Re: [Intel-gfx] [PATCH v2 5/9] drm/i915/perf: Fail modprobe if i915_perf_init fails on OOM

["Dixit, Ashutosh" <ashutosh.dixit@intel.com>]

On Thu, 16 Feb 2023 16:58:46 -0800, Umesh Nerlige Ramappa wrote:
>
> i915_perf_init can fail due to OOM. Fail driver init if i915_perf_init
> fails.
>
> v2: (Jani)
> - Reorder patch in the series

Jani seemed ok with this: that a drm_err will get lost in the dmesg deluge
on OOM so it's better to fail the probe as long as it's only due to OOM.

> Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_driver.c | 4 +++-
>  drivers/gpu/drm/i915/i915_perf.c   | 8 ++++++--
>  drivers/gpu/drm/i915/i915_perf.h   | 2 +-
>  3 files changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c
> index 0c0ae3eabb4b..998ca41c9713 100644
> --- a/drivers/gpu/drm/i915/i915_driver.c
> +++ b/drivers/gpu/drm/i915/i915_driver.c
> @@ -477,7 +477,9 @@ static int i915_driver_hw_probe(struct drm_i915_private *dev_priv)
>	if (ret)
>		return ret;
>
> -	i915_perf_init(dev_priv);
> +	ret = i915_perf_init(dev_priv);

Maybe add a comment here like this to allay people's concerns?

	/* The only non-zero ret here is -ENOMEM */

or even:

	drm_WARN_ON(&dev_priv->drm, ret && ret != -ENOMEM);

Otherwise this is:

Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>

> +	if (ret)
> +		return ret;
>
>	ret = i915_ggtt_probe_hw(dev_priv);
>	if (ret)
> diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
> index 37c4cc44d68c..3306653c0b85 100644
> --- a/drivers/gpu/drm/i915/i915_perf.c
> +++ b/drivers/gpu/drm/i915/i915_perf.c
> @@ -4941,7 +4941,7 @@ static void i915_perf_init_info(struct drm_i915_private *i915)
>   * Note: i915-perf initialization is split into an 'init' and 'register'
>   * phase with the i915_perf_register() exposing state to userspace.
>   */
> -void i915_perf_init(struct drm_i915_private *i915)
> +int i915_perf_init(struct drm_i915_private *i915)
>  {
>	struct i915_perf *perf = &i915->perf;
>
> @@ -5057,12 +5057,16 @@ void i915_perf_init(struct drm_i915_private *i915)
>		perf->i915 = i915;
>
>		ret = oa_init_engine_groups(perf);
> -		if (ret)
> +		if (ret) {
>			drm_err(&i915->drm,
>				"OA initialization failed %d\n", ret);
> +			return ret;
> +		}
>
>		oa_init_supported_formats(perf);
>	}
> +
> +	return 0;
>  }
>
>  static int destroy_config(int id, void *p, void *data)
> diff --git a/drivers/gpu/drm/i915/i915_perf.h b/drivers/gpu/drm/i915/i915_perf.h
> index f96e09a4af04..253637651d5e 100644
> --- a/drivers/gpu/drm/i915/i915_perf.h
> +++ b/drivers/gpu/drm/i915/i915_perf.h
> @@ -18,7 +18,7 @@ struct i915_oa_config;
>  struct intel_context;
>  struct intel_engine_cs;
>
> -void i915_perf_init(struct drm_i915_private *i915);
> +int i915_perf_init(struct drm_i915_private *i915);
>  void i915_perf_fini(struct drm_i915_private *i915);
>  void i915_perf_register(struct drm_i915_private *i915);
>  void i915_perf_unregister(struct drm_i915_private *i915);
> --
> 2.36.1
>