Re: [RFC PATCH -tip 1/5] kprobes: Use ENOTSUPP instead of ENOSYS

[Masami Hiramatsu]

On Fri, 20 Oct 2017 10:57:22 +0200
Ingo Molnar <mingo@xxxxxxxxxx> wrote:

> 
> * Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:
> 
> > Use ENOTSUPP instead of ENOSYS because ENOSYS is reserved
> > only for invalid syscall number.
> 
> Is this actually true? We use -ENOSYS in a ton of code in kernel/ already, not 
> just for non-existing syscall number.

I got a warning from checkpatches.pl, also in include/uapi/asm-generic/errno.h,

/*
 * This error code is special: arch syscall entry code will return
 * -ENOSYS if users try to call a syscall that doesn't exist.  To keep
 * failures of syscalls that really do exist distinguishable from
 * failures due to attempts to use a nonexistent syscall, syscall
 * implementations should refrain from returning -ENOSYS.
 */
#define ENOSYS          38      /* Invalid system call number */

So, I decided not to use ENOSYS for this error.

Thank you,


> 
> 	Ingo


-- 
Masami Hiramatsu <mhiramat@xxxxxxxxxx>