Messages in this thread Patch in this message | | | Date | Tue, 27 Jun 2023 16:41:35 +0800 | Subject | Re: [PATCH] drm: Remove the deprecated drm_put_dev() function | From | Sui Jingfeng <> |
| |
Hi,
On 2023/6/26 15:56, Thomas Zimmermann wrote: > Hi > > Am 25.06.23 um 07:09 schrieb Sui Jingfeng: >> As this function can be replaced with drm_dev_unregister() + >> drm_dev_put(), >> it is already marked as deprecated, so remove it. No functional change. >> >> Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn> >> --- >> drivers/gpu/drm/drm_drv.c | 28 ---------------------------- >> drivers/gpu/drm/drm_pci.c | 3 ++- >> drivers/gpu/drm/radeon/radeon_drv.c | 3 ++- >> include/drm/drm_drv.h | 1 - >> 4 files changed, 4 insertions(+), 31 deletions(-) >> >> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c >> index 12687dd9e1ac..5057307fe22a 100644 >> --- a/drivers/gpu/drm/drm_drv.c >> +++ b/drivers/gpu/drm/drm_drv.c >> @@ -406,34 +406,6 @@ void drm_minor_release(struct drm_minor *minor) >> * possibly leaving the hardware enabled. >> */ >> -/** >> - * drm_put_dev - Unregister and release a DRM device >> - * @dev: DRM device >> - * >> - * Called at module unload time or when a PCI device is unplugged. >> - * >> - * Cleans up all DRM device, calling drm_lastclose(). >> - * >> - * Note: Use of this function is deprecated. It will eventually go away >> - * completely. Please use drm_dev_unregister() and drm_dev_put() >> explicitly >> - * instead to make sure that the device isn't userspace accessible >> any more >> - * while teardown is in progress, ensuring that userspace can't >> access an >> - * inconsistent state. >> - */ >> -void drm_put_dev(struct drm_device *dev) >> -{ >> - DRM_DEBUG("\n"); >> - >> - if (!dev) { >> - DRM_ERROR("cleanup called no dev\n"); >> - return; >> - } >> - >> - drm_dev_unregister(dev); >> - drm_dev_put(dev); >> -} >> -EXPORT_SYMBOL(drm_put_dev); >> - >> /** >> * drm_dev_enter - Enter device critical section >> * @dev: DRM device >> diff --git a/drivers/gpu/drm/drm_pci.c b/drivers/gpu/drm/drm_pci.c >> index 39d35fc3a43b..b3a68a92eaa6 100644 >> --- a/drivers/gpu/drm/drm_pci.c >> +++ b/drivers/gpu/drm/drm_pci.c >> @@ -257,7 +257,8 @@ void drm_legacy_pci_exit(const struct drm_driver >> *driver, >> legacy_dev_list) { >> if (dev->driver == driver) { >> list_del(&dev->legacy_dev_list); >> - drm_put_dev(dev); >> + drm_dev_unregister(dev); >> + drm_dev_put(dev); >> } >> } >> mutex_unlock(&legacy_dev_list_lock); >> diff --git a/drivers/gpu/drm/radeon/radeon_drv.c >> b/drivers/gpu/drm/radeon/radeon_drv.c >> index e4374814f0ef..a4955ae10659 100644 >> --- a/drivers/gpu/drm/radeon/radeon_drv.c >> +++ b/drivers/gpu/drm/radeon/radeon_drv.c >> @@ -357,7 +357,8 @@ radeon_pci_remove(struct pci_dev *pdev) >> { >> struct drm_device *dev = pci_get_drvdata(pdev); >> - drm_put_dev(dev); > > Did you verify that dev cannot be NULL here? There was a check in > drm_put_dev() for !dev. >
I have verified :
1)
If there is no radeon card(say R5-340) mounted in the system, I modprobe the radeon.ko manually.
then both the radeon_pci_probe() and the radeon_pci_remove() function won't get called.
There is no chance that the driver_probe_device() function getting called.
|- driver_register()
|-- bus_add_driver()
|--- driver_attach()
|---- bus_for_each_dev(drv->bus, NULL, drv, __driver_attach)
|----- __driver_attach()
|------ __device_attach_driver()
// There is no chance that the driver_probe_device() function get called.
|------- driver_probe_device(drv, dev)
```
2) normal case:
If there are radeon cards mounted in the system,
then as long as the pci_set_drvdata(pdev, dev) get called,
the 'driver_data' member of struct device will hold the pointer to the 'struct drm_device';
So, it will be fine as long as the radeon.ko get loaded normally.
I'm sure it will works as expected on normal case, with 100% confident.
3) Abnormal case
If there is a error happen before the 'pci_set_drvdata(pdev, dev)' function get called.
It is also don't need to worry, if the ->probe() failed, then the ->remove will be get called.
I have verified that
if the ->probe() failed, then the ->remove will be get called.
I'm doing the test by add a line before the drm_dev_alloc()
function in the body of radeon_pci_probe() function.
See below:
```
return -ENODEV;
dev = drm_dev_alloc(&kms_driver, &pdev->dev); if (IS_ERR(dev)) return PTR_ERR(dev);
ret = pci_enable_device(pdev); if (ret) goto err_free; ```
So, there is no problem, as far as I can see.
> Best regards > Thomas > >> + drm_dev_unregister(dev); >> + drm_dev_put(dev); >> } >> static void >> diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h >> index 89e2706cac56..289c97b12e82 100644 >> --- a/include/drm/drm_drv.h >> +++ b/include/drm/drm_drv.h >> @@ -511,7 +511,6 @@ void drm_dev_unregister(struct drm_device *dev); >> void drm_dev_get(struct drm_device *dev); >> void drm_dev_put(struct drm_device *dev); >> -void drm_put_dev(struct drm_device *dev); >> bool drm_dev_enter(struct drm_device *dev, int *idx); >> void drm_dev_exit(int idx); >> void drm_dev_unplug(struct drm_device *dev); > -- Jingfeng
| |