[PATCH 2/2] drm/xe: Don't unload the driver until all drm devices are freed

["Thomas Hellström" <thomas.hellstrom@linux.intel.com>]

Don't unload the driver until all drm devices are freed.
This will help ensure that helper components don't need to
maintain a module reference while holding a drm device reference.

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
---
 drivers/gpu/drm/xe/xe_device.c | 19 +++++++++++++++++++
 drivers/gpu/drm/xe/xe_device.h |  2 ++
 drivers/gpu/drm/xe/xe_module.c |  5 ++++-
 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
index 3462645ca13c..738124a73064 100644
--- a/drivers/gpu/drm/xe/xe_device.c
+++ b/drivers/gpu/drm/xe/xe_device.c
@@ -415,6 +415,8 @@ static struct drm_driver driver = {
 	.patchlevel = DRIVER_PATCHLEVEL,
 };
 
+static atomic_t xe_device_count;
+
 static void xe_device_destroy(struct drm_device *dev, void *dummy)
 {
 	struct xe_device *xe = to_xe_device(dev);
@@ -434,6 +436,9 @@ static void xe_device_destroy(struct drm_device *dev, void *dummy)
 		destroy_workqueue(xe->destroy_wq);
 
 	ttm_device_fini(&xe->ttm);
+
+	if (atomic_dec_and_test(&xe_device_count))
+		wake_up_var(&xe_device_count);
 }
 
 struct xe_device *xe_device_create(struct pci_dev *pdev,
@@ -459,6 +464,7 @@ struct xe_device *xe_device_create(struct pci_dev *pdev,
 		return ERR_PTR(err);
 
 	xe_bo_dev_init(&xe->bo_device);
+	atomic_inc(&xe_device_count);
 	err = drmm_add_action_or_reset(&xe->drm, xe_device_destroy, NULL);
 	if (err)
 		return ERR_PTR(err);
@@ -1397,3 +1403,16 @@ struct xe_vm *xe_device_asid_to_vm(struct xe_device *xe, u32 asid)
 
 	return vm;
 }
+
+/**
+ * xe_device_exit() - Device subsystem exit function.
+ *
+ * Exit function to be called at module unload time.
+ */
+void xe_device_exit(void)
+{
+	/* Wait for all devices to be freed. */
+	wait_var_event(&xe_device_count, !atomic_read(&xe_device_count));
+	/* Wait for any driver release callbacks to complete */
+	drm_dev_release_barrier();
+}
diff --git a/drivers/gpu/drm/xe/xe_device.h b/drivers/gpu/drm/xe/xe_device.h
index 39464650533b..d827a443e3d4 100644
--- a/drivers/gpu/drm/xe/xe_device.h
+++ b/drivers/gpu/drm/xe/xe_device.h
@@ -206,6 +206,8 @@ bool xe_is_xe_file(const struct file *file);
 
 struct xe_vm *xe_device_asid_to_vm(struct xe_device *xe, u32 asid);
 
+void xe_device_exit(void);
+
 /*
  * Occasionally it is seen that the G2H worker starts running after a delay of more than
  * a second even after being queued and activated by the Linux workqueue subsystem. This
diff --git a/drivers/gpu/drm/xe/xe_module.c b/drivers/gpu/drm/xe/xe_module.c
index 4cb578182912..816e02f4bdaf 100644
--- a/drivers/gpu/drm/xe/xe_module.c
+++ b/drivers/gpu/drm/xe/xe_module.c
@@ -11,7 +11,7 @@
 #include <drm/drm_module.h>
 
 #include "xe_defaults.h"
-#include "xe_device_types.h"
+#include "xe_device.h"
 #include "xe_drv.h"
 #include "xe_configfs.h"
 #include "xe_hw_fence.h"
@@ -97,6 +97,9 @@ struct init_funcs {
 };
 
 static const struct init_funcs init_funcs[] = {
+	{
+		.exit = xe_device_exit,
+	},
 	{
 		.init = xe_check_nomodeset,
 	},
-- 
2.53.0