Revert "drm/i915: fix context/engine cleanup order"

This reverts commit 1b39a917.

Chris retracted his reviewed-by (which I failed to notice) and somehow
it blows up (I did it again!) as reported by Mika with the below
backtrace on module reload:

[   58.170374] IP: [<ffffffffa00e04d3>]
intel_logical_ring_cleanup+0x83/0x100 [i915]
...
[   58.170469] Call Trace:
[   58.170479]  [<ffffffffa00d0ed4>] i915_gem_cleanup_engines+0x34/0x60
[i915]
[   58.170493]  [<ffffffffa0154520>] i915_driver_unload+0x140/0x220
[i915]
[   58.170497]  [<ffffffff8154a4f4>] drm_dev_unregister+0x24/0xa0
[   58.170501]  [<ffffffff8154aace>] drm_put_dev+0x1e/0x60
[   58.170506]  [<ffffffffa00912a0>] i915_pci_remove+0x10/0x20 [i915]
[   58.170510]  [<ffffffff814766e4>] pci_device_remove+0x34/0xb0
[   58.170514]  [<ffffffff8156e7d5>] __device_release_driver+0x95/0x140
[   58.170518]  [<ffffffff8156e97c>] driver_detach+0xbc/0xc0
[   58.170521]  [<ffffffff8156d883>] bus_remove_driver+0x53/0xd0
[   58.170525]  [<ffffffff8156f3a7>] driver_unregister+0x27/0x50
[   58.170528]  [<ffffffff81475725>] pci_unregister_driver+0x25/0x70
[   58.170531]  [<ffffffff8154c274>] drm_pci_exit+0x74/0x90
[   58.170543]  [<ffffffffa0154cb0>] i915_exit+0x20/0x1aa [i915]
[   58.170548]  [<ffffffff8111846f>] SyS_delete_module+0x18f/0x1f0

Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Dave Gordon <david.s.gordon@intel.com>
Cc: Nick Hoath <nicholas.hoath@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

drivers/gpu/drm/i915/i915_dma.c

@@ -444,8 +444,8 @@ static int i915_load_modeset_init(struct drm_device *dev)
 
 cleanup_gem:
 	mutex_lock(&dev->struct_mutex);
+	i915_gem_cleanup_ringbuffer(dev);
 	i915_gem_context_fini(dev);
-	i915_gem_cleanup_engines(dev);
 	mutex_unlock(&dev->struct_mutex);
 cleanup_irq:
 	intel_guc_ucode_fini(dev);
@@ -1256,8 +1256,8 @@ int i915_driver_unload(struct drm_device *dev)
 
 	intel_guc_ucode_fini(dev);
 	mutex_lock(&dev->struct_mutex);
+	i915_gem_cleanup_ringbuffer(dev);
 	i915_gem_context_fini(dev);
-	i915_gem_cleanup_engines(dev);
 	mutex_unlock(&dev->struct_mutex);
 	intel_fbc_cleanup_cfb(dev_priv);
 

drivers/gpu/drm/i915/i915_drv.h

@@ -3058,7 +3058,7 @@ int i915_gem_init_rings(struct drm_device *dev);
 int __must_check i915_gem_init_hw(struct drm_device *dev);
 int i915_gem_l3_remap(struct drm_i915_gem_request *req, int slice);
 void i915_gem_init_swizzling(struct drm_device *dev);
-void i915_gem_cleanup_engines(struct drm_device *dev);
+void i915_gem_cleanup_ringbuffer(struct drm_device *dev);
 int __must_check i915_gpu_idle(struct drm_device *dev);
 int __must_check i915_gem_suspend(struct drm_device *dev);
 void __i915_add_request(struct drm_i915_gem_request *req,

drivers/gpu/drm/i915/i915_gem.c

@@ -4913,7 +4913,7 @@ i915_gem_init_hw(struct drm_device *dev)
 		req = i915_gem_request_alloc(ring, NULL);
 		if (IS_ERR(req)) {
 			ret = PTR_ERR(req);
-			i915_gem_cleanup_engines(dev);
+			i915_gem_cleanup_ringbuffer(dev);
 			goto out;
 		}
 
@@ -4926,7 +4926,7 @@ i915_gem_init_hw(struct drm_device *dev)
 		if (ret && ret != -EIO) {
 			DRM_ERROR("PPGTT enable ring #%d failed %d\n", i, ret);
 			i915_gem_request_cancel(req);
-			i915_gem_cleanup_engines(dev);
+			i915_gem_cleanup_ringbuffer(dev);
 			goto out;
 		}
 
@@ -4934,7 +4934,7 @@ i915_gem_init_hw(struct drm_device *dev)
 		if (ret && ret != -EIO) {
 			DRM_ERROR("Context enable ring #%d failed %d\n", i, ret);
 			i915_gem_request_cancel(req);
-			i915_gem_cleanup_engines(dev);
+			i915_gem_cleanup_ringbuffer(dev);
 			goto out;
 		}
 
@@ -5009,7 +5009,7 @@ int i915_gem_init(struct drm_device *dev)
 }
 
 void
-i915_gem_cleanup_engines(struct drm_device *dev)
+i915_gem_cleanup_ringbuffer(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_engine_cs *ring;
@@ -5018,14 +5018,13 @@ i915_gem_cleanup_engines(struct drm_device *dev)
 	for_each_ring(ring, dev_priv, i)
 		dev_priv->gt.cleanup_ring(ring);
 
-	if (i915.enable_execlists) {
-		/*
-		 * Neither the BIOS, ourselves or any other kernel
-		 * expects the system to be in execlists mode on startup,
-		 * so we need to reset the GPU back to legacy mode.
-		 */
-		intel_gpu_reset(dev);
-	}
+    if (i915.enable_execlists)
+            /*
+             * Neither the BIOS, ourselves or any other kernel
+             * expects the system to be in execlists mode on startup,
+             * so we need to reset the GPU back to legacy mode.
+             */
+            intel_gpu_reset(dev);
 }
 
 static void