[PATCH] drm/i915/gt: Taint the reset mutex with the shrinker

[Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>]

Declare that, under extreme circumstances, the shrinker may need to wait
upon a request, in which case reset must not itself deadlock in order to
ensure forward progress of the driver. That is since the shrinker may
depend upon a reset, any reset cannot touch the shrinker.

Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/i915/gt/intel_reset.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/intel_reset.c b/drivers/gpu/drm/i915/gt/intel_reset.c
index b85b6f3dcd60..e14b23c3b1cb 100644
--- a/drivers/gpu/drm/i915/gt/intel_reset.c
+++ b/drivers/gpu/drm/i915/gt/intel_reset.c
@@ -1394,6 +1394,9 @@ void intel_gt_init_reset(struct intel_gt *gt)
 	mutex_init(&gt->reset.mutex);
 	init_srcu_struct(&gt->reset.backoff_srcu);
 
+	/* While undesirable to wait inside the shrinker, complain anyway */
+	i915_gem_shrinker_taints_mutex(gt->i915, &gt->reset.mutex);
+
 	/* no GPU until we are ready! */
 	__set_bit(I915_WEDGED, &gt->reset.flags);
 }
-- 
2.20.1

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