[PATCH] sys_setpgid: eliminate unnecessary do_each_task_pid(PIDTYPE_PGID)
All tasks in the process group have the same sid, we don't need to iterate
them all to check that the caller of sys_setpgid() doesn't change its
session.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/sys.c b/kernel/sys.c
index 4f9d23a..c7675c1 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1397,16 +1397,13 @@
goto out;
if (pgid != pid) {
- struct task_struct *p;
+ struct task_struct *g =
+ find_task_by_pid_type(PIDTYPE_PGID, pgid);
- do_each_task_pid(pgid, PIDTYPE_PGID, p) {
- if (process_session(p) == process_session(group_leader))
- goto ok_pgid;
- } while_each_task_pid(pgid, PIDTYPE_PGID, p);
- goto out;
+ if (!g || process_session(g) != process_session(group_leader))
+ goto out;
}
-ok_pgid:
err = security_task_setpgid(p, pgid);
if (err)
goto out;