[PATCH v2 1/1] module: replace use of system_wq with system_dfl_wq

From: Marco Crivellari

Date: Thu Sep 18 2025 - 04:56:35 EST


Currently if a user enqueue a work item using schedule_delayed_work() the
used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use
WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to
schedule_work() that is using system_wq and queue_work(), that makes use
again of WORK_CPU_UNBOUND.

This lack of consistentcy cannot be addressed without refactoring the API.

This specific patch replace system_wq with system_dfl_wq, the new unbound
workqueue, because the users does not benefit from a per-cpu wq.

Suggested-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Marco Crivellari <marco.crivellari@xxxxxxxx>
---
kernel/module/dups.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/module/dups.c b/kernel/module/dups.c
index bd2149fbe117..0b633f2edda6 100644
--- a/kernel/module/dups.c
+++ b/kernel/module/dups.c
@@ -113,7 +113,7 @@ static void kmod_dup_request_complete(struct work_struct *work)
* let this linger forever as this is just a boot optimization for
* possible abuses of vmalloc() incurred by finit_module() thrashing.
*/
- queue_delayed_work(system_wq, &kmod_req->delete_work, 60 * HZ);
+ queue_delayed_work(system_dfl_wq, &kmod_req->delete_work, 60 * HZ);
}

bool kmod_dup_request_exists_wait(char *module_name, bool wait, int *dup_ret)
@@ -240,7 +240,7 @@ void kmod_dup_request_announce(char *module_name, int ret)
* There is no rush. But we also don't want to hold the
* caller up forever or introduce any boot delays.
*/
- queue_work(system_wq, &kmod_req->complete_work);
+ queue_work(system_dfl_wq, &kmod_req->complete_work);

out:
mutex_unlock(&kmod_dup_mutex);
--
2.51.0