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

["Sharma, Shashank" <shashank.sharma@amd.com>]

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.

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
>>>>>>>>