On Wed, Nov 25, 2020 at 02:03:22PM +0100, Peter Zijlstra wrote:
> On Tue, Nov 17, 2020 at 06:19:52PM -0500, Joel Fernandes (Google) wrote:
> > +static bool sched_core_get_task_cookie(unsigned long cookie)
> > +{
> > + struct sched_core_cookie *ptr = (struct sched_core_cookie *)cookie;
> > +
> > + /*
> > + * NOTE: sched_core_put() is not done by put_task_cookie(). Instead, it
> > + * is done after the stopper runs.
> > + */
> > + sched_core_get();
> > + return refcount_inc_not_zero(&ptr->refcnt);
>
> See below, but afaict this should be refcount_inc().
Fully agreed with all these. Updated with diff as below. Will test further
and post next version soon. Thanks!
---8<-----------------------
diff --git a/kernel/sched/coretag.c b/kernel/sched/coretag.c
index 2fb5544a4a18..8fce3f4b7cae 100644
--- a/kernel/sched/coretag.c
+++ b/kernel/sched/coretag.c
@@ -288,12 +288,12 @@ static unsigned long sched_core_alloc_task_cookie(void)
return (unsigned long)ck;
}
-static bool sched_core_get_task_cookie(unsigned long cookie)
+static void sched_core_get_task_cookie(unsigned long cookie)
{
struct sched_core_task_cookie *ptr =
(struct sched_core_task_cookie *)cookie;
- return refcount_inc_not_zero(&ptr->refcnt);
+ refcount_inc(&ptr->refcnt);
}
static void sched_core_put_task_cookie(unsigned long cookie)
@@ -392,10 +392,7 @@ int sched_core_share_tasks(struct task_struct *t1, struct
task_struct *t2)
sched_core_get(); /* For the alloc. */
/* Add another reference for the other task. */
- if (!sched_core_get_task_cookie(cookie)) {
- ret = -EINVAL;
- goto out_unlock;
- }
+ sched_core_get_task_cookie(cookie);
sched_core_get(); /* For the other task. */
wr.tasks[0] = t1;
@@ -411,10 +408,7 @@ int sched_core_share_tasks(struct task_struct *t1, struct
task_struct *t2)
} else if (!t1->core_task_cookie && t2->core_task_cookie) {
/* CASE 3. */
- if (!sched_core_get_task_cookie(t2->core_task_cookie)) {
- ret = -EINVAL;
- goto out_unlock;
- }
+ sched_core_get_task_cookie(t2->core_task_cookie);
sched_core_get();
wr.tasks[0] = t1;
@@ -422,10 +416,7 @@ int sched_core_share_tasks(struct task_struct *t1, struct
task_struct *t2)
} else {
/* CASE 4. */
- if (!sched_core_get_task_cookie(t2->core_task_cookie)) {
- ret = -EINVAL;
- goto out_unlock;
- }
+ sched_core_get_task_cookie(t2->core_task_cookie);
sched_core_get();
sched_core_put_task_cookie(t1->core_task_cookie);
--
2.29.2.454.gaff20da3a2-goog
