Merge tag 'v3.16-rc5' into sched/core, to refresh the branch before applying bigger tree-wide changes

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 14 insertions, 4 deletions

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 6f8017a7e937..267f069765ad 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2847,10 +2847,14 @@ static int semaphore_passed(struct intel_engine_cs *ring)
         struct intel_engine_cs *signaller;
         u32 seqno, ctl;
 
-        ring->hangcheck.deadlock = true;
+        ring->hangcheck.deadlock++;
 
         signaller = semaphore_waits_for(ring, &seqno);
-        if (signaller == NULL || signaller->hangcheck.deadlock)
+        if (signaller == NULL)
+                return -1;
+
+        /* Prevent pathological recursion due to driver bugs */
+        if (signaller->hangcheck.deadlock >= I915_NUM_RINGS)
                 return -1;
 
         /* cursory check for an unkickable deadlock */
@@ -2858,7 +2862,13 @@ static int semaphore_passed(struct intel_engine_cs *ring)
         if (ctl & RING_WAIT_SEMAPHORE && semaphore_passed(signaller) < 0)
                 return -1;
 
-        return i915_seqno_passed(signaller->get_seqno(signaller, false), seqno);
+        if (i915_seqno_passed(signaller->get_seqno(signaller, false), seqno))
+                return 1;
+
+        if (signaller->hangcheck.deadlock)
+                return -1;
+
+        return 0;
 }
 
 static void semaphore_clear_deadlocks(struct drm_i915_private *dev_priv)
@@ -2867,7 +2877,7 @@ static void semaphore_clear_deadlocks(struct drm_i915_private *dev_priv)
         int i;
 
         for_each_ring(ring, dev_priv, i)
-                ring->hangcheck.deadlock = false;
+                ring->hangcheck.deadlock = 0;
 }
 
 static enum intel_ring_hangcheck_action