net: add annotation for sock_{lock,unlock}_fast

The static checker is fooled by the non-static locking scheme
implemented by the mentioned helpers.
Let's make its life easier adding some unconditional annotation
so that the helpers are now interpreted as a plain spinlock from
sparse.

v1 -> v2:
 - add __releases() annotation to unlock_sock_fast()

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/6ed7ae627d8271fb7f20e0a9c6750fbba1ac2635.1605634911.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/net/sock.h b/include/net/sock.h
index 1d29aea..093b517 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1595,7 +1595,8 @@ void release_sock(struct sock *sk);
                                SINGLE_DEPTH_NESTING)
 #define bh_unlock_sock(__sk)   spin_unlock(&((__sk)->sk_lock.slock))
 
-bool lock_sock_fast(struct sock *sk);
+bool lock_sock_fast(struct sock *sk) __acquires(&sk->sk_lock.slock);
+
 /**
  * unlock_sock_fast - complement of lock_sock_fast
  * @sk: socket
@@ -1605,11 +1606,14 @@ bool lock_sock_fast(struct sock *sk);
  * If slow mode is on, we call regular release_sock()
  */
 static inline void unlock_sock_fast(struct sock *sk, bool slow)
+       __releases(&sk->sk_lock.slock)
 {
-       if (slow)
+       if (slow) {
                release_sock(sk);
-       else
+               __release(&sk->sk_lock.slock);
+       } else {
                spin_unlock_bh(&sk->sk_lock.slock);
+       }
 }
 
 /* Used by processes to "lock" a socket state, so that

diff --git a/net/core/sock.c b/net/core/sock.c
index 727ea1c..9badbe7 100644 (file)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -3078,7 +3078,7 @@ EXPORT_SYMBOL(release_sock);
  *
  *   sk_lock.slock unlocked, owned = 1, BH enabled
  */
-bool lock_sock_fast(struct sock *sk)
+bool lock_sock_fast(struct sock *sk) __acquires(&sk->sk_lock.slock)
 {
        might_sleep();
        spin_lock_bh(&sk->sk_lock.slock);
@@ -3096,6 +3096,7 @@ bool lock_sock_fast(struct sock *sk)
         * The sk_lock has mutex_lock() semantics here:
         */
        mutex_acquire(&sk->sk_lock.dep_map, 0, 0, _RET_IP_);
+       __acquire(&sk->sk_lock.slock);
        local_bh_enable();
        return true;
 }