bsdacct: fix and add comments around acct_process()
Fix the one describing what this function is and add one more - about
locking absence around pid namespaces loop.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/acct.c b/kernel/acct.c
index 0feba97..dd68b90 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -657,7 +657,8 @@
}
/**
- * acct_process - now just a wrapper around do_acct_process
+ * acct_process - now just a wrapper around acct_process_in_ns,
+ * which in turn is a wrapper around do_acct_process.
*
* handles process accounting for an exiting task
*/
@@ -665,6 +666,11 @@
{
struct pid_namespace *ns;
+ /*
+ * This loop is safe lockless, since current is still
+ * 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);
}