Hi,
On Fri, Apr 21, 2017 at 1:14 AM, Michal Kubecek <[email protected]> wrote:
> I tried to think about a solution but there doesn't seem to be an easy
> way to fix this in vmw_stream_sendmsg() as moving prepare_to_wait()
> inside the loop would result in missed wake-ups (that was the problem
> with the original fix); IMHO the right way to resolve the issue would be
> rewriting the vmci queue pair code to allow performing the has_space()
> check without taking a mutex.
Can you try the attached patch (compile only)?
Thanks.
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 6f7f675..dfc8c51e 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -1540,8 +1540,7 @@ static int vsock_stream_sendmsg(struct socket *sock,
struct msghdr *msg,
long timeout;
int err;
struct vsock_transport_send_notify_data send_data;
-
- DEFINE_WAIT(wait);
+ DEFINE_WAIT_FUNC(wait, woken_wake_function);
sk = sock->sk;
vsk = vsock_sk(sk);
@@ -1584,11 +1583,10 @@ static int vsock_stream_sendmsg(struct socket *sock,
struct msghdr *msg,
if (err < 0)
goto out;
-
while (total_written < len) {
ssize_t written;
- prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
+ add_wait_queue(sk_sleep(sk), &wait);
while (vsock_stream_has_space(vsk) == 0 &&
sk->sk_err == 0 &&
!(sk->sk_shutdown & SEND_SHUTDOWN) &&
@@ -1597,33 +1595,30 @@ static int vsock_stream_sendmsg(struct socket *sock,
struct msghdr *msg,
/* Don't wait for non-blocking sockets. */
if (timeout == 0) {
err = -EAGAIN;
- finish_wait(sk_sleep(sk), &wait);
+ remove_wait_queue(sk_sleep(sk), &wait);
goto out_err;
}
err = transport->notify_send_pre_block(vsk, &send_data);
if (err < 0) {
- finish_wait(sk_sleep(sk), &wait);
+ remove_wait_queue(sk_sleep(sk), &wait);
goto out_err;
}
release_sock(sk);
- timeout = schedule_timeout(timeout);
+ timeout = wait_woken(&wait, TASK_INTERRUPTIBLE,
timeout);
lock_sock(sk);
if (signal_pending(current)) {
err = sock_intr_errno(timeout);
- finish_wait(sk_sleep(sk), &wait);
+ remove_wait_queue(sk_sleep(sk), &wait);
goto out_err;
} else if (timeout == 0) {
err = -EAGAIN;
- finish_wait(sk_sleep(sk), &wait);
+ remove_wait_queue(sk_sleep(sk), &wait);
goto out_err;
}
-
- prepare_to_wait(sk_sleep(sk), &wait,
- TASK_INTERRUPTIBLE);
}
- finish_wait(sk_sleep(sk), &wait);
+ remove_wait_queue(sk_sleep(sk), &wait);
/* These checks occur both as part of and after the loop
* conditional since we need to check before and after
