fs: configfs: don't return anything from drop_link

Documentation/filesystems/configfs/configfs.txt says:

"When unlink(2) is called on the symbolic link, the source item is
notified via the ->drop_link() method.  Like the ->drop_item() method,
this is a void function and cannot return failure."

The ->drop_item() is indeed a void function, the ->drop_link() is
actually not. This, together with the fact that the value of ->drop_link()
is silently ignored suggests, that it is the ->drop_link() return
type that should be corrected and changed to void.

This patch changes drop_link() signature and all its users.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
[hch: reverted reformatting of some code]
Signed-off-by: Christoph Hellwig <hch@lst.de>

Author: Andrzej Pietrasiewicz

Documentation/filesystems/configfs/configfs.txt

@@ -174,7 +174,7 @@ among other things.  For that, it needs a type.
 		void (*release)(struct config_item *);
 		int (*allow_link)(struct config_item *src,
 				  struct config_item *target);
-		int (*drop_link)(struct config_item *src,
+		void (*drop_link)(struct config_item *src,
 				 struct config_item *target);
 	};
 

drivers/nvme/target/configfs.c

@@ -466,7 +466,7 @@ static int nvmet_port_subsys_allow_link(struct config_item *parent,
 	return ret;
 }
 
-static int nvmet_port_subsys_drop_link(struct config_item *parent,
+static void nvmet_port_subsys_drop_link(struct config_item *parent,
 		struct config_item *target)
 {
 	struct nvmet_port *port = to_nvmet_port(parent->ci_parent);
@@ -479,7 +479,7 @@ static int nvmet_port_subsys_drop_link(struct config_item *parent,
 			goto found;
 	}
 	up_write(&nvmet_config_sem);
-	return -EINVAL;
+	return;
 
 found:
 	list_del(&p->entry);
@@ -488,7 +488,6 @@ static int nvmet_port_subsys_drop_link(struct config_item *parent,
 		nvmet_disable_port(port);
 	up_write(&nvmet_config_sem);
 	kfree(p);
-	return 0;
 }
 
 static struct configfs_item_operations nvmet_port_subsys_item_ops = {
@@ -542,7 +541,7 @@ static int nvmet_allowed_hosts_allow_link(struct config_item *parent,
 	return ret;
 }
 
-static int nvmet_allowed_hosts_drop_link(struct config_item *parent,
+static void nvmet_allowed_hosts_drop_link(struct config_item *parent,
 		struct config_item *target)
 {
 	struct nvmet_subsys *subsys = to_subsys(parent->ci_parent);
@@ -555,14 +554,13 @@ static int nvmet_allowed_hosts_drop_link(struct config_item *parent,
 			goto found;
 	}
 	up_write(&nvmet_config_sem);
-	return -EINVAL;
+	return;
 
 found:
 	list_del(&p->entry);
 	nvmet_genctr++;
 	up_write(&nvmet_config_sem);
 	kfree(p);
-	return 0;
 }
 
 static struct configfs_item_operations nvmet_allowed_hosts_item_ops = {

drivers/target/target_core_fabric_configfs.c

@@ -137,7 +137,7 @@ static int target_fabric_mappedlun_link(
 	return core_dev_add_initiator_node_lun_acl(se_tpg, lacl, lun, lun_access_ro);
 }
 
-static int target_fabric_mappedlun_unlink(
+static void target_fabric_mappedlun_unlink(
 	struct config_item *lun_acl_ci,
 	struct config_item *lun_ci)
 {
@@ -146,7 +146,7 @@ static int target_fabric_mappedlun_unlink(
 	struct se_lun *lun = container_of(to_config_group(lun_ci),
 			struct se_lun, lun_group);
 
-	return core_dev_del_initiator_node_lun_acl(lun, lacl);
+	core_dev_del_initiator_node_lun_acl(lun, lacl);
 }
 
 static struct se_lun_acl *item_to_lun_acl(struct config_item *item)
@@ -669,7 +669,7 @@ static int target_fabric_port_link(
 	return ret;
 }
 
-static int target_fabric_port_unlink(
+static void target_fabric_port_unlink(
 	struct config_item *lun_ci,
 	struct config_item *se_dev_ci)
 {
@@ -688,7 +688,6 @@ static int target_fabric_port_unlink(
 	}
 
 	core_dev_del_lun(se_tpg, lun);
-	return 0;
 }
 
 static void target_fabric_port_release(struct config_item *item)

drivers/usb/gadget/configfs.c

@@ -408,7 +408,7 @@ static int config_usb_cfg_link(
 	return ret;
 }
 
-static int config_usb_cfg_unlink(
+static void config_usb_cfg_unlink(
 	struct config_item *usb_cfg_ci,
 	struct config_item *usb_func_ci)
 {
@@ -437,12 +437,11 @@ static int config_usb_cfg_unlink(
 			list_del(&f->list);
 			usb_put_function(f);
 			mutex_unlock(&gi->lock);
-			return 0;
+			return;
 		}
 	}
 	mutex_unlock(&gi->lock);
 	WARN(1, "Unable to locate function to unbind\n");
-	return 0;
 }
 
 static struct configfs_item_operations gadget_config_item_ops = {
@@ -865,7 +864,7 @@ static int os_desc_link(struct config_item *os_desc_ci,
 	return ret;
 }
 
