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-rw-r--r--net/core/utils.c48
1 files changed, 48 insertions, 0 deletions
diff --git a/net/core/utils.c b/net/core/utils.c
index aa88e23fc87a..bf09371e19b1 100644
--- a/net/core/utils.c
+++ b/net/core/utils.c
@@ -338,3 +338,51 @@ void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
csum_unfold(*sum)));
}
EXPORT_SYMBOL(inet_proto_csum_replace16);
+
+struct __net_random_once_work {
+ struct work_struct work;
+ struct static_key *key;
+};
+
+static void __net_random_once_deferred(struct work_struct *w)
+{
+ struct __net_random_once_work *work =
+ container_of(w, struct __net_random_once_work, work);
+ if (!static_key_enabled(work->key))
+ static_key_slow_inc(work->key);
+ kfree(work);
+}
+
+static void __net_random_once_disable_jump(struct static_key *key)
+{
+ struct __net_random_once_work *w;
+
+ w = kmalloc(sizeof(*w), GFP_ATOMIC);
+ if (!w)
+ return;
+
+ INIT_WORK(&w->work, __net_random_once_deferred);
+ w->key = key;
+ schedule_work(&w->work);
+}
+
+bool __net_get_random_once(void *buf, int nbytes, bool *done,
+ struct static_key *done_key)
+{
+ static DEFINE_SPINLOCK(lock);
+
+ spin_lock_bh(&lock);
+ if (*done) {
+ spin_unlock_bh(&lock);
+ return false;
+ }
+
+ get_random_bytes(buf, nbytes);
+ *done = true;
+ spin_unlock_bh(&lock);
+
+ __net_random_once_disable_jump(done_key);
+
+ return true;
+}
+EXPORT_SYMBOL(__net_get_random_once);