[PATCH v2 2/2] drm/i915: Never return 0 if not all requests retired

[Janusz Krzysztofik]

Users of intel_gt_retire_requests_timeout() expect 0 return value on
success.  However, we have no protection from passing back 0 potentially
returned by a call to dma_fence_wait_timeout() when it succedes right
after its timeout has expired.

Replace 0 with -ETIME before potentially using the timeout value as return
code, so -ETIME is returned if there are still some requests not retired
after timeout, 0 otherwise.

v2: Move the added lines down so flush_submission() is not affected.

Fixes: f33a8a51602c ("drm/i915: Merge wait_for_timelines with retire_request")
Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik at linux.intel.com>
Cc: stable at vger.kernel.org # v5.5+
---
 drivers/gpu/drm/i915/gt/intel_gt_requests.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.c b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
index edb881d756309..3ac4603eeb4ee 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_requests.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
@@ -199,6 +199,9 @@ out_active:	spin_lock(&timelines->lock);
 	if (remaining_timeout)
 		*remaining_timeout = timeout;
 
+	if (!timeout)
+		timeout = -ETIME;
+
 	return active_count ? timeout : 0;
 }
 
-- 
2.25.1