Hi Pavel,

> diff --git a/src/include/liburing.h b/src/include/liburing.h
> index 8ca6cd9..9ff2a54 100644
> --- a/src/include/liburing.h
> +++ b/src/include/liburing.h
> @@ -191,6 +191,17 @@ static inline void io_uring_prep_rw(int op, struct io_uring_sqe *sqe, int fd,
>  	sqe->__pad2[0] = sqe->__pad2[1] = sqe->__pad2[2] = 0;
>  }
>  
> +static inline void io_uring_prep_splice(struct io_uring_sqe *sqe,
> +					int fd_in, loff_t off_in,
> +					int fd_out, loff_t off_out,
> +					unsigned int nbytes, int splice_flags)
> +{

The splice() syscall takes 'size_t len' and 'unsigned int flags',
I think we should at least change this to 'unsigned int splice_flags'.

> diff --git a/src/include/liburing/io_uring.h b/src/include/liburing/io_uring.h
> index 424fb4b..dc78697 100644
> --- a/src/include/liburing/io_uring.h
> +++ b/src/include/liburing/io_uring.h
> @@ -23,7 +23,10 @@ struct io_uring_sqe {
>  		__u64	off;	/* offset into file */
>  		__u64	addr2;
>  	};
> -	__u64	addr;		/* pointer to buffer or iovecs */
> +	union {
> +		__u64	addr;	/* pointer to buffer or iovecs */
> +		__u64	off_in;
> +	};
>  	__u32	len;		/* buffer size or number of iovecs */
>  	union {
>  		__kernel_rwf_t	rw_flags;
> @@ -37,6 +40,7 @@ struct io_uring_sqe {
>  		__u32		open_flags;
>  		__u32		statx_flags;
>  		__u32		fadvise_advice;
> +		__u32		splice_flags;
>  	};
>  	__u64	user_data;	/* data to be passed back at completion time */
>  	union {
> @@ -45,6 +49,7 @@ struct io_uring_sqe {
>  			__u16	buf_index;
>  			/* personality to use, if used */
>  			__u16	personality;
> +			__u32	splice_fd_in;

Shouldn't this be __s32 in order to match "__s32 fd"?

>  		};

Can you please add BUILD_BUG_SQE_ELEM() checks for the new elements
in io_uring_init()?

Thanks!
metze