From: Tomas Hruby <tom@minix3.org>
Date: Sat, 10 Apr 2010 15:17:09 +0000 (+0000)
Subject: do_schedule() cleanup
X-Git-Tag: v3.1.7~161
X-Git-Url: http://zhaoyanbai.com/repos/%22http:/www.isc.org/icons/man.rndc.html?a=commitdiff_plain;h=485a037563527117840f92ecf3215c1663814398;p=minix.git

do_schedule() cleanup

- it is not neccessary to test whether the scheduler is a system
  process as the process already head permissions to make this call.

- it is better to test whether the scheduler has permission to make
  changes to this process before testing whether the values are valid.
---

diff --git a/kernel/system/do_schedule.c b/kernel/system/do_schedule.c
index f9c37e4db..7e75bf8da 100644
--- a/kernel/system/do_schedule.c
+++ b/kernel/system/do_schedule.c
@@ -12,19 +12,15 @@ PUBLIC int do_schedule(struct proc * caller, message * m_ptr)
 
 	p = proc_addr(_ENDPOINT_P(m_ptr->SCHEDULING_ENDPOINT));
 
+	/* Only this process' scheduler can schedule it */
+	if (caller != p->p_scheduler)
+		return(EPERM);
+
 	/* Make sure the priority number given is within the allowed range.*/
 	if (m_ptr->SCHEDULING_PRIORITY < TASK_Q ||
 		m_ptr->SCHEDULING_PRIORITY > NR_SCHED_QUEUES)
 		return(EINVAL);
 
-	/* Only system processes can schedule processes */
-	if (! (priv(caller)->s_flags & SYS_PROC))
-		return(EPERM);
-
-	/* Only this process' scheduler can schedule it */
-	if (caller != p->p_scheduler)
-		return(EPERM);
-
 	/* In some cases, we might be rescheduling a runnable process. In such
 	 * a case (i.e. if we are updating the priority) we set the NO_QUANTUM
 	 * flag before the generic unset to dequeue/enqueue the process