[PATCH 15/16] drm/i915/execlists: Make submission tasklet hardirq safe

[Chris Wilson]

Prepare to allow the execlists submission to be run from underneath a
hardirq timer context (and not just the current softirq context) as is
required for fast preemption resets.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/intel_lrc.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index e17b25f214e9..66d594c73bc1 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -573,6 +573,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 		&execlists->port[execlists->port_mask];
 	struct i915_request *last = port_request(port);
 	struct rb_node *rb;
+	unsigned long flags;
 	bool submit = false;
 
 	/* Hardware submission is through 2 ports. Conceptually each port
@@ -596,7 +597,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 	 * and context switches) submission.
 	 */
 
-	spin_lock_irq(&engine->timeline.lock);
+	spin_lock_irqsave(&engine->timeline.lock, flags);
 	rb = execlists->first;
 	GEM_BUG_ON(rb_first(&execlists->queue) != rb);
 
@@ -757,7 +758,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 	GEM_BUG_ON(execlists->first && !port_isset(execlists->port));
 
 unlock:
-	spin_unlock_irq(&engine->timeline.lock);
+	spin_unlock_irqrestore(&engine->timeline.lock, flags);
 
 	if (submit) {
 		execlists_user_begin(execlists, execlists->port);
-- 
2.17.0