增加进程的调度policy属性 (#63)

* 添加进程的policy属性

* update

* 修改设置进程策略

* 删除重复定义

* 更正注释及格式

Co-authored-by: longjin <longjin@RinGoTek.cn>

kernel/sched/sched.c

@@ -1,9 +1,53 @@
 #include "sched.h"
 #include <common/kprint.h>
-#include <driver/video/video.h>
 #include <common/spinlock.h>
+#include <driver/video/video.h>
 #include <sched/cfs.h>
 
+/**
+ * @brief 
+ * 
+ * @param p pcb
+ * @param attr 调度属性
+ * @param user 请求是否来自用户态
+ * @param pi 
+ * @return int 
+ */
+static int __sched_setscheduler(struct process_control_block *p, const struct sched_attr *attr, bool user, bool pi)
+{
+    int policy = attr->sched_policy;
+recheck:;
+    // 这里policy的设置小于0是因为，需要在临界区内更新值之后，重新到这里判断
+    if (!IS_VALID_SCHED_POLICY(policy))
+    {
+        return -EINVAL;
+    }
+    // 修改成功
+    p->policy = policy;
+    return 0;
+}
+
+static int _sched_setscheduler(struct process_control_block *p, int policy, const struct sched_param *param, bool check)
+{
+    struct sched_attr attr = {.sched_policy = policy};
+
+    return __sched_setscheduler(p, &attr, check, true);
+}
+
+/**
+ * sched_setscheduler -设置进程的调度策略
+ * @param p 需要修改的pcb
+ * @param policy 需要设置的policy
+ * @param param structure containing the new RT priority. 目前没有用
+ *
+ * @return 成功返回0,否则返回对应的错误码
+ *
+ */
+int sched_setscheduler(struct process_control_block *p, int policy, const struct sched_param *param)
+{
+    return _sched_setscheduler(p, policy, param, true);
+}
+
 /**
  * @brief 包裹shced_cfs_enqueue(),将PCB加入就绪队列
  *