diff options
Diffstat (limited to 'net/core/skbuff.c')
| -rw-r--r-- | net/core/skbuff.c | 32 |
1 files changed, 22 insertions, 10 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index a56133902c0d..4887099e8678 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -307,6 +307,23 @@ static struct sk_buff *napi_skb_cache_get(bool alloc) return skb; } +/* + * Only clear those fields we need to clear, not those that we will + * actually initialise later. Hence, don't put any more fields after + * the tail pointer in struct sk_buff! + */ +static inline void skbuff_clear(struct sk_buff *skb) +{ + /* Replace memset(skb, 0, offsetof(struct sk_buff, tail)) + * with two smaller memset(), with a barrier() between them. + * This forces the compiler to inline both calls. + */ + BUILD_BUG_ON(offsetof(struct sk_buff, tail) <= 128); + memset(skb, 0, 128); + barrier(); + memset((void *)skb + 128, 0, offsetof(struct sk_buff, tail) - 128); +} + /** * napi_skb_cache_get_bulk - obtain a number of zeroed skb heads from the cache * @skbs: pointer to an at least @n-sized array to fill with skb pointers @@ -357,7 +374,7 @@ get: skbs[i] = nc->skb_cache[base + i]; kasan_mempool_unpoison_object(skbs[i], skbuff_cache_size); - memset(skbs[i], 0, offsetof(struct sk_buff, tail)); + skbuff_clear(skbs[i]); } nc->skb_count -= n; @@ -424,7 +441,7 @@ struct sk_buff *slab_build_skb(void *data) if (unlikely(!skb)) return NULL; - memset(skb, 0, offsetof(struct sk_buff, tail)); + skbuff_clear(skb); data = __slab_build_skb(data, &size); __finalize_skb_around(skb, data, size); @@ -476,7 +493,7 @@ struct sk_buff *__build_skb(void *data, unsigned int frag_size) if (unlikely(!skb)) return NULL; - memset(skb, 0, offsetof(struct sk_buff, tail)); + skbuff_clear(skb); __build_skb_around(skb, data, frag_size); return skb; @@ -537,7 +554,7 @@ static struct sk_buff *__napi_build_skb(void *data, unsigned int frag_size) if (unlikely(!skb)) return NULL; - memset(skb, 0, offsetof(struct sk_buff, tail)); + skbuff_clear(skb); __build_skb_around(skb, data, frag_size); return skb; @@ -696,12 +713,7 @@ fallback: */ prefetchw(data + SKB_WITH_OVERHEAD(size)); - /* - * Only clear those fields we need to clear, not those that we will - * actually initialise below. Hence, don't put any more fields after - * the tail pointer in struct sk_buff! - */ - memset(skb, 0, offsetof(struct sk_buff, tail)); + skbuff_clear(skb); __build_skb_around(skb, data, size); skb->pfmemalloc = pfmemalloc; |