On Tue, May 05, 2020 at 07:55:00AM +0200, Michał Orzeł wrote:
>
>
> On 04.05.2020 13:53, Daniel Vetter wrote:
> > On Fri, May 01, 2020 at 05:49:33PM +0200, Michał Orzeł wrote:
> >>
> >>
> >> On 30.04.2020 20:30, Daniel Vetter wrote:
> >>> On Thu, Apr 30, 2020 at 5:38 PM Sean Paul <seanpaul@xxxxxxxxxxxx> wrote:
> >>>>
> >>>> On Wed, Apr 29, 2020 at 4:57 AM Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx> 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.
> >>>>>
> >>>>
> >>>> What's the alternative? Seems like the options without the macros is
> >>>> to use incorrect scope or have a bunch of retry/backoff cargo-cult
> >>>> everywhere (and hope the copy source is done correctly).
> >>>
> >>> Yeah Sean & me had a bunch of bikesheds and this is the least worst
> >>> option we could come up with. You can't make it a function because of
> >>> the control flow. You don't want to open code this because it's tricky
> >>> to get right, if all you want is to just grab all locks. But it is
> >>> magic hidden behind a macro, which occasionally ends up hurting.
> >>> -Daniel
> >> So what are we doing with this problem? Should we replace at once approx. 60 calls?
> >
> > I'm confused by your question - dradual conversion is entirely orthogonal
> > to what exactly we're converting too. All I added here is that we've
> > discussed this at length, and the macro is the best thing we've come up
> > with. I still think it's the best compromise.
> >
> > Flag-day conversion for over 60 calls doesn't work, no matter what.
> > -Daniel
> >
> I agree with that. All I wanted to ask was whether I should add something additional to this patch or not.
Patch looks good and passed CI, so I went ahead and applied it.
Thanks, Daniel
>
> Thanks,
> Michal
> >>
> >> Michal
> >>>
> >>>> Sean
> >>>>
> >>>>> BR,
> >>>>> Jani.
> >>>>>
> >>>>>
> >>>>>>
> >>>>>> 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;
> >>>>>> }
> >>>>>
> >>>>> --
> >>>>> Jani Nikula, Intel Open Source Graphics Center
> >>>
> >>>
> >>>
> >
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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