sched, tracing: Fix trace_sched_pi_setprio() for deboosting

Since the following commit:

b91473ff6e97 ("sched,tracing: Update trace_sched_pi_setprio()")

the sched_pi_setprio trace point shows the "newprio" during a deboost:

|futex sched_pi_setprio: comm=futex_requeue_p pid"34 oldprio˜ newprio=3D98
|futex sched_switch: prev_comm=futex_requeue_p prev_pid"34 prev_prio=120

This patch open codes __rt_effective_prio() in the tracepoint as the
'newprio' to get the old behaviour back / the correct priority:

|futex sched_pi_setprio: comm=futex_requeue_p pid"20 oldprio˜ newprio=3D120
|futex sched_switch: prev_comm=futex_requeue_p prev_pid"20 prev_prio=120

Peter suggested to open code the new priority so people using tracehook
could get the deadline data out.

Reported-by: Mansky Christian <[e-mail]>
Signed-off-by: Sebastian Andrzej Siewior <[e-mail]>
Signed-off-by: Peter Zijlstra (Intel) <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Steven Rostedt <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Fixes: b91473ff6e97 ("sched,tracing: Update trace_sched_pi_setprio()")
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

include/trace/events/sched.h

···
 		memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN);
 		__entry->pid		= tsk->pid;
 		__entry->oldprio	= tsk->prio;
-		__entry->newprio	= pi_task ? pi_task->prio : tsk->prio;
+		__entry->newprio	= pi_task ?
+				min(tsk->normal_prio, pi_task->prio) :
+				tsk->normal_prio;
 		/* XXX SCHED_DEADLINE bits missing */
 	),