From b4601d096aac8ed26afa88ef8b249975b0530ca1 Mon Sep 17 00:00:00 2001 From: Suren Baghdasaryan Date: Fri, 14 Jun 2024 15:59:51 -0700 Subject: [PATCH] mm/slab: fix 'variable obj_exts set but not used' warning slab_post_alloc_hook() uses prepare_slab_obj_exts_hook() to obtain slabobj_ext object. Currently the only user of slabobj_ext object in this path is memory allocation profiling, therefore when it's not enabled this object is not needed. This also generates a warning when compiling with CONFIG_MEM_ALLOC_PROFILING=n. Move the code under this configuration to fix the warning. If more slabobj_ext users appear in the future, the code will have to be changed back to call prepare_slab_obj_exts_hook(). Link: https://lkml.kernel.org/r/20240614225951.3845577-1-surenb@google.com Fixes: 4b8736964640 ("mm/slab: add allocation accounting into slab allocation and free paths") Signed-off-by: Suren Baghdasaryan Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202406150444.F6neSaiy-lkp@intel.com/ Cc: Kent Overstreet Cc: Kees Cook Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- mm/slub.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 1373ac365a46..4927edec6a8c 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3902,7 +3902,6 @@ bool slab_post_alloc_hook(struct kmem_cache *s, struct list_lru *lru, unsigned int orig_size) { unsigned int zero_size = s->object_size; - struct slabobj_ext *obj_exts; bool kasan_init = init; size_t i; gfp_t init_flags = flags & gfp_allowed_mask; @@ -3945,9 +3944,11 @@ bool slab_post_alloc_hook(struct kmem_cache *s, struct list_lru *lru, kmemleak_alloc_recursive(p[i], s->object_size, 1, s->flags, init_flags); kmsan_slab_alloc(s, p[i], init_flags); - if (need_slab_obj_ext()) { - obj_exts = prepare_slab_obj_exts_hook(s, flags, p[i]); #ifdef CONFIG_MEM_ALLOC_PROFILING + if (need_slab_obj_ext()) { + struct slabobj_ext *obj_exts; + + obj_exts = prepare_slab_obj_exts_hook(s, flags, p[i]); /* * Currently obj_exts is used only for allocation profiling. * If other users appear then mem_alloc_profiling_enabled() @@ -3955,8 +3956,8 @@ bool slab_post_alloc_hook(struct kmem_cache *s, struct list_lru *lru, */ if (likely(obj_exts)) alloc_tag_add(&obj_exts->ref, current->alloc_tag, s->size); -#endif } +#endif } return memcg_slab_post_alloc_hook(s, lru, flags, size, p);