Re: [PATCH] i915: gvt: no need to check return value of debugfs_create functions

[Zhenyu Wang <zhenyuw@linux.intel.com>]

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On 2019.06.13 15:34:19 +0200, Greg Kroah-Hartman wrote:
> When calling debugfs functions, there is no need to ever check the
> return value.  The function can work or not, but the code logic should
> never do something different based on this.

Looks fine to me. We'd follow this idiom.

Reviewed-by: Zhenyu Wang <zhenyuw@linux.intel.com>

> 
> Because there is no need to check these functions, a number of local
> functions can be made to return void to simplify things as nothing can
> fail.
> 
> Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
> Cc: Zhi Wang <zhi.a.wang@intel.com>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: intel-gvt-dev@lists.freedesktop.org
> Cc: intel-gfx@lists.freedesktop.org
> Cc: dri-devel@lists.freedesktop.org
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>  drivers/gpu/drm/i915/gvt/debugfs.c | 47 ++++++------------------------
>  drivers/gpu/drm/i915/gvt/gvt.c     |  4 +--
>  drivers/gpu/drm/i915/gvt/gvt.h     |  4 +--
>  drivers/gpu/drm/i915/gvt/kvmgt.c   |  3 --
>  drivers/gpu/drm/i915/gvt/vgpu.c    |  4 +--
>  5 files changed, 13 insertions(+), 49 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/debugfs.c b/drivers/gpu/drm/i915/gvt/debugfs.c
> index 8a9606f91e68..fdd9058ab8f2 100644
> --- a/drivers/gpu/drm/i915/gvt/debugfs.c
> +++ b/drivers/gpu/drm/i915/gvt/debugfs.c
> @@ -189,36 +189,19 @@ DEFINE_SIMPLE_ATTRIBUTE(vgpu_scan_nonprivbb_fops,
>  /**
>   * intel_gvt_debugfs_add_vgpu - register debugfs entries for a vGPU
>   * @vgpu: a vGPU
> - *
> - * Returns:
> - * Zero on success, negative error code if failed.
>   */
> -int intel_gvt_debugfs_add_vgpu(struct intel_vgpu *vgpu)
> +void intel_gvt_debugfs_add_vgpu(struct intel_vgpu *vgpu)
>  {
> -	struct dentry *ent;
>  	char name[16] = "";
>  
>  	snprintf(name, 16, "vgpu%d", vgpu->id);
>  	vgpu->debugfs = debugfs_create_dir(name, vgpu->gvt->debugfs_root);
> -	if (!vgpu->debugfs)
> -		return -ENOMEM;
> -
> -	ent = debugfs_create_bool("active", 0444, vgpu->debugfs,
> -				  &vgpu->active);
> -	if (!ent)
> -		return -ENOMEM;
> -
> -	ent = debugfs_create_file("mmio_diff", 0444, vgpu->debugfs,
> -				  vgpu, &vgpu_mmio_diff_fops);
> -	if (!ent)
> -		return -ENOMEM;
>  
> -	ent = debugfs_create_file("scan_nonprivbb", 0644, vgpu->debugfs,
> -				 vgpu, &vgpu_scan_nonprivbb_fops);
> -	if (!ent)
> -		return -ENOMEM;
> -
> -	return 0;
> +	debugfs_create_bool("active", 0444, vgpu->debugfs, &vgpu->active);
> +	debugfs_create_file("mmio_diff", 0444, vgpu->debugfs, vgpu,
> +			    &vgpu_mmio_diff_fops);
> +	debugfs_create_file("scan_nonprivbb", 0644, vgpu->debugfs, vgpu,
> +			    &vgpu_scan_nonprivbb_fops);
>  }
>  
>  /**
> @@ -234,27 +217,15 @@ void intel_gvt_debugfs_remove_vgpu(struct intel_vgpu *vgpu)
>  /**
>   * intel_gvt_debugfs_init - register gvt debugfs root entry
>   * @gvt: GVT device
> - *
> - * Returns:
> - * zero on success, negative if failed.
>   */
