diff options
Diffstat (limited to 'net/core/utils.c')
-rw-r--r-- | net/core/utils.c | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/net/core/utils.c b/net/core/utils.c index aa88e23..bf09371 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); |