Re: [PATCH 6.12.y] drm/amdgpu: Replace Mutex with Spinlock for RLCG register access to avoid Priority Inversion in SRIOV

[Sasha Levin <sashal@kernel.org>]

[ Sasha's backport helper bot ]

Hi,

✅ All tests passed successfully. No issues detected.
No action required from the submitter.

The upstream commit SHA1 provided is correct: dc0297f3198bd60108ccbd167ee5d9fa4af31ed0

WARNING: Author mismatch between patch and upstream commit:
Backport author: jetlan9@163.com
Commit author: Srinivasan Shanmugam<srinivasan.shanmugam@amd.com>

Status in newer kernel trees:
6.15.y | Present (exact SHA1)

Note: The patch differs from the upstream commit:
---
1:  dc0297f3198bd ! 1:  3da0142a2c955 drm/amdgpu: Replace Mutex with Spinlock for RLCG register access to avoid Priority Inversion in SRIOV
    @@ Metadata
      ## Commit message ##
         drm/amdgpu: Replace Mutex with Spinlock for RLCG register access to avoid Priority Inversion in SRIOV
     
    +    [ Upstream commit dc0297f3198bd60108ccbd167ee5d9fa4af31ed0 ]
    +
         RLCG Register Access is a way for virtual functions to safely access GPU
         registers in a virtualized environment., including TLB flushes and
         register reads. When multiple threads or VFs try to access the same
    @@ Commit message
         Suggested-by: Alex Deucher <alexander.deucher@amd.com>
         Reviewed-by: Christian König <christian.koenig@amd.com>
         Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
    +    [ Minor context change fixed. ]
    +    Signed-off-by: Wenshan Lan <jetlan9@163.com>
     
      ## drivers/gpu/drm/amd/amdgpu/amdgpu_device.c ##
     @@ drivers/gpu/drm/amd/amdgpu/amdgpu_device.c: int amdgpu_device_init(struct amdgpu_device *adev,
    @@ drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h: struct amdgpu_virt {
     -	struct mutex rlcg_reg_lock;
     +	/* Spinlock to protect access to the RLCG register interface */
     +	spinlock_t rlcg_reg_lock;
    + };
      
    - 	union amd_sriov_ras_caps ras_en_caps;
    - 	union amd_sriov_ras_caps ras_telemetry_en_caps;
    + struct amdgpu_video_codec_info;
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.12.y       |  Success    |  Success   |