Messages in this thread | | | From | David Laight <> | Subject | RE: [PATCH 13/14] net: inline part of skb_csum_hwoffload_help | Date | Tue, 11 Jan 2022 17:25:35 +0000 |
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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.)
David
- Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
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