drm/i915: execlist request keeps ptr/ref to gem_request

Add a reference and pointer from the execlist queue item to the associated
gem request. For execlist requests that don't have a request, create one
as a placeholder.

Issue: VIZ-4274
v1: Rebase after upstream of "Replace seqno values with request structures" patchset.

Signed-off-by: Nick Hoath <nicholas.hoath@intel.com>
Reviewed-by: Thomas Daniel <thomas.daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

2 files changed, 30 insertions, 7 deletions

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index e405b61cdac5..7992af808404 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -534,7 +534,8 @@ void intel_lrc_irq_handler(struct intel_engine_cs *ring)
 
 static int execlists_context_queue(struct intel_engine_cs *ring,
                                    struct intel_context *to,
-                                   u32 tail)
+                                   u32 tail,
+                                   struct drm_i915_gem_request *request)
 {
         struct intel_ctx_submit_request *req = NULL, *cursor;
         struct drm_i915_private *dev_priv = ring->dev->dev_private;
@@ -553,6 +554,21 @@ static int execlists_context_queue(struct intel_engine_cs *ring,
         req->ring = ring;
         req->tail = tail;
 
+        if (!request) {
+                /*
+                 * If there isn't a request associated with this submission,
+                 * create one as a temporary holder.
+                 */
+                WARN(1, "execlist context submission without request");
+                request = kzalloc(sizeof(*request), GFP_KERNEL);
+                if (request == NULL)
+                        return -ENOMEM;
+                request->ctx = to;
+                request->ring = ring;
+        }
+        req->request = request;
+        i915_gem_request_reference(request);
+
         intel_runtime_pm_get(dev_priv);
 
         spin_lock_irqsave(&ring->execlist_lock, flags);
@@ -766,6 +782,7 @@ void intel_execlists_retire_requests(struct intel_engine_cs *ring)
                         intel_lr_context_unpin(ring, ctx);
                 intel_runtime_pm_put(dev_priv);
                 i915_gem_context_unreference(req->ctx);
+                i915_gem_request_unreference(req->request);
                 list_del(&req->execlist_link);
                 kfree(req);
         }
@@ -818,7 +835,8 @@ int logical_ring_flush_all_caches(struct intel_ringbuffer *ringbuf)
  * on a queue waiting for the ELSP to be ready to accept a new context submission. At that
  * point, the tail *inside* the context is updated and the ELSP written to.
  */
-void intel_logical_ring_advance_and_submit(struct intel_ringbuffer *ringbuf)
+void intel_logical_ring_advance_and_submit(struct intel_ringbuffer *ringbuf,
+                                           struct drm_i915_gem_request *request)
 {
         struct intel_engine_cs *ring = ringbuf->ring;
         struct intel_context *ctx = ringbuf->FIXME_lrc_ctx;
@@ -828,7 +846,7 @@ void intel_logical_ring_advance_and_submit(struct intel_ringbuffer *ringbuf)
         if (intel_ring_stopped(ring))
                 return;
 
-        execlists_context_queue(ring, ctx, ringbuf->tail);
+        execlists_context_queue(ring, ctx, ringbuf->tail, request);
 }
 
 static int intel_lr_context_pin(struct intel_engine_cs *ring,
@@ -972,7 +990,7 @@ static int logical_ring_wait_for_space(struct intel_ringbuffer *ringbuf,
                 return ret;
 
         /* Force the context submission in case we have been skipping it */
-        intel_logical_ring_advance_and_submit(ringbuf);
+        intel_logical_ring_advance_and_submit(ringbuf, NULL);
 
         /* With GEM the hangcheck timer should kick us out of the loop,
          * leaving it early runs the risk of corrupting GEM state (due
@@ -1311,7 +1329,8 @@ static void gen8_set_seqno(struct intel_engine_cs *ring, u32 seqno)
         intel_write_status_page(ring, I915_GEM_HWS_INDEX, seqno);
 }
 
-static int gen8_emit_request(struct intel_ringbuffer *ringbuf)
+static int gen8_emit_request(struct intel_ringbuffer *ringbuf,
+                             struct drm_i915_gem_request *request)
 {
         struct intel_engine_cs *ring = ringbuf->ring;
         u32 cmd;
@@ -1333,7 +1352,7 @@ static int gen8_emit_request(struct intel_ringbuffer *ringbuf)
                 i915_gem_request_get_seqno(ring->outstanding_lazy_request));
         intel_logical_ring_emit(ringbuf, MI_USER_INTERRUPT);
         intel_logical_ring_emit(ringbuf, MI_NOOP);
-        intel_logical_ring_advance_and_submit(ringbuf);
+        intel_logical_ring_advance_and_submit(ringbuf, request);
 
         return 0;
 }
diff --git a/drivers/gpu/drm/i915/intel_lrc.h b/drivers/gpu/drm/i915/intel_lrc.h
index 960fcbd2c98a..7a82bc9b03a7 100644
--- a/drivers/gpu/drm/i915/intel_lrc.h
+++ b/drivers/gpu/drm/i915/intel_lrc.h
@@ -39,7 +39,9 @@ void intel_logical_ring_cleanup(struct intel_engine_cs *ring);
 int intel_logical_rings_init(struct drm_device *dev);
 
 int logical_ring_flush_all_caches(struct intel_ringbuffer *ringbuf);
-void intel_logical_ring_advance_and_submit(struct intel_ringbuffer *ringbuf);
+void intel_logical_ring_advance_and_submit(
+                                struct intel_ringbuffer *ringbuf,
+                                struct drm_i915_gem_request *request);
 /**
  * intel_logical_ring_advance() - advance the ringbuffer tail
  * @ringbuf: Ringbuffer to advance.
@@ -110,6 +112,8 @@ struct intel_ctx_submit_request {
         struct list_head execlist_link;
 
         int elsp_submitted;
+
+        struct drm_i915_gem_request *request;
 };
 
 void intel_lrc_irq_handler(struct intel_engine_cs *ring);