drm/i915: Use drmm_add_final_kfree

With this we can drop the final kfree from the release function.

The mock device in the selftests needed it's pci_device split
up from the drm_device. In the future we could simplify this again
by allocating the pci_device as a managed allocation too.

v2: I overlooked that i915_driver_destroy is also called in the
unwind code of the error path. There we need a drm_dev_put.
Similar for the mock object.

Now the problem with that is that the drm_driver->release callbacks
for both the real driver and the mock one assume everything has been
set up. Hence going through that path for a partially set up driver
will result in issues. Quickest fix is to disable the ->release() hook
until the driver is fully initialized, and keep the onion unwinding.
Long term would be cleanest to move everything over to drmm_ release
actions, but that's a lot of work for a big driver like i915. Plus
more core work needed first anyway.

v3: Fix i915_drm pointer wrangling in mock_gem_device. Also switch
over to start using drm_dev_put() to clean up even on the error path.
Aside I think the current error path is leaking the allocation.

v4: more fixes for intel-gfx-ci, some if it damage from v3 :-/
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Andi Shyti <andi.shyti@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Link: https://patchwork.freedesktop.org/patch/msgid/20200323144950.3018436-9-daniel.vetter@ffwll.ch

drivers/gpu/drm/i915/i915_drv.c

@@ -43,6 +43,7 @@
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_ioctl.h>
 #include <drm/drm_irq.h>
+#include <drm/drm_managed.h>
 #include <drm/drm_probe_helper.h>
 
 #include "display/intel_acpi.h"
@@ -890,6 +891,8 @@ i915_driver_create(struct pci_dev *pdev, const struct pci_device_id *ent)
 		return ERR_PTR(err);
 	}
 
+	drmm_add_final_kfree(&i915->drm, i915);
+
 	i915->drm.pdev = pdev;
 	pci_set_drvdata(pdev, i915);
 
@@ -906,7 +909,6 @@ i915_driver_create(struct pci_dev *pdev, const struct pci_device_id *ent)
 static void i915_driver_destroy(struct drm_i915_private *i915)
 {
 	drm_dev_fini(&i915->drm);
-	kfree(i915);
 }
 
 /**
@@ -990,6 +992,8 @@ int i915_driver_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	i915_welcome_messages(i915);
 
+	i915->do_release = true;
+
 	return 0;
 
 out_cleanup_irq:
@@ -1010,6 +1014,7 @@ int i915_driver_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 out_fini:
 	i915_probe_error(i915, "Device initialization failed (%d)\n", ret);
 	i915_driver_destroy(i915);
+	drm_dev_put(&i915->drm);
 	return ret;
 }
 
@@ -1049,6 +1054,9 @@ static void i915_driver_release(struct drm_device *dev)
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct intel_runtime_pm *rpm = &dev_priv->runtime_pm;
 
+	if (!dev_priv->do_release)
+		return;
+
 	disable_rpm_wakeref_asserts(rpm);
 
 	i915_gem_driver_release(dev_priv);

drivers/gpu/drm/i915/i915_drv.h

@@ -823,6 +823,9 @@ struct i915_selftest_stash {
 struct drm_i915_private {
 	struct drm_device drm;
 
+	/* FIXME: Device release actions should all be moved to drmm_ */
+	bool do_release;
+
 	const struct intel_device_info __info; /* Use INTEL_INFO() to access. */
 	struct intel_runtime_info __runtime; /* Use RUNTIME_INFO() to access. */
 	struct intel_driver_caps caps;

drivers/gpu/drm/i915/selftests/mock_gem_device.c

@@ -25,6 +25,8 @@
 #include <linux/pm_domain.h>
 #include <linux/pm_runtime.h>
 
+#include <drm/drm_managed.h>
+
 #include "gt/intel_gt.h"
 #include "gt/intel_gt_requests.h"
 #include "gt/mock_engine.h"
@@ -55,6 +57,9 @@ static void mock_device_release(struct drm_device *dev)
 {
 	struct drm_i915_private *i915 = to_i915(dev);
 
+	if (!i915->do_release)
+		goto out;
+
 	mock_device_flush(i915);
 	intel_gt_driver_remove(&i915->gt);
 
@@ -72,7 +77,9 @@ static void mock_device_release(struct drm_device *dev)
 	drm_mode_config_cleanup(&i915->drm);
 
 	drm_dev_fini(&i915->drm);
+out:
 	put_device(&i915->drm.pdev->dev);
+	i915->drm.pdev = NULL;
 }
 
 static struct drm_driver mock_driver = {
@@ -114,9 +121,14 @@ struct drm_i915_private *mock_gem_device(void)
 	struct pci_dev *pdev;
 	int err;
 
-	pdev = kzalloc(sizeof(*pdev) + sizeof(*i915), GFP_KERNEL);
+	pdev = kzalloc(sizeof(*pdev), GFP_KERNEL);
 	if (!pdev)
-		goto err;
+		return NULL;
+	i915 = kzalloc(sizeof(*i915), GFP_KERNEL);
+	if (!i915) {
+		kfree(pdev);
+		return NULL;
+	}
 
 	device_initialize(&pdev->dev);
 	pdev->class = PCI_BASE_CLASS_DISPLAY << 16;
@@ -129,7 +141,6 @@ struct drm_i915_private *mock_gem_device(void)
 	pdev->dev.archdata.iommu = (void *)-1;
 #endif
 
-	i915 = (struct drm_i915_private *)(pdev + 1);
 	pci_set_drvdata(pdev, i915);
 
 	dev_pm_domain_set(&pdev->dev, &pm_domain);
@@ -141,9 +152,13 @@ struct drm_i915_private *mock_gem_device(void)
 	err = drm_dev_init(&i915->drm, &mock_driver, &pdev->dev);
 	if (err) {
 		pr_err("Failed to initialise mock GEM device: err=%d\n", err);
-		goto put_device;
+		put_device(&pdev->dev);
+		kfree(i915);
+
+		return NULL;
 	}
 	i915->drm.pdev = pdev;
+	drmm_add_final_kfree(&i915->drm, i915);
 
 	intel_runtime_pm_init_early(&i915->runtime_pm);
 
@@ -188,6 +203,8 @@ struct drm_i915_private *mock_gem_device(void)
 	__clear_bit(I915_WEDGED, &i915->gt.reset.flags);
 	intel_engines_driver_register(i915);
 
+	i915->do_release = true;
+
 	return i915;
 
 err_context:
@@ -199,8 +216,7 @@ struct drm_i915_private *mock_gem_device(void)
 	intel_memory_regions_driver_release(i915);
 	drm_mode_config_cleanup(&i915->drm);
 	drm_dev_fini(&i915->drm);
-put_device:
-	put_device(&pdev->dev);
-err:
+	drm_dev_put(&i915->drm);
+
 	return NULL;
 }