On Tue, Apr 26, 2016 at 07:29:42PM +0200, Daniel Vetter wrote:
> Finally all the core gem and a lot of drivers are entirely free of
> dev->struct_mutex depencies, and we can start to have an entirely
> lockless unref path.
>
> To make sure that no one who touches the core code accidentally breaks
> existing drivers which still require dev->struct_mutex I've made the
> might_lock check unconditional.
>
> While at it de-inline the ref/unref functions, they've become a bit
> too big.
>
> v2: Make it not leak like a sieve.
>
> Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
> ---
> drivers/gpu/drm/drm_gem.c | 64 ++++++++++++++++++++++++++++++++++++++---------
> include/drm/drmP.h | 12 ++++++++-
> include/drm/drm_gem.h | 45 ++-------------------------------
> 3 files changed, 65 insertions(+), 56 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> index 25dac31eef37..8f2eff448bb5 100644
> --- a/drivers/gpu/drm/drm_gem.c
> +++ b/drivers/gpu/drm/drm_gem.c
> @@ -788,16 +788,7 @@ drm_gem_object_release(struct drm_gem_object *obj)
> }
> EXPORT_SYMBOL(drm_gem_object_release);
>
> -/**
> - * drm_gem_object_free - free a GEM object
> - * @kref: kref of the object to free
> - *
> - * Called after the last reference to the object has been lost.
> - * Must be called holding struct_ mutex
> - *
> - * Frees the object
> - */
> -void
> +static void
> drm_gem_object_free(struct kref *kref)
> {
> struct drm_gem_object *obj =
> @@ -806,10 +797,59 @@ drm_gem_object_free(struct kref *kref)
>
> WARN_ON(!mutex_is_locked(&dev->struct_mutex));
>
> - if (dev->driver->gem_free_object != NULL)
> + if (dev->driver->gem_free_object_unlocked != NULL)
> + dev->driver->gem_free_object_unlocked(obj);
> + else if (dev->driver->gem_free_object != NULL)
> dev->driver->gem_free_object(obj);
> }
> -EXPORT_SYMBOL(drm_gem_object_free);
> +
> +/**
> + * drm_gem_object_unreference_unlocked - release a GEM BO reference
> + * @obj: GEM buffer object
> + *
> + * This releases a reference to @obj. Callers must not hold the
> + * dev->struct_mutex lock when calling this function.
> + */
> +void
> +drm_gem_object_unreference_unlocked(struct drm_gem_object *obj)
> +{
I have i915.ko in a state where we could use this as well. I would like
to have our inlines back though. I would add
static inline void
i915_gem_object_put(struct drm_i915_gem_object *obj)
{
kref_put(&obj->base.refcount, drm_gem_object_free);
}
Hmm, considering how simple that is, maybe I won't ask for
static inline void
__drm_gem_object_unreference_unlocked(struct drm_gem_object *obj)
{
BUG_ON(obj->dev->driver->gem_free_object == NULL);
kref_put(&obj->refcount, drm_gem_object_free);
}
after all!
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
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