RDMA/uverbs: Use device.groups to initialize device attributes

Instead of explicitly adding device attribute files and handling such
error conditions, depend on device core layer to create device attributes
files based group pointer NULL terminated array.
Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/uverbs.h

@@ -101,6 +101,8 @@ struct ib_uverbs_device {
 	int					num_comp_vectors;
 	struct completion			comp;
 	struct device				dev;
+	/* First group for device attributes, NULL terminated array */
+	const struct attribute_group		*groups[2];
 	struct ib_device	__rcu	       *ib_dev;
 	int					devnum;
 	struct cdev			        cdev;

drivers/infiniband/core/uverbs_main.c

@@ -947,7 +947,7 @@ static struct ib_client uverbs_client = {
 	.remove = ib_uverbs_remove_one
 };
 
-static ssize_t show_ibdev(struct device *device, struct device_attribute *attr,
+static ssize_t ibdev_show(struct device *device, struct device_attribute *attr,
 			  char *buf)
 {
 	struct ib_uverbs_device *dev =
@@ -964,10 +964,10 @@ static ssize_t show_ibdev(struct device *device, struct device_attribute *attr,
 
 	return ret;
 }
-static DEVICE_ATTR(ibdev, S_IRUGO, show_ibdev, NULL);
+static DEVICE_ATTR_RO(ibdev);
 
-static ssize_t show_dev_abi_version(struct device *device,
-				    struct device_attribute *attr, char *buf)
+static ssize_t abi_version_show(struct device *device,
+				struct device_attribute *attr, char *buf)
 {
 	struct ib_uverbs_device *dev =
 			container_of(device, struct ib_uverbs_device, dev);
@@ -983,7 +983,17 @@ static ssize_t show_dev_abi_version(struct device *device,
 
 	return ret;
 }
-static DEVICE_ATTR(abi_version, S_IRUGO, show_dev_abi_version, NULL);
+static DEVICE_ATTR_RO(abi_version);
+
+static struct attribute *ib_dev_attrs[] = {
+	&dev_attr_abi_version.attr,
+	&dev_attr_ibdev.attr,
+	NULL,
+};
+
+static const struct attribute_group dev_attr_group = {
+	.attrs = ib_dev_attrs,
+};
 
 static CLASS_ATTR_STRING(abi_version, S_IRUGO,
 			 __stringify(IB_USER_VERBS_ABI_VERSION));
@@ -1050,6 +1060,8 @@ static void ib_uverbs_add_one(struct ib_device *device)
 	uverbs_dev->dev.parent = device->dev.parent;
 	uverbs_dev->dev.devt = base;
 	uverbs_dev->dev.release = ib_uverbs_release_dev;
+	uverbs_dev->groups[0] = &dev_attr_group;
+	uverbs_dev->dev.groups = uverbs_dev->groups;
 	dev_set_name(&uverbs_dev->dev, "uverbs%d", uverbs_dev->devnum);
 
 	cdev_init(&uverbs_dev->cdev,
@@ -1060,17 +1072,9 @@ static void ib_uverbs_add_one(struct ib_device *device)
 	if (ret)
 		goto err_cdev;
 
-	if (device_create_file(&uverbs_dev->dev, &dev_attr_ibdev))
-		goto err_file;
-	if (device_create_file(&uverbs_dev->dev, &dev_attr_abi_version))
-		goto err_file;
-
 	ib_set_client_data(device, &uverbs_client, uverbs_dev);
-
 	return;
 
-err_file:
-	cdev_device_del(&uverbs_dev->cdev, &uverbs_dev->dev);
 err_cdev:
 	cdev_del(&uverbs_dev->cdev);
 	put_device(&uverbs_dev->dev);