gpu: nvgpu: expose device creation

Allow gk20a_create_device() to happen outside the main ioctl logic and
rename it to have the modern nvgpu_ prefix. Add a separate function to
do cdev allocation and refactor the existing two callers slightly to
avoid repetition on the cdev struct initialization.

As a side effect, this modification fixes the error path that used to
not return an error if adding a device fails and also leaked the
allocated cdev memory.

Jira NVGPU-6788

Change-Id: Ia1f018b88d78fafdfcf4e95f6aa66e2368e58974
Signed-off-by: Konsta Hölttä <kholtta@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2674426
Reviewed-by: Alex Waterman <alexw@nvidia.com>
GVS: Gerrit_Virtual_Submit

drivers/gpu/nvgpu/os/linux/ioctl.c

@@ -251,11 +251,10 @@ static char *nvgpu_mig_fgpu_devnode(struct device *dev, umode_t *mode)
 				priv_data->minor_instance_id, dev_name(dev));
 }
 
-static int gk20a_create_device(
+int nvgpu_create_device(
 	struct device *dev, int devno,
 	const char *cdev_name,
 	struct cdev *cdev, struct device **out,
-	const struct file_operations *ops,
 	struct nvgpu_class *class)
 {
 	struct device *subdev;
@@ -265,9 +264,6 @@ static int gk20a_create_device(
 
 	nvgpu_log_fn(g, " ");
 
-	cdev_init(cdev, ops);
-	cdev->owner = THIS_MODULE;
-
 	err = cdev_add(cdev, devno, 1);
 	if (err) {
 		dev_err(dev, "failed to add %s cdev\n", cdev_name);
@@ -297,6 +293,45 @@ static int gk20a_create_device(
 	return 0;
 }
 
+static int nvgpu_alloc_and_create_device(
+	struct device *dev, int devno,
+	const char *cdev_name,
+	const struct file_operations *ops,
+	struct nvgpu_class *class)
+{
+	struct gk20a *g = gk20a_from_dev(dev);
+	struct nvgpu_os_linux *l = nvgpu_os_linux_from_gk20a(g);
+	struct nvgpu_cdev *cdev;
+	int err;
+
+	cdev = nvgpu_kzalloc(g, sizeof(*cdev));
+	if (cdev == NULL) {
+		dev_err(dev, "failed to allocate cdev\n");
+		err = -ENOMEM;
+		goto out;
+	}
+
+	cdev_init(&cdev->cdev, ops);
+	cdev->cdev.owner = THIS_MODULE;
+
+	err = nvgpu_create_device(dev, devno, cdev_name,
+			&cdev->cdev, &cdev->node, class);
+	if (err) {
+		goto free_cdev;
+	}
+
+	cdev->class = class;
+	nvgpu_init_list_node(&cdev->list_entry);
+	nvgpu_list_add(&cdev->list_entry, &l->cdev_list_head);
+
+	return 0;
+
+free_cdev:
+	nvgpu_kfree(g, cdev);
+out:
+	return err;
+}
+
 void gk20a_remove_devices_and_classes(struct gk20a *g, bool power_node)
 {
 	struct nvgpu_os_linux *l = nvgpu_os_linux_from_gk20a(g);
@@ -568,7 +603,6 @@ int gk20a_power_node_init(struct device *dev)
 	struct nvgpu_class *class;
 	u32 total_cdevs;
 	u32 num_classes;
-	struct nvgpu_cdev *cdev;
 
 	if (!l->cdev_list_init_done) {
 		nvgpu_init_list_node(&l->cdev_list_head);
@@ -591,28 +625,17 @@ int gk20a_power_node_init(struct device *dev)
 
 	l->power_cdev_region = devno;
 	nvgpu_list_for_each_entry(class, &l->class_list_head, nvgpu_class, list_entry) {
-		cdev = nvgpu_kzalloc(g, sizeof(*cdev));
-		if (cdev == NULL) {
-			dev_err(dev, "failed to allocate cdev\n");
-			goto fail;
-		}
-
 		/*
 		 * dev_node_list[0] is the power node to issue
 		 * power-on to the GPU.
 		 */
-		err = gk20a_create_device(dev, devno++,
+		err = nvgpu_alloc_and_create_device(dev, devno++,
 			dev_node_list[0].name,
-			&cdev->cdev, &cdev->node,
 			dev_node_list[0].fops,
 			class);
 		if (err) {
 			goto fail;
 		}
-
-		cdev->class = class;
-		nvgpu_init_list_node(&cdev->list_entry);
-		nvgpu_list_add(&cdev->list_entry, &l->cdev_list_head);
 	}
 
 	l->power_cdevs = total_cdevs;
@@ -632,7 +655,6 @@ int gk20a_user_nodes_init(struct device *dev)
 	struct nvgpu_class *class;
 	u32 num_cdevs, total_cdevs;
 	u32 num_classes;
-	struct nvgpu_cdev *cdev;
 	u32 cdev_index;
 
 	if (!l->cdev_list_init_done) {
@@ -683,24 +705,13 @@ int gk20a_user_nodes_init(struct device *dev)
 				continue;
 			}
 
-			cdev = nvgpu_kzalloc(g, sizeof(*cdev));
+			err = nvgpu_alloc_and_create_device(dev, devno++,
-			if (cdev == NULL) {
-				dev_err(dev, "failed to allocate cdev\n");
-				goto fail;
-			}
-
-			err = gk20a_create_device(dev, devno++,
 					dev_node_list[cdev_index].name,
-					&cdev->cdev, &cdev->node,
 					dev_node_list[cdev_index].fops,
 					class);
 			if (err) {
 				goto fail;
 			}
-
-			cdev->class = class;
-			nvgpu_init_list_node(&cdev->list_entry);
-			nvgpu_list_add(&cdev->list_entry, &l->cdev_list_head);
 		}
 	}
 

drivers/gpu/nvgpu/os/linux/ioctl.h

@@ -75,4 +75,10 @@ unsigned int nvgpu_allocate_cdev_minor(struct gk20a *g);
 struct gk20a *nvgpu_get_gk20a_from_cdev(struct nvgpu_cdev *cdev);
 u32 nvgpu_get_gpu_instance_id_from_cdev(struct gk20a *g, struct nvgpu_cdev *cdev);
 
+int nvgpu_create_device(
+	struct device *dev, int devno,
+	const char *cdev_name,
+	struct cdev *cdev, struct device **out,
+	struct nvgpu_class *class);
+
 #endif