Messages in this thread | | | Date | Wed, 12 Jan 2022 16:43:32 +0000 | Subject | Re: [PATCH 13/14] net: inline part of skb_csum_hwoffload_help | From | Pavel Begunkov <> |
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On 1/12/22 02:41, David Laight wrote: > From: Pavel Begunkov >> Sent: 11 January 2022 20:48 >> On 1/11/22 17:25, David Laight wrote: >>> From: Pavel Begunkov >>>> Sent: 11 January 2022 16:59 >>>> >>>> On 1/11/22 09:24, David Laight wrote: >>>>> From: Pavel Begunkov >>>>>> Sent: 11 January 2022 01:22 >>>>>> >>>>>> Inline a HW csum'ed part of skb_csum_hwoffload_help(). >>>>>> >>>>>> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> >>>>>> --- >>>>>> include/linux/netdevice.h | 16 ++++++++++++++-- >>>>>> net/core/dev.c | 13 +++---------- >>>>>> 2 files changed, 17 insertions(+), 12 deletions(-) >>>>>> >>>>>> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h >>>>>> index 3213c7227b59..fbe6c764ce57 100644 >>>>>> --- a/include/linux/netdevice.h >>>>>> +++ b/include/linux/netdevice.h >>>>>> @@ -4596,8 +4596,20 @@ void netdev_rss_key_fill(void *buffer, size_t len); >>>>>> >>>>>> int skb_checksum_help(struct sk_buff *skb); >>>>>> int skb_crc32c_csum_help(struct sk_buff *skb); >>>>>> -int skb_csum_hwoffload_help(struct sk_buff *skb, >>>>>> - const netdev_features_t features); >>>>>> +int __skb_csum_hwoffload_help(struct sk_buff *skb, >>>>>> + const netdev_features_t features); >>>>>> + >>>>>> +static inline int skb_csum_hwoffload_help(struct sk_buff *skb, >>>>>> + const netdev_features_t features) >>>>>> +{ >>>>>> + if (unlikely(skb_csum_is_sctp(skb))) >>>>>> + return !!(features & NETIF_F_SCTP_CRC) ? 0 : >>>>> >>>>> If that !! doing anything? - doesn't look like it. >>>> >>>> It doesn't, but left the original style >>> >>> It just makes you think it is needed... >>> >>>>>> + skb_crc32c_csum_help(skb); >>>>>> + >>>>>> + if (features & NETIF_F_HW_CSUM) >>>>>> + return 0; >>>>>> + return __skb_csum_hwoffload_help(skb, features); >>>>>> +} >>>>> >>>>> Maybe you should remove some bloat by moving the sctp code >>>>> into the called function. >>>>> This probably needs something like? >>>>> >>>>> { >>>>> if (features & NETIF_F_HW_CSUM && !skb_csum_is_sctp(skb)) >>>>> return 0; >>>>> return __skb_csum_hw_offload(skb, features); >>>>> } >>>> >>>> I don't like inlining that sctp chunk myself. It seems your way would >>>> need another skb_csum_is_sctp() in __skb_csum_hw_offload(), if so I >>>> don't think it's worth it. Would've been great to put the >>>> NETIF_F_HW_CSUM check first and hide sctp, but don't think it's >>>> correct. Would be great to hear some ideas. >>> >>> Given the definition: >>> >>> static inline bool skb_csum_is_sctp(struct sk_buff *skb) >>> { >>> return skb->csum_not_inet; >>> } >>> >>> I wouldn't worry about doing it twice. >>> >>> Also skb_crc32_csum_help() is only called one. >>> Make it static (so inlined) and pass 'features' into it. >>> >>> In reality sctp is such a slow crappy protocol that a few extra >>> function calls will make diddly-squit difference. >>> (And yes, we do actually use the sctp stack.) >> >> I was more thinking about non-sctp path without NETIF_F_HW_CSUM > > In which case you need the body of __skb_csum_hw_offload() > and end up doing the 'sctp' check once inside it. > The 'sctp' check is only done twice for sctp.
Ah yes, might be better indeed
-- Pavel Begunkov
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