drm/i915: Store LRC hardware id in the request

This way in the following patch we can disconnect requests
from contexts.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1461833819-3991-23-git-send-email-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_drv.h

@@ -2352,6 +2352,8 @@ struct drm_i915_gem_request {
 	/** Execlists no. of times this request has been sent to the ELSP */
 	int elsp_submitted;
 
+	/** Execlists context hardware id. */
+	unsigned ctx_hw_id;
 };
 
 struct drm_i915_gem_request * __must_check

drivers/gpu/drm/i915/intel_lrc.c

@@ -481,7 +481,7 @@ execlists_check_remove_request(struct intel_engine_cs *engine, u32 request_id)
 	if (!head_req)
 		return 0;
 
-	if (unlikely(head_req->ctx->hw_id != request_id))
+	if (unlikely(head_req->ctx_hw_id != request_id))
 		return 0;
 
 	WARN(head_req->elsp_submitted == 0, "Never submitted head request\n");
@@ -619,6 +619,7 @@ static void execlists_context_queue(struct drm_i915_gem_request *request)
 	}
 
 	list_add_tail(&request->execlist_link, &engine->execlist_queue);
+	request->ctx_hw_id = request->ctx->hw_id;
 	if (num_elements == 0)
 		execlists_context_unqueue(engine);