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

[Jani Nikula <jani.nikula@linux.intel.com>]

On Thu, 16 Feb 2023, "Dixit, Ashutosh" <ashutosh.dixit@intel.com> wrote:
> 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);

Frankly I would not clutter the high level hw probe function with the
above.

BR,
Jani.


>
> 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
>>

-- 
Jani Nikula, Intel Open Source Graphics Center