Commit 04240e30 authored by Chris Wilson's avatar Chris Wilson Committed by Joonas Lahtinen
Browse files

drm/i915: Skip taking acquire mutex for no ref->active callback 



If no active callback is defined for i915_active, we do not need to
serialise its enabling with the mutex. We still do only want to call the
debug activate once, and must still serialise with a concurrent retire.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: default avatarThomas Hellström <thomas.hellstrom@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200731085015.32368-2-chris@chris-wilson.co.uk


Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
parent bde246d8

drivers/gpu/drm/i915/i915_active.c

+16 −8
Original line number Diff line number Diff line
@@ -416,6 +416,14 @@ bool i915_active_acquire_if_busy(struct i915_active *ref) 
	return atomic_add_unless(&ref->count, 1, 0);

}



static void __i915_active_activate(struct i915_active *ref)

{

	spin_lock_irq(&ref->tree_lock); /* __active_retire() */

	if (!atomic_fetch_inc(&ref->count))

		debug_active_activate(ref);

	spin_unlock_irq(&ref->tree_lock);

}



int i915_active_acquire(struct i915_active *ref)

{

	int err;
@@ -423,19 +431,19 @@ int i915_active_acquire(struct i915_active *ref) 
	if (i915_active_acquire_if_busy(ref))

		return 0;



	if (!ref->active) {

		__i915_active_activate(ref);

		return 0;

	}



	err = mutex_lock_interruptible(&ref->mutex);

	if (err)

		return err;



	if (likely(!i915_active_acquire_if_busy(ref))) {

		if (ref->active)

		err = ref->active(ref);

		if (!err) {

			spin_lock_irq(&ref->tree_lock); /* __active_retire() */

			debug_active_activate(ref);

			atomic_inc(&ref->count);

			spin_unlock_irq(&ref->tree_lock);

		}

		if (!err)

			__i915_active_activate(ref);

	}



	mutex_unlock(&ref->mutex);