On 2020-07-15 13:50, Chris Wilson wrote:
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: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Minor nit below,
Otherwise
Reviewed-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_active.c | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c
index d960d0be5bd2..841b5c30950a 100644
--- a/drivers/gpu/drm/i915/i915_active.c
+++ b/drivers/gpu/drm/i915/i915_active.c
@@ -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;
@@ -423,23 +431,22 @@ 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);
- }
+ err = ref->active(ref);
+ if (!err)
+ __i915_active_activate(ref);
}
mutex_unlock(&ref->mutex);
-
Unrelated
return err;
}
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