sched,watchdog: Convert to sched_set_fifo()

Peter Zijlstra · Peter Zijlstra · commit 94beddacb53c · 2020-06-15T14:10:24.000+02:00
Because SCHED_FIFO is a broken scheduler model (see previous patches)
take away the priority field, the kernel can't possibly make an
informed decision.

Effectively changes prio from 99 to 50.

Cc: wim@linux-watchdog.org
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: Ingo Molnar &lt;mingo@kernel.org&gt;
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
@@ -1144,14 +1144,13 @@ void watchdog_dev_unregister(struct watchdog_device *wdd)
 int __init watchdog_dev_init(void)
 {
 	int err;
-	struct sched_param param = {.sched_priority = MAX_RT_PRIO - 1,};
 
 	watchdog_kworker = kthread_create_worker(0, "watchdogd");
 	if (IS_ERR(watchdog_kworker)) {
 		pr_err("Failed to create watchdog kworker\n");
 		return PTR_ERR(watchdog_kworker);
 	}
-	sched_setscheduler(watchdog_kworker->task, SCHED_FIFO, &param);
+	sched_set_fifo(watchdog_kworker->task);
 
 	err = class_register(&watchdog_class);
 	if (err < 0) {

Original file line number	Diff line number	Diff line change
`@@ -1144,14 +1144,13 @@ void watchdog_dev_unregister(struct watchdog_device *wdd)`
`1144`	`1144`	`int __init watchdog_dev_init(void)`
`1145`	`1145`	`{`
`1146`	`1146`	`int err;`
`1147`		`- struct sched_param param = {.sched_priority = MAX_RT_PRIO - 1,};`
`1148`	`1147`
`1149`	`1148`	`watchdog_kworker = kthread_create_worker(0, "watchdogd");`
`1150`	`1149`	`if (IS_ERR(watchdog_kworker)) {`
`1151`	`1150`	`pr_err("Failed to create watchdog kworker\n");`
`1152`	`1151`	`return PTR_ERR(watchdog_kworker);`
`1153`	`1152`	`}`
`1154`		`- sched_setscheduler(watchdog_kworker->task, SCHED_FIFO, &param);`
	`1153`	`+ sched_set_fifo(watchdog_kworker->task);`
`1155`	`1154`
`1156`	`1155`	`err = class_register(&watchdog_class);`
`1157`	`1156`	`if (err < 0) {`