drm/i915/execlists: Ensure the tasklet is decoupled upon shutdown

Commit Message

Chris Wilson Nov. 29, 2019, 5:25 p.m. UTC

As we only cancel the timers asynchronously, they may
still be running on another CPU as we shutdown, raising one last
softirq. So be safe and make sure the tasklet is flushed before
destroying the engine's memory.

Signed-off-by: Chris Wilson <[e-mail]>
---
 drivers/gpu/drm/i915/gt/intel_lrc.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

Patch

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 4cd0d46b5da6..fef4b7e823f5 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -3777,8 +3777,18 @@  void intel_execlists_set_default_submission(struct intel_engine_cs *engine)
 		engine->flags |= I915_ENGINE_HAS_RELATIVE_MMIO;
 }
 
+static void execlists_shutdown(struct intel_engine_cs *engine)
+{
+	/* Synchronise with residual timers and any softirq they raise */
+	del_timer_sync(&engine->execlists.timer);
+	del_timer_sync(&engine->execlists.preempt);
+	tasklet_kill(&engine->execlists.tasklet);
+}
+
 static void execlists_destroy(struct intel_engine_cs *engine)
 {
+	execlists_shutdown(engine);
+
 	intel_engine_cleanup_common(engine);
 	lrc_destroy_wa_ctx(engine);
 	kfree(engine);