The locks (active.lock and rq->lock) need to be taken with disabled
interrupts. This is done in i915_request_retire() by disabling the
interrupts independently of the locks itself.
While local_irq_disable()+spin_lock() equals spin_lock_irq() on vanilla
it does not on PREEMPT_RT. Also, it is not obvious if there is a special reason
to why the interrupts are disabled independently of the lock.
Enable/disable interrupts as part of the locking instruction.
Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de>
---
drivers/gpu/drm/i915/i915_request.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -251,15 +251,13 @@ static bool i915_request_retire(struct i
active->retire(active, rq);
}
- local_irq_disable();
-
/*
* We only loosely track inflight requests across preemption,
* and so we may find ourselves attempting to retire a _completed_
* request that we have removed from the HW and put back on a run
* queue.
*/
- spin_lock(&rq->engine->active.lock);
+ spin_lock_irq(&rq->engine->active.lock);
list_del(&rq->sched.link);
spin_unlock(&rq->engine->active.lock);
@@ -278,9 +276,7 @@ static bool i915_request_retire(struct i
__notify_execute_cb(rq);
}
GEM_BUG_ON(!list_empty(&rq->execute_cb));
- spin_unlock(&rq->lock);
-
- local_irq_enable();
+ spin_unlock_irq(&rq->lock);
remove_from_client(rq);
list_del(&rq->link);
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