2020-02-10 11:38:49

by Gerd Hoffmann

[permalink] [raw]
Subject: [PATCH v2 2/2] drm/qxl: add drm_driver.release callback.

Move final cleanups to qxl_drm_release() callback.
Add drm_atomic_helper_shutdown() call to qxl_pci_remove().

Signed-off-by: Gerd Hoffmann <[email protected]>
---
drivers/gpu/drm/qxl/qxl_drv.c | 26 +++++++++++++++++++-------
1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/qxl/qxl_drv.c b/drivers/gpu/drm/qxl/qxl_drv.c
index 1d601f57a6ba..4fda3f9b29f4 100644
--- a/drivers/gpu/drm/qxl/qxl_drv.c
+++ b/drivers/gpu/drm/qxl/qxl_drv.c
@@ -34,6 +34,7 @@
#include <linux/pci.h>

#include <drm/drm.h>
+#include <drm/drm_atomic_helper.h>
#include <drm/drm_drv.h>
#include <drm/drm_file.h>
#include <drm/drm_modeset_helper.h>
@@ -132,21 +133,30 @@ qxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
return ret;
}

+static void qxl_drm_release(struct drm_device *dev)
+{
+ struct qxl_device *qdev = dev->dev_private;
+
+ /*
+ * TODO: qxl_device_fini() call should be in qxl_pci_remove(),
+ * reodering qxl_modeset_fini() + qxl_device_fini() calls is
+ * non-trivial though.
+ */
+ qxl_modeset_fini(qdev);
+ qxl_device_fini(qdev);
+ dev->dev_private = NULL;
+ kfree(qdev);
+}
+
static void
qxl_pci_remove(struct pci_dev *pdev)
{
struct drm_device *dev = pci_get_drvdata(pdev);
- struct qxl_device *qdev = dev->dev_private;

drm_dev_unregister(dev);
-
- qxl_modeset_fini(qdev);
- qxl_device_fini(qdev);
+ drm_atomic_helper_shutdown(dev);
if (is_vga(pdev))
vga_put(pdev, VGA_RSRC_LEGACY_IO);
-
- dev->dev_private = NULL;
- kfree(qdev);
drm_dev_put(dev);
}

@@ -279,6 +289,8 @@ static struct drm_driver qxl_driver = {
.major = 0,
.minor = 1,
.patchlevel = 0,
+
+ .release = qxl_drm_release,
};

static int __init qxl_init(void)
--
2.18.1


2020-02-10 15:07:31

by Daniel Vetter

[permalink] [raw]
Subject: Re: [PATCH v2 2/2] drm/qxl: add drm_driver.release callback.

On Mon, Feb 10, 2020 at 12:37:52PM +0100, Gerd Hoffmann wrote:
> Move final cleanups to qxl_drm_release() callback.
> Add drm_atomic_helper_shutdown() call to qxl_pci_remove().
>
> Signed-off-by: Gerd Hoffmann <[email protected]>
> ---
> drivers/gpu/drm/qxl/qxl_drv.c | 26 +++++++++++++++++++-------
> 1 file changed, 19 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/qxl/qxl_drv.c b/drivers/gpu/drm/qxl/qxl_drv.c
> index 1d601f57a6ba..4fda3f9b29f4 100644
> --- a/drivers/gpu/drm/qxl/qxl_drv.c
> +++ b/drivers/gpu/drm/qxl/qxl_drv.c
> @@ -34,6 +34,7 @@
> #include <linux/pci.h>
>
> #include <drm/drm.h>
> +#include <drm/drm_atomic_helper.h>
> #include <drm/drm_drv.h>
> #include <drm/drm_file.h>
> #include <drm/drm_modeset_helper.h>
> @@ -132,21 +133,30 @@ qxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
> return ret;
> }
>
> +static void qxl_drm_release(struct drm_device *dev)
> +{
> + struct qxl_device *qdev = dev->dev_private;
> +
> + /*
> + * TODO: qxl_device_fini() call should be in qxl_pci_remove(),
> + * reodering qxl_modeset_fini() + qxl_device_fini() calls is
> + * non-trivial though.
> + */
> + qxl_modeset_fini(qdev);

So the drm_mode_config_cleanup call in here belongs in ->release, but the
qxl_destroy_monitors_object feels like should be perfectly fine in the
remove hook. You might need to sprinkle a few drm_dev_enter/exit around to
protect code paths thought.

Aside from this lgtm, for the series

Acked-by: Daniel Vetter <[email protected]>

And up to you whether you want to fix this or not really.

Btw for testing all these patches that add a ->release hook I think it'd
be good if the drm core checks that drm_device->dev is set to NULL, and
that we do this in the remove hook. Since that's guaranteed to be gone at
that point, so anything in ->release that still needs the device is
broken. Ofc maybe do that check only for drivers which have a ->release
hook, and we might need a few fixups.

