From: Edward Cree <ecree@solarflare.com>
Date: Mon, 2 Jul 2018 16:14:44 +0100
Subject: net: don't bother calling list RX functions on empty lists
Patch-mainline: v4.19-rc1
Git-commit: b9f463d6c9849230043123a6335d59ac7fea4d5a
References: bsc#1109837
Generally the check should be very cheap, as the sk_buff_head is in cache.
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
net/core/dev.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4862,7 +4862,8 @@ static void __netif_receive_skb_list(str
/* Handle the previous sublist */
list_cut_before(&sublist, head, &skb->list);
- __netif_receive_skb_list_core(&sublist, pfmemalloc);
+ if (!list_empty(&sublist))
+ __netif_receive_skb_list_core(&sublist, pfmemalloc);
pfmemalloc = !pfmemalloc;
/* See comments in __netif_receive_skb */
if (pfmemalloc)
@@ -4872,7 +4873,8 @@ static void __netif_receive_skb_list(str
}
}
/* Handle the remaining sublist */
- __netif_receive_skb_list_core(head, pfmemalloc);
+ if (!list_empty(head))
+ __netif_receive_skb_list_core(head, pfmemalloc);
/* Restore pflags */
if (pfmemalloc)
memalloc_noreclaim_restore(noreclaim_flag);
@@ -5033,6 +5035,8 @@ void netif_receive_skb_list(struct list_
{
struct sk_buff *skb;
+ if (list_empty(head))
+ return;
list_for_each_entry(skb, head, list)
trace_netif_receive_skb_list_entry(skb);
netif_receive_skb_list_internal(head);