Re: [PATCH 2/4] m68k: Replace NR_syscalls macro from asm/unistd.h

From: Geert Uytterhoeven
Date: Thu Aug 09 2018 - 03:31:03 EST

Hi Firoz,

One first comment below...

On Thu, Aug 9, 2018 at 7:16 AM Firoz Khan <firoz.khan@xxxxxxxxxx> wrote:
> NR_syscalls macro holds the number of system call exist in m68k
> architecture. This macro is currently the part of asm/unistd.h file.
> We have to change the value of NR_syscalls, if we add or delete a
> system call.
> One of patch in this patch series has a script which will generate
> a uapi header based on syscall.tbl file. The syscall.tbl file
> contains the number of system call information. So we have two
> option to update NR_syscalls value.
> 1. Update NR_syscalls in asm/unistd.h manually by counting the
> no.of system calls. No need to update NR_syscalls untill
> we either add a new system call or delete an existing system
> call.
> 2. We can keep this feature it above mentioned script, that'll
> count the number of syscalls and keep it in a generated file.
> In this case we don't need to explicitly update NR_syscalls
> in asm/unistd.h file.
> The 2nd option will be the recommended one. For that, I moved the
> NR_syscalls macro from asm/unistd.h to uapi/asm/unistd.h. The macro
> name also changed form NR_syscalls to __NR_syscalls for making the
> name convention same across all architecture. While __NR_syscalls
> isn't strictly part of the uapi, having it as part of the generated
> header to simplifies the implementation.

It can indeed not be part of the UAPI, as UAPI definitions can never change,
while new syscalls will be added in the future, increasing the number ;-)



Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds