diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/ext.c | 34 |
1 files changed, 26 insertions, 8 deletions
diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index b685f45b4fd0..fbdc1819d4cb 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -903,6 +903,24 @@ static void __scx_task_iter_maybe_relock(struct scx_task_iter *iter) } /** + * scx_task_iter_relock - Re-acquire scx_tasks_lock and, optionally, @p's rq + * @iter: iterator to relock + * @p: task whose rq to lock, or %NULL for scx_tasks_lock only + * + * Counterpart to scx_task_iter_unlock(). Locking @p's rq is optional. Once + * re-acquired, both locks are managed by the iterator from here on. + */ +static void scx_task_iter_relock(struct scx_task_iter *iter, + struct task_struct *p) +{ + __scx_task_iter_maybe_relock(iter); + if (p) { + iter->rq = task_rq_lock(p, &iter->rf); + iter->locked_task = p; + } +} + +/** * scx_task_iter_stop - Stop a task iteration and unlock scx_tasks_lock * @iter: iterator to exit * @@ -7064,6 +7082,9 @@ static void scx_root_enable_workfn(struct kthread_work *work) scx_task_iter_unlock(&sti); ret = scx_init_task(sch, p, false); + + scx_task_iter_relock(&sti, p); + if (ret) { put_task_struct(p); scx_task_iter_stop(&sti); @@ -7076,15 +7097,12 @@ static void scx_root_enable_workfn(struct kthread_work *work) scx_set_task_state(p, SCX_TASK_READY); /* - * Insert into the tid hash under scx_tasks_lock so we can't - * race sched_ext_dead() and leave a stale entry for an already - * exited task. + * Insert into the tid hash. scx_tasks_lock is held by the iter; + * list_empty() guards against sched_ext_dead() having taken @p + * off the list while init ran unlocked. */ - if (scx_tid_to_task_enabled()) { - guard(raw_spinlock_irq)(&scx_tasks_lock); - if (!list_empty(&p->scx.tasks_node)) - scx_tid_hash_insert(p); - } + if (scx_tid_to_task_enabled() && !list_empty(&p->scx.tasks_node)) + scx_tid_hash_insert(p); put_task_struct(p); } |