[PATCH v6 5/6] Bluetooth: switch to lock_sock in RFCOMM

From: Desmond Cheong Zhi Xi
Date: Tue Aug 10 2021 - 00:18:13 EST


Other than rfcomm_sk_state_change and rfcomm_connect_ind, functions in
RFCOMM use lock_sock to lock the socket.

Since bh_lock_sock and spin_lock_bh do not provide synchronization
with lock_sock, these calls should be changed to lock_sock.

This is now safe to do because packet processing is now done in a
workqueue instead of a tasklet, so bh_lock_sock/spin_lock_bh are no
longer necessary to synchronise between user contexts and SOFTIRQ
processing.

Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@xxxxxxxxx>
---
net/bluetooth/rfcomm/sock.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index ae6f80730561..2c95bb58f901 100644
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -70,7 +70,7 @@ static void rfcomm_sk_state_change(struct rfcomm_dlc *d, int err)

BT_DBG("dlc %p state %ld err %d", d, d->state, err);

- spin_lock_bh(&sk->sk_lock.slock);
+ lock_sock(sk);

if (err)
sk->sk_err = err;
@@ -91,7 +91,7 @@ static void rfcomm_sk_state_change(struct rfcomm_dlc *d, int err)
sk->sk_state_change(sk);
}

- spin_unlock_bh(&sk->sk_lock.slock);
+ release_sock(sk);

if (parent && sock_flag(sk, SOCK_ZAPPED)) {
/* We have to drop DLC lock here, otherwise
@@ -974,7 +974,7 @@ int rfcomm_connect_ind(struct rfcomm_session *s, u8 channel, struct rfcomm_dlc *
if (!parent)
return 0;

- bh_lock_sock(parent);
+ lock_sock(parent);

/* Check for backlog size */
if (sk_acceptq_is_full(parent)) {
@@ -1001,7 +1001,7 @@ int rfcomm_connect_ind(struct rfcomm_session *s, u8 channel, struct rfcomm_dlc *
result = 1;

done:
- bh_unlock_sock(parent);
+ release_sock(parent);

if (test_bit(BT_SK_DEFER_SETUP, &bt_sk(parent)->flags))
parent->sk_state_change(parent);
--
2.25.1