2020-10-30 09:28:45

by Tian Tao

[permalink] [raw]
Subject: [PATCH] drm/hisilicon: Remove redundant null check

drm_irq_uninstall can handle the case where dev->irq_enable is false,
so Remove redundant null check.

Signed-off-by: Tian Tao <[email protected]>
---
drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
index 0c1b40d..b71589b1 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
@@ -246,13 +246,13 @@ static int hibmc_unload(struct drm_device *dev)

drm_atomic_helper_shutdown(dev);

- if (dev->irq_enabled)
- drm_irq_uninstall(dev);
-
+ drm_irq_uninstall(dev);
pci_disable_msi(dev->pdev);
+
hibmc_kms_fini(priv);
hibmc_mm_fini(priv);
dev->dev_private = NULL;
+
return 0;
}

--
2.7.4


2020-11-02 08:35:03

by Thomas Zimmermann

[permalink] [raw]
Subject: Re: [PATCH] drm/hisilicon: Remove redundant null check

Hi

Am 30.10.20 um 10:27 schrieb Tian Tao:
> drm_irq_uninstall can handle the case where dev->irq_enable is false,
> so Remove redundant null check.
>
> Signed-off-by: Tian Tao <[email protected]>
> ---
> drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
> index 0c1b40d..b71589b1 100644
> --- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
> +++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
> @@ -246,13 +246,13 @@ static int hibmc_unload(struct drm_device *dev)
>
> drm_atomic_helper_shutdown(dev);
>
> - if (dev->irq_enabled)
> - drm_irq_uninstall(dev);
> -
> + drm_irq_uninstall(dev);

Removing this check would at least result in an error, [1] so rather
leave it in for now.

Instead, we could discuss if drm_irq_install() should become a managed
interface.

Best regards
Thomas

[1]
https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/drm_irq.c#L201

> pci_disable_msi(dev->pdev);
> +
> hibmc_kms_fini(priv);
> hibmc_mm_fini(priv);
> dev->dev_private = NULL;
> +
> return 0;
> }
>
>

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer


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2020-11-02 08:51:07

by tiantao (H)

[permalink] [raw]
Subject: Re: [PATCH] drm/hisilicon: Remove redundant null check



在 2020/11/2 16:32, Thomas Zimmermann 写道:
> Hi
>
> Am 30.10.20 um 10:27 schrieb Tian Tao:
>> drm_irq_uninstall can handle the case where dev->irq_enable is false,
>> so Remove redundant null check.
>>
>> Signed-off-by: Tian Tao <[email protected]>
>> ---
>> drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
>> index 0c1b40d..b71589b1 100644
>> --- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
>> +++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
>> @@ -246,13 +246,13 @@ static int hibmc_unload(struct drm_device *dev)
>>
>> drm_atomic_helper_shutdown(dev);
>>
>> - if (dev->irq_enabled)
>> - drm_irq_uninstall(dev);
>> -
>> + drm_irq_uninstall(dev);
>
> Removing this check would at least result in an error, [1] so rather
> leave it in for now.
>
Now there seems to be no driver to check the return value of
drm_irq_uninstall
> Instead, we could discuss if drm_irq_install() should become a managed
> interface.

Codes like the following
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 09d6e9e..572357c 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -172,6 +172,9 @@ int drm_irq_uninstall(struct drm_device *dev)
bool irq_enabled;
int i;

+ if(!dev->irq_enabled || !dev)
+ return 0;

>
> Best regards
> Thomas
>
> [1]
> https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/drm_irq.c#L201
>
>> pci_disable_msi(dev->pdev);
>> +
>> hibmc_kms_fini(priv);
>> hibmc_mm_fini(priv);
>> dev->dev_private = NULL;
>> +
>> return 0;
>> }
>>
>>
>

2020-11-02 09:07:22

by Thomas Zimmermann

[permalink] [raw]
Subject: Re: [PATCH] drm/hisilicon: Remove redundant null check

Hi

Am 02.11.20 um 09:46 schrieb tiantao (H):
>
>
> 在 2020/11/2 16:32, Thomas Zimmermann 写道:
>> Hi
>>
>> Am 30.10.20 um 10:27 schrieb Tian Tao:
>>> drm_irq_uninstall can handle the case where dev->irq_enable is false,
>>> so Remove redundant null check.
>>>
>>> Signed-off-by: Tian Tao <[email protected]>
>>> ---
>>>   drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c | 6 +++---
>>>   1 file changed, 3 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
>>> b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
>>> index 0c1b40d..b71589b1 100644
>>> --- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
>>> +++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
>>> @@ -246,13 +246,13 @@ static int hibmc_unload(struct drm_device *dev)
>>>         drm_atomic_helper_shutdown(dev);
>>>   -    if (dev->irq_enabled)
>>> -        drm_irq_uninstall(dev);
>>> -
>>> +    drm_irq_uninstall(dev);
>>
>> Removing this check would at least result in an error, [1] so rather
>> leave it in for now.
>>
> Now there seems to be no driver to check the return value of
> drm_irq_uninstall

True. No clean-up code should ever fail. But currently, it's not handled
by drm_irq_uninstall().