Cheers, Daniel

> + qxl_device_fini(qdev);
> + dev->dev_private = NULL;
> + kfree(qdev);
> +}
> +
> static void
> qxl_pci_remove(struct pci_dev *pdev)
> {
> struct drm_device *dev = pci_get_drvdata(pdev);
> - struct qxl_device *qdev = dev->dev_private;
>
> drm_dev_unregister(dev);
> -
> - qxl_modeset_fini(qdev);
> - qxl_device_fini(qdev);
> + drm_atomic_helper_shutdown(dev);
> if (is_vga(pdev))
> vga_put(pdev, VGA_RSRC_LEGACY_IO);
> -
> - dev->dev_private = NULL;
> - kfree(qdev);
> drm_dev_put(dev);
> }
>
> @@ -279,6 +289,8 @@ static struct drm_driver qxl_driver = {
> .major = 0,
> .minor = 1,
> .patchlevel = 0,
> +
> + .release = qxl_drm_release,
> };
>
> static int __init qxl_init(void)
> --
> 2.18.1
>

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

2020-02-10 16:58:38

by Noralf Trønnes

[permalink] [raw]
Subject: Re: [PATCH v2 2/2] drm/qxl: add drm_driver.release callback.



Den 10.02.2020 16.06, skrev Daniel Vetter:
> On Mon, Feb 10, 2020 at 12:37:52PM +0100, Gerd Hoffmann wrote:
>> Move final cleanups to qxl_drm_release() callback.
>> Add drm_atomic_helper_shutdown() call to qxl_pci_remove().
>>
>> Signed-off-by: Gerd Hoffmann <[email protected]>
>> ---
>> drivers/gpu/drm/qxl/qxl_drv.c | 26 +++++++++++++++++++-------
>> 1 file changed, 19 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/qxl/qxl_drv.c b/drivers/gpu/drm/qxl/qxl_drv.c
>> index 1d601f57a6ba..4fda3f9b29f4 100644
>> --- a/drivers/gpu/drm/qxl/qxl_drv.c
>> +++ b/drivers/gpu/drm/qxl/qxl_drv.c
>> @@ -34,6 +34,7 @@
>> #include <linux/pci.h>
>>
>> #include <drm/drm.h>
>> +#include <drm/drm_atomic_helper.h>
>> #include <drm/drm_drv.h>
>> #include <drm/drm_file.h>
>> #include <drm/drm_modeset_helper.h>
>> @@ -132,21 +133,30 @@ qxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>> return ret;
>> }
>>
>> +static void qxl_drm_release(struct drm_device *dev)
>> +{
>> + struct qxl_device *qdev = dev->dev_private;
>> +
>> + /*
>> + * TODO: qxl_device_fini() call should be in qxl_pci_remove(),
>> + * reodering qxl_modeset_fini() + qxl_device_fini() calls is
>> + * non-trivial though.
>> + */
>> + qxl_modeset_fini(qdev);
>
> So the drm_mode_config_cleanup call in here belongs in ->release, but the
> qxl_destroy_monitors_object feels like should be perfectly fine in the
> remove hook. You might need to sprinkle a few drm_dev_enter/exit around to
> protect code paths thought.
>
> Aside from this lgtm, for the series
>
> Acked-by: Daniel Vetter <[email protected]>
>
> And up to you whether you want to fix this or not really.
>
> Btw for testing all these patches that add a ->release hook I think it'd
> be good if the drm core checks that drm_device->dev is set to NULL, and
> that we do this in the remove hook. Since that's guaranteed to be gone at
> that point, so anything in ->release that still needs the device is
> broken. Ofc maybe do that check only for drivers which have a ->release
> hook, and we might need a few fixups.
>

We take a ref on the parent device in drm_dev_init() and release it in
drm_dev_fini(). I added this because of the DRM_DEV_* macros we have, to
protect access to the device struct after it was unregistered. Setting
drm_device->dev to NULL in drm_dev_unregister() instead will provide the
same protection I think.

commit 56be6503aab2
drm/drv: Hold ref on parent device during drm_device lifetime

Noralf.

> Cheers, Daniel
>
>> + qxl_device_fini(qdev);
>> + dev->dev_private = NULL;
>> + kfree(qdev);
>> +}
>> +
>> static void
>> qxl_pci_remove(struct pci_dev *pdev)
>> {
>> struct drm_device *dev = pci_get_drvdata(pdev);
>> - struct qxl_device *qdev = dev->dev_private;
>>
>> drm_dev_unregister(dev);
>> -
>> - qxl_modeset_fini(qdev);
>> - qxl_device_fini(qdev);
>> + drm_atomic_helper_shutdown(dev);
>> if (is_vga(pdev))
>> vga_put(pdev, VGA_RSRC_LEGACY_IO);
>> -
>> - dev->dev_private = NULL;
>> - kfree(qdev);
>> drm_dev_put(dev);
>> }
>>
>> @@ -279,6 +289,8 @@ static struct drm_driver qxl_driver = {
>> .major = 0,
>> .minor = 1,
>> .patchlevel = 0,
>> +
>> + .release = qxl_drm_release,
>> };
>>
>> static int __init qxl_init(void)
>> --
>> 2.18.1
>>
>

2020-02-10 17:00:02

by Noralf Trønnes

[permalink] [raw]
Subject: Re: [PATCH v2 2/2] drm/qxl: add drm_driver.release callback.

