Re: [PATCH] [NIU] VLAN does not work with niu driver

[Matheos Worku <Matheos.Worku@Sun.COM>]

David Miller wrote:
> From: Joyce Yu <Joyce.Yu@sun.com>
> Date: Wed, 09 Sep 2009 14:10:48 -0700
> 
>> drivers/net/niu.h |    2 +-
>> 1 files changed, 1 insertions(+), 1 deletions(-)
> 
> Can I get a more verbose commit message than this?
> 
>> @@ -2700,7 +2700,7 @@ struct fcram_hash_ipv6 {
>> #define RCR_PKT_TYPE_UDP               0x2
>> #define RCR_PKT_TYPE_SCTP              0x3
>>
>> -#define NIU_RXPULL_MAX                 ETH_HLEN
>> +#define NIU_RXPULL_MAX                 64
>>
> 
> See, that's why I want a detailed commit message, because if you
> described things more clearly I'd understand why you choose the value
> '64' as opposed to, say, the size of a VLAN header which to me would
> be a more appropriate value to use here.

Dave,

The frame type in NIU HW  is embedded  in a  HW header,  so it is 
possible to check the HW header and decide whether to pull up ETH_HLEN 
or  VLAN header size of bytes. However, considering the amount of work 
required to get and examine the HW header (including endianess issues), 
we thought pulling up 64 bytes by default (as used in cassini.c) would 
be efficient.

Regards,
Matheos

> 
> You just seem to be reverting a change I made a while back, and it
> just so happens to fix your problem.  But '64' is too large a value
> to use here and it will impact performance.
> 
> You did check to see if there were any performance regressions
> resulting from your change, right?
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