do_wait-wakeup-optimization: simplify task_pid_type()

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>

1 files changed, 6 insertions, 8 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index 3fb9a77863d5..650c1d1a55d0 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -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;