drm/i915: Use shorter route to dev_private where possible

Where we have a request we can use req->i915 directly instead
of going through the engine and device. Coccinelle script:

@@
function f;
identifier r;
@@
f(..., struct drm_i915_gem_request *r, ...)
{
...
- engine->dev->dev_private
+ r->i915
...
}
@@
struct drm_i915_gem_request *req;
@@
(
  req->
- engine->dev->dev_private
+ i915
)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1458219850-21007-1-git-send-email-tvrtko.ursulin@linux.intel.com

drivers/gpu/drm/i915/i915_gem.c

@@ -2550,7 +2550,7 @@ void __i915_add_request(struct drm_i915_gem_request *request,
 		return;
 
 	engine = request->engine;
-	dev_priv = engine->dev->dev_private;
+	dev_priv = request->i915;
 	ringbuf = request->ringbuf;
 
 	/*

drivers/gpu/drm/i915/i915_gem_context.c

@@ -656,7 +656,7 @@ static int do_switch(struct drm_i915_gem_request *req)
 {
 	struct intel_context *to = req->ctx;
 	struct intel_engine_cs *engine = req->engine;
-	struct drm_i915_private *dev_priv = engine->dev->dev_private;
+	struct drm_i915_private *dev_priv = req->i915;
 	struct intel_context *from = engine->last_context;
 	u32 hw_flags = 0;
 	bool uninitialized = false;
@@ -829,7 +829,7 @@ unpin_out:
 int i915_switch_context(struct drm_i915_gem_request *req)
 {
 	struct intel_engine_cs *engine = req->engine;
-	struct drm_i915_private *dev_priv = engine->dev->dev_private;
+	struct drm_i915_private *dev_priv = req->i915;
 
 	WARN_ON(i915.enable_execlists);
 	WARN_ON(!mutex_is_locked(&dev_priv->dev->struct_mutex));

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -2192,7 +2192,7 @@ int i915_ppgtt_init_hw(struct drm_device *dev)
 
 int i915_ppgtt_init_ring(struct drm_i915_gem_request *req)
 {
-	struct drm_i915_private *dev_priv = req->engine->dev->dev_private;
+	struct drm_i915_private *dev_priv = req->i915;
 	struct i915_hw_ppgtt *ppgtt = dev_priv->mm.aliasing_ppgtt;
 
 	if (i915.enable_execlists)

drivers/gpu/drm/i915/intel_lrc.c

@@ -897,7 +897,7 @@ int intel_logical_ring_begin(struct drm_i915_gem_request *req, int num_dwords)
 	int ret;
 
 	WARN_ON(req == NULL);
-	dev_priv = req->engine->dev->dev_private;
+	dev_priv = req->i915;
 
 	ret = i915_gem_check_wedge(&dev_priv->gpu_error,
 				   dev_priv->mm.interruptible);

drivers/gpu/drm/i915/intel_ringbuffer.c

@@ -2499,7 +2499,7 @@ int intel_ring_begin(struct drm_i915_gem_request *req,
 
 	WARN_ON(req == NULL);
 	engine = req->engine;
-	dev_priv = engine->dev->dev_private;
+	dev_priv = req->i915;
 
 	ret = i915_gem_check_wedge(&dev_priv->gpu_error,
 				   dev_priv->mm.interruptible);