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@xxxxxxxxxxxxxxxxxx>
---
v2: minor commit log fixes
* s/woken_wait_function/woken_wake_function/
* indent 'set TASK_RUNNING' under wait_woken to clarify
wait_woken() performs that operation
net/bluetooth/l2cap_sock.c | 9 ++++-----
net/bluetooth/rfcomm/sock.c | 9 ++++-----
net/bluetooth/sco.c | 8 +++-----
3 files changed, 11 insertions(+), 15 deletions(-)
diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index f65caf4..c41c689 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)
diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index 2348176..0f985ff 100644
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -468,7 +468,7 @@ done:
static int rfcomm_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;
@@ -487,8 +487,6 @@ static int rfcomm_sock_accept(struct socket *sock, struct socket *newsock, int f
/* 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;
@@ -509,10 +507,11 @@ static int rfcomm_sock_accept(struct socket *sock, struct socket *newsock, int f
}
release_sock(sk);
- timeo = schedule_timeout(timeo);
+
+ timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, timeo);
+
lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
}
- __set_current_state(TASK_RUNNING);
remove_wait_queue(sk_sleep(sk), &wait);
if (err)
diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index 30e5ea3..b935003 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -618,7 +618,7 @@ done:
static int sco_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, *ch;
long timeo;
int err = 0;
@@ -632,8 +632,6 @@ static int sco_sock_accept(struct socket *sock, struct socket *newsock, int flag
/* 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;
@@ -654,10 +652,10 @@ static int sco_sock_accept(struct socket *sock, struct socket *newsock, int flag
}
release_sock(sk);
- timeo = schedule_timeout(timeo);
+
+ timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, timeo);
lock_sock(sk);
}
- __set_current_state(TASK_RUNNING);
remove_wait_queue(sk_sleep(sk), &wait);
if (err)
--
2.2.2
--
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