Commit 58b1a450 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched: Collate affine_move_task() stoppers 



The SCA_MIGRATE_ENABLE and task_running() cases are almost identical,
collapse them to avoid further duplication.

Fixes: 6d337eab ("sched: Fix migrate_disable() vs set_cpus_allowed_ptr()")
Cc: stable@kernel.org
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Reviewed-by: default avatarValentin Schneider <valentin.schneider@arm.com>
Link: https://lkml.kernel.org/r/20210224131355.500108964@infradead.org
parent c20cf065

kernel/sched/core.c

+8 −15
Original line number Diff line number Diff line
@@ -2239,30 +2239,23 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag 
		return -EINVAL;

	}



	if (flags & SCA_MIGRATE_ENABLE) {



		refcount_inc(&pending->refs); /* pending->{arg,stop_work} */

		p->migration_flags &= ~MDF_PUSH;

		task_rq_unlock(rq, p, rf);



		stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop,

				    &pending->arg, &pending->stop_work);



		return 0;

	}



	if (task_running(rq, p) || p->state == TASK_WAKING) {

		/*

		 * Lessen races (and headaches) by delegating

		 * is_migration_disabled(p) checks to the stopper, which will

		 * run on the same CPU as said p.

		 * MIGRATE_ENABLE gets here because 'p == current', but for

		 * anything else we cannot do is_migration_disabled(), punt

		 * and have the stopper function handle it all race-free.

		 */



		refcount_inc(&pending->refs); /* pending->{arg,stop_work} */

		if (flags & SCA_MIGRATE_ENABLE)

			p->migration_flags &= ~MDF_PUSH;

		task_rq_unlock(rq, p, rf);



		stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop,

				    &pending->arg, &pending->stop_work);



		if (flags & SCA_MIGRATE_ENABLE)

			return 0;

	} else {



		if (!is_migration_disabled(p)) {