Re: [kvm-unit-tests PATCH v2 4/8] s390x: lib: css: separate wait for IRQ and check I/O completion

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

On Thu, 25 Mar 2021 10:39:03 +0100
Pierre Morel <pmorel@linux.ibm.com> wrote:

> We will may want to check the result of an I/O without waiting
> for an interrupt.
> For example because we do not handle interrupt.
> Let's separate waiting for interrupt and the I/O complretion check.
                                                   ^^^^^^^^^^^
                                                   completion

> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>

> ---
>  lib/s390x/css.h     |  1 +
>  lib/s390x/css_lib.c | 13 ++++++++++---
>  2 files changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/s390x/css.h b/lib/s390x/css.h
> index 0058355..5d1e1f0 100644
> --- a/lib/s390x/css.h
> +++ b/lib/s390x/css.h
> @@ -317,6 +317,7 @@ int css_residual_count(unsigned int schid);
>  
>  void enable_io_isc(uint8_t isc);
>  int wait_and_check_io_completion(int schid);
> +int check_io_completion(int schid);
>  
>  /*
>   * CHSC definitions
> diff --git a/lib/s390x/css_lib.c b/lib/s390x/css_lib.c
> index f5c4f37..1e5c409 100644
> --- a/lib/s390x/css_lib.c
> +++ b/lib/s390x/css_lib.c
> @@ -487,18 +487,25 @@ struct ccw1 *ccw_alloc(int code, void *data,
> int count, unsigned char flags) }
>  
>  /* wait_and_check_io_completion:
> + * @schid: the subchannel ID
> + */
> +int wait_and_check_io_completion(int schid)
> +{
> +	wait_for_interrupt(PSW_MASK_IO);
> +	return check_io_completion(schid);
> +}
> +
> +/* check_io_completion:
>   * @schid: the subchannel ID
>   *
>   * Makes the most common check to validate a successful I/O
>   * completion.
>   * Only report failures.
>   */
> -int wait_and_check_io_completion(int schid)
> +int check_io_completion(int schid)
>  {
>  	int ret = 0;
>  
> -	wait_for_interrupt(PSW_MASK_IO);
> -
>  	report_prefix_push("check I/O completion");
>  
>  	if (lowcore_ptr->io_int_param != schid) {