Re: [PATCH net-next] net/mlx4_en: optimizes get_fixed_ipv6_csum()

[Eric Dumazet]

On 05/04/2018 08:59 AM, David Miller wrote:

> 
> No need to extra round-trip, I applied it directly ;)
> 

Very nice, thanks David !

Re: [PATCH net-next] net/mlx4_en: optimizes get_fixed_ipv6_csum()

[David Miller]

From: Eric Dumazet 
Date: Thu, 3 May 2018 19:10:29 -0700

> 
> 
> On 05/03/2018 06:52 PM, David Miller wrote:
>> From: Eric Dumazet 
>> Date: Thu, 3 May 2018 17:05:06 -0700
>> 
>>>
>>>
>>> On 05/02/2018 07:18 AM, Tariq Toukan wrote:


 On 27/04/2018 1:56 AM, Saeed Mahameed wrote:
>>>
> LGTM,
>
> Reviewed-by: Saeed Mahameed 
>

 Acked-by: Tariq Toukan 

 Thanks Eric.
>>>
>>> Thanks guys. 
>>>
>>> I see this patch  ( http://patchwork.ozlabs.org/patch/901336/ ) in
>>> a state I do not know : "Awaiting Upstream"
>> 
>> THat means I expect to see this change from the upstream
>> maintainer, which in this case is Tariq.
>> 
> 
> I see, but it seems Tariq does not know that, otherwise he would
> not have sent an "Acked-by:"
> 
> I guess this will need an extra round-trip ...

No need to extra round-trip, I applied it directly ;)

Re: [PATCH net-next] net/mlx4_en: optimizes get_fixed_ipv6_csum()

[Eric Dumazet]

On 05/03/2018 06:52 PM, David Miller wrote:
> From: Eric Dumazet 
> Date: Thu, 3 May 2018 17:05:06 -0700
> 
>>
>>
>> On 05/02/2018 07:18 AM, Tariq Toukan wrote:
>>>
>>>
>>> On 27/04/2018 1:56 AM, Saeed Mahameed wrote:
>>
 LGTM,

 Reviewed-by: Saeed Mahameed 

>>>
>>> Acked-by: Tariq Toukan 
>>>
>>> Thanks Eric.
>>
>> Thanks guys. 
>>
>> I see this patch  ( http://patchwork.ozlabs.org/patch/901336/ ) in
>> a state I do not know : "Awaiting Upstream"
> 
> THat means I expect to see this change from the upstream
> maintainer, which in this case is Tariq.
> 

I see, but it seems Tariq does not know that, otherwise he would
not have sent an "Acked-by:"

I guess this will need an extra round-trip ...

Re: [PATCH net-next] net/mlx4_en: optimizes get_fixed_ipv6_csum()

[David Miller]

From: Eric Dumazet 
Date: Thu, 3 May 2018 17:05:06 -0700

> 
> 
> On 05/02/2018 07:18 AM, Tariq Toukan wrote:
>> 
>> 
>> On 27/04/2018 1:56 AM, Saeed Mahameed wrote:
> 
>>> LGTM,
>>>
>>> Reviewed-by: Saeed Mahameed 
>>>
>> 
>> Acked-by: Tariq Toukan 
>> 
>> Thanks Eric.
> 
> Thanks guys. 
> 
> I see this patch  ( http://patchwork.ozlabs.org/patch/901336/ ) in
> a state I do not know : "Awaiting Upstream"

THat means I expect to see this change from the upstream
maintainer, which in this case is Tariq.

Re: [PATCH net-next] net/mlx4_en: optimizes get_fixed_ipv6_csum()

[Eric Dumazet]

On 05/02/2018 07:18 AM, Tariq Toukan wrote:
> 
> 
> On 27/04/2018 1:56 AM, Saeed Mahameed wrote:

>> LGTM,
>>
>> Reviewed-by: Saeed Mahameed 
>>
> 
> Acked-by: Tariq Toukan 
> 
> Thanks Eric.

Thanks guys. 

I see this patch  ( http://patchwork.ozlabs.org/patch/901336/ ) in
a state I do not know : "Awaiting Upstream"

Re: [PATCH net-next] net/mlx4_en: optimizes get_fixed_ipv6_csum()

[Tariq Toukan]

On 27/04/2018 1:56 AM, Saeed Mahameed wrote:

On Thu, 2018-04-19 at 08:49 -0700, Eric Dumazet wrote:

While trying to support CHECKSUM_COMPLETE for IPV6 fragments,
I had to experiments various hacks in get_fixed_ipv6_csum().
I must admit I could not find how to implement this :/

However, get_fixed_ipv6_csum() does a lot of redundant operations,
calling csum_partial() twice.

First csum_partial() computes the checksum of saddr and daddr,
put in @csum_pseudo_hdr. Undone later in the second csum_partial()
computed on whole ipv6 header.

Then nexthdr is added once, added a second time, then substracted.

payload_len is added once, then substracted.

Really all this can be reduced to two add_csum(), to add back 6 bytes
that were removed by mlx4 when providing hw_checksum in RX
descriptor.

Signed-off-by: Eric Dumazet 
Cc: Saeed Mahameed 
Cc: Tariq Toukan 
---
Note: This patch, like other mlx4 patches can definitely wait
Tariq approval, thanks !



