2011-07-24 04:10:52

by Peter Hurley

Subject: [PATCH 4/7] Bluetooth: l2cap: Fix lost wakeups waiting to accept socket

Fix race conditions which can cause lost wakeups (or misssed signals)
while waiting to accept an l2cap socket connection.

Signed-off-by: Peter Hurley <[email protected]>
---
net/bluetooth/l2cap_sock.c | 28 ++++++++++++++--------------
1 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index 8248303..e13a5cc 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -274,30 +274,26 @@ static int l2cap_sock_accept(struct socket *sock, struct socket *newsock, int fl

lock_sock_nested(sk, SINGLE_DEPTH_NESTING);

- if (sk->sk_state != BT_LISTEN) {
- err = -EBADFD;
- goto done;
- }
-
timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);

BT_DBG("sk %p timeo %ld", sk, timeo);

/* Wait for an incoming connection. (wake-one). */
add_wait_queue_exclusive(sk_sleep(sk), &wait);
- while (!(nsk = bt_accept_dequeue(sk, newsock))) {
+ while (1) {
set_current_state(TASK_INTERRUPTIBLE);
- if (!timeo) {
- err = -EAGAIN;
+
+ if (sk->sk_state != BT_LISTEN) {
+ err = -EBADFD;
break;
}

- release_sock(sk);
- timeo = schedule_timeout(timeo);
- lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
+ nsk = bt_accept_dequeue(sk, newsock);
+ if (nsk)
+ break;

- if (sk->sk_state != BT_LISTEN) {
- err = -EBADFD;
+ if (!timeo) {
+ err = -EAGAIN;
break;
}

@@ -305,8 +301,12 @@ static int l2cap_sock_accept(struct socket *sock, struct socket *newsock, int fl
err = sock_intr_errno(timeo);
break;
}
+
+ release_sock(sk);
+ timeo = schedule_timeout(timeo);
+ lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
}
- set_current_state(TASK_RUNNING);
+ __set_current_state(TASK_RUNNING);
remove_wait_queue(sk_sleep(sk), &wait);

if (err)
--
1.7.4.1