(adding back Daniel)

Den 10.02.2020 17.57, skrev Noralf Trønnes:
>
>
> Den 10.02.2020 16.06, skrev Daniel Vetter:
>> On Mon, Feb 10, 2020 at 12:37:52PM +0100, Gerd Hoffmann wrote:
>>> Move final cleanups to qxl_drm_release() callback.
>>> Add drm_atomic_helper_shutdown() call to qxl_pci_remove().
>>>
>>> Signed-off-by: Gerd Hoffmann <[email protected]>
>>> ---
>>> drivers/gpu/drm/qxl/qxl_drv.c | 26 +++++++++++++++++++-------
>>> 1 file changed, 19 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/qxl/qxl_drv.c b/drivers/gpu/drm/qxl/qxl_drv.c
>>> index 1d601f57a6ba..4fda3f9b29f4 100644
>>> --- a/drivers/gpu/drm/qxl/qxl_drv.c
>>> +++ b/drivers/gpu/drm/qxl/qxl_drv.c
>>> @@ -34,6 +34,7 @@
>>> #include <linux/pci.h>
>>>
>>> #include <drm/drm.h>
>>> +#include <drm/drm_atomic_helper.h>
>>> #include <drm/drm_drv.h>
>>> #include <drm/drm_file.h>
>>> #include <drm/drm_modeset_helper.h>
>>> @@ -132,21 +133,30 @@ qxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>>> return ret;
>>> }
>>>
>>> +static void qxl_drm_release(struct drm_device *dev)
>>> +{
>>> + struct qxl_device *qdev = dev->dev_private;
>>> +
>>> + /*
>>> + * TODO: qxl_device_fini() call should be in qxl_pci_remove(),
>>> + * reodering qxl_modeset_fini() + qxl_device_fini() calls is
>>> + * non-trivial though.
>>> + */
>>> + qxl_modeset_fini(qdev);
>>
>> So the drm_mode_config_cleanup call in here belongs in ->release, but the
>> qxl_destroy_monitors_object feels like should be perfectly fine in the
>> remove hook. You might need to sprinkle a few drm_dev_enter/exit around to
>> protect code paths thought.
>>
>> Aside from this lgtm, for the series
>>
>> Acked-by: Daniel Vetter <[email protected]>
>>
>> And up to you whether you want to fix this or not really.
>>
>> Btw for testing all these patches that add a ->release hook I think it'd
>> be good if the drm core checks that drm_device->dev is set to NULL, and
>> that we do this in the remove hook. Since that's guaranteed to be gone at
>> that point, so anything in ->release that still needs the device is
>> broken. Ofc maybe do that check only for drivers which have a ->release
>> hook, and we might need a few fixups.
>>
>
> We take a ref on the parent device in drm_dev_init() and release it in
> drm_dev_fini(). I added this because of the DRM_DEV_* macros we have, to
> protect access to the device struct after it was unregistered. Setting
> drm_device->dev to NULL in drm_dev_unregister() instead will provide the
> same protection I think.
>
> commit 56be6503aab2
> drm/drv: Hold ref on parent device during drm_device lifetime
>
> Noralf.
>
>> Cheers, Daniel
>>
>>> + qxl_device_fini(qdev);
>>> + dev->dev_private = NULL;
>>> + kfree(qdev);
>>> +}
>>> +
>>> static void
>>> qxl_pci_remove(struct pci_dev *pdev)
>>> {
>>> struct drm_device *dev = pci_get_drvdata(pdev);
>>> - struct qxl_device *qdev = dev->dev_private;
>>>
>>> drm_dev_unregister(dev);
>>> -
>>> - qxl_modeset_fini(qdev);
>>> - qxl_device_fini(qdev);
>>> + drm_atomic_helper_shutdown(dev);
>>> if (is_vga(pdev))
>>> vga_put(pdev, VGA_RSRC_LEGACY_IO);
>>> -
>>> - dev->dev_private = NULL;
>>> - kfree(qdev);
>>> drm_dev_put(dev);
>>> }
>>>
>>> @@ -279,6 +289,8 @@ static struct drm_driver qxl_driver = {
>>> .major = 0,
>>> .minor = 1,
>>> .patchlevel = 0,
>>> +
>>> + .release = qxl_drm_release,
>>> };
>>>
>>> static int __init qxl_init(void)
>>> --
>>> 2.18.1
>>>
>>
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