On Wed, 2013-08-07 at 16:36 -0700, David Miller wrote:
> From: David Miller <davem@xxxxxxxxxxxxx>
> Date: Wed, 07 Aug 2013 16:27:48 -0700 (PDT)
>
> > Look, I'm going to fix this myself, because I'm pretty tired of
> > waiting for the obvious fix.
>
> Someone please test this:
>
> diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
> index c623861..afc02a6 100644
> --- a/include/linux/etherdevice.h
> +++ b/include/linux/etherdevice.h
> @@ -29,6 +29,7 @@
>
> #ifdef __KERNEL__
> extern __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev);
> +extern __be16 __eth_type_trans(struct sk_buff *skb, struct net_device *dev);
> extern const struct header_ops eth_header_ops;
>
> extern int eth_header(struct sk_buff *skb, struct net_device *dev,
> diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
> index be1f64d..35dc1be 100644
> --- a/net/ethernet/eth.c
> +++ b/net/ethernet/eth.c
> @@ -146,6 +146,45 @@ int eth_rebuild_header(struct sk_buff *skb)
> EXPORT_SYMBOL(eth_rebuild_header);
>
> /**
> + * __eth_type_trans - only determine the packet's protocol ID.
> + * @skb: packet
> + * @dev: device
> + */
> +__be16 __eth_type_trans(struct sk_buff *skb, struct net_device *dev)
> +{
We probably want an inline here
Or else, we are adding an extra function call in rx fast path.
(At least my compiler did this)
0000000000000470 <eth_type_trans>:
470: e8 00 00 00 00 callq 475 <eth_type_trans+0x5>
471: R_X86_64_PC32 __fentry__-0x4
475: 48 8b 8f d0 00 00 00 mov 0xd0(%rdi),%rcx
47c: 48 8b 87 c8 00 00 00 mov 0xc8(%rdi),%rax
483: 44 8b 47 60 mov 0x60(%rdi),%r8d
487: 55 push %rbp
488: 48 89 77 20 mov %rsi,0x20(%rdi)
48c: 48 89 ca mov %rcx,%rdx
48f: 48 89 e5 mov %rsp,%rbp
492: 48 29 c2 sub %rax,%rdx
495: 41 83 f8 0d cmp $0xd,%r8d
499: 66 89 97 b8 00 00 00 mov %dx,0xb8(%rdi)
4a0: 76 19 jbe 4bb <eth_type_trans+0x4b>
4a2: 41 83 e8 0e sub $0xe,%r8d
4a6: 44 3b 47 64 cmp 0x64(%rdi),%r8d
4aa: 44 89 47 60 mov %r8d,0x60(%rdi)
4ae: 72 36 jb 4e6 <eth_type_trans+0x76>
4b0: 48 83 c1 0e add $0xe,%rcx
4b4: 48 89 8f d0 00 00 00 mov %rcx,0xd0(%rdi)
4bb: 81 e2 ff ff 00 00 and $0xffff,%edx
4c1: 48 01 d0 add %rdx,%rax
4c4: f6 00 01 testb $0x1,(%rax)
4c7: 75 2e jne 4f7 <eth_type_trans+0x87>
4c9: 48 8b 96 88 02 00 00 mov 0x288(%rsi),%rdx
4d0: 48 8b 00 mov (%rax),%rax
4d3: 48 33 02 xor (%rdx),%rax
4d6: 48 c1 e0 10 shl $0x10,%rax
4da: 48 85 c0 test %rax,%rax
4dd: 75 09 jne 4e8 <eth_type_trans+0x78>
4df: e8 00 00 00 00 callq 4e4 <eth_type_trans+0x74>
4e0: R_X86_64_PC32 __eth_type_trans-0x4
4e4: 5d pop %rbp
4e5: c3 retq
4e6: 0f 0b ud2
4e8: 0f b6 47 75 movzbl 0x75(%rdi),%eax
4ec: 83 e0 f8 and $0xfffffff8,%eax
4ef: 83 c8 03 or $0x3,%eax
4f2: 88 47 75 mov %al,0x75(%rdi)
4f5: eb e8 jmp 4df <eth_type_trans+0x6f>
4f7: 48 8b 00 mov (%rax),%rax
4fa: 48 33 86 b8 02 00 00 xor 0x2b8(%rsi),%rax
501: 48 c1 e0 10 shl $0x10,%rax
505: 48 85 c0 test %rax,%rax
508: 0f b6 47 75 movzbl 0x75(%rdi),%eax
50c: 75 0b jne 519 <eth_type_trans+0xa9>
50e: 83 e0 f8 and $0xfffffff8,%eax
511: 83 c8 01 or $0x1,%eax
514: 88 47 75 mov %al,0x75(%rdi)
517: eb c6 jmp 4df <eth_type_trans+0x6f>
519: 83 e0 f8 and $0xfffffff8,%eax
51c: 83 c8 02 or $0x2,%eax
51f: 88 47 75 mov %al,0x75(%rdi)
522: eb bb jmp 4df <eth_type_trans+0x6f>
--
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