Subject: Re: [PATCH] drm/amd/powerplay/hwmgr: Remove null check before kfree
To: Himanshu Jha <himanshujha199640@gmail.com>, airlied@linux.ie
Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        amd-gfx@lists.freedesktop.org, alexander.deucher@amd.com,
        Rex.Zhu@amd.com, christian.koenig@amd.com
References: <1504012347-14702-1-git-send-email-himanshujha199640@gmail.com>
From: Harry Wentland <harry.wentland@amd.com>
Message-ID: <337d5257-2d0a-8482-f8d8-4a44234347d4@amd.com>
Date: Tue, 29 Aug 2017 09:34:01 -0400
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On 2017-08-29 09:12 AM, Himanshu Jha wrote:
> kfree on NULL pointer is a no-op and therefore checking is redundant.
> 
> Signed-off-by: Himanshu Jha <himanshujha199640@gmail.com>

Reviewed-by: Harry Wentland <harry.wentland@amd.com>

Harry

> ---
>  drivers/gpu/drm/amd/powerplay/hwmgr/cz_hwmgr.c     |  6 +-
>  .../gpu/drm/amd/powerplay/hwmgr/processpptables.c  | 96 ++++++++--------------
>  drivers/gpu/drm/amd/powerplay/hwmgr/rv_hwmgr.c     | 52 ++++--------
>  drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c   | 12 +--
>  4 files changed, 56 insertions(+), 110 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/cz_hwmgr.c b/drivers/gpu/drm/amd/powerplay/hwmgr/cz_hwmgr.c
> index bc839ff..9f2c037 100644
> --- a/drivers/gpu/drm/amd/powerplay/hwmgr/cz_hwmgr.c
> +++ b/drivers/gpu/drm/amd/powerplay/hwmgr/cz_hwmgr.c
> @@ -1225,10 +1225,8 @@ static int cz_hwmgr_backend_fini(struct pp_hwmgr *hwmgr)
>  		phm_destroy_table(hwmgr, &(hwmgr->power_down_asic));
>  		phm_destroy_table(hwmgr, &(hwmgr->setup_asic));
>  
> -		if (NULL != hwmgr->dyn_state.vddc_dep_on_dal_pwrl) {
> -			kfree(hwmgr->dyn_state.vddc_dep_on_dal_pwrl);
> -			hwmgr->dyn_state.vddc_dep_on_dal_pwrl = NULL;
> -		}
> +		kfree(hwmgr->dyn_state.vddc_dep_on_dal_pwrl);
> +		hwmgr->dyn_state.vddc_dep_on_dal_pwrl = NULL;
>  
>  		kfree(hwmgr->backend);
>  		hwmgr->backend = NULL;
> diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/processpptables.c b/drivers/gpu/drm/amd/powerplay/hwmgr/processpptables.c
> index 2716721..a6dbc55 100644
> --- a/drivers/gpu/drm/amd/powerplay/hwmgr/processpptables.c
> +++ b/drivers/gpu/drm/amd/powerplay/hwmgr/processpptables.c
> @@ -1615,85 +1615,53 @@ static int pp_tables_uninitialize(struct pp_hwmgr *hwmgr)
>  	if (hwmgr->chip_id == CHIP_RAVEN)
>  		return 0;
>  
> -	if (NULL != hwmgr->dyn_state.vddc_dependency_on_sclk) {
> -		kfree(hwmgr->dyn_state.vddc_dependency_on_sclk);
> -		hwmgr->dyn_state.vddc_dependency_on_sclk = NULL;
> -	}
> +	kfree(hwmgr->dyn_state.vddc_dependency_on_sclk);
> +	hwmgr->dyn_state.vddc_dependency_on_sclk = NULL;
>  
> -	if (NULL != hwmgr->dyn_state.vddci_dependency_on_mclk) {
> -		kfree(hwmgr->dyn_state.vddci_dependency_on_mclk);
> -		hwmgr->dyn_state.vddci_dependency_on_mclk = NULL;
> -	}
> +	kfree(hwmgr->dyn_state.vddci_dependency_on_mclk);
> +	hwmgr->dyn_state.vddci_dependency_on_mclk = NULL;
>  
> -	if (NULL != hwmgr->dyn_state.vddc_dependency_on_mclk) {
> -		kfree(hwmgr->dyn_state.vddc_dependency_on_mclk);
> -		hwmgr->dyn_state.vddc_dependency_on_mclk = NULL;
> -	}
> +	kfree(hwmgr->dyn_state.vddc_dependency_on_mclk);
> +	hwmgr->dyn_state.vddc_dependency_on_mclk = NULL;
>  
> -	if (NULL != hwmgr->dyn_state.mvdd_dependency_on_mclk) {
> -		kfree(hwmgr->dyn_state.mvdd_dependency_on_mclk);
> -		hwmgr->dyn_state.mvdd_dependency_on_mclk = NULL;
