diff options
| -rw-r--r-- | include/linux/skbuff.h | 1 | ||||
| -rw-r--r-- | net/core/skbuff.c | 62 |
2 files changed, 63 insertions, 0 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 171aa15f6541..14517e95a46c 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1320,6 +1320,7 @@ struct sk_buff *build_skb_around(struct sk_buff *skb, void *data, unsigned int frag_size); void skb_attempt_defer_free(struct sk_buff *skb); +u32 napi_skb_cache_get_bulk(void **skbs, u32 n); struct sk_buff *napi_build_skb(void *data, unsigned int frag_size); struct sk_buff *slab_build_skb(void *data); diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 5b241c9e6f38..f12815f9c83d 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -295,6 +295,68 @@ static struct sk_buff *napi_skb_cache_get(void) return skb; } +/** + * 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 + * @n: number of entries to provide + * + * Tries to obtain @n &sk_buff entries from the NAPI percpu cache and writes + * the pointers into the provided array @skbs. If there are less entries + * available, tries to replenish the cache and bulk-allocates the diff from + * the MM layer if needed. + * The heads are being zeroed with either memset() or %__GFP_ZERO, so they are + * ready for {,__}build_skb_around() and don't have any data buffers attached. + * Must be called *only* from the BH context. + * + * Return: number of successfully allocated skbs (@n if no actual allocation + * needed or kmem_cache_alloc_bulk() didn't fail). + */ +u32 napi_skb_cache_get_bulk(void **skbs, u32 n) +{ + struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache); + u32 bulk, total = n; + + local_lock_nested_bh(&napi_alloc_cache.bh_lock); + + if (nc->skb_count >= n) + goto get; + + /* No enough cached skbs. Try refilling the cache first */ + bulk = min(NAPI_SKB_CACHE_SIZE - nc->skb_count, NAPI_SKB_CACHE_BULK); + nc->skb_count += kmem_cache_alloc_bulk(net_hotdata.skbuff_cache, + GFP_ATOMIC | __GFP_NOWARN, bulk, + &nc->skb_cache[nc->skb_count]); + if (likely(nc->skb_count >= n)) + goto get; + + /* Still not enough. Bulk-allocate the missing part directly, zeroed */ + n -= kmem_cache_alloc_bulk(net_hotdata.skbuff_cache, + GFP_ATOMIC | __GFP_ZERO | __GFP_NOWARN, + n - nc->skb_count, &skbs[nc->skb_count]); + if (likely(nc->skb_count >= n)) + goto get; + + /* kmem_cache didn't allocate the number we need, limit the output */ + total -= n - nc->skb_count; + n = nc->skb_count; + +get: + for (u32 base = nc->skb_count - n, i = 0; i < n; i++) { + u32 cache_size = kmem_cache_size(net_hotdata.skbuff_cache); + + skbs[i] = nc->skb_cache[base + i]; + + kasan_mempool_unpoison_object(skbs[i], cache_size); + memset(skbs[i], 0, offsetof(struct sk_buff, tail)); + } + + nc->skb_count -= n; + local_unlock_nested_bh(&napi_alloc_cache.bh_lock); + + return total; +} +EXPORT_SYMBOL_GPL(napi_skb_cache_get_bulk); + static inline void __finalize_skb_around(struct sk_buff *skb, void *data, unsigned int size) { |