From: Qianli Zhao <zhaoqia...@xiaomi.com> There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2].
Make use of the struct_size() helper instead of an open-coded version in order to avoid any potential type mistakes. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://github.com/KSPP/linux/issues/21 Signed-off-by: Qianli Zhao <zhaoqia...@xiaomi.com> --- mm/slab.h | 2 +- mm/slab_common.c | 7 ++----- 2 files changed, 3 insertions(+), 6 deletions(-) diff --git a/mm/slab.h b/mm/slab.h index 74f7e09..c12fb65 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -34,7 +34,7 @@ struct kmem_cache { struct memcg_cache_array { struct rcu_head rcu; - struct kmem_cache *entries[0]; + struct kmem_cache *entries[]; }; /* diff --git a/mm/slab_common.c b/mm/slab_common.c index fe8b684..56f4818 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -166,9 +166,7 @@ static int init_memcg_params(struct kmem_cache *s, if (!memcg_nr_cache_ids) return 0; - arr = kvzalloc(sizeof(struct memcg_cache_array) + - memcg_nr_cache_ids * sizeof(void *), - GFP_KERNEL); + arr = kvzalloc(struct_size(arr, entries, memcg_nr_cache_ids), GFP_KERNEL); if (!arr) return -ENOMEM; @@ -199,8 +197,7 @@ static int update_memcg_params(struct kmem_cache *s, int new_array_size) { struct memcg_cache_array *old, *new; - new = kvzalloc(sizeof(struct memcg_cache_array) + - new_array_size * sizeof(void *), GFP_KERNEL); + new = kvzalloc(struct_size(new, entries, new_array_size), GFP_KERNEL); if (!new) return -ENOMEM; -- 2.7.4
