From ee7aece608178e322ba150a73613ebace31df885 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 27 Jul 2026 11:20:32 -1000 Subject: sched_ext: Report scx_link_sched() failures inline scx_link_sched() carries each failure out of the locked section through err_msg and ret because scx_error() used to take scx_sched_lock and couldn't be called under it. That restriction is gone, so report each failure at the site it's detected and return directly. The scx_error() here claims the exit on the sched being linked, which has no descendants yet, and the locked propagation walk is deferred, so nothing reacquires scx_sched_lock inline. Signed-off-by: Tejun Heo Reviewed-by: Andrea Righi --- kernel/sched/ext/ext.c | 29 +++++++++-------------------- 1 file changed, 9 insertions(+), 20 deletions(-) diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c index f99c2b8557e6..312938179e52 100644 --- a/kernel/sched/ext/ext.c +++ b/kernel/sched/ext/ext.c @@ -5975,31 +5975,30 @@ static void refresh_watchdog(void) s32 scx_link_sched(struct scx_sched *sch) { - const char *err_msg = ""; - s32 ret = 0; - scoped_guard(raw_spinlock_irqsave, &scx_bypass_lock) /* for the parent bypass check */ scoped_guard(raw_spinlock, &scx_sched_lock) { #ifdef CONFIG_EXT_SUB_SCHED struct scx_sched *parent = scx_parent(sch); if (parent) { + s32 ret; + /* * Bypass state is spread across per-cpu flags and a * depth count, so inheriting it is tricky and has no * valid use case. Refuse it. */ if (READ_ONCE(parent->bypass_depth)) { - err_msg = "parent bypassing"; - ret = -EBUSY; - break; + scx_error(sch, "parent bypassing (%d)", -EBUSY); + return -EBUSY; } ret = rhashtable_lookup_insert_fast(&scx_sched_hash, &sch->hash_node, scx_sched_hash_params); if (ret) { - err_msg = "failed to insert into scx_sched_hash"; - break; + scx_error(sch, "failed to insert into scx_sched_hash (%d)", + ret); + return ret; } list_add_tail_rcu(&sch->sibling, &parent->children); @@ -6014,9 +6013,8 @@ s32 scx_link_sched(struct scx_sched *sch) rhashtable_remove_fast(&scx_sched_hash, &sch->hash_node, scx_sched_hash_params); list_del_rcu(&sch->sibling); - err_msg = "parent disabled"; - ret = -ENOENT; - break; + scx_error(sch, "parent disabled (%d)", -ENOENT); + return -ENOENT; } sch->linked = true; @@ -6026,15 +6024,6 @@ s32 scx_link_sched(struct scx_sched *sch) list_add_tail_rcu(&sch->all, &scx_sched_all); } - /* - * scx_error() takes scx_sched_lock via scx_claim_exit(), so it must run after - * the guard above is released. - */ - if (ret) { - scx_error(sch, "%s (%d)", err_msg, ret); - return ret; - } - refresh_watchdog(); return 0; } -- cgit v1.2.3