Merge tag 'configfs-for-4.19' of git://git.infradead.org/users/hch/configfs

Pull configfs updates from Christoph Hellwig:

 - simplify the cide by using kvasprintf (Bart Van Assche)

 - fix a gcc 8 string truncation warning by making the code simpler
   (Guenter Roeck)

 - fix a bug in rmdir() handling (Mike Christie)

* tag 'configfs-for-4.19' of git://git.infradead.org/users/hch/configfs:
  configfs: fix registered group removal
  configfs: replace strncpy with memcpy
  configfs: use kvasprintf() instead of open-coding it

fs/configfs/dir.c

@@ -1777,6 +1777,16 @@ void configfs_unregister_group(struct config_group *group)
 	struct dentry *dentry = group->cg_item.ci_dentry;
 	struct dentry *parent = group->cg_item.ci_parent->ci_dentry;
 
+	mutex_lock(&subsys->su_mutex);
+	if (!group->cg_item.ci_parent->ci_group) {
+		/*
+		 * The parent has already been unlinked and detached
+		 * due to a rmdir.
+		 */
+		goto unlink_group;
+	}
+	mutex_unlock(&subsys->su_mutex);
+
 	inode_lock_nested(d_inode(parent), I_MUTEX_PARENT);
 	spin_lock(&configfs_dirent_lock);
 	configfs_detach_prep(dentry, NULL);
@@ -1791,6 +1801,7 @@ void configfs_unregister_group(struct config_group *group)
 	dput(dentry);
 
 	mutex_lock(&subsys->su_mutex);
+unlink_group:
 	unlink_group(group);
 	mutex_unlock(&subsys->su_mutex);
 }

fs/configfs/item.c

@@ -64,7 +64,6 @@ static void config_item_init(struct config_item *item)
  */
 int config_item_set_name(struct config_item *item, const char *fmt, ...)
 {
-	int error = 0;
 	int limit = CONFIGFS_ITEM_NAME_LEN;
 	int need;
 	va_list args;
@@ -79,25 +78,11 @@ int config_item_set_name(struct config_item *item, const char *fmt, ...)
 	if (need < limit)
 		name = item->ci_namebuf;
 	else {
-		/*
-		 * Need more space? Allocate it and try again
-		 */
-		limit = need + 1;
-		name = kmalloc(limit, GFP_KERNEL);
-		if (!name) {
-			error = -ENOMEM;
-			goto Done;
-		}
 		va_start(args, fmt);
-		need = vsnprintf(name, limit, fmt, args);
+		name = kvasprintf(GFP_KERNEL, fmt, args);
 		va_end(args);
-
-		/* Still? Give up. */
-		if (need >= limit) {
-			kfree(name);
-			error = -EFAULT;
-			goto Done;
-		}
+		if (!name)
+			return -EFAULT;
 	}
 
 	/* Free the old name, if necessary. */
@@ -106,8 +91,7 @@ int config_item_set_name(struct config_item *item, const char *fmt, ...)
 
 	/* Now, set the new name */
 	item->ci_name = name;
- Done:
-	return error;
+	return 0;
 }
 EXPORT_SYMBOL(config_item_set_name);
 

fs/configfs/symlink.c

@@ -64,7 +64,7 @@ static void fill_item_path(struct config_item * item, char * buffer, int length)
 
 		/* back up enough to print this bus id with '/' */
 		length -= cur;
-		strncpy(buffer + length,config_item_name(p),cur);
+		memcpy(buffer + length, config_item_name(p), cur);
 		*(buffer + --length) = '/';
 	}
 }