> -	}
> +	kfree(hwmgr->dyn_state.mvdd_dependency_on_mclk);
> +	hwmgr->dyn_state.mvdd_dependency_on_mclk = NULL;
>  
> -	if (NULL != hwmgr->dyn_state.valid_mclk_values) {
> -		kfree(hwmgr->dyn_state.valid_mclk_values);
> -		hwmgr->dyn_state.valid_mclk_values = NULL;
> -	}
> +	kfree(hwmgr->dyn_state.valid_mclk_values);
> +	hwmgr->dyn_state.valid_mclk_values = NULL;
>  
> -	if (NULL != hwmgr->dyn_state.valid_sclk_values) {
> -		kfree(hwmgr->dyn_state.valid_sclk_values);
> -		hwmgr->dyn_state.valid_sclk_values = NULL;
> -	}
> +	kfree(hwmgr->dyn_state.valid_sclk_values);
> +	hwmgr->dyn_state.valid_sclk_values = NULL;
>  
> -	if (NULL != hwmgr->dyn_state.cac_leakage_table) {
> -		kfree(hwmgr->dyn_state.cac_leakage_table);
> -		hwmgr->dyn_state.cac_leakage_table = NULL;
> -	}
> +	kfree(hwmgr->dyn_state.cac_leakage_table);
> +	hwmgr->dyn_state.cac_leakage_table = NULL;
>  
> -	if (NULL != hwmgr->dyn_state.vddc_phase_shed_limits_table) {
> -		kfree(hwmgr->dyn_state.vddc_phase_shed_limits_table);
> -		hwmgr->dyn_state.vddc_phase_shed_limits_table = NULL;
> -	}
> +	kfree(hwmgr->dyn_state.vddc_phase_shed_limits_table);
> +	hwmgr->dyn_state.vddc_phase_shed_limits_table = NULL;
>  
> -	if (NULL != hwmgr->dyn_state.vce_clock_voltage_dependency_table) {
> -		kfree(hwmgr->dyn_state.vce_clock_voltage_dependency_table);
> -		hwmgr->dyn_state.vce_clock_voltage_dependency_table = NULL;
> -	}
> +	kfree(hwmgr->dyn_state.vce_clock_voltage_dependency_table);
> +	hwmgr->dyn_state.vce_clock_voltage_dependency_table = NULL;
>  
> -	if (NULL != hwmgr->dyn_state.uvd_clock_voltage_dependency_table) {
> -		kfree(hwmgr->dyn_state.uvd_clock_voltage_dependency_table);
> -		hwmgr->dyn_state.uvd_clock_voltage_dependency_table = NULL;
> -	}
> +	kfree(hwmgr->dyn_state.uvd_clock_voltage_dependency_table);
> +	hwmgr->dyn_state.uvd_clock_voltage_dependency_table = NULL;
>  
> -	if (NULL != hwmgr->dyn_state.samu_clock_voltage_dependency_table) {
> -		kfree(hwmgr->dyn_state.samu_clock_voltage_dependency_table);
> -		hwmgr->dyn_state.samu_clock_voltage_dependency_table = NULL;
> -	}
> +	kfree(hwmgr->dyn_state.samu_clock_voltage_dependency_table);
> +	hwmgr->dyn_state.samu_clock_voltage_dependency_table = NULL;
>  
> -	if (NULL != hwmgr->dyn_state.acp_clock_voltage_dependency_table) {
> -		kfree(hwmgr->dyn_state.acp_clock_voltage_dependency_table);
> -		hwmgr->dyn_state.acp_clock_voltage_dependency_table = NULL;
> -	}
> +	kfree(hwmgr->dyn_state.acp_clock_voltage_dependency_table);
> +	hwmgr->dyn_state.acp_clock_voltage_dependency_table = NULL;
>  
> -	if (NULL != hwmgr->dyn_state.cac_dtp_table) {
> -		kfree(hwmgr->dyn_state.cac_dtp_table);
> -		hwmgr->dyn_state.cac_dtp_table = NULL;
> -	}
> +	kfree(hwmgr->dyn_state.cac_dtp_table);
> +	hwmgr->dyn_state.cac_dtp_table = NULL;
>  
> -	if (NULL != hwmgr->dyn_state.ppm_parameter_table) {
> -		kfree(hwmgr->dyn_state.ppm_parameter_table);
> -		hwmgr->dyn_state.ppm_parameter_table = NULL;
> -	}
> +	kfree(hwmgr->dyn_state.ppm_parameter_table);
> +	hwmgr->dyn_state.ppm_parameter_table = NULL;
>  
> -	if (NULL != hwmgr->dyn_state.vdd_gfx_dependency_on_sclk) {
> -		kfree(hwmgr->dyn_state.vdd_gfx_dependency_on_sclk);
> -		hwmgr->dyn_state.vdd_gfx_dependency_on_sclk = NULL;
> -	}
> +	kfree(hwmgr->dyn_state.vdd_gfx_dependency_on_sclk);
> +	hwmgr->dyn_state.vdd_gfx_dependency_on_sclk = NULL;
>  