> -int intel_gvt_debugfs_init(struct intel_gvt *gvt)
> +void intel_gvt_debugfs_init(struct intel_gvt *gvt)
>  {
>  	struct drm_minor *minor = gvt->dev_priv->drm.primary;
> -	struct dentry *ent;
>  
>  	gvt->debugfs_root = debugfs_create_dir("gvt", minor->debugfs_root);
> -	if (!gvt->debugfs_root) {
> -		gvt_err("Cannot create debugfs dir\n");
> -		return -ENOMEM;
> -	}
>  
> -	ent = debugfs_create_ulong("num_tracked_mmio", 0444, gvt->debugfs_root,
> -				   &gvt->mmio.num_tracked_mmio);
> -	if (!ent)
> -		return -ENOMEM;
> -
> -	return 0;
> +	debugfs_create_ulong("num_tracked_mmio", 0444, gvt->debugfs_root,
> +			     &gvt->mmio.num_tracked_mmio);
>  }
>  
>  /**
> diff --git a/drivers/gpu/drm/i915/gvt/gvt.c b/drivers/gpu/drm/i915/gvt/gvt.c
> index 43f4242062dd..8f37eefa0a02 100644
> --- a/drivers/gpu/drm/i915/gvt/gvt.c
> +++ b/drivers/gpu/drm/i915/gvt/gvt.c
> @@ -375,9 +375,7 @@ int intel_gvt_init_device(struct drm_i915_private *dev_priv)
>  	}
>  	gvt->idle_vgpu = vgpu;
>  
> -	ret = intel_gvt_debugfs_init(gvt);
> -	if (ret)
> -		gvt_err("debugfs registration failed, go on.\n");
> +	intel_gvt_debugfs_init(gvt);
>  
>  	gvt_dbg_core("gvt device initialization is done\n");
>  	dev_priv->gvt = gvt;
> diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
> index f5a328b5290a..b73c7e63b2d5 100644
> --- a/drivers/gpu/drm/i915/gvt/gvt.h
> +++ b/drivers/gpu/drm/i915/gvt/gvt.h
> @@ -682,9 +682,9 @@ static inline void intel_gvt_mmio_set_in_ctx(
>  	gvt->mmio.mmio_attribute[offset >> 2] |= F_IN_CTX;
>  }
>  
> -int intel_gvt_debugfs_add_vgpu(struct intel_vgpu *vgpu);
> +void intel_gvt_debugfs_add_vgpu(struct intel_vgpu *vgpu);
>  void intel_gvt_debugfs_remove_vgpu(struct intel_vgpu *vgpu);
> -int intel_gvt_debugfs_init(struct intel_gvt *gvt);
> +void intel_gvt_debugfs_init(struct intel_gvt *gvt);
>  void intel_gvt_debugfs_clean(struct intel_gvt *gvt);
>  
>  
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index a68addf95c23..3c26fb28a2d1 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -1798,9 +1798,6 @@ static int kvmgt_guest_init(struct mdev_device *mdev)
>  						"kvmgt_nr_cache_entries",
>  						0444, vgpu->debugfs,
>  						&vgpu->vdev.nr_cache_entries);
> -	if (!info->debugfs_cache_entries)
> -		gvt_vgpu_err("Cannot create kvmgt debugfs entry\n");
> -
>  	return 0;
>  }
>  
> diff --git a/drivers/gpu/drm/i915/gvt/vgpu.c b/drivers/gpu/drm/i915/gvt/vgpu.c
> index 44ce3c2b9ac1..d5a6e4e3d0fd 100644
> --- a/drivers/gpu/drm/i915/gvt/vgpu.c
> +++ b/drivers/gpu/drm/i915/gvt/vgpu.c
> @@ -420,9 +420,7 @@ static struct intel_vgpu *__intel_gvt_create_vgpu(struct intel_gvt *gvt,
>  	if (ret)
>  		goto out_clean_submission;
>  
> -	ret = intel_gvt_debugfs_add_vgpu(vgpu);
> -	if (ret)
> -		goto out_clean_sched_policy;
> +	intel_gvt_debugfs_add_vgpu(vgpu);
>  
>  	ret = intel_gvt_hypervisor_set_opregion(vgpu);
>  	if (ret)
> -- 
> 2.22.0
> 
> _______________________________________________
> intel-gvt-dev mailing list
> intel-gvt-dev@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gvt-dev

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