[PATCH v2 02/13] mm/slub: skip handle_failed_objexts_alloc() with profiling disabled

["Vlastimil Babka (SUSE)" <vbabka@kernel.org>]

The function might get called with memory allocation profiling disabled,
when the obj_ext array is allocated for objcg pointers only. The
handling is however unnecessary in that case, so skip it.

This would otherwise become a real bug later, as pointed out by sashiko.
For now it's just an optimization.

Link: https://sashiko.dev/#/patchset/20260715-b4-objext_split-v1-0-9a49c4ccf4c3@kernel.org?part=10
Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
---
 mm/slub.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 76acb78f2655..95fa6fbad11a 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2101,15 +2101,16 @@ static inline bool mark_failed_objexts_alloc(struct slab *slab)
 static inline void handle_failed_objexts_alloc(unsigned long obj_exts,
 			struct slabobj_ext *vec, unsigned int objects)
 {
+	if (!mem_alloc_profiling_enabled())
+		return;
+
 	/*
 	 * If vector previously failed to allocate then we have live
 	 * objects with no tag reference. Mark all references in this
 	 * vector as empty to avoid warnings later on.
 	 */
 	if (obj_exts == OBJEXTS_ALLOC_FAIL) {
-		unsigned int i;
-
-		for (i = 0; i < objects; i++)
+		for (unsigned int i = 0; i < objects; i++)
 			set_codetag_empty(&vec[i].ref);
 	}
 }

-- 
2.55.0