From 50c1b316358ef2e00c7b7d768c45389c7a7f1139 Mon Sep 17 00:00:00 2001
From: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Date: Fri, 16 Sep 2022 11:24:02 +0200
Subject: drm/i915/gem: Flush contexts on driver release
Git-commit: 5ce8f7444f8fbb5adee644590c0e4e1890ab004c
Patch-mainline: v6.0-rc7
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225 jsc#PED-2849
Alt-commit: 1cec34442408a77ba5396b19725fed2c398005c3

Due to i915_perf assuming that it can use the i915_gem_context reference
to protect its i915->gem.contexts.list iteration, we need to defer removal
of the context from the list until last reference to the context is put.
However, there is a risk of triggering kernel warning on contexts list not
empty at driver release time if we deleagate that task to a worker for
i915_gem_context_release_work(), unless that work is flushed first.
Unfortunately, it is not flushed on driver release.  Fix it.

Instead of additionally calling flush_workqueue(), either directly or via
a new dedicated wrapper around it, replace last call to
i915_gem_drain_freed_objects() with existing i915_gem_drain_workqueue()
that performs both tasks.

Fixes: 75eefd82581f ("drm/i915: Release i915_gem_context from a worker")
Suggested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Cc: stable@kernel.org # v5.16+
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220916092403.201355-2-janusz.krzysztofik@linux.intel.com
(cherry picked from commit 1cec34442408a77ba5396b19725fed2c398005c3)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/i915/i915_gem.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 702e5b89be22..b605d0ceaefa 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1191,7 +1191,8 @@ void i915_gem_driver_release(struct drm_i915_private *dev_priv)
 
 	intel_uc_cleanup_firmwares(&to_gt(dev_priv)->uc);
 
-	i915_gem_drain_freed_objects(dev_priv);
+	/* Flush any outstanding work, including i915_gem_context.release_work. */
+	i915_gem_drain_workqueue(dev_priv);
 
 	drm_WARN_ON(&dev_priv->drm, !list_empty(&dev_priv->gem.contexts.list));
 }
-- 
2.38.1