Re: [RFC][v8][PATCH 0/10] Implement clone3() system call

["H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>]

On 10/14/2009 03:36 PM, Sukadev Bhattiprolu wrote:
> H. Peter Anvin [hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org] wrote:
> | 
> | Overall it seems sane to:
> | 
> | a) make it an actual 3-argument call;
> | b) make the existing flags a u32 forever, and make it a separate
> |    argument;
> | c) any new expansion can be via the struct, which may want to have
> |    an "c3_flags" field first in the structure.
> 
> Ok, So will this work ?
> 
> 	struct clone_args {
> 		u32 flags_high;		/* new clone flags (higher bits) */ 
> 		u32 reserved1;
> 		u32 nr_pids;
> 		u32 reserved2;
> 		u64 child_stack_base;
> 		u64 child_stack_size;
> 		u64 parent_tid_ptr;
> 		u64 child_tid_ptr;
> 		u64 reserved3;
> 	};
> 
> 	sys_clone3(u32 flags_low, struct clone_args *args, pid_t *pid_list)
> 
> Even on 64bit architectures the applications have to use sys_clone3() for
> the extended features.

Yes, although I'd just make flags_high a u64.  The other thing that
might be worthwhile is to have a length field on the structure; that way
we could add new fields at the end if ever necessary in the future.

	-hpa