Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[~andy/linux] / drivers / char / virtio_console.c

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index e905d5f5305180cd7cc77a8690e51ae53bed3fec..ce5f3fc25d6dbf1f7c45ff4cad6d2349da202d1a 100644 (file)
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -149,7 +149,8 @@ struct ports_device {
        spinlock_t ports_lock;
 
        /* To protect the vq operations for the control channel */
-       spinlock_t cvq_lock;
+       spinlock_t c_ivq_lock;
+       spinlock_t c_ovq_lock;
 
        /* The current config space is stored here */
        struct virtio_console_config config;
@@ -569,11 +570,14 @@ static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id,
        vq = portdev->c_ovq;
 
        sg_init_one(sg, &cpkt, sizeof(cpkt));
+
+       spin_lock(&portdev->c_ovq_lock);
        if (virtqueue_add_buf(vq, sg, 1, 0, &cpkt, GFP_ATOMIC) == 0) {
                virtqueue_kick(vq);
                while (!virtqueue_get_buf(vq, &len))
                        cpu_relax();
        }
+       spin_unlock(&portdev->c_ovq_lock);
        return 0;
 }
 
@@ -1436,7 +1440,7 @@ static int add_port(struct ports_device *portdev, u32 id)
                 * rproc_serial does not want the console port, only
                 * the generic port implementation.
                 */
-               port->host_connected = port->guest_connected = true;
+               port->host_connected = true;
        else if (!use_multiport(port->portdev)) {
                /*
                 * If we're not using multiport support,
@@ -1709,23 +1713,23 @@ static void control_work_handler(struct work_struct *work)
        portdev = container_of(work, struct ports_device, control_work);
        vq = portdev->c_ivq;
 
-       spin_lock(&portdev->cvq_lock);
+       spin_lock(&portdev->c_ivq_lock);
        while ((buf = virtqueue_get_buf(vq, &len))) {
-               spin_unlock(&portdev->cvq_lock);
+               spin_unlock(&portdev->c_ivq_lock);
 
                buf->len = len;
                buf->offset = 0;
 
                handle_control_message(portdev, buf);
 
-               spin_lock(&portdev->cvq_lock);
+               spin_lock(&portdev->c_ivq_lock);
                if (add_inbuf(portdev->c_ivq, buf) < 0) {
                        dev_warn(&portdev->vdev->dev,
                                 "Error adding buffer to queue\n");
                        free_buf(buf, false);
                }
        }
-       spin_unlock(&portdev->cvq_lock);
+       spin_unlock(&portdev->c_ivq_lock);
 }
 
 static void out_intr(struct virtqueue *vq)
@@ -1752,13 +1756,23 @@ static void in_intr(struct virtqueue *vq)
        port->inbuf = get_inbuf(port);
 
        /*
-        * Don't queue up data when port is closed.  This condition
+        * Normally the port should not accept data when the port is
+        * closed. For generic serial ports, the host won't (shouldn't)
+        * send data till the guest is connected. But this condition
         * can be reached when a console port is not yet connected (no
-        * tty is spawned) and the host sends out data to console
-        * ports.  For generic serial ports, the host won't
-        * (shouldn't) send data till the guest is connected.
+        * tty is spawned) and the other side sends out data over the
+        * vring, or when a remote devices start sending data before
+        * the ports are opened.
+        *
+        * A generic serial port will discard data if not connected,
+        * while console ports and rproc-serial ports accepts data at
+        * any time. rproc-serial is initiated with guest_connected to
+        * false because port_fops_open expects this. Console ports are
+        * hooked up with an HVC console and is initialized with
+        * guest_connected to true.
         */
-       if (!port->guest_connected)
+
+       if (!port->guest_connected && !is_rproc_serial(port->portdev->vdev))
                discard_port_data(port);
 
        spin_unlock_irqrestore(&port->inbuf_lock, flags);
@@ -1986,10 +2000,12 @@ static int virtcons_probe(struct virtio_device *vdev)
        if (multiport) {
                unsigned int nr_added_bufs;
 
-               spin_lock_init(&portdev->cvq_lock);
+               spin_lock_init(&portdev->c_ivq_lock);
+               spin_lock_init(&portdev->c_ovq_lock);
                INIT_WORK(&portdev->control_work, &control_work_handler);
 
-               nr_added_bufs = fill_queue(portdev->c_ivq, &portdev->cvq_lock);
+               nr_added_bufs = fill_queue(portdev->c_ivq,
+                                          &portdev->c_ivq_lock);
                if (!nr_added_bufs) {
                        dev_err(&vdev->dev,
                                "Error allocating buffers for control queue\n");
@@ -2140,7 +2156,7 @@ static int virtcons_restore(struct virtio_device *vdev)
                return ret;
 
        if (use_multiport(portdev))
-               fill_queue(portdev->c_ivq, &portdev->cvq_lock);
+               fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);
 
        list_for_each_entry(port, &portdev->ports, list) {
                port->in_vq = portdev->in_vqs[port->id];