[Intel-gfx] [PATCH 19/26] drm/i915: Dirty hack to fix selftests locking inversion
Maarten Lankhorst
maarten.lankhorst at linux.intel.com
Tue Jun 23 14:28:36 UTC 2020
Some i915 selftests still use i915_vma_lock() as inner lock, and
intel_context_create_request() intel_timeline->mutex as outer lock.
Fortunately for selftests this is not an issue, they should be fixed
but we can move ahead and cleanify lockdep now.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
---
drivers/gpu/drm/i915/gt/intel_context.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c
index 64948386630f..fe9fff5a63b1 100644
--- a/drivers/gpu/drm/i915/gt/intel_context.c
+++ b/drivers/gpu/drm/i915/gt/intel_context.c
@@ -459,6 +459,18 @@ struct i915_request *intel_context_create_request(struct intel_context *ce)
rq = i915_request_create(ce);
intel_context_unpin(ce);
+ if (IS_ERR(rq))
+ return rq;
+
+ /*
+ * timeline->mutex should be the inner lock, but is used as outer lock.
+ * Hack around this to shut up lockdep in selftests..
+ */
+ lockdep_unpin_lock(&ce->timeline->mutex, rq->cookie);
+ mutex_release(&ce->timeline->mutex.dep_map, _RET_IP_);
+ mutex_acquire(&ce->timeline->mutex.dep_map, SINGLE_DEPTH_NESTING, 0, _RET_IP_);
+ rq->cookie = lockdep_pin_lock(&ce->timeline->mutex);
+
return rq;
}
--
2.27.0
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