[PATCH i-g-t v2 3/5] tests/intel/xe_fault_injection: Add helper functions to inject fault with specific budget parameter.

[Francois Dugast]

Hi,

On Wed, Feb 19, 2025 at 01:04:43PM +0530, Satyanarayana K V P wrote:
> As per the current implementation, the fault is injected on the first call
> of the error injection function. Introduce an environment variable
> IGT_FAULT_INJECT_ITERATION using which, an error can be injected at
> specific function call.

This makes sense to me but not the commit title. What about something like:
tests/intel/xe_fault_injection: Add helper to start injecting fault after x iterations

> If the environment is not exported, an error will
> be injected in every possible function call starting from first up to the
> max number of iteration defined by INJECT_ITERATIONS, currently hardcoded
> as 100.

I would remove this part as this is not what this patch does and can be
misleading.

> 
> Signed-off-by: Satyanarayana K V P <satyanarayana.k.v.p at intel.com>
> Cc: Michał Wajdeczko <michal.wajdeczko at intel.com>
> Cc: Francois Dugast <francois.dugast at intel.com>
> ---
>  tests/intel/xe_fault_injection.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/tests/intel/xe_fault_injection.c b/tests/intel/xe_fault_injection.c
> index bc05515a8..32733fec5 100644
> --- a/tests/intel/xe_fault_injection.c
> +++ b/tests/intel/xe_fault_injection.c
> @@ -25,6 +25,7 @@
>  #define INJECT_ERRNO	-ENOMEM
>  #define BO_ADDR		0x1a0000
>  #define BO_SIZE		(1024*1024)
> +#define INJECT_ITERATIONS	100

It seems this line does not belong to this patch as INJECT_ITERATIONS is
not used.

>  
>  enum injection_list_action {
>  	INJECTION_LIST_ADD,
> @@ -42,6 +43,21 @@ struct fault_injection_params {
>  	uint32_t space;
>  };
>  
> +static int get_fault_inject_iter(void)
> +{
> +	/**
> +	 *  Introduce a new env variable IGT_FAULT_INJECT_ITERATION.
> +	 *  When unset test will run for INJECT_ITERATIONS iterations.
> +	 *  When set to <=0 or malformed - same as unset.
> +	 *  When set to >0 it will run single n-th iteration only.
> +	 */

The function description should be before its definition, like this:

    /**
     * ...
     */
    static int get_fault_inject_iter(void)
    ...

Also, I find the description in the commit message better describes the
purpose of this new env variable and function: "... an error can be
injected at specific function call".

Francois

> +
> +	const char *env = getenv("IGT_FAULT_INJECT_ITERATION");
> +
> +	/* Return 0 if not exported / -ve value */
> +	return env ? (atoi(env) > 0 ? atoi(env) : 0) : 0;
> +}
> +
>  static int fail_function_open(void)
>  {
>  	int debugfs_fail_function_dir_fd;
> -- 
> 2.35.3
>