drm/i915: Use engine->context_pin() to report the intel_ring

Since unifying ringbuffer/execlist submission to use
engine->pin_context, we ensure that the intel_ring is available before
we start constructing the request. We can therefore move the assignment
of the request->ring to the central i915_gem_request_alloc() and not
require it in every engine->request_alloc() callback. Another small step
towards simplification (of the core, but at a cost of handling error
pointers in less important callers of engine->pin_context).

v2: Rearrange a few branches to reduce impact of PTR_ERR() on gcc's code
generation.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Oscar Mateo <oscar.mateo@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170504093308.4137-1-chris@chris-wilson.co.uk

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/gpu/drm/i915/selftests/mock_engine.c b/drivers/gpu/drm/i915/selftests/mock_engine.c
index b8e53bd..5b18a2d 100644
--- a/drivers/gpu/drm/i915/selftests/mock_engine.c
+++ b/drivers/gpu/drm/i915/selftests/mock_engine.c
@@ -52,11 +52,12 @@ static void hw_delay_complete(unsigned long data)
 	spin_unlock(&engine->hw_lock);
 }
 
-static int mock_context_pin(struct intel_engine_cs *engine,
-			    struct i915_gem_context *ctx)
+static struct intel_ring *
+mock_context_pin(struct intel_engine_cs *engine,
+		 struct i915_gem_context *ctx)
 {
 	i915_gem_context_get(ctx);
-	return 0;
+	return engine->buffer;
 }
 
 static void mock_context_unpin(struct intel_engine_cs *engine,
@@ -72,7 +73,6 @@ static int mock_request_alloc(struct drm_i915_gem_request *request)
 	INIT_LIST_HEAD(&mock->link);
 	mock->delay = 0;
 
-	request->ring = request->engine->buffer;
 	return 0;
 }