[PATCH v2 1/8] drm/fb-helper: Handle function NULL argument

[Noralf Trønnes]

Den 17.10.2017 14.38, skrev Daniel Vetter:
> On Sun, Oct 15, 2017 at 06:30:35PM +0200, Noralf Trønnes wrote:
>> Make functions tolerate that the drm_fb_helper argument is NULL.
>> This is useful for drivers that continue probing when fbdev emulation
>> fails and not having to do this check themselves.
>> Update docs for functions that already handles this.
>>
>> Signed-off-by: Noralf Trønnes <noralf at tronnes.org>
> Is there callsites that we can now simplify? Should we add a todo.rst
> entry if there's too many?

A quick scan didn't reveal any except for some .lastclose implementations
that will be taken care of by the new lastclose helper.

Noralf.

> Patch itself looks good.
>
> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
>
>> ---
>>   drivers/gpu/drm/drm_fb_helper.c | 28 +++++++++++++++++-----------
>>   1 file changed, 17 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
>> index 116d1f1337c7..954cdd48de92 100644
>> --- a/drivers/gpu/drm/drm_fb_helper.c
>> +++ b/drivers/gpu/drm/drm_fb_helper.c
>> @@ -150,6 +150,9 @@ int drm_fb_helper_add_one_connector(struct drm_fb_helper *fb_helper,
>>   {
>>   	int err;
>>   
>> +	if (!fb_helper)
>> +		return 0;
>> +
>>   	mutex_lock(&fb_helper->lock);
>>   	err = __drm_fb_helper_add_one_connector(fb_helper, connector);
>>   	mutex_unlock(&fb_helper->lock);
>> @@ -161,7 +164,7 @@ EXPORT_SYMBOL(drm_fb_helper_add_one_connector);
>>   /**
>>    * drm_fb_helper_single_add_all_connectors() - add all connectors to fbdev
>>    * 					       emulation helper
>> - * @fb_helper: fbdev initialized with drm_fb_helper_init
>> + * @fb_helper: fbdev initialized with drm_fb_helper_init, can be NULL
>>    *
>>    * This functions adds all the available connectors for use with the given
>>    * fb_helper. This is a separate step to allow drivers to freely assign
>> @@ -179,7 +182,7 @@ int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
>>   	struct drm_connector_list_iter conn_iter;
>>   	int i, ret = 0;
>>   
>> -	if (!drm_fbdev_emulation)
>> +	if (!drm_fbdev_emulation || !fb_helper)
>>   		return 0;
>>   
>>   	mutex_lock(&fb_helper->lock);
>> @@ -245,6 +248,9 @@ int drm_fb_helper_remove_one_connector(struct drm_fb_helper *fb_helper,
>>   {
>>   	int err;
>>   
>> +	if (!fb_helper)
>> +		return 0;
>> +
>>   	mutex_lock(&fb_helper->lock);
>>   	err = __drm_fb_helper_remove_one_connector(fb_helper, connector);
>>   	mutex_unlock(&fb_helper->lock);
>> @@ -484,7 +490,7 @@ static int restore_fbdev_mode(struct drm_fb_helper *fb_helper)
>>   
>>   /**
>>    * drm_fb_helper_restore_fbdev_mode_unlocked - restore fbdev configuration
>> - * @fb_helper: fbcon to restore
>> + * @fb_helper: driver-allocated fbdev helper, can be NULL
>>    *
>>    * This should be called from driver's drm &drm_driver.lastclose callback
>>    * when implementing an fbcon on top of kms using this helper. This ensures that
>> @@ -498,7 +504,7 @@ int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper)
>>   	bool do_delayed;
>>   	int ret;
>>   
>> -	if (!drm_fbdev_emulation)
>> +	if (!drm_fbdev_emulation || !fb_helper)
>>   		return -ENODEV;
>>   
>>   	if (READ_ONCE(fb_helper->deferred_setup))
>> @@ -883,7 +889,7 @@ EXPORT_SYMBOL(drm_fb_helper_alloc_fbi);
>>   
>>   /**
>>    * drm_fb_helper_unregister_fbi - unregister fb_info framebuffer device
>> - * @fb_helper: driver-allocated fbdev helper
>> + * @fb_helper: driver-allocated fbdev helper, can be NULL
>>    *
>>    * A wrapper around unregister_framebuffer, to release the fb_info
>>    * framebuffer device. This must be called before releasing all resources for
>> @@ -898,7 +904,7 @@ EXPORT_SYMBOL(drm_fb_helper_unregister_fbi);
>>   
>>   /**
>>    * drm_fb_helper_fini - finialize a &struct drm_fb_helper
>> - * @fb_helper: driver-allocated fbdev helper
>> + * @fb_helper: driver-allocated fbdev helper, can be NULL
>>    *
>>    * This cleans up all remaining resources associated with @fb_helper. Must be
>>    * called after drm_fb_helper_unlink_fbi() was called.
>> @@ -937,7 +943,7 @@ EXPORT_SYMBOL(drm_fb_helper_fini);
>>   
>>   /**
>>    * drm_fb_helper_unlink_fbi - wrapper around unlink_framebuffer
>> - * @fb_helper: driver-allocated fbdev helper
>> + * @fb_helper: driver-allocated fbdev helper, can be NULL
>>    *
>>    * A wrapper around unlink_framebuffer implemented by fbdev core
>>    */
>> @@ -1138,7 +1144,7 @@ EXPORT_SYMBOL(drm_fb_helper_cfb_imageblit);
>>   
>>   /**
>>    * drm_fb_helper_set_suspend - wrapper around fb_set_suspend
>> - * @fb_helper: driver-allocated fbdev helper
>> + * @fb_helper: driver-allocated fbdev helper, can be NULL
>>    * @suspend: whether to suspend or resume
>>    *
>>    * A wrapper around fb_set_suspend implemented by fbdev core.
>> @@ -1155,7 +1161,7 @@ EXPORT_SYMBOL(drm_fb_helper_set_suspend);
>>   /**
>>    * drm_fb_helper_set_suspend_unlocked - wrapper around fb_set_suspend that also
>>    *                                      takes the console lock
>> - * @fb_helper: driver-allocated fbdev helper
>> + * @fb_helper: driver-allocated fbdev helper, can be NULL
>>    * @suspend: whether to suspend or resume
>>    *
>>    * A wrapper around fb_set_suspend() that takes the console lock. If the lock
>> @@ -2568,7 +2574,7 @@ EXPORT_SYMBOL(drm_fb_helper_initial_config);
>>   /**
>>    * drm_fb_helper_hotplug_event - respond to a hotplug notification by
>>    *                               probing all the outputs attached to the fb
>> - * @fb_helper: the drm_fb_helper
>> + * @fb_helper: driver-allocated fbdev helper, can be NULL
>>    *
>>    * Scan the connectors attached to the fb_helper and try to put together a
>>    * setup after notification of a change in output configuration.
>> @@ -2590,7 +2596,7 @@ int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
>>   {
>>   	int err = 0;
>>   
>> -	if (!drm_fbdev_emulation)
>> +	if (!drm_fbdev_emulation || !fb_helper)
>>   		return 0;
>>   
>>   	mutex_lock(&fb_helper->lock);
>> -- 
>> 2.14.2
>>