-static int os_desc_unlink(struct config_item *os_desc_ci,
+static void os_desc_unlink(struct config_item *os_desc_ci,
 			  struct config_item *usb_cfg_ci)
 {
 	struct gadget_info *gi = container_of(to_config_group(os_desc_ci),
@@ -878,7 +877,6 @@ static int os_desc_unlink(struct config_item *os_desc_ci,
 	cdev->os_desc_config = NULL;
 	WARN_ON(gi->composite.gadget_driver.udc_name);
 	mutex_unlock(&gi->lock);
-	return 0;
 }
 
 static struct configfs_item_operations os_desc_ops = {

drivers/usb/gadget/function/uvc_configfs.c

@@ -547,15 +547,14 @@ static int uvcg_control_class_allow_link(struct config_item *src,
 	return ret;
 }
 
-static int uvcg_control_class_drop_link(struct config_item *src,
+static void uvcg_control_class_drop_link(struct config_item *src,
 					struct config_item *target)
 {
 	struct config_item *control, *header;
 	struct f_uvc_opts *opts;
 	struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
 	struct uvc_descriptor_header **class_array;
 	struct uvcg_control_header *target_hdr;
-	int ret = -EINVAL;
 
 	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
 
@@ -569,23 +568,17 @@ static int uvcg_control_class_drop_link(struct config_item *src,
 	mutex_lock(&opts->lock);
 
 	class_array = uvcg_get_ctl_class_arr(src, opts);
-	if (!class_array)
-		goto unlock;
-	if (opts->refcnt) {
-		ret = -EBUSY;
+	if (!class_array || opts->refcnt)
 		goto unlock;
-	}
 
 	target_hdr = to_uvcg_control_header(target);
 	--target_hdr->linked;
 	class_array[0] = NULL;
-	ret = 0;
 
 unlock:
 	mutex_unlock(&opts->lock);
 out:
 	mutex_unlock(su_mutex);
-	return ret;
 }
 
 static struct configfs_item_operations uvcg_control_class_item_ops = {
@@ -777,7 +770,7 @@ static int uvcg_streaming_header_allow_link(struct config_item *src,
 	return ret;
 }
 
-static int uvcg_streaming_header_drop_link(struct config_item *src,
+static void uvcg_streaming_header_drop_link(struct config_item *src,
 					   struct config_item *target)
 {
 	struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
@@ -786,7 +779,6 @@ static int uvcg_streaming_header_drop_link(struct config_item *src,
 	struct uvcg_streaming_header *src_hdr;
 	struct uvcg_format *target_fmt = NULL;
 	struct uvcg_format_ptr *format_ptr, *tmp;
-	int ret = -EINVAL;
 
 	src_hdr = to_uvcg_streaming_header(src);
 	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
@@ -811,8 +803,6 @@ static int uvcg_streaming_header_drop_link(struct config_item *src,
 out:
 	mutex_unlock(&opts->lock);
 	mutex_unlock(su_mutex);
-	return ret;
-
 }
 
 static struct configfs_item_operations uvcg_streaming_header_item_ops = {
@@ -2051,15 +2041,14 @@ static int uvcg_streaming_class_allow_link(struct config_item *src,
 	return ret;
 }
 
-static int uvcg_streaming_class_drop_link(struct config_item *src,
+static void uvcg_streaming_class_drop_link(struct config_item *src,
 					  struct config_item *target)
 {
 	struct config_item *streaming, *header;
 	struct f_uvc_opts *opts;
 	struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
 	struct uvc_descriptor_header ***class_array;
 	struct uvcg_streaming_header *target_hdr;
-	int ret = -EINVAL;
 
 	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
 
@@ -2076,23 +2065,19 @@ static int uvcg_streaming_class_drop_link(struct config_item *src,
 	if (!class_array || !*class_array)
 		goto unlock;
 
-	if (opts->refcnt) {
-		ret = -EBUSY;
+	if (opts->refcnt)
 		goto unlock;
-	}
 
 	target_hdr = to_uvcg_streaming_header(target);
 	--target_hdr->linked;
 	kfree(**class_array);
 	kfree(*class_array);
 	*class_array = NULL;
-	ret = 0;
 
 unlock:
 	mutex_unlock(&opts->lock);
 out:
 	mutex_unlock(su_mutex);
-	return ret;
 }
 
 static struct configfs_item_operations uvcg_streaming_class_item_ops = {

include/linux/configfs.h

@@ -228,7 +228,7 @@ static struct configfs_bin_attribute _pfx##attr_##_name = {	\
 struct configfs_item_operations {
 	void (*release)(struct config_item *);
 	int (*allow_link)(struct config_item *src, struct config_item *target);
-	int (*drop_link)(struct config_item *src, struct config_item *target);
+	void (*drop_link)(struct config_item *src, struct config_item *target);
 };
 
 struct configfs_group_operations {