> -	if (NULL != hwmgr->dyn_state.vq_budgeting_table) {
> -		kfree(hwmgr->dyn_state.vq_budgeting_table);
> -		hwmgr->dyn_state.vq_budgeting_table = NULL;
> -	}
> +	kfree(hwmgr->dyn_state.vq_budgeting_table);
> +	hwmgr->dyn_state.vq_budgeting_table = NULL;
>  
>  	return 0;
>  }
> diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/rv_hwmgr.c b/drivers/gpu/drm/amd/powerplay/hwmgr/rv_hwmgr.c
> index 2c3e6ba..5547ed3 100644
> --- a/drivers/gpu/drm/amd/powerplay/hwmgr/rv_hwmgr.c
> +++ b/drivers/gpu/drm/amd/powerplay/hwmgr/rv_hwmgr.c
> @@ -640,40 +640,24 @@ static int rv_hwmgr_backend_fini(struct pp_hwmgr *hwmgr)
>  	phm_destroy_table(hwmgr, &(hwmgr->power_down_asic));
>  	phm_destroy_table(hwmgr, &(hwmgr->setup_asic));
>  
> -	if (pinfo->vdd_dep_on_dcefclk) {
> -		kfree(pinfo->vdd_dep_on_dcefclk);
> -		pinfo->vdd_dep_on_dcefclk = NULL;
> -	}
> -	if (pinfo->vdd_dep_on_socclk) {
> -		kfree(pinfo->vdd_dep_on_socclk);
> -		pinfo->vdd_dep_on_socclk = NULL;
> -	}
> -	if (pinfo->vdd_dep_on_fclk) {
> -		kfree(pinfo->vdd_dep_on_fclk);
> -		pinfo->vdd_dep_on_fclk = NULL;
> -	}
> -	if (pinfo->vdd_dep_on_dispclk) {
> -		kfree(pinfo->vdd_dep_on_dispclk);
> -		pinfo->vdd_dep_on_dispclk = NULL;
> -	}
> -	if (pinfo->vdd_dep_on_dppclk) {
> -		kfree(pinfo->vdd_dep_on_dppclk);
> -		pinfo->vdd_dep_on_dppclk = NULL;
> -	}
> -	if (pinfo->vdd_dep_on_phyclk) {
> -		kfree(pinfo->vdd_dep_on_phyclk);
> -		pinfo->vdd_dep_on_phyclk = NULL;
> -	}
> -
> -	if (NULL != hwmgr->dyn_state.vddc_dep_on_dal_pwrl) {
> -		kfree(hwmgr->dyn_state.vddc_dep_on_dal_pwrl);
> -		hwmgr->dyn_state.vddc_dep_on_dal_pwrl = NULL;
> -	}
> -
> -	if (NULL != hwmgr->dyn_state.vq_budgeting_table) {
> -		kfree(hwmgr->dyn_state.vq_budgeting_table);
> -		hwmgr->dyn_state.vq_budgeting_table = NULL;
> -	}
> +	kfree(pinfo->vdd_dep_on_dcefclk);
> +	pinfo->vdd_dep_on_dcefclk = NULL;
> +	kfree(pinfo->vdd_dep_on_socclk);
> +	pinfo->vdd_dep_on_socclk = NULL;
> +	kfree(pinfo->vdd_dep_on_fclk);
> +	pinfo->vdd_dep_on_fclk = NULL;
> +	kfree(pinfo->vdd_dep_on_dispclk);
> +	pinfo->vdd_dep_on_dispclk = NULL;
> +	kfree(pinfo->vdd_dep_on_dppclk);
> +	pinfo->vdd_dep_on_dppclk = NULL;
> +	kfree(pinfo->vdd_dep_on_phyclk);
> +	pinfo->vdd_dep_on_phyclk = NULL;
> +
> +	kfree(hwmgr->dyn_state.vddc_dep_on_dal_pwrl);
> +	hwmgr->dyn_state.vddc_dep_on_dal_pwrl = NULL;
> +
> +	kfree(hwmgr->dyn_state.vq_budgeting_table);
> +	hwmgr->dyn_state.vq_budgeting_table = NULL;
>  
>  	kfree(hwmgr->backend);
>  	hwmgr->backend = NULL;
> diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c b/drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c
> index c274323..eb8a3ff 100644
> --- a/drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c
> +++ b/drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c
> @@ -2282,15 +2282,11 @@ static int smu7_set_private_data_based_on_pptable_v0(struct pp_hwmgr *hwmgr)
>  
>  static int smu7_hwmgr_backend_fini(struct pp_hwmgr *hwmgr)
>  {
> -	if (NULL != hwmgr->dyn_state.vddc_dep_on_dal_pwrl) {
> -		kfree(hwmgr->dyn_state.vddc_dep_on_dal_pwrl);
> -		hwmgr->dyn_state.vddc_dep_on_dal_pwrl = NULL;
> -	}
> +	kfree(hwmgr->dyn_state.vddc_dep_on_dal_pwrl);
> +	hwmgr->dyn_state.vddc_dep_on_dal_pwrl = NULL;
>  	pp_smu7_thermal_fini(hwmgr);
> -	if (NULL != hwmgr->backend) {
> -		kfree(hwmgr->backend);
> -		hwmgr->backend = NULL;
> -	}
> +	kfree(hwmgr->backend);
> +	hwmgr->backend = NULL;
>  
>  	return 0;
>  }
>