[PATCH v2 1/6] module/dups: Inform duplicate requests about the result directly
From: Petr Pavlu <petr.pavlu@suse.com>
Date: 2026-07-23 08:26:43
Also in:
lkml
Subsystem:
module support, the rest · Maintainers:
Luis Chamberlain, Petr Pavlu, Daniel Gomez, Sami Tolvanen, Linus Torvalds
When kmod_dup_request_announce() announces the completion of a request_module() call to duplicate waiters, it queues a work item to invoke kmod_dup_request_complete(), and only that function calls complete_all(). This adds an arbitrary delay that is unnecessary and provides little benefit. Call complete_all() directly from kmod_dup_request_announce() instead. Signed-off-by: Petr Pavlu <petr.pavlu@suse.com> --- kernel/module/dups.c | 43 +++++++++---------------------------------- 1 file changed, 9 insertions(+), 34 deletions(-)
diff --git a/kernel/module/dups.c b/kernel/module/dups.c
index 1d720a5311ba..b063bc423aa8 100644
--- a/kernel/module/dups.c
+++ b/kernel/module/dups.c@@ -48,7 +48,6 @@ struct kmod_dup_req { struct list_head list; char name[MODULE_NAME_LEN]; struct completion first_req_done; - struct work_struct complete_work; struct delayed_work delete_work; int dup_ret; };
@@ -93,29 +92,6 @@ static void kmod_dup_request_delete(struct work_struct *work) kfree(kmod_req); } -static void kmod_dup_request_complete(struct work_struct *work) -{ - struct kmod_dup_req *kmod_req; - - kmod_req = container_of(work, struct kmod_dup_req, complete_work); - - /* - * This will ensure that the kernel will let all the waiters get - * informed its time to check the return value. It's time to - * go home. - */ - complete_all(&kmod_req->first_req_done); - - /* - * Now that we have allowed prior request_module() calls to go on - * with life, let's schedule deleting this entry. We don't have - * to do it right away, but we *eventually* want to do it so to not - * 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_dfl_wq, &kmod_req->delete_work, 60 * HZ); -} - bool kmod_dup_request_exists_wait(char *module_name, bool wait, int *dup_ret) { struct kmod_dup_req *kmod_req, *new_kmod_req;
@@ -130,7 +106,6 @@ bool kmod_dup_request_exists_wait(char *module_name, bool wait, int *dup_ret) return false; memcpy(new_kmod_req->name, module_name, strlen(module_name)); - INIT_WORK(&new_kmod_req->complete_work, kmod_dup_request_complete); INIT_DELAYED_WORK(&new_kmod_req->delete_work, kmod_dup_request_delete); init_completion(&new_kmod_req->first_req_done);
@@ -230,17 +205,17 @@ void kmod_dup_request_announce(char *module_name, int ret) kmod_req->dup_ret = ret; + /* Inform all duplicate waiters to check the return value. */ + complete_all(&kmod_req->first_req_done); + /* - * If we complete() here we may allow duplicate threads - * to continue before the first one that submitted the - * request. We're in no rush also, given that each and - * every bounce back to userspace is slow we avoid that - * with a slight delay here. So queueue up the completion - * and let duplicates suffer, just wait a tad bit longer. - * There is no rush. But we also don't want to hold the - * caller up forever or introduce any boot delays. + * Now that we have allowed prior request_module() calls to go on + * with life, let's schedule deleting this entry. We don't have + * to do it right away, but we *eventually* want to do it so to not + * let this linger forever as this is just a boot optimization for + * possible abuses of vmalloc() incurred by finit_module() thrashing. */ - queue_work(system_dfl_wq, &kmod_req->complete_work); + queue_delayed_work(system_dfl_wq, &kmod_req->delete_work, 60 * HZ); out: mutex_unlock(&kmod_dup_mutex);
--
2.54.0