The following commit has been merged into the sched/urgent branch of tip: Commit-ID: dbf983c0a5c37da2d476564792bd84e0e8f067fc Gitweb: https://git.kernel.org/tip/dbf983c0a5c37da2d476564792bd84e0e8f067fc Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx> AuthorDate: Wed, 24 Feb 2021 11:15:23 +01:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Mon, 01 Mar 2021 11:02:14 +01:00 sched: Collate affine_move_task() stoppers The SCA_MIGRATE_ENABLE and task_running() cases are almost identical, collapse them to avoid further duplication. Fixes: 6d337eab041d ("sched: Fix migrate_disable() vs set_cpus_allowed_ptr()") Cc: stable@xxxxxxxxxx Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Reviewed-by: Valentin Schneider <valentin.schneider@xxxxxxx> Link: https://lkml.kernel.org/r/20210224131355.500108964@xxxxxxxxxxxxx --- kernel/sched/core.c | 23 ++++++++--------------- 1 file changed, 8 insertions(+), 15 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 088e8f4..84b657f 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -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)) {
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