sched/deadline: Remove unnecessary comment in dl_add_task_root_domain()

The comments above dl_get_task_effective_cpus() and
dl_add_task_root_domain() already explain how to fetch a valid
root domain and protect against races. There's no need to repeat
this inside dl_add_task_root_domain(). Remove the redundant comment
to keep the code clean.

No functional change.

Signed-off-by: Pingfan Liu <piliu@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://patch.msgid.link/20251125032630.8746-2-piliu@redhat.com

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 319439fe18702687ee9b8ea5a927ddf073763cf2..463ba50f9fffbb477ac1c2acbb53cb45ab570f29 100644 (file)
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -3162,20 +3162,11 @@ void dl_add_task_root_domain(struct task_struct *p)
                return;
        }
 
-       /*
-        * Get an active rq, whose rq->rd traces the correct root
-        * domain.
-        * Ideally this would be under cpuset reader lock until rq->rd is
-        * fetched.  However, sleepable locks cannot nest inside pi_lock, so we
-        * rely on the caller of dl_add_task_root_domain() holds 'cpuset_mutex'
-        * to guarantee the CPU stays in the cpuset.
-        */
        dl_get_task_effective_cpus(p, msk);
        cpu = cpumask_first_and(cpu_active_mask, msk);
        BUG_ON(cpu >= nr_cpu_ids);
        rq = cpu_rq(cpu);
        dl_b = &rq->rd->dl_bw;
-       /* End of fetching rd */
 
        raw_spin_lock(&dl_b->lock);
        __dl_add(dl_b, p->dl.dl_bw, cpumask_weight(rq->rd->span));