[PATCH] kernel/params.c: make use of unused but set variable

[Louis Langholtz <lou_langholtz@me.com>]

While Rusty Russell wants the return value of sysfs_create_file
ignored, it's annotated '__must_check'. Tejun Heo made the annotaion
and suggests just using BUG_ON(). Meanwhile the compiler warns that
the 'err' variable is set but unused. This patch uses Tejun's
suggestion. This eliminates the warning, satisfies the required check,
and fails-fast with notice if sysfs_create_file actually ever fails
(something that Rusty says should never happen when this code runs).

Signed-off-by: Louis Langholtz <lou_langholtz@me.com>
---

diff --git a/kernel/params.c b/kernel/params.c
index a22d6a7..b04a752 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -853,6 +853,7 @@ static void __init version_sysfs_builtin(void)
 		mk = locate_module_kobject(vattr->module_name);
 		if (mk) {
 			err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
+			BUG_ON(err);
 			kobject_uevent(&mk->kobj, KOBJ_ADD);
 			kobject_put(&mk->kobj);
 		}