diff options
| author | Peter Hurley <peter@hurleysoftware.com> | 2015-01-23 18:16:53 +0100 |
|---|---|---|
| committer | Johan Hedberg <johan.hedberg@intel.com> | 2015-01-23 19:29:42 +0100 |
| commit | dfb2fae7cd0a1aa13610b11d54203bcd3893da07 (patch) | |
| tree | 3aa293285c349233441ae31661c72773992e603e /net/bluetooth/l2cap_sock.c | |
| parent | Bluetooth: Convert Set SC to use HCI Request (diff) | |
| download | linux-dfb2fae7cd0a1aa13610b11d54203bcd3893da07.tar.xz linux-dfb2fae7cd0a1aa13610b11d54203bcd3893da07.zip | |
Bluetooth: Fix nested sleeps
l2cap/rfcomm/sco_sock_accept() are wait loops which may acquire
sleeping locks. Since both wait loops and sleeping locks use
task_struct.state to sleep and wake, the nested sleeping locks
destroy the wait loop state.
Use the newly-minted wait_woken() and DEFINE_WAIT_FUNC() for the
wait loop. DEFINE_WAIT_FUNC() allows an alternate wake function
to be specified; in this case, the predefined scheduler function,
woken_wake_function(). This wait construct ensures wakeups will
not be missed without requiring the wait loop to set the
task state before condition evaluation. How this works:
CPU 0 | CPU 1
|
| is <condition> set?
| no
set <condition> |
|
wake_up_interruptible |
woken_wake_function |
set WQ_FLAG_WOKEN |
try_to_wake_up |
| wait_woken
| set TASK_INTERRUPTIBLE
| WQ_FLAG_WOKEN? yes
| set TASK_RUNNING
|
| - loop -
|
| is <condition> set?
| yes - exit wait loop
Fixes "do not call blocking ops when !TASK_RUNNING" warnings
in l2cap_sock_accept(), rfcomm_sock_accept() and sco_sock_accept().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Diffstat (limited to 'net/bluetooth/l2cap_sock.c')
| -rw-r--r-- | net/bluetooth/l2cap_sock.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c index 20206cd3acbc..60694f0f4c73 100644 --- a/net/bluetooth/l2cap_sock.c +++ b/net/bluetooth/l2cap_sock.c @@ -302,7 +302,7 @@ done: static int l2cap_sock_accept(struct socket *sock, struct socket *newsock, int flags) { - DECLARE_WAITQUEUE(wait, current); + DEFINE_WAIT_FUNC(wait, woken_wake_function); struct sock *sk = sock->sk, *nsk; long timeo; int err = 0; @@ -316,8 +316,6 @@ static int l2cap_sock_accept(struct socket *sock, struct socket *newsock, /* Wait for an incoming connection. (wake-one). */ add_wait_queue_exclusive(sk_sleep(sk), &wait); while (1) { - set_current_state(TASK_INTERRUPTIBLE); - if (sk->sk_state != BT_LISTEN) { err = -EBADFD; break; @@ -338,10 +336,11 @@ static int l2cap_sock_accept(struct socket *sock, struct socket *newsock, } release_sock(sk); - timeo = schedule_timeout(timeo); + + timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, timeo); + lock_sock_nested(sk, L2CAP_NESTING_PARENT); } - __set_current_state(TASK_RUNNING); remove_wait_queue(sk_sleep(sk), &wait); if (err) |