Quoting Sebastian Andrzej Siewior (2019-10-10 17:06:40) > 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 <bigeasy@xxxxxxxxxxxxx> > --- > 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); Nothing screams about the imbalance? irq off from one lock to the other? -Chris _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
