From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/lib/once.c | 41 +++++++++++++++++++++++++++++++++--------
1 files changed, 33 insertions(+), 8 deletions(-)
diff --git a/kernel/lib/once.c b/kernel/lib/once.c
index 59149bf..1b71cd7 100644
--- a/kernel/lib/once.c
+++ b/kernel/lib/once.c
@@ -3,12 +3,10 @@
#include <linux/spinlock.h>
#include <linux/once.h>
#include <linux/random.h>
-#include <linux/module.h>
struct once_work {
struct work_struct work;
struct static_key_true *key;
- struct module *module;
};
static void once_deferred(struct work_struct *w)
@@ -18,11 +16,10 @@
work = container_of(w, struct once_work, work);
BUG_ON(!static_key_enabled(work->key));
static_branch_disable(work->key);
- module_put(work->module);
kfree(work);
}
-static void once_disable_jump(struct static_key_true *key, struct module *mod)
+static void once_disable_jump(struct static_key_true *key)
{
struct once_work *w;
@@ -32,8 +29,6 @@
INIT_WORK(&w->work, once_deferred);
w->key = key;
- w->module = mod;
- __module_get(mod);
schedule_work(&w->work);
}
@@ -58,11 +53,41 @@
EXPORT_SYMBOL(__do_once_start);
void __do_once_done(bool *done, struct static_key_true *once_key,
- unsigned long *flags, struct module *mod)
+ unsigned long *flags)
__releases(once_lock)
{
*done = true;
spin_unlock_irqrestore(&once_lock, *flags);
- once_disable_jump(once_key, mod);
+ once_disable_jump(once_key);
}
EXPORT_SYMBOL(__do_once_done);
+
+static DEFINE_MUTEX(once_mutex);
+
+bool __do_once_slow_start(bool *done)
+ __acquires(once_mutex)
+{
+ mutex_lock(&once_mutex);
+ if (*done) {
+ mutex_unlock(&once_mutex);
+ /* Keep sparse happy by restoring an even lock count on
+ * this mutex. In case we return here, we don't call into
+ * __do_once_done but return early in the DO_ONCE_SLOW() macro.
+ */
+ __acquire(once_mutex);
+ return false;
+ }
+
+ return true;
+}
+EXPORT_SYMBOL(__do_once_slow_start);
+
+void __do_once_slow_done(bool *done, struct static_key_true *once_key,
+ struct module *mod)
+ __releases(once_mutex)
+{
+ *done = true;
+ mutex_unlock(&once_mutex);
+ once_disable_jump(once_key);
+}
+EXPORT_SYMBOL(__do_once_slow_done);
--
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