Re: [PATCH v2 1/5] drm: Add reservation_object to drm_gem_object

[Daniel Vetter <daniel-/w4YWyX8dFk@public.gmane.org>]

On Fri, Feb 08, 2019 at 08:23:44AM +0100, Christian Gmeiner wrote:
> Am Sa., 2. Feb. 2019 um 16:42 Uhr schrieb Rob Herring <robh@kernel.org>:
> >
> > Many users of drm_gem_object embed a struct reservation_object into
> > their subclassed struct, so let's add one to struct drm_gem_object.
> > This will allow removing the reservation object from the subclasses
> > and removing the ->gem_prime_res_obj callback.
> >
> > With the addition, add a drm_gem_reservation_object_wait() helper
> > function for drivers to use in wait ioctls.
> >
> > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> > Cc: Maxime Ripard <maxime.ripard@bootlin.com>
> > Cc: Sean Paul <sean@poorly.run>
> > Cc: David Airlie <airlied@linux.ie>
> > Cc: Daniel Vetter <daniel@ffwll.ch>
> > Signed-off-by: Rob Herring <robh@kernel.org>
> 
> Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>

Does this extend to 2/5 to update etnaviv?
-Daniel

> 
> > ---
> > v2:
> >  - Fix missing kerneldoc
> >  - Reword todo with what is left todo.
> >  - Fix timeout error handling (added to drm_gem_reservation_object_wait)
> >
> >  Documentation/gpu/todo.rst  |  8 +++----
> >  drivers/gpu/drm/drm_gem.c   | 43 +++++++++++++++++++++++++++++++++++++
> >  drivers/gpu/drm/drm_prime.c |  1 +
> >  include/drm/drm_gem.h       | 21 ++++++++++++++++++
> >  4 files changed, 69 insertions(+), 4 deletions(-)
> >
> > diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
> > index 14191b64446d..c9ed55605641 100644
> > --- a/Documentation/gpu/todo.rst
> > +++ b/Documentation/gpu/todo.rst
> > @@ -209,12 +209,12 @@ Would be great to refactor this all into a set of small common helpers.
> >
> >  Contact: Daniel Vetter
> >
> > -Put a reservation_object into drm_gem_object
> > +Remove the ->gem_prime_res_obj callback
> >  --------------------------------------------
> >
> > -This would remove the need for the ->gem_prime_res_obj callback. It would also
> > -allow us to implement generic helpers for waiting for a bo, allowing for quite a
> > -bit of refactoring in the various wait ioctl implementations.
> > +The ->gem_prime_res_obj callback can be removed from drivers by using the
> > +reservation_object in the drm_gem_object. It may also be possible to use the
> > +generic drm_gem_reservation_object_wait helper for waiting for a bo.
> >
> >  Contact: Daniel Vetter
> >
> > diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> > index 8b55ece97967..b09acbc5a655 100644
> > --- a/drivers/gpu/drm/drm_gem.c
> > +++ b/drivers/gpu/drm/drm_gem.c
> > @@ -170,6 +170,10 @@ void drm_gem_private_object_init(struct drm_device *dev,
> >         kref_init(&obj->refcount);
> >         obj->handle_count = 0;
> >         obj->size = size;
> > +       reservation_object_init(&obj->_resv);
> > +       if (!obj->resv)
> > +               obj->resv = &obj->_resv;
> > +
> >         drm_vma_node_reset(&obj->vma_node);
> >  }
> >  EXPORT_SYMBOL(drm_gem_private_object_init);
> > @@ -657,6 +661,44 @@ drm_gem_object_lookup(struct drm_file *filp, u32 handle)
> >  }
> >  EXPORT_SYMBOL(drm_gem_object_lookup);
> >
> > +/**
> > + * drm_gem_reservation_object_wait - Wait on GEM object's reservation's objects
> > + * shared and/or exclusive fences.
> > + * @filep: DRM file private date
> > + * @handle: userspace handle
> > + * @wait_all: if true, wait on all fences, else wait on just exclusive fence
> > + * @timeout: timeout value in jiffies or zero to return immediately
> > + *
> > + * Returns:
> > + *
> > + * Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or
> > + * greater than 0 on success.
> > + */
> > +long drm_gem_reservation_object_wait(struct drm_file *filep, u32 handle,
> > +                                   bool wait_all, unsigned long timeout)
> > +{
> > +       long ret;
> > +       struct drm_gem_object *obj;
> > +
> > +       obj = drm_gem_object_lookup(filep, handle);
> > +       if (!obj) {
> > +               DRM_DEBUG("Failed to look up GEM BO %d\n", handle);
> > +               return -EINVAL;
> > +       }
> > +
> > +       ret = reservation_object_wait_timeout_rcu(obj->resv, wait_all,
> > +                                                 true, timeout);
> > +       if (ret == 0)
> > +               ret = -ETIME;
> > +       else if (ret > 0)
> > +               ret = 0;
> > +
> > +       drm_gem_object_put_unlocked(obj);
> > +
> > +       return ret;
> > +}
> > +EXPORT_SYMBOL(drm_gem_reservation_object_wait);
> > +
> >  /**
> >   * drm_gem_close_ioctl - implementation of the GEM_CLOSE ioctl
> >   * @dev: drm_device
> > @@ -821,6 +863,7 @@ drm_gem_object_release(struct drm_gem_object *obj)
> >         if (obj->filp)
> >                 fput(obj->filp);
> >
> > +       reservation_object_fini(&obj->_resv);
> >         drm_gem_free_mmap_offset(obj);
> >  }
> >  EXPORT_SYMBOL(drm_gem_object_release);
> > diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
> > index 231e3f6d5f41..dc079efb3b0f 100644
> > --- a/drivers/gpu/drm/drm_prime.c
> > +++ b/drivers/gpu/drm/drm_prime.c
> > @@ -504,6 +504,7 @@ struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
> >                 .size = obj->size,
> >                 .flags = flags,
> >                 .priv = obj,
> > +               .resv = obj->resv,
> >         };
> >
> >         if (dev->driver->gem_prime_res_obj)
> > diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
> > index c95727425284..25f1ff2df464 100644
> > --- a/include/drm/drm_gem.h
> > +++ b/include/drm/drm_gem.h
> > @@ -35,6 +35,7 @@
> >   */
> >
> >  #include <linux/kref.h>
> > +#include <linux/reservation.h>
> >
> >  #include <drm/drm_vma_manager.h>
> >
> > @@ -262,6 +263,24 @@ struct drm_gem_object {
> >          */
> >         struct dma_buf_attachment *import_attach;
> >
> > +       /**
> > +        * @resv:
> > +        *
> > +        * Pointer to reservation object associated with the this GEM object.
> > +        *
> > +        * Normally (@resv == &@_resv) except for imported GEM objects.
> > +        */
> > +       struct reservation_object *resv;
> > +
> > +       /**
> > +        * @_resv:
> > +        *
> > +        * A reservation object for this GEM object.
> > +        *
> > +        * This is unused for imported GEM objects.
> > +        */
> > +       struct reservation_object _resv;
> > +
> >         /**
> >          * @funcs:
> >          *
> > @@ -363,6 +382,8 @@ void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages,
> >                 bool dirty, bool accessed);
> >
> >  struct drm_gem_object *drm_gem_object_lookup(struct drm_file *filp, u32 handle);
> > +long drm_gem_reservation_object_wait(struct drm_file *filep, u32 handle,
> > +                                   bool wait_all, unsigned long timeout);
> >  int drm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev,
> >                             u32 handle, u64 *offset);
> >  int drm_gem_dumb_destroy(struct drm_file *file,
> > --
> > 2.19.1
> >
> 
> 
> -- 
> greets
> --
> Christian Gmeiner, MSc
> 
> https://christian-gmeiner.info

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