
already allocated.

After that move, memblocks_present() is called exactly once from
sparse_init().  Under CONFIG_SPARSEMEM_EXTREME, mem_section is always NULL
when it is called.

So remove unnecessary NULL check before allocating mem_section.  No
functional change.

Link: https://lore.kernel.org/20260419144225.2875654-1-ekffu200098@gmail.com
Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed by: Donet Tom <donettom@linux.ibm.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/sparse.c b/mm/sparse.c
index effdac6b0ab1..e13f9f5fa090 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -201,13 +201,11 @@ static void __init memblocks_present(void)
 	int i, nid;
 
 #ifdef CONFIG_SPARSEMEM_EXTREME
-	if (unlikely(!mem_section)) {
-		unsigned long size, align;
+	unsigned long size, align;
 
-		size = sizeof(struct mem_section *) * NR_SECTION_ROOTS;
-		align = 1 << (INTERNODE_CACHE_SHIFT);
-		mem_section = memblock_alloc_or_panic(size, align);
-	}
+	size = sizeof(struct mem_section *) * NR_SECTION_ROOTS;
+	align = 1 << (INTERNODE_CACHE_SHIFT);
+	mem_section = memblock_alloc_or_panic(size, align);
 #endif
 
 	for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid)