[Intel-gfx] [PATCH] drm/i915: Check for an invalid seqno before __i915_gem_request_started

[Chris Wilson]

__i915_gem_request_started() asserts that the seqno is valid, but
i915_spin_request() was not checking before querying whether the request
had started.

Reported-by: Michał Winiarski <michal.winiarski at intel.com>
Fixes: 754c9fd57649 ("drm/i915: Protect the request->global_seqno with the engine->timeline lock")
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Cc: Michał Winiarski <michal.winiarski at intel.com>
---
 drivers/gpu/drm/i915/i915_gem_request.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem_request.h b/drivers/gpu/drm/i915/i915_gem_request.h
index 6fdfb801bcee..cb4e7f3e279e 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.h
+++ b/drivers/gpu/drm/i915/i915_gem_request.h
@@ -348,6 +348,9 @@ static inline bool i915_spin_request(const struct drm_i915_gem_request *request,
 	u32 seqno;
 
 	seqno = i915_gem_request_global_seqno(request);
+	if (!seqno)
+		return 0;
+
 	return (__i915_gem_request_started(request, seqno) &&
 		__i915_spin_request(request, seqno, state, timeout_us));
 }
-- 
2.11.0