Re: [PATCH 2/2] drm/amdgpu: cleanup debugfs for amdgpu rings

["Das, Nirmoy" <nirmoy.das@amd.com>]

On 9/6/2021 6:45 PM, Sharma, Shashank wrote:
>
>
> On 9/5/2021 5:01 PM, Das, Nirmoy wrote:
>>
>> On 9/5/2021 10:03 AM, Sharma, Shashank wrote:
>>>
>>>
>>> On 9/3/2021 9:44 PM, Das, Nirmoy wrote:
>>>> Hi Shashank,
>>>>
>>>> On 9/3/2021 5:51 PM, Das, Nirmoy wrote:
>>>>>
>>>>> On 9/3/2021 5:26 PM, Sharma, Shashank wrote:
>>>>>>
>>>>>>
>>>>>> On 9/3/2021 1:39 PM, Das, Nirmoy wrote:
>>>>>>>
>>>>>>> On 9/3/2021 8:36 AM, Sharma, Shashank wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> On 9/2/2021 5:14 PM, Nirmoy Das wrote:
>>>>>>>>> Use debugfs_create_file_size API for creating ring debugfs
>>>>>>>>> file, also cleanup surrounding code.
>>>>>>>>>
>>>>>>>>> Signed-off-by: Nirmoy Das <nirmoy.das@amd.com>
>>>>>>>>> ---
>>>>>>>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c |  4 +---
>>>>>>>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c    | 16 
>>>>>>>>> +++++-----------
>>>>>>>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h    |  8 +-------
>>>>>>>>>   3 files changed, 7 insertions(+), 21 deletions(-)
>>>>>>>>>
>>>>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c 
>>>>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
>>>>>>>>> index 077f9baf74fe..dee56ab19a8f 100644
>>>>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
>>>>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
>>>>>>>>> @@ -1734,9 +1734,7 @@ int amdgpu_debugfs_init(struct 
>>>>>>>>> amdgpu_device *adev)
>>>>>>>>>           if (!ring)
>>>>>>>>>               continue;
>>>>>>>>>   -        if (amdgpu_debugfs_ring_init(adev, ring)) {
>>>>>>>>> -            DRM_ERROR("Failed to register debugfs file for 
>>>>>>>>> rings !\n");
>>>>>>>>> -        }
>>>>>>>>> +        amdgpu_debugfs_ring_init(adev, ring);
>>>>>>>>>       }
>>>>>>>>>         amdgpu_ras_debugfs_create_all(adev);
>>>>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c 
>>>>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
>>>>>>>>> index f40753e1a60d..968521d80514 100644
>>>>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
>>>>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
>>>>>>>>> @@ -415,26 +415,20 @@ static const struct file_operations 
>>>>>>>>> amdgpu_debugfs_ring_fops = {
>>>>>>>>>     #endif
>>>>>>>>>   -int amdgpu_debugfs_ring_init(struct amdgpu_device *adev,
>>>>>>>>> +void amdgpu_debugfs_ring_init(struct amdgpu_device *adev,
>>>>>>>>>                    struct amdgpu_ring *ring)
>>>>>>>>>   {
>>>>>>>>>   #if defined(CONFIG_DEBUG_FS)
>>>>>>>>>       struct drm_minor *minor = adev_to_drm(adev)->primary;
>>>>>>>>> -    struct dentry *ent, *root = minor->debugfs_root;
>>>>>>>>> +    struct dentry *root = minor->debugfs_root;
>>>>>>>>>       char name[32];
>>>>>>>>>         sprintf(name, "amdgpu_ring_%s", ring->name);
>>>>>>>>>   -    ent = debugfs_create_file(name,
>>>>>>>>> -                  S_IFREG | S_IRUGO, root,
>>>>>>>>> -                  ring, &amdgpu_debugfs_ring_fops);
>>>>>>>>> -    if (IS_ERR(ent))
>>>>>>>>> -        return -ENOMEM;
>>>>>>>>
>>>>>>>> Why are we doing this ? Why to make it void from int ?
>>>>>>>
>>>>>>>
>>>>>>> We tend to ignore debugfs return values as those are not serious 
>>>>>>> errors. This to sync with rest of our
>>>>>>>
>>>>>>> debugfs calls.
>>>>>>>
>>>>>>>
>>>>>>> Regards,
>>>>>>>
>>>>>>> Nirmoy
>>>>>>>
>>>>>>
>>>>>>
>>>>>> I am not suere if completely removing the provision of return 
>>>>>> value is a good way of doing it, we can always ignore it at the 
>>>>>> caller side, isn't it ?
>>>>
>>>>
>>>>
>>>> I just realized while making the change debugfs_create_file_size() 
>>>> is void return, so we don't have anything useful to return in 
>>>> amdgpu_debugfs_ring_init()
>>>>
>>>>
>>>
>>> Ah, it makes better sense now. Probably just a mention in the body 
>>> of the message that we are moving from debugfs_create_file() to 
>>> debugfs_create_file_size(), will make this change of return type 
>>> more logical.
>>
>>
>> Yes, I have that "Use debugfs_create_file_size API for creating ring 
>> debugfs file,..."
>>
>>
>
> My bad, I was too focused (and a bit confused due to uasge of 
> clean-up) around the code change.
>
> Suggestion for message: Use debugfs_create_file_size API for creating 
> ring debugfs, and as its a NULL returning API, change the return type 
> for amdgpu_debugfs_ring_init API as well.


