[Accel-config] Re: [PATCH v1 2/4] accel-config: Add compatibility mode detection

On 3/11/2021 11:03 AM, ramesh.thomas(a)intel.com wrote:
> From: Ramesh Thomas <ramesh.thomas(a)intel.com>
>
> Add a flag in accfg context to store commpatibility mode. Absence of
> /sys/bus/dsa/drivers/idxd indicates compatibility mode.
>
> Signed-off-by: Ramesh Thomas <ramesh.thomas(a)intel.com>
> ---
>   accfg/lib/libaccfg.c | 5 +++++
>   accfg/lib/private.h  | 1 +
>   2 files changed, 6 insertions(+)
>
> diff --git a/accfg/lib/libaccfg.c b/accfg/lib/libaccfg.c
> index 450be4f..25d783c 100644
> --- a/accfg/lib/libaccfg.c
> +++ b/accfg/lib/libaccfg.c
> @@ -28,6 +28,8 @@
>   #include "private.h"
>   
>   #define MDEV_POSTFIX "mdev_supported_types"
> +#define IDXD_DRIVER_PATH "/sys/bus/dsa/drivers/"
> +#define IDXD_DRIVER_PORTAL "idxd"

Portal is actually a device term. We have portal drivers for the WQ but 
not the device. Maybe IDXD_DRIVER_BIND_PATH?

>   
>   const char *accfg_wq_mode_str[] = {
>   	[ACCFG_WQ_SHARED]	= "shared",
> @@ -310,6 +312,9 @@ ACCFG_EXPORT int accfg_new(struct accfg_ctx **ctx)
>   	c->refcount = 1;
>   	log_init(&c->ctx, "libaccfg", "ACCFG_LOG");
>   	c->timeout = 5000;
> +	if (access(IDXD_DRIVER_PATH IDXD_DRIVER_PORTAL, R_OK))

I think you want to detect /sys/bus/dsa/drivers/dsa to be in compat 
mode? If COMPAT is turned off, /sys/bus/dsa/drivers/dsa would not exist.


> +		c->compat = true;
> +
>   	list_head_init(&c->devices);
>   
>   	info(c, "ctx %p created\n", c);
> diff --git a/accfg/lib/private.h b/accfg/lib/private.h
> index 0fdc5d5..f407643 100644
> --- a/accfg/lib/private.h
> +++ b/accfg/lib/private.h
> @@ -146,6 +146,7 @@ struct accfg_ctx {
>   	struct list_head devices;
>   	uint64_t timeout;
>   	void *private_data;
> +	bool compat;
>   };
>   
>   static inline int check_udev(struct udev *udev)