try_sock lock is an opportunistic attempt to acquire a socket lock
without blocking or sleeping. If the socket lock is acquired then
true is returned, else false is returned.
Signed-off-by: Tom Herbert <t...@quantonium.net>
---
include/net/sock.h | 7 +++++++
net/core/sock.c | 20 ++++++++++++++++++++
2 files changed, 27 insertions(+)
diff --git a/include/net/sock.h b/include/net/sock.h
index 3b4ca2046f8c..69fdd1a89591 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1462,6 +1462,13 @@ static inline void lock_sock(struct sock *sk)
lock_sock_nested(sk, 0);
}
+bool try_lock_sock_nested(struct sock *sk, int subclass);
+
+static inline bool try_lock_sock(struct sock *sk)
+{
+ return try_lock_sock_nested(sk, 0);
+}
+
void release_sock(struct sock *sk);
/* BH context may only use the following locking interface. */
diff --git a/net/core/sock.c b/net/core/sock.c
index 72d14b221784..40fb772e2d52 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2782,6 +2782,26 @@ void lock_sock_nested(struct sock *sk, int subclass)
}
EXPORT_SYMBOL(lock_sock_nested);
+bool try_lock_sock_nested(struct sock *sk, int subclass)
+{
+ spin_lock_bh(&sk->sk_lock.slock);
+ if (sk->sk_lock.owned) {
+ spin_unlock_bh(&sk->sk_lock.slock);
+ return false;
+ }
+
+ sk->sk_lock.owned = 1;
+ spin_unlock(&sk->sk_lock.slock);
+
+ /* The sk_lock has mutex_lock() semantics here: */
+
+ mutex_acquire(&sk->sk_lock.dep_map, subclass, 0, _RET_IP_);
+ local_bh_enable();
+
+ return true;
+}
+EXPORT_SYMBOL(try_lock_sock_nested);
+
void release_sock(struct sock *sk)
{
spin_lock_bh(&sk->sk_lock.slock);
--
2.11.0
