skbuff: allow to optionally use NAPI cache from __alloc_skb()

Reuse the old and forgotten SKB_ALLOC_NAPI to add an option to get
an skbuff_head from the NAPI cache instead of inplace allocation
inside __alloc_skb().
This implies that the function is called from softirq or BH-off
context, not for allocating a clone or from a distant node.

Cc: Alexander Duyck <alexander.duyck@gmail.com> # Simplified flags check
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 9e1a8ded4accb6d20f2b4373cee644aaaaeeb4e6..a80581eed7fc04d68652b4613adf83226c6126c5 100644 (file)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -405,7 +405,11 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
                gfp_mask |= __GFP_MEMALLOC;
 
        /* Get the HEAD */
-       skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node);
+       if ((flags & (SKB_ALLOC_FCLONE | SKB_ALLOC_NAPI)) == SKB_ALLOC_NAPI &&
+           likely(node == NUMA_NO_NODE || node == numa_mem_id()))
+               skb = napi_skb_cache_get();
+       else
+               skb = kmem_cache_alloc_node(cache, gfp_mask & ~GFP_DMA, node);
        if (unlikely(!skb))
                return NULL;
        prefetchw(skb);