Re: Fwd: Re: [PATCH] net: ipv6: change %8s to %s for rt->dst.dev->name in seq_printf of rt6_info_route

[Chen Gang <gang.chen@asianux.com>]

于 2012年11月27日 11:17, Shan Wei 写道:
> Chen Gang said, at 2012/11/23 11:35:
>> 2) about %*s:
>>  since kernel is an open system, IFNAMSIZ is belong to OS API level for outside
>>    it has effect both on individual kernel modules and user mode system call
>>    we need obey this rule, and %8s is not match this rule.
>>    so %8s is not suitable. (and now we have to choose %16s or %s).
> 
> Your patch will change the format of /proc/net/ipv6_route.

  Yes, it will be changed.
  although it belongs to "User Experience", it is not belong to os api level.
    for os api level: we must commit them not be changed (they are testament)
    for User Experience: we can change it, but maybe users feel 'not good'.

> Why we need to keep be consistent with user mode?

  it is for "keep source code simple and clear"
  when others see the %8s, easy to make them miss understanding (not quite clear)
  so better to change it to %s.


> However user operates device name, no effect on the showing of /proc/net/ipv6_route.

  now, no effect.


all together:
  since we are not user interactive program,
    "keeping source code simple and clear" is more important than "User Experience"


> 
>>
>>  for the format of information which seq_printf output:
>>    it is not belong to OS API level for outside (at least, for current case, it is true). 
>>    so we need not keep 'compatible' of it, so %16s is not necessary.
> 
> Can you explain If we don't change to %s, what will happen?
> 

  for outside, nothing will happen.

  so it is not for correctness, it is only for "keep source code simple and clear".

>>
>>  for keeping source code simple and clearly:
>>    %s is better than %16s.
>>
>>  so for result, we should choose %s only (neither %16s nor %8s).
> 
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-- 
Chen Gang

Asianux Corporation