[Intel-gfx] [CI 5/5] drm/i915: Cancel context if it hangs after it is closed

[Chris Wilson]

If we detect a hang in a closed context, just flush all of its requests
and cancel any remaining execution along the context. Note that after
closing the context, the last reference to the context may be dropped,
leaving it only valid under RCU.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>
---
 drivers/gpu/drm/i915/gt/intel_reset.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/intel_reset.c b/drivers/gpu/drm/i915/gt/intel_reset.c
index 86d52383bf9d..b7007cd78c6f 100644
--- a/drivers/gpu/drm/i915/gt/intel_reset.c
+++ b/drivers/gpu/drm/i915/gt/intel_reset.c
@@ -81,6 +81,11 @@ static bool context_mark_guilty(struct i915_gem_context *ctx)
 	bool banned;
 	int i;
 
+	if (i915_gem_context_is_closed(ctx)) {
+		i915_gem_context_set_banned(ctx);
+		return true;
+	}
+
 	atomic_inc(&ctx->guilty_count);
 
 	/* Cool contexts are too cool to be banned! (Used for reset testing.) */
@@ -128,6 +133,7 @@ void __i915_request_reset(struct i915_request *rq, bool guilty)
 
 	GEM_BUG_ON(i915_request_completed(rq));
 
+	rcu_read_lock(); /* protect the GEM context */
 	if (guilty) {
 		i915_request_skip(rq, -EIO);
 		if (context_mark_guilty(rq->gem_context))
@@ -136,6 +142,7 @@ void __i915_request_reset(struct i915_request *rq, bool guilty)
 		dma_fence_set_error(&rq->fence, -EAGAIN);
 		context_mark_innocent(rq->gem_context);
 	}
+	rcu_read_unlock();
 }
 
 static bool i915_in_reset(struct pci_dev *pdev)
-- 
2.24.0