1 files changed, 38 insertions, 7 deletions

diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index c0f084ca4f29..ade010fe6e26 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -130,6 +130,13 @@ struct i915_request {
         struct i915_sched_node sched;
         struct i915_dependency dep;
 
+        /*
+         * A convenience pointer to the current breadcrumb value stored in
+         * the HW status page (or our timeline's local equivalent). The full
+         * path would be rq->hw_context->ring->timeline->hwsp_seqno.
+         */
+        const u32 *hwsp_seqno;
+
         /**
          * GEM sequence number associated with this request on the
          * global execution timeline. It is zero when the request is not
@@ -285,11 +292,6 @@ static inline bool i915_request_signaled(const struct i915_request *rq)
         return test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &rq->fence.flags);
 }
 
-static inline bool intel_engine_has_started(struct intel_engine_cs *engine,
-                                            u32 seqno);
-static inline bool intel_engine_has_completed(struct intel_engine_cs *engine,
-                                              u32 seqno);
-
 /**
  * Returns true if seq1 is later than seq2.
  */
@@ -298,6 +300,35 @@ static inline bool i915_seqno_passed(u32 seq1, u32 seq2)
         return (s32)(seq1 - seq2) >= 0;
 }
 
+static inline u32 __hwsp_seqno(const struct i915_request *rq)
+{
+        return READ_ONCE(*rq->hwsp_seqno);
+}
+
+/**
+ * hwsp_seqno - the current breadcrumb value in the HW status page
+ * @rq: the request, to chase the relevant HW status page
+ *
+ * The emphasis in naming here is that hwsp_seqno() is not a property of the
+ * request, but an indication of the current HW state (associated with this
+ * request). Its value will change as the GPU executes more requests.
+ *
+ * Returns the current breadcrumb value in the associated HW status page (or
+ * the local timeline's equivalent) for this request. The request itself
+ * has the associated breadcrumb value of rq->fence.seqno, when the HW
+ * status page has that breadcrumb or later, this request is complete.
+ */
+static inline u32 hwsp_seqno(const struct i915_request *rq)
+{
+        u32 seqno;
+
+        rcu_read_lock(); /* the HWSP may be freed at runtime */
+        seqno = __hwsp_seqno(rq);
+        rcu_read_unlock();
+
+        return seqno;
+}
+
 /**
  * i915_request_started - check if the request has begun being executed
  * @rq: the request
@@ -315,14 +346,14 @@ static inline bool i915_request_started(const struct i915_request *rq)
         if (!seqno) /* not yet submitted to HW */
                 return false;
 
-        return intel_engine_has_started(rq->engine, seqno);
+        return i915_seqno_passed(hwsp_seqno(rq), seqno - 1);
 }
 
 static inline bool
 __i915_request_completed(const struct i915_request *rq, u32 seqno)
 {
         GEM_BUG_ON(!seqno);
-        return intel_engine_has_completed(rq->engine, seqno) &&
+        return i915_seqno_passed(hwsp_seqno(rq), seqno) &&
                 seqno == i915_request_global_seqno(rq);
 }