virtio: console: Add a find_port_by_devt() function

To convert to using cdev as a pointer to avoid kref troubles, we have to
use a different method to get to a port from an inode than the current
container_of method.

Add find_port_by_devt() that looks up all portdevs and ports with those
portdevs to find the right port.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index b70fe96c1ccd5aff9ad52f641eb7456e646271bf..0c8f2aa3074a589e54a15a86b79abe6aeec9701e 100644 (file)
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -227,6 +227,41 @@ out:
        return port;
 }
 
+static struct port *find_port_by_devt_in_portdev(struct ports_device *portdev,
+                                                dev_t dev)
+{
+       struct port *port;
+       unsigned long flags;
+
+       spin_lock_irqsave(&portdev->ports_lock, flags);
+       list_for_each_entry(port, &portdev->ports, list)
+               if (port->cdev.dev == dev)
+                       goto out;
+       port = NULL;
+out:
+       spin_unlock_irqrestore(&portdev->ports_lock, flags);
+
+       return port;
+}
+
+static struct port *find_port_by_devt(dev_t dev)
+{
+       struct ports_device *portdev;
+       struct port *port;
+       unsigned long flags;
+
+       spin_lock_irqsave(&pdrvdata_lock, flags);
+       list_for_each_entry(portdev, &pdrvdata.portdevs, list) {
+               port = find_port_by_devt_in_portdev(portdev, dev);
+               if (port)
+                       goto out;
+       }
+       port = NULL;
+out:
+       spin_unlock_irqrestore(&pdrvdata_lock, flags);
+       return port;
+}
+
 static struct port *find_port_by_id(struct ports_device *portdev, u32 id)
 {
        struct port *port;
@@ -719,7 +754,7 @@ static int port_fops_open(struct inode *inode, struct file *filp)
        struct port *port;
        int ret;
 
-       port = container_of(cdev, struct port, cdev);
+       port = find_port_by_devt(cdev->dev);
        filp->private_data = port;
 
        /*