[PATCH net-next] skbuff: remove some unnecessary operation in skb_segment_list()
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From: Yunsheng Lin <linyunsheng@huawei.com> gro list uses skb_shinfo(skb)->frag_list to link two skb together, and NAPI_GRO_CB(p)->last->next is used when there are more skb, see skb_gro_receive_list(). gso expects that each segmented skb is linked together using skb->next, so only the first skb->next need to set to skb_shinfo(skb)-> frag_list when doing gso list segment. It is the same reason that nskb->next does not need to be set to list_skb before goto the error handling, because nskb->next already pointers to list_skb. And nskb is also the last skb at the end of loop, so remove tail variable and use nskb instead. Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com> --- net/core/skbuff.c | 15 +++------------ 1 file changed, 3 insertions(+), 12 deletions(-) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index c421c8f..e8320b5 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -3732,13 +3732,13 @@ struct sk_buff *skb_segment_list(struct sk_buff *skb, unsigned int tnl_hlen = skb_tnl_header_len(skb); unsigned int delta_truesize = 0; unsigned int delta_len = 0; - struct sk_buff *tail = NULL; struct sk_buff *nskb, *tmp; int err; skb_push(skb, -skb_network_offset(skb) + offset); skb_shinfo(skb)->frag_list = NULL; + skb->next = list_skb; do { nskb = list_skb; @@ -3756,17 +3756,8 @@ struct sk_buff *skb_segment_list(struct sk_buff *skb, } } - if (!tail) - skb->next = nskb; - else - tail->next = nskb; - - if (unlikely(err)) { - nskb->next = list_skb; + if (unlikely(err)) goto err_linearize; - } - - tail = nskb; delta_len += nskb->len; delta_truesize += nskb->truesize; @@ -3793,7 +3784,7 @@ struct sk_buff *skb_segment_list(struct sk_buff *skb, skb_gso_reset(skb); - skb->prev = tail; + skb->prev = nskb; if (skb_needs_linearize(skb, features) && __skb_linearize(skb)) -- 2.7.4
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Hello: This patch was applied to netdev/net-next.git (refs/heads/master): On Wed, 10 Mar 2021 16:28:58 +0800 you wrote:
From: Yunsheng Lin <linyunsheng@huawei.com>
gro list uses skb_shinfo(skb)->frag_list to link two skb together, and NAPI_GRO_CB(p)->last->next is used when there are more skb, see skb_gro_receive_list(). gso expects that each segmented skb is linked together using skb->next, so only the first skb->next need to set to skb_shinfo(skb)-> frag_list when doing gso list segment.
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Here is the summary with links: - [net-next] skbuff: remove some unnecessary operation in skb_segment_list() https://git.kernel.org/netdev/net-next/c/1ddc3229ad3c You are awesome, thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html
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