Re: [musl] [PATCH] sys/epoll.h: add epoll ioctls

[Rich Felker <dalias@libc.org>]

On Wed, May 29, 2024 at 06:49:59AM +0000, Joe Damato wrote:
> add two ioctls to get and set struct epoll_params to allow users to
> control epoll based busy polling of network sockets.
> 
> added to uapi in commit 18e2bf0edf4dd88d9656ec92395aa47392e85b61 (Linux
> kernel 6.9 and newer).
> ---
>  include/sys/epoll.h | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/include/sys/epoll.h b/include/sys/epoll.h
> index ac81a841..5f975c4a 100644
> --- a/include/sys/epoll.h
> +++ b/include/sys/epoll.h
> @@ -7,6 +7,7 @@ extern "C" {
>  
>  #include <stdint.h>
>  #include <sys/types.h>
> +#include <sys/ioctl.h>
>  #include <fcntl.h>
>  
>  #define __NEED_sigset_t
> @@ -54,6 +55,17 @@ __attribute__ ((__packed__))
>  #endif
>  ;
>  
> +struct epoll_params {
> +	uint32_t busy_poll_usecs;
> +	uint16_t busy_poll_budget;
> +	uint8_t prefer_busy_poll;
> +
> +	uint8_t __pad;
> +};
> +
> +#define EPOLL_IOC_TYPE 0x8A
> +#define EPIOCSPARAMS _IOW(EPOLL_IOC_TYPE, 0x01, struct epoll_params)
> +#define EPIOCGPARAMS _IOR(EPOLL_IOC_TYPE, 0x02, struct epoll_params)
>  
>  int epoll_create(int);
>  int epoll_create1(int);
> -- 
> 2.34.1

This is probably okay, but we should at least ask if sys/ioctl.h is
going to be a namespace mess. Is the intent to bring all of it in, or
just to get the EPIOC* macros which depend on _IOW and _IOR? On glibc,
does it pull in sys/ioctl.h?

Rich