A better fix would be to have drm_irq_uninstall() return early with a
warning if IRQs are disabled. And for most drivers, a managed version of
drm_irq_install() would be useful.

Best regards
Thomas

>> Instead, we could discuss if drm_irq_install() should become a managed
>> interface.
>
> Codes like the following
> diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
> index 09d6e9e..572357c 100644
> --- a/drivers/gpu/drm/drm_irq.c
> +++ b/drivers/gpu/drm/drm_irq.c
> @@ -172,6 +172,9 @@ int drm_irq_uninstall(struct drm_device *dev)
>         bool irq_enabled;
>         int i;
>
> +       if(!dev->irq_enabled || !dev)
> +               return 0;
>
>>
>> Best regards
>> Thomas
>>
>> [1]
>> https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/drm_irq.c#L201
>>
>>
>>>       pci_disable_msi(dev->pdev);
>>> +
>>>       hibmc_kms_fini(priv);
>>>       hibmc_mm_fini(priv);
>>>       dev->dev_private = NULL;
>>> +
>>>       return 0;
>>>   }
>>>  
>>
>

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer


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2020-11-02 09:12:51

by tiantao (H)

[permalink] [raw]
Subject: Re: [PATCH] drm/hisilicon: Remove redundant null check



在 2020/11/2 17:03, Thomas Zimmermann 写道:
> Hi
>
> Am 02.11.20 um 09:46 schrieb tiantao (H):
>>
>>
>> 在 2020/11/2 16:32, Thomas Zimmermann 写道:
>>> Hi
>>>
>>> Am 30.10.20 um 10:27 schrieb Tian Tao:
>>>> drm_irq_uninstall can handle the case where dev->irq_enable is false,
>>>> so Remove redundant null check.
>>>>
>>>> Signed-off-by: Tian Tao <[email protected]>
>>>> ---
>>>>   drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c | 6 +++---
>>>>   1 file changed, 3 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
>>>> b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
>>>> index 0c1b40d..b71589b1 100644
>>>> --- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
>>>> +++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
>>>> @@ -246,13 +246,13 @@ static int hibmc_unload(struct drm_device *dev)
>>>>         drm_atomic_helper_shutdown(dev);
>>>>   -    if (dev->irq_enabled)
>>>> -        drm_irq_uninstall(dev);
>>>> -
>>>> +    drm_irq_uninstall(dev);
>>>
>>> Removing this check would at least result in an error, [1] so rather
>>> leave it in for now.
>>>
>> Now there seems to be no driver to check the return value of
>> drm_irq_uninstall
>
> True. No clean-up code should ever fail. But currently, it's not handled
> by drm_irq_uninstall().
>
> A better fix would be to have drm_irq_uninstall() return early with a
> warning if IRQs are disabled. And for most drivers, a managed version of
> drm_irq_install() would be useful.
>
Codes like the following
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 09d6e9e..572357c 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -172,6 +172,9 @@ int drm_irq_uninstall(struct drm_device *dev)
bool irq_enabled;
int i;

+ if(!dev->irq_enabled || !dev)
+ return 0;
> Best regards
> Thomas
>
>>> Instead, we could discuss if drm_irq_install() should become a managed
>>> interface.
>>
>> Codes like the following
>> diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
>> index 09d6e9e..572357c 100644
>> --- a/drivers/gpu/drm/drm_irq.c
>> +++ b/drivers/gpu/drm/drm_irq.c
>> @@ -172,6 +172,9 @@ int drm_irq_uninstall(struct drm_device *dev)
>>         bool irq_enabled;
>>         int i;
>>
>> +       if(!dev->irq_enabled || !dev)
>> +               return 0;
>>
>>>
>>> Best regards
>>> Thomas
>>>
>>> [1]
>>> https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/drm_irq.c#L201
>>>
>>>
>>>>       pci_disable_msi(dev->pdev);
>>>> +
>>>>       hibmc_kms_fini(priv);
>>>>       hibmc_mm_fini(priv);
>>>>       dev->dev_private = NULL;
>>>> +
>>>>       return 0;
>>>>   }
>>>>
>>>
>>
>