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    Subject[PATCH 4.4 07/96] vsock: use new wait API for vsock_stream_sendmsg()
    Date
    4.4-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: WANG Cong <xiyou.wangcong@gmail.com>

    commit 499fde662f1957e3cb8d192a94a099ebe19c714b upstream.

    As reported by Michal, vsock_stream_sendmsg() could still
    sleep at vsock_stream_has_space() after prepare_to_wait():

    vsock_stream_has_space
    vmci_transport_stream_has_space
    vmci_qpair_produce_free_space
    qp_lock
    qp_acquire_queue_mutex
    mutex_lock

    Just switch to the new wait API like we did for commit
    d9dc8b0f8b4e ("net: fix sleeping for sk_wait_event()").

    Reported-by: Michal Kubecek <mkubecek@suse.cz>
    Cc: Stefan Hajnoczi <stefanha@redhat.com>
    Cc: Jorgen Hansen <jhansen@vmware.com>
    Cc: "Michael S. Tsirkin" <mst@redhat.com>
    Cc: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
    Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
    Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Cc: "Jorgen S. Hansen" <jhansen@vmware.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    net/vmw_vsock/af_vsock.c | 21 ++++++++-------------
    1 file changed, 8 insertions(+), 13 deletions(-)

    --- a/net/vmw_vsock/af_vsock.c
    +++ b/net/vmw_vsock/af_vsock.c
    @@ -1512,8 +1512,7 @@ static int vsock_stream_sendmsg(struct s
    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);
    @@ -1556,11 +1555,10 @@ static int vsock_stream_sendmsg(struct s
    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) &&
    @@ -1569,33 +1567,30 @@ static int vsock_stream_sendmsg(struct s
    /* 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

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