2022-11-08 13:02:18

by Richard Gobert

Subject: [PATCH net-next v2] gro: avoid checking for a failed search

After searching for a protocol handler in dev_gro_receive, checking for
failure is redundant. Skip the failure code after finding the
corresponding handler.

Suggested-by: Eric Dumazet <[email protected]>
Signed-off-by: Richard Gobert <[email protected]>
---
net/core/gro.c | 72 +++++++++++++++++++++++++-------------------------
1 file changed, 36 insertions(+), 36 deletions(-)

diff --git a/net/core/gro.c b/net/core/gro.c
index bc9451743307..8e0fe85a647d 100644
--- a/net/core/gro.c
+++ b/net/core/gro.c
@@ -489,45 +489,45 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff

rcu_read_lock();
list_for_each_entry_rcu(ptype, head, list) {
- if (ptype->type != type || !ptype->callbacks.gro_receive)
- continue;
-
- skb_set_network_header(skb, skb_gro_offset(skb));
- skb_reset_mac_len(skb);
- BUILD_BUG_ON(sizeof_field(struct napi_gro_cb, zeroed) != sizeof(u32));
- BUILD_BUG_ON(!IS_ALIGNED(offsetof(struct napi_gro_cb, zeroed),
- sizeof(u32))); /* Avoid slow unaligned acc */
- *(u32 *)&NAPI_GRO_CB(skb)->zeroed = 0;
- NAPI_GRO_CB(skb)->flush = skb_has_frag_list(skb);
- NAPI_GRO_CB(skb)->is_atomic = 1;
- NAPI_GRO_CB(skb)->count = 1;
- if (unlikely(skb_is_gso(skb))) {
- NAPI_GRO_CB(skb)->count = skb_shinfo(skb)->gso_segs;
- /* Only support TCP at the moment. */
- if (!skb_is_gso_tcp(skb))
- NAPI_GRO_CB(skb)->flush = 1;
- }
-
- /* Setup for GRO checksum validation */
- switch (skb->ip_summed) {
- case CHECKSUM_COMPLETE:
- NAPI_GRO_CB(skb)->csum = skb->csum;
- NAPI_GRO_CB(skb)->csum_valid = 1;
- break;
- case CHECKSUM_UNNECESSARY:
- NAPI_GRO_CB(skb)->csum_cnt = skb->csum_level + 1;
- break;
- }
-
- pp = INDIRECT_CALL_INET(ptype->callbacks.gro_receive,
- ipv6_gro_receive, inet_gro_receive,
- &gro_list->list, skb);
- break;
+ if (ptype->type == type && ptype->callbacks.gro_receive)
+ goto found_ptype;
}
rcu_read_unlock();
+ goto normal;

- if (&ptype->list == head)
- goto normal;
+found_ptype:
+ skb_set_network_header(skb, skb_gro_offset(skb));
+ skb_reset_mac_len(skb);
+ BUILD_BUG_ON(sizeof_field(struct napi_gro_cb, zeroed) != sizeof(u32));
+ BUILD_BUG_ON(!IS_ALIGNED(offsetof(struct napi_gro_cb, zeroed),
+ sizeof(u32))); /* Avoid slow unaligned acc */
+ *(u32 *)&NAPI_GRO_CB(skb)->zeroed = 0;
+ NAPI_GRO_CB(skb)->flush = skb_has_frag_list(skb);
+ NAPI_GRO_CB(skb)->is_atomic = 1;
+ NAPI_GRO_CB(skb)->count = 1;
+ if (unlikely(skb_is_gso(skb))) {
+ NAPI_GRO_CB(skb)->count = skb_shinfo(skb)->gso_segs;
+ /* Only support TCP at the moment. */
+ if (!skb_is_gso_tcp(skb))
+ NAPI_GRO_CB(skb)->flush = 1;
+ }
+
+ /* Setup for GRO checksum validation */
+ switch (skb->ip_summed) {
+ case CHECKSUM_COMPLETE:
+ NAPI_GRO_CB(skb)->csum = skb->csum;
+ NAPI_GRO_CB(skb)->csum_valid = 1;
+ break;
+ case CHECKSUM_UNNECESSARY:
+ NAPI_GRO_CB(skb)->csum_cnt = skb->csum_level + 1;
+ break;
+ }
+
+ pp = INDIRECT_CALL_INET(ptype->callbacks.gro_receive,
+ ipv6_gro_receive, inet_gro_receive,
+ &gro_list->list, skb);
+
+ rcu_read_unlock();

if (PTR_ERR(pp) == -EINPROGRESS) {
ret = GRO_CONSUMED;
--
2.20.1

2022-11-09 06:08:43

by Eric Dumazet

Subject: Re: [PATCH net-next v2] gro: avoid checking for a failed search

On Tue, Nov 8, 2022 at 4:34 AM Richard Gobert <[email protected]> wrote:
>
> After searching for a protocol handler in dev_gro_receive, checking for
> failure is redundant. Skip the failure code after finding the
> corresponding handler.
>
> Suggested-by: Eric Dumazet <[email protected]>
> Signed-off-by: Richard Gobert <[email protected]>
> ---

Reviewed-by: Eric Dumazet <[email protected]>

2022-11-10 11:02:29

by patchwork-bot+netdevbpf

Subject: Re: [PATCH net-next v2] gro: avoid checking for a failed search

Hello:

This patch was applied to netdev/net-next.git (master)
by Paolo Abeni <[email protected]>:

On Tue, 8 Nov 2022 13:33:28 +0100 you wrote:
> After searching for a protocol handler in dev_gro_receive, checking for
> failure is redundant. Skip the failure code after finding the
> corresponding handler.
>
> Suggested-by: Eric Dumazet <[email protected]>
> Signed-off-by: Richard Gobert <[email protected]>
>
> [...]

Here is the summary with links:
- [net-next,v2] gro: avoid checking for a failed search
https://git.kernel.org/netdev/net-next/c/e081ecf084d3

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html