[Accel-config] Re: [PATCH] accel-config: Refactor handling of cdev_minor at wq enable/disable

On 5/18/2021 6:08 PM, ramesh.thomas(a)intel.com wrote:
> From: Ramesh Thomas <ramesh.thomas(a)intel.com>
>
> cdev_minor depends on wq being enabled, of type "user" and in non uacce
> mode. Update the cached value of cdev_minor when wq state changes by
> reading sysfs. If the read fails, a negative value will be stored
> indicating it is not valid for the current state of the wq.
>
> Signed-off-by: Ramesh Thomas <ramesh.thomas(a)intel.com>
Reviewed-by: Dave Jiang <dave.jiang(a)intel.com>
> ---
>   accfg/lib/libaccfg.c | 64 ++++++--------------------------------------
>   1 file changed, 8 insertions(+), 56 deletions(-)
>
> diff --git a/accfg/lib/libaccfg.c b/accfg/lib/libaccfg.c
> index 0796f08..1463a4d 100644
> --- a/accfg/lib/libaccfg.c
> +++ b/accfg/lib/libaccfg.c
> @@ -1925,62 +1925,16 @@ ACCFG_EXPORT int accfg_wq_priority_boundary(struct accfg_wq *wq)
>   
>   static int accfg_wq_retrieve_cdev_minor(struct accfg_wq *wq)
>   {
> +	int dfd;
>   	struct accfg_ctx *ctx = accfg_wq_get_ctx(wq);
> -	char *path = wq->wq_buf;
> -	char buf[SYSFS_ATTR_SIZE];
> -	int rc;
> -
> -	rc = sprintf(wq->wq_buf, "%s/%s", wq->wq_path, "cdev_minor");
> -	if (rc < 0)
> -		return -errno;
> -
> -	if (sysfs_read_attr(ctx, path, buf) < 0) {
> -		err(ctx, "%s: retrieve cdev minor failed: '%s': %s\n",
> -				__func__, wq->wq_path, strerror(errno));
> -		return -errno;
> -	}
> -
> -	wq->cdev_minor = atoi(buf);
> -	return 0;
> -}
>   
> -static int accfg_wq_post_enable(struct accfg_wq *wq)
> -{
> -	enum accfg_wq_type type;
> -	int rc;
> -
> -	type = accfg_wq_get_type(wq);
> -
> -	if (type == ACCFG_WQT_USER) {
> -		rc = accfg_wq_retrieve_cdev_minor(wq);
> -		if (rc < 0)
> -			return rc;
> -	}
> -
> -	return 0;
> -}
> -
> -static int accfg_wq_post_disable(struct accfg_wq *wq)
> -{
> -	enum accfg_wq_type type;
> -
> -	type = accfg_wq_get_type(wq);
> -
> -	if (type == ACCFG_WQT_USER)
> -		wq->cdev_minor = -1;
> +	dfd = open(wq->wq_path, O_PATH);
> +	if (dfd < 0)
> +		return -ENXIO;
>   
> -	return 0;
> -}
> +	wq->cdev_minor = accfg_get_param_long(ctx, dfd, "cdev_minor");
>   
> -static int accfg_wq_control_post_processing(struct accfg_wq *wq,
> -		enum accfg_control_flag flag)
> -{
> -	if (flag == ACCFG_WQ_ENABLE)
> -		return accfg_wq_post_enable(wq);
> -	else if (flag == ACCFG_WQ_DISABLE)
> -		return accfg_wq_post_disable(wq);
> -	else
> -		return -EINVAL;
> +	close(dfd);
>   
>   	return 0;
>   }
> @@ -2052,10 +2006,8 @@ static int accfg_wq_control(struct accfg_wq *wq, enum accfg_control_flag flag,
>   		return -ENXIO;
>   	}
>   
> -	/* post processing */
> -	rc = accfg_wq_control_post_processing(wq, flag);
> -	if (rc < 0)
> -		return rc;
> +	if (accfg_wq_retrieve_cdev_minor(wq))
> +		return -ENXIO;
>   
>   	return 0;
>   }