Re: [PATCH] drm: Replace drm_modeset_lock/unlock_all with DRM_MODESET_LOCK_ALL_* helpers

From: MichaÅ OrzeÅ
Date: Thu Apr 30 2020 - 01:53:00 EST




On 29.04.2020 10:57, Jani Nikula wrote:
> On Tue, 28 Apr 2020, Michal Orzel <michalorzel.eng@xxxxxxxxx> wrote:
>> As suggested by the TODO list for the kernel DRM subsystem, replace
>> the deprecated functions that take/drop modeset locks with new helpers.
>>
>> Signed-off-by: Michal Orzel <michalorzel.eng@xxxxxxxxx>
>> ---
>> drivers/gpu/drm/drm_mode_object.c | 10 ++++++----
>> 1 file changed, 6 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_mode_object.c b/drivers/gpu/drm/drm_mode_object.c
>> index 35c2719..901b078 100644
>> --- a/drivers/gpu/drm/drm_mode_object.c
>> +++ b/drivers/gpu/drm/drm_mode_object.c
>> @@ -402,12 +402,13 @@ int drm_mode_obj_get_properties_ioctl(struct drm_device *dev, void *data,
>> {
>> struct drm_mode_obj_get_properties *arg = data;
>> struct drm_mode_object *obj;
>> + struct drm_modeset_acquire_ctx ctx;
>> int ret = 0;
>>
>> if (!drm_core_check_feature(dev, DRIVER_MODESET))
>> return -EOPNOTSUPP;
>>
>> - drm_modeset_lock_all(dev);
>> + DRM_MODESET_LOCK_ALL_BEGIN(dev, ctx, 0, ret);
>
> I cry a little every time I look at the DRM_MODESET_LOCK_ALL_BEGIN and
> DRM_MODESET_LOCK_ALL_END macros. :(
>
> Currently only six users... but there are ~60 calls to
> drm_modeset_lock_all{,_ctx} that I presume are to be replaced. I wonder
> if this will come back and haunt us.
>
> BR,
> Jani.

Hm, so we can either replace all of these calls(I think it's a better option) or abandon the idea of removing this deprecated function.
In the latter scenario, it'd be beneficial to remove this from TODO.

Best regards
Michal

>
>
>>
>> obj = drm_mode_object_find(dev, file_priv, arg->obj_id, arg->obj_type);
>> if (!obj) {
>> @@ -427,7 +428,7 @@ int drm_mode_obj_get_properties_ioctl(struct drm_device *dev, void *data,
>> out_unref:
>> drm_mode_object_put(obj);
>> out:
>> - drm_modeset_unlock_all(dev);
>> + DRM_MODESET_LOCK_ALL_END(ctx, ret);
>> return ret;
>> }
>>
>> @@ -449,12 +450,13 @@ static int set_property_legacy(struct drm_mode_object *obj,
>> {
>> struct drm_device *dev = prop->dev;
>> struct drm_mode_object *ref;
>> + struct drm_modeset_acquire_ctx ctx;
>> int ret = -EINVAL;
>>
>> if (!drm_property_change_valid_get(prop, prop_value, &ref))
>> return -EINVAL;
>>
>> - drm_modeset_lock_all(dev);
>> + DRM_MODESET_LOCK_ALL_BEGIN(dev, ctx, 0, ret);
>> switch (obj->type) {
>> case DRM_MODE_OBJECT_CONNECTOR:
>> ret = drm_connector_set_obj_prop(obj, prop, prop_value);
>> @@ -468,7 +470,7 @@ static int set_property_legacy(struct drm_mode_object *obj,
>> break;
>> }
>> drm_property_change_valid_put(prop, ref);
>> - drm_modeset_unlock_all(dev);
>> + DRM_MODESET_LOCK_ALL_END(ctx, ret);
>>
>> return ret;
>> }
>