2022-12-16 16:24:41

by Deepak R Varma

Subject: [PATCH] drm/i915/gvt: Replace DEFINE_SIMPLE_ATTRIBUTE by DEFINE_DEBUGFS_ATTRIBUTE

The DEFINE_DEBUGFS_ATTRIBUTE macro has implementation for protecting the
read/write file operations from removal race conditions. This further
enables using debugfs_create_file_unsafe() function since there is no need
for a proxy file operations struct for protection. Hence replace the
DEFINE_SIMPLE_ATTRIBUTE macro by DEFINE_DEBUGFS_ATTRIBUTE and the
debugfs_create_file() by the lightweight debugfs_create_file_unsafe()
versions.

This issue was identified using the coccinelle debugfs_simple_attr.cocci
semantic patch.

Signed-off-by: Deepak R Varma <[email protected]>
---
Please note: The changes are compile tested only.

drivers/gpu/drm/i915/gvt/debugfs.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/debugfs.c b/drivers/gpu/drm/i915/gvt/debugfs.c
index 9f1c209d9251..a45a43c35a6b 100644
--- a/drivers/gpu/drm/i915/gvt/debugfs.c
+++ b/drivers/gpu/drm/i915/gvt/debugfs.c
@@ -147,9 +147,9 @@ vgpu_scan_nonprivbb_set(void *data, u64 val)
return 0;
}

-DEFINE_SIMPLE_ATTRIBUTE(vgpu_scan_nonprivbb_fops,
- vgpu_scan_nonprivbb_get, vgpu_scan_nonprivbb_set,
- "0x%llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(vgpu_scan_nonprivbb_fops,
+ vgpu_scan_nonprivbb_get, vgpu_scan_nonprivbb_set,
+ "0x%llx\n");

/**
* intel_gvt_debugfs_add_vgpu - register debugfs entries for a vGPU
@@ -165,8 +165,8 @@ void intel_gvt_debugfs_add_vgpu(struct intel_vgpu *vgpu)
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);
+ debugfs_create_file_unsafe("scan_nonprivbb", 0644, vgpu->debugfs, vgpu,
+ &vgpu_scan_nonprivbb_fops);
}

/**
--
2.34.1

2022-12-23 14:00:21

by Deepak R Varma

Subject: Re: [PATCH] drm/i915/gvt: Replace DEFINE_SIMPLE_ATTRIBUTE by DEFINE_DEBUGFS_ATTRIBUTE

On Fri, Dec 16, 2022 at 09:37:47PM +0530, Deepak R Varma wrote:
> The DEFINE_DEBUGFS_ATTRIBUTE macro has implementation for protecting the
> read/write file operations from removal race conditions. This further
> enables using debugfs_create_file_unsafe() function since there is no need
> for a proxy file operations struct for protection. Hence replace the
> DEFINE_SIMPLE_ATTRIBUTE macro by DEFINE_DEBUGFS_ATTRIBUTE and the
> debugfs_create_file() by the lightweight debugfs_create_file_unsafe()
> versions.
>
> This issue was identified using the coccinelle debugfs_simple_attr.cocci
> semantic patch.
>
> Signed-off-by: Deepak R Varma <[email protected]>

Hello,
May I please request a review and feedback on this change proposal?

Thank you,
./drv


> ---
> Please note: The changes are compile tested only.
>
> drivers/gpu/drm/i915/gvt/debugfs.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gvt/debugfs.c b/drivers/gpu/drm/i915/gvt/debugfs.c
> index 9f1c209d9251..a45a43c35a6b 100644
> --- a/drivers/gpu/drm/i915/gvt/debugfs.c
> +++ b/drivers/gpu/drm/i915/gvt/debugfs.c
> @@ -147,9 +147,9 @@ vgpu_scan_nonprivbb_set(void *data, u64 val)
> return 0;
> }
>
> -DEFINE_SIMPLE_ATTRIBUTE(vgpu_scan_nonprivbb_fops,
> - vgpu_scan_nonprivbb_get, vgpu_scan_nonprivbb_set,
> - "0x%llx\n");
> +DEFINE_DEBUGFS_ATTRIBUTE(vgpu_scan_nonprivbb_fops,
> + vgpu_scan_nonprivbb_get, vgpu_scan_nonprivbb_set,
> + "0x%llx\n");
>
> /**
> * intel_gvt_debugfs_add_vgpu - register debugfs entries for a vGPU
> @@ -165,8 +165,8 @@ void intel_gvt_debugfs_add_vgpu(struct intel_vgpu *vgpu)
> 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);
> + debugfs_create_file_unsafe("scan_nonprivbb", 0644, vgpu->debugfs, vgpu,
> + &vgpu_scan_nonprivbb_fops);
> }
>
> /**
> --
> 2.34.1
>