split the slow path in acct_process() off

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

diff --git a/kernel/acct.c b/kernel/acct.c
index efa891beeaa3b5855a79870a79f7f764df863f86..51188603b2588dd25fd0d8db6b6618648e075c20 100644 (file)
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -599,34 +599,35 @@ void acct_collect(long exitcode, int group_dead)
        spin_unlock_irq(&current->sighand->siglock);
 }
 
-static void acct_process_in_ns(struct pid_namespace *ns)
+static void slow_acct_process(struct pid_namespace *ns)
 {
-       struct file *file = NULL;
-       struct bsd_acct_struct *acct;
+       for ( ; ns; ns = ns->parent) {
+               struct file *file = NULL;
+               struct bsd_acct_struct *acct;
 
-       acct = ns->bacct;
-       /*
-        * accelerate the common fastpath:
-        */
-       if (!acct || !acct->file)
-               return;
+               acct = ns->bacct;
+               /*
+                * accelerate the common fastpath:
+                */
+               if (!acct || !acct->file)
+                       continue;
 
-       spin_lock(&acct_lock);
-       file = acct->file;
-       if (unlikely(!file)) {
+               spin_lock(&acct_lock);
+               file = acct->file;
+               if (unlikely(!file)) {
+                       spin_unlock(&acct_lock);
+                       continue;
+               }
+               get_file(file);
                spin_unlock(&acct_lock);
-               return;
-       }
-       get_file(file);
-       spin_unlock(&acct_lock);
 
-       do_acct_process(acct, ns, file);
-       fput(file);
+               do_acct_process(acct, ns, file);
+               fput(file);
+       }
 }
 
 /**
- * acct_process - now just a wrapper around acct_process_in_ns,
- * which in turn is a wrapper around do_acct_process.
+ * acct_process
  *
  * handles process accounting for an exiting task
  */
@@ -639,6 +640,11 @@ void acct_process(void)
         * alive and holds its namespace, which in turn holds
         * its parent.
         */
-       for (ns = task_active_pid_ns(current); ns != NULL; ns = ns->parent)
-               acct_process_in_ns(ns);
+       for (ns = task_active_pid_ns(current); ns != NULL; ns = ns->parent) {
+               struct bsd_acct_struct *acct = ns->bacct;
+               if (acct && acct->file)
+                       break;
+       }
+       if (unlikely(ns))
+               slow_acct_process(ns);
 }