From d98bf1fcd7b10f6aa5605f8ea3536dbb9dda29bb Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Fri, 29 Nov 2019 17:25:42 +0000
Subject: drm/i915/execlists: Ensure the tasklet is decoupled upon shutdown
Git-commit: 97c16353970aa28418a49ef6980b6e4f36e35feb
Patch-mainline: v5.6-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322

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 <chris@chris-wilson.co.uk>
Acked-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191129172542.1222810-1-chris@chris-wilson.co.uk
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/i915/gt/intel_lrc.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index ccae586d2430..2d8ede7f7fe1 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -3781,8 +3781,18 @@ 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);
-- 
2.28.0