drm/i915: Update alloc_request to return the allocated request

The alloc_request() function does not actually return the newly allocated
request. Instead, it must be pulled from ring->outstanding_lazy_request. This
patch fixes this so that code can create a request and start using it knowing
exactly which request it actually owns.

v2: Updated for new i915_gem_request_alloc() scheme.

For: VIZ-5115
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Tomas Elf <tomas.elf@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -2206,7 +2206,8 @@ struct drm_i915_gem_request {
 };
 
 int i915_gem_request_alloc(struct intel_engine_cs *ring,
-			   struct intel_context *ctx);
+			   struct intel_context *ctx,
+			   struct drm_i915_gem_request **req_out);
 void i915_gem_request_cancel(struct drm_i915_gem_request *req);
 void i915_gem_request_free(struct kref *req_ref);
 

drivers/gpu/drm/i915/i915_gem.c

@@ -2634,13 +2634,17 @@ void i915_gem_request_free(struct kref *req_ref)
 }
 
 int i915_gem_request_alloc(struct intel_engine_cs *ring,
-			   struct intel_context *ctx)
+			   struct intel_context *ctx,
+			   struct drm_i915_gem_request **req_out)
 {
 	struct drm_i915_private *dev_priv = to_i915(ring->dev);
 	struct drm_i915_gem_request *req;
 	int ret;
 
-	if (ring->outstanding_lazy_request)
+	if (!req_out)
+		return -EINVAL;
+
+	if ((*req_out = ring->outstanding_lazy_request) != NULL)
 		return 0;
 
 	req = kmem_cache_zalloc(dev_priv->requests, GFP_KERNEL);
@@ -2686,7 +2690,7 @@ int i915_gem_request_alloc(struct intel_engine_cs *ring,
 	 */
 	intel_ring_reserved_space_reserve(req->ringbuf, MIN_SPACE_FOR_ADD_REQUEST);
 
-	ring->outstanding_lazy_request = req;
+	*req_out = ring->outstanding_lazy_request = req;
 	return 0;
 
 err:

drivers/gpu/drm/i915/i915_gem_execbuffer.c

@@ -1415,6 +1415,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
 	struct i915_address_space *vm;
 	struct i915_execbuffer_params params_master; /* XXX: will be removed later */
 	struct i915_execbuffer_params *params = &params_master;
+	struct drm_i915_gem_request *request;
 	const u32 ctx_id = i915_execbuffer2_get_context_id(*args);
 	u32 dispatch_flags;
 	int ret;
@@ -1614,7 +1615,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
 		params->batch_obj_vm_offset = i915_gem_obj_offset(batch_obj, vm);
 
 	/* Allocate a request for this batch buffer nice and early. */
-	ret = i915_gem_request_alloc(ring, ctx);
+	ret = i915_gem_request_alloc(ring, ctx, &request);
 	if (ret)
 		goto err_batch_unpin;
 

drivers/gpu/drm/i915/intel_lrc.c

@@ -818,6 +818,7 @@ static int logical_ring_prepare(struct intel_ringbuffer *ringbuf,
 static int intel_logical_ring_begin(struct intel_ringbuffer *ringbuf,
 				    struct intel_context *ctx, int num_dwords)
 {
+	struct drm_i915_gem_request *req;
 	struct intel_engine_cs *ring = ringbuf->ring;
 	struct drm_device *dev = ring->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -833,7 +834,7 @@ static int intel_logical_ring_begin(struct intel_ringbuffer *ringbuf,
 		return ret;
 
 	/* Preallocate the olr before touching the ring */
-	ret = i915_gem_request_alloc(ring, ctx);
+	ret = i915_gem_request_alloc(ring, ctx, &req);
 	if (ret)
 		return ret;
 

drivers/gpu/drm/i915/intel_ringbuffer.c

@@ -2277,6 +2277,7 @@ static int __intel_ring_prepare(struct intel_engine_cs *ring, int bytes)
 int intel_ring_begin(struct intel_engine_cs *ring,
 		     int num_dwords)
 {
+	struct drm_i915_gem_request *req;
 	struct drm_i915_private *dev_priv = ring->dev->dev_private;
 	int ret;
 
@@ -2290,7 +2291,7 @@ int intel_ring_begin(struct intel_engine_cs *ring,
 		return ret;
 
 	/* Preallocate the olr before touching the ring */
-	ret = i915_gem_request_alloc(ring, ring->default_context);
+	ret = i915_gem_request_alloc(ring, ring->default_context, &req);
 	if (ret)
 		return ret;