Re: [PATCH] ax25.h unsigned long type for ax25 timers

[Bernard Pidoux <bpidoux@xxxxxxx>]

David,

Unfortunately I don't quite understand exactly why a structure in user 
space cannot be changed.
But this means that I have to make some effort to learn a bit more about 
the kernel structure and userspace.
However, thank you for your explanation about how to fix the discrepancy 
between both timer structures.
I will try to dig out more information on this subject.

Bernard Pidoux, f6bvp


David Miller a écrit :
> From: Bernard Pidoux <bpidoux@xxxxxxx>
> Date: Tue, 17 Jun 2008 15:04:38 +0200
>
>   
> > In linux/include/linux/ax25.h
> > ax25_info_struct timers types remain unsigned
> >
> > struct ax25_info_struct {
> > 	unsigned int	n2, n2count;
> > 	unsigned int	t1, t1timer;
> > 	unsigned int	t2, t2timer;
> > 	unsigned int	t3, t3timer;
> > 	unsigned int	idle, idletimer;
> >         .....
> > };
> >
> > while in linux/include/net/ax25.h timers are unsigned long according
> > to kernel 2.6 timers.
> >
> > typedef struct ax25_cb {
> >         .....
> >         struct timer_list       t1timer, t2timer, t3timer, idletimer;
> >         unsigned long           t1, t2, t3, idle, rtt;
> >         ....
> >
> > Although ax25_info_struct is not much used it is refered at least
> > into libax25 and xfbb BBS application program.
> >
> > It seems thus reasonable to make the change.
> >
> > Signed-off-by: Bernard Pidoux <f6bvp@xxxxxxxxx>
> >     
>
> Unfortunately this datastructure is exported to userspace,
> and therefore we cannot change the structure layout without
> breaking userspace.
>
> We cannot, as a result, make this change.
>
> The only way to fix this is to make a new fixed structure, and add new
> ax25 calls that accept this new structure.
>
>
>   

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