LGTM,

Reviewed-by: Saeed Mahameed 



Acked-by: Tariq Toukan 

Thanks Eric.


  drivers/net/ethernet/mellanox/mlx4/en_rx.c | 21 --
---
  1 file changed, 8 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
index
5c613c6663da51a4ae792eeb4d8956b54655786b..38c56fb6e5f5970f245dd56c38e
1fc63a9349a07 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
@@ -593,30 +593,25 @@ static int get_fixed_ipv4_csum(__wsum
hw_checksum, struct sk_buff *skb,
  }
  
  #if IS_ENABLED(CONFIG_IPV6)

-/* In IPv6 packets, besides subtracting the pseudo header checksum,
- * we also compute/add the IP header checksum which
- * is not added by the HW.
+/* In IPv6 packets, hw_checksum lacks 6 bytes from IPv6 header:
+ * 4 first bytes : priority, version, flow_lbl
+ * and 2 additional bytes : nexthdr, hop_limit.
   */
  static int get_fixed_ipv6_csum(__wsum hw_checksum, struct sk_buff
*skb,
   struct ipv6hdr *ipv6h)
  {
__u8 nexthdr = ipv6h->nexthdr;
-   __wsum csum_pseudo_hdr = 0;
+   __wsum temp;
  
  	if (unlikely(nexthdr == IPPROTO_FRAGMENT ||

 nexthdr == IPPROTO_HOPOPTS ||
 nexthdr == IPPROTO_SCTP))
return -1;
-   hw_checksum = csum_add(hw_checksum, (__force
__wsum)htons(nexthdr));
  
-	csum_pseudo_hdr = csum_partial(>saddr,

-  sizeof(ipv6h->saddr) +
sizeof(ipv6h->daddr), 0);
-   csum_pseudo_hdr = csum_add(csum_pseudo_hdr, (__force
__wsum)ipv6h->payload_len);
-   csum_pseudo_hdr = csum_add(csum_pseudo_hdr,
-  (__force __wsum)htons(nexthdr));
-
-   skb->csum = csum_sub(hw_checksum, csum_pseudo_hdr);
-   skb->csum = csum_add(skb->csum, csum_partial(ipv6h,
sizeof(struct ipv6hdr), 0));
+   /* priority, version, flow_lbl */
+   temp = csum_add(hw_checksum, *(__wsum *)ipv6h);
+   /* nexthdr and hop_limit */
+   skb->csum = csum_add(temp, (__force __wsum)*(__be16
*)>nexthdr);
return 0;
  }
  #endif

Re: [PATCH net-next] net/mlx4_en: optimizes get_fixed_ipv6_csum()

[Saeed Mahameed]

On Thu, 2018-04-19 at 08:49 -0700, Eric Dumazet wrote:
> While trying to support CHECKSUM_COMPLETE for IPV6 fragments,
> I had to experiments various hacks in get_fixed_ipv6_csum().
> I must admit I could not find how to implement this :/
> 
> However, get_fixed_ipv6_csum() does a lot of redundant operations,
> calling csum_partial() twice.
> 
> First csum_partial() computes the checksum of saddr and daddr,
> put in @csum_pseudo_hdr. Undone later in the second csum_partial()
> computed on whole ipv6 header.
> 
> Then nexthdr is added once, added a second time, then substracted.
> 
> payload_len is added once, then substracted.
> 
> Really all this can be reduced to two add_csum(), to add back 6 bytes
> that were removed by mlx4 when providing hw_checksum in RX
> descriptor.
> 
> Signed-off-by: Eric Dumazet 
> Cc: Saeed Mahameed 
> Cc: Tariq Toukan 
> ---
> Note: This patch, like other mlx4 patches can definitely wait
> Tariq approval, thanks !
> 

LGTM,

Reviewed-by: Saeed Mahameed 

>  drivers/net/ethernet/mellanox/mlx4/en_rx.c | 21 --
> ---
>  1 file changed, 8 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> index
> 5c613c6663da51a4ae792eeb4d8956b54655786b..38c56fb6e5f5970f245dd56c38e
> 1fc63a9349a07 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> @@ -593,30 +593,25 @@ static int get_fixed_ipv4_csum(__wsum
> hw_checksum, struct sk_buff *skb,
>  }
>  
>  #if IS_ENABLED(CONFIG_IPV6)
> -/* In IPv6 packets, besides subtracting the pseudo header checksum,
> - * we also compute/add the IP header checksum which
> - * is not added by the HW.
> +/* In IPv6 packets, hw_checksum lacks 6 bytes from IPv6 header:
> + * 4 first bytes : priority, version, flow_lbl
> + * and 2 additional bytes : nexthdr, hop_limit.
>   */
>  static int get_fixed_ipv6_csum(__wsum hw_checksum, struct sk_buff
> *skb,
>  struct ipv6hdr *ipv6h)
>  {
>   __u8 nexthdr = ipv6h->nexthdr;
> - __wsum csum_pseudo_hdr = 0;
> + __wsum temp;
>  
>   if (unlikely(nexthdr == IPPROTO_FRAGMENT ||
>nexthdr == IPPROTO_HOPOPTS ||
>nexthdr == IPPROTO_SCTP))
>   return -1;
> - hw_checksum = csum_add(hw_checksum, (__force
> __wsum)htons(nexthdr));
>  
> - csum_pseudo_hdr = csum_partial(>saddr,
> -sizeof(ipv6h->saddr) +
> sizeof(ipv6h->daddr), 0);
> - csum_pseudo_hdr = csum_add(csum_pseudo_hdr, (__force
> __wsum)ipv6h->payload_len);
> - csum_pseudo_hdr = csum_add(csum_pseudo_hdr,
> -(__force __wsum)htons(nexthdr));
> -
> - skb->csum = csum_sub(hw_checksum, csum_pseudo_hdr);
> - skb->csum = csum_add(skb->csum, csum_partial(ipv6h,
> sizeof(struct ipv6hdr), 0));
> + /* priority, version, flow_lbl */
> + temp = csum_add(hw_checksum, *(__wsum *)ipv6h);
> + /* nexthdr and hop_limit */
> + skb->csum = csum_add(temp, (__force __wsum)*(__be16
> *)>nexthdr);
>   return 0;
>  }
>  #endif