Thanks Shashank, I pushed the change with your suggested commit message.


Nirmoy


>
> With (or even without) this change, please feel free to use:
>
> Reviewed-by: Shashank Sharma <shashank.sharma@amd.com>
>
> - Shashank
>
>> Nirmoy
>>
>>>
>>> - Shashank
>>>
>>>> Regards,
>>>>
>>>> Nirmoy
>>>>
>>>>
>>>>>
>>>>>
>>>>> Yes, we are currently throwing an error msg and ignoring it. I 
>>>>> don't have a strong opinion regarding this, I will send a v2 
>>>>> restoring previous behavior.
>>>>>
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Nirmoy
>>>>>
>>>>>
>>>>>>
>>>>>> - Shashank
>>>>>>
>>>>>>>>
>>>>>>>> - Shashank
>>>>>>>>
>>>>>>>>
>>>>>>>>> -
>>>>>>>>> -    i_size_write(ent->d_inode, ring->ring_size + 12);
>>>>>>>>> -    ring->ent = ent;
>>>>>>>>> +    debugfs_create_file_size(name, S_IFREG | S_IRUGO, root, 
>>>>>>>>> ring,
>>>>>>>>> +                 &amdgpu_debugfs_ring_fops,
>>>>>>>>> +                 ring->ring_size + 12);
>>>>>>>>>   #endif
>>>>>>>>> -    return 0;
>>>>>>>>>   }
>>>>>>>>>     /**
>>>>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h 
>>>>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
>>>>>>>>> index 88d80eb3fea1..c29fbce0a5b4 100644
>>>>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
>>>>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
>>>>>>>>> @@ -253,10 +253,6 @@ struct amdgpu_ring {
>>>>>>>>>       bool            has_compute_vm_bug;
>>>>>>>>>       bool            no_scheduler;
>>>>>>>>>       int            hw_prio;
>>>>>>>>> -
>>>>>>>>> -#if defined(CONFIG_DEBUG_FS)
>>>>>>>>> -    struct dentry *ent;
>>>>>>>>> -#endif
>>>>>>>>>   };
>>>>>>>>>     #define amdgpu_ring_parse_cs(r, p, ib) 
>>>>>>>>> ((r)->funcs->parse_cs((p), (ib)))
>>>>>>>>> @@ -356,8 +352,6 @@ static inline void 
>>>>>>>>> amdgpu_ring_write_multiple(struct amdgpu_ring *ring,
>>>>>>>>>     int amdgpu_ring_test_helper(struct amdgpu_ring *ring);
>>>>>>>>>   -int amdgpu_debugfs_ring_init(struct amdgpu_device *adev,
>>>>>>>>> +void amdgpu_debugfs_ring_init(struct amdgpu_device *adev,
>>>>>>>>>                    struct amdgpu_ring *ring);
>>>>>>>>> -void amdgpu_debugfs_ring_fini(struct amdgpu_ring *ring);
>>>>>>>>> -
>>>>>>>>>   #endif
>>>>>>>>>