efivars: Make efivars bin_attributes dynamic

In preparation for encapsulating efivars, we need to have the
bin_attributes be dynamically allocated so that we can use their
->private fields to get back to the struct efivars structure.
Signed-off-by: Mike Waychison <mikew@google.com>
Cc: Matt Domsch <Matt_Domsch@dell.com>,
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/firmware/efivars.c

@@ -101,6 +101,7 @@ struct efivars {
 	spinlock_t lock;
 	struct list_head list;
 	struct kset *kset;
+	struct bin_attribute *new_var, *del_var;
 };
 static struct efivars __efivars;
 static struct efivars *efivars = &__efivars;
@@ -525,16 +526,6 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
 	return count;
 }
 
-static struct bin_attribute var_subsys_attr_new_var = {
-	.attr = {.name = "new_var", .mode = 0200},
-	.write = efivar_create,
-};
-
-static struct bin_attribute var_subsys_attr_del_var = {
-	.attr = {.name = "del_var", .mode = 0200},
-	.write = efivar_delete,
-};
-
 /*
  * Let's not leave out systab information that snuck into
  * the efivars driver
@@ -640,6 +631,66 @@ efivar_create_sysfs_entry(unsigned long variable_name_size,
 
 	return 0;
 }
+
+static int
+create_efivars_bin_attributes(struct efivars *efivars)
+{
+	struct bin_attribute *attr;
+	int error;
+
+	/* new_var */
+	attr = kzalloc(sizeof(*attr), GFP_KERNEL);
+	if (!attr)
+		return -ENOMEM;
+
+	attr->attr.name = "new_var";
+	attr->attr.mode = 0200;
+	attr->write = efivar_create;
+	attr->private = efivars;
+	efivars->new_var = attr;
+
+	/* del_var */
+	attr = kzalloc(sizeof(*attr), GFP_KERNEL);
+	if (!attr) {
+		error = -ENOMEM;
+		goto out_free;
+	}
+	attr->attr.name = "del_var";
+	attr->attr.mode = 0200;
+	attr->write = efivar_delete;
+	attr->private = efivars;
+	efivars->del_var = attr;
+
+	sysfs_bin_attr_init(efivars->new_var);
+	sysfs_bin_attr_init(efivars->del_var);
+
+	/* Register */
+	error = sysfs_create_bin_file(&efivars->kset->kobj,
+				      efivars->new_var);
+	if (error) {
+		printk(KERN_ERR "efivars: unable to create new_var sysfs file"
+			" due to error %d\n", error);
+		goto out_free;
+	}
+	error = sysfs_create_bin_file(&efivars->kset->kobj,
+				      efivars->del_var);
+	if (error) {
+		printk(KERN_ERR "efivars: unable to create del_var sysfs file"
+			" due to error %d\n", error);
+		sysfs_remove_bin_file(&efivars->kset->kobj,
+				      efivars->new_var);
+		goto out_free;
+	}
+
+	return 0;
+out_free:
+	kfree(efivars->new_var);
+	efivars->new_var = NULL;
+	kfree(efivars->new_var);
+	efivars->new_var = NULL;
+	return error;
+}
+
 /*
  * For now we register the efi subsystem with the firmware subsystem
  * and the vars subsystem with the efi subsystem.  In the future, it
@@ -714,20 +765,7 @@ efivars_init(void)
 		}
 	} while (status != EFI_NOT_FOUND);
 
-	/*
-	 * Now add attributes to allow creation of new vars
-	 * and deletion of existing ones...
-	 */
-	error = sysfs_create_bin_file(&efivars->kset->kobj,
-				      &var_subsys_attr_new_var);
-	if (error)
-		printk(KERN_ERR "efivars: unable to create new_var sysfs file"
-			" due to error %d\n", error);
-	error = sysfs_create_bin_file(&efivars->kset->kobj,
-				      &var_subsys_attr_del_var);
-	if (error)
-		printk(KERN_ERR "efivars: unable to create del_var sysfs file"
-			" due to error %d\n", error);
+	error = create_efivars_bin_attributes(efivars);
 
 	/* Don't forget the systab entry */
 	error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
@@ -758,7 +796,12 @@ efivars_exit(void)
 		spin_unlock(&efivars->lock);
 		efivar_unregister(entry);
 	}
-
+	if (efivars->new_var)
+		sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
+	if (efivars->del_var)
+		sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
+	kfree(efivars->new_var);
+	kfree(efivars->del_var);
 	kset_unregister(efivars->kset);
 	kobject_put(efi_kobj);
 }