module: Replace over-engineered nested sleep
Since the introduction of the nested sleep warning; we've established
that the occasional sleep inside a wait_event() is fine.
wait_event() loops are invariant wrt. spurious wakeups, and the
occasional sleep has a similar effect on them. As long as its occasional
its harmless.
Therefore replace the 'correct' but verbose wait_woken() thing with
a simple annotation to shut up the warning.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/kernel/module.c b/kernel/module.c
index d7a9268..82dc1f8 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2984,6 +2984,12 @@
struct module *mod;
bool ret;
+ /*
+ * The module_mutex should not be a heavily contended lock;
+ * if we get the occasional sleep here, we'll go an extra iteration
+ * in the wait_event_interruptible(), which is harmless.
+ */
+ sched_annotate_sleep();
mutex_lock(&module_mutex);
mod = find_module_all(name, strlen(name), true);
ret = !mod || mod->state == MODULE_STATE_LIVE
@@ -3126,32 +3132,6 @@
}
/*
- * Can't use wait_event_interruptible() because our condition
- * 'finished_loading()' contains a blocking primitive itself (mutex_lock).
- */
-static int wait_finished_loading(struct module *mod)
-{
- DEFINE_WAIT_FUNC(wait, woken_wake_function);
- int ret = 0;
-
- add_wait_queue(&module_wq, &wait);
- for (;;) {
- if (finished_loading(mod->name))
- break;
-
- if (signal_pending(current)) {
- ret = -ERESTARTSYS;
- break;
- }
-
- wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
- }
- remove_wait_queue(&module_wq, &wait);
-
- return ret;
-}
-
-/*
* We try to place it in the list now to make sure it's unique before
* we dedicate too many resources. In particular, temporary percpu
* memory exhaustion.
@@ -3171,8 +3151,8 @@
|| old->state == MODULE_STATE_UNFORMED) {
/* Wait in case it fails to load. */
mutex_unlock(&module_mutex);
-
- err = wait_finished_loading(mod);
+ err = wait_event_interruptible(module_wq,
+ finished_loading(mod->name));
if (err)
goto out_unlocked;
goto again;