Re: [patch] Assigning syscall numbers for testing

[Doug Ledford <dledford@redhat.com>]

Alan Cox wrote:

>>syscall bindings.  My example was about code using the predefined syscall 
>>number for new functions on an older kernel where those functions don't 
>>exist, but where they overlap with the older dynamic syscall numbers.  In 
>>short, the patch is safe for code that uses the lazy binding, but it can 
>>still overlap with future syscall numbers and code that doesn't use the lazy 
>>binding but instead uses predefined numbers.
>>
> 
> Now I follow you. So if Linus takes that patch he needs to allocate a block
> of per architecture dynamic syscall number space for it to use. Negative
> syscall numbers seem the most promising approach ?
> 
> 

Something like that.  It needs to be a large enough range to reasonably 
support the maximum number of expected syscalls that could possibly be in 
testing at one time (which is a total guesstimate if you ask me), and it 
should hopefully be up high so that we aren't allocating new numbers around 
it.  However, I think it needs to be allocated *regardless* of whether Linus 
takes the patch into his kernel.  Even if the patch is simply used outside 
Linus's kernel, it still needs the allocation to truly be safe.

-- 

  Doug Ledford <dledford@redhat.com>  http://people.redhat.com/dledford
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