What is __KERNEL_SYSCALLS__ for?

[Timur Tabi <timur.tabi@xxxxxxxxxxx>]

What is __KERNEL_SYSCALLS__ for?  I've been trying to find information 
on it, but there isn't a lot out there.  It appears to be something that 
was used in older 2.4 kernels, but is now being phased out.  What was 
it's original purpose, and why is it no longer desirable?

The reason I ask is that I have a driver that needs to work with several 
different kernel versions.  It's mostly working, but one kernel in 
particular has become a real thorn in my side.  It's some variation of 
2.4.25, and for some reason, I need to define __KERNEL_SYSCALLS__ before 
#including unistd.h in order for my code to compile (I need to find the 
entry point for sys_read in my driver).  I'm eliminating that code for 
2.6, but for 2.4 kernels it's still neccessary.  I just want to know 
what the deal is with __KERNEL_SYSCALLS__.

--
Timur Tabi
Staff Software Engineer
timur.tabi@xxxxxxxxxxx

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