net: skbuff: update and rename __kfree_skb_defer()

__kfree_skb_defer() uses the old naming where "defer" meant
slab bulk free/alloc APIs. In the meantime we also made
__kfree_skb_defer() feed the per-NAPI skb cache, which
implies bulk APIs. So take away the 'defer' and add 'napi'.

While at it add a drop reason. This only matters on the
tx_action path, if the skb has a frag_list. But getting
rid of a SKB_DROP_REASON_NOT_SPECIFIED seems like a net
benefit so why not.

Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://lore.kernel.org/r/20230420020005.815854-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/linux/skbuff.h

@@ -3253,7 +3253,7 @@ static inline struct sk_buff *napi_alloc_skb(struct napi_struct *napi,
 void napi_consume_skb(struct sk_buff *skb, int budget);
 
 void napi_skb_free_stolen_head(struct sk_buff *skb);
-void __kfree_skb_defer(struct sk_buff *skb);
+void __napi_kfree_skb(struct sk_buff *skb, enum skb_drop_reason reason);
 
 /**
  * __dev_alloc_pages - allocate page for network Rx

net/core/dev.c

@@ -5040,7 +5040,8 @@ static __latent_entropy void net_tx_action(struct softirq_action *h)
 			if (skb->fclone != SKB_FCLONE_UNAVAILABLE)
 				__kfree_skb(skb);
 			else
-				__kfree_skb_defer(skb);
+				__napi_kfree_skb(skb,
+						 get_kfree_skb_cb(skb)->reason);
 		}
 	}
 

net/core/gro.c

@@ -633,7 +633,7 @@ static gro_result_t napi_skb_finish(struct napi_struct *napi,
 		else if (skb->fclone != SKB_FCLONE_UNAVAILABLE)
 			__kfree_skb(skb);
 		else
-			__kfree_skb_defer(skb);
+			__napi_kfree_skb(skb, SKB_CONSUMED);
 		break;
 
 	case GRO_HELD:

net/core/skbuff.c

@@ -1226,9 +1226,9 @@ static void napi_skb_cache_put(struct sk_buff *skb)
 	}
 }
 
-void __kfree_skb_defer(struct sk_buff *skb)
+void __napi_kfree_skb(struct sk_buff *skb, enum skb_drop_reason reason)
 {
-	skb_release_all(skb, SKB_DROP_REASON_NOT_SPECIFIED, true);
+	skb_release_all(skb, reason, true);
 	napi_skb_cache_put(skb);
 }