do_wait-wakeup-optimization: simplify task_pid_type()
Oleg Nesterov [Wed, 23 Sep 2009 22:56:49 +0000 (15:56 -0700)]
task_pid_type() is only used by eligible_pid() which has to check wo_type
!= PIDTYPE_MAX anyway.  Remove this check from task_pid_type() and factor
out ->pids[type] access, this shrinks .text a bit and simplifies the code.

The matches the behaviour of other similar helpers, say get_task_pid().
The caller must ensure that pid_type is valid, not the callee.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/exit.c

index 3fb9a77..650c1d1 100644 (file)
@@ -1101,17 +1101,15 @@ struct wait_opts {
        int                     notask_error;
 };
 
-static struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
+static inline
+struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
 {
-       struct pid *pid = NULL;
-       if (type == PIDTYPE_PID)
-               pid = task->pids[type].pid;
-       else if (type < PIDTYPE_MAX)
-               pid = task->group_leader->pids[type].pid;
-       return pid;
+       if (type != PIDTYPE_PID)
+               task = task->group_leader;
+       return task->pids[type].pid;
 }
 
-static inline int eligible_pid(struct wait_opts *wo, struct task_struct *p)
+static int eligible_pid(struct wait_opts *wo, struct task_struct *p)
 {
        return  wo->wo_type == PIDTYPE_MAX ||
                task_pid_type(p, wo->wo_type) == wo->wo_pid;