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authorChris Wilson <chris@chris-wilson.co.uk>2017-09-18 17:27:34 +0100
committerChris Wilson <chris@chris-wilson.co.uk>2017-09-22 12:47:19 +0100
commitde4d2106f88ad7d98bf3adc602885d1d9071b644 (patch)
tree72474958d42400b8cded1e4f23627cee8c701682 /drivers/gpu/drm/i915/i915_irq.c
parent17b51ad8e5c051032d8e1d698e7dfd01d9133a92 (diff)
downloadop-kernel-dev-de4d2106f88ad7d98bf3adc602885d1d9071b644.zip
op-kernel-dev-de4d2106f88ad7d98bf3adc602885d1d9071b644.tar.gz
drm/i915: Check waiter->seqno carefully in case of preemption
If preemption occurs at precisely the right moment, we may decide that the wait is complete even though the wait's request is no longer executing (having been preempted). We handle this situation by double checking that request following deciding whether the wait is complete. Reported-by: Michał Winiarski <michal.winiarski@intel.com> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Michał Winiarski <michal.winiarski@intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20170918162734.21294-2-chris@chris-wilson.co.uk Reviewed-by: Michał Winiarski <michal.winiarski@intel.com>
Diffstat (limited to 'drivers/gpu/drm/i915/i915_irq.c')
-rw-r--r--drivers/gpu/drm/i915/i915_irq.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 2190e42..bd38c69 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1053,10 +1053,13 @@ static void notify_ring(struct intel_engine_cs *engine)
*/
if (i915_seqno_passed(intel_engine_get_seqno(engine),
wait->seqno)) {
+ struct drm_i915_gem_request *waiter = wait->request;
+
wakeup = true;
if (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
- &wait->request->fence.flags))
- rq = i915_gem_request_get(wait->request);
+ &waiter->fence.flags) &&
+ intel_wait_check_request(wait, waiter))
+ rq = i915_gem_request_get(waiter);
}
if (wakeup)
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