get rid of the second argument of acct_kill()

Replace the old ns->bacct only with NULL and only if it still points
to acct.  And assign the new value to it *before* calling acct_kill()
in acct_on().  That way we don't need to pass the new acct to acct_kill().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/kernel/acct.c b/kernel/acct.c
index b8fbefb..cf6588a 100644 (file)
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -168,8 +168,7 @@ static void close_work(struct work_struct *work)
        complete(&acct->done);
 }
 
-static void acct_kill(struct bsd_acct_struct *acct,
-                     struct bsd_acct_struct *new)
+static void acct_kill(struct bsd_acct_struct *acct)
 {
        if (acct) {
                struct pid_namespace *ns = acct->ns;
@@ -179,7 +178,7 @@ static void acct_kill(struct bsd_acct_struct *acct,
                schedule_work(&acct->work);
                wait_for_completion(&acct->done);
                pin_remove(&acct->pin);
-               ns->bacct = new;
+               cmpxchg(&ns->bacct, acct, NULL);
                acct->ns = NULL;
                atomic_long_dec(&acct->count);
                mutex_unlock(&acct->lock);
@@ -203,7 +202,7 @@ static void acct_pin_kill(struct fs_pin *pin)
                acct_put(acct);
                acct = NULL;
        }
-       acct_kill(acct, NULL);
+       acct_kill(acct);
 }
 
 static int acct_on(struct filename *pathname)
@@ -262,10 +261,8 @@ static int acct_on(struct filename *pathname)
        pin_insert(&acct->pin, mnt);
 
        old = acct_get(ns);
-       if (old)
-               acct_kill(old, acct);
-       else
-               ns->bacct = acct;
+       ns->bacct = acct;
+       acct_kill(old);
        mutex_unlock(&acct->lock);
        mnt_drop_write(mnt);
        mntput(mnt);
@@ -302,7 +299,7 @@ SYSCALL_DEFINE1(acct, const char __user *, name)
                mutex_unlock(&acct_on_mutex);
                putname(tmp);
        } else {
-               acct_kill(acct_get(task_active_pid_ns(current)), NULL);
+               acct_kill(acct_get(task_active_pid_ns(current)));
        }
 
        return error;
@@ -310,7 +307,7 @@ SYSCALL_DEFINE1(acct, const char __user *, name)
 
 void acct_exit_ns(struct pid_namespace *ns)
 {
-       acct_kill(acct_get(ns), NULL);
+       acct_kill(acct_get(ns));
 }
 
 /*