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authorMichael S. Tsirkin <mst@redhat.com>2015-03-05 10:45:49 +1030
committerRusty Russell <rusty@rustcorp.com.au>2015-03-05 13:36:18 +1030
commiteeb8a7e8bb123e84daeef84f5a2eab99ad2839a2 (patch)
tree85ef0ee0a9064144e2562ea28e88c19fe9dec842
parent4f6e24ed9de8634d6471ef86b382cba6d4e57ca8 (diff)
downloadop-kernel-dev-eeb8a7e8bb123e84daeef84f5a2eab99ad2839a2.zip
op-kernel-dev-eeb8a7e8bb123e84daeef84f5a2eab99ad2839a2.tar.gz
virtio_console: avoid config access from irq
when multiport is off, virtio console invokes config access from irq context, config access is blocking on s390. Fix this up by scheduling work from config irq - similar to what we do for multiport configs. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: stable@kernel.org
-rw-r--r--drivers/char/virtio_console.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index def736d..72d7028 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -142,6 +142,7 @@ struct ports_device {
* notification
*/
struct work_struct control_work;
+ struct work_struct config_work;
struct list_head ports;
@@ -1837,10 +1838,21 @@ static void config_intr(struct virtio_device *vdev)
portdev = vdev->priv;
+ if (!use_multiport(portdev))
+ schedule_work(&portdev->config_work);
+}
+
+static void config_work_handler(struct work_struct *work)
+{
+ struct ports_device *portdev;
+
+ portdev = container_of(work, struct ports_device, control_work);
if (!use_multiport(portdev)) {
+ struct virtio_device *vdev;
struct port *port;
u16 rows, cols;
+ vdev = portdev->vdev;
virtio_cread(vdev, struct virtio_console_config, cols, &cols);
virtio_cread(vdev, struct virtio_console_config, rows, &rows);
@@ -2040,6 +2052,7 @@ static int virtcons_probe(struct virtio_device *vdev)
virtio_device_ready(portdev->vdev);
+ INIT_WORK(&portdev->config_work, &config_work_handler);
INIT_WORK(&portdev->control_work, &control_work_handler);
if (multiport) {
@@ -2114,6 +2127,8 @@ static void virtcons_remove(struct virtio_device *vdev)
/* Finish up work that's lined up */
if (use_multiport(portdev))
cancel_work_sync(&portdev->control_work);
+ else
+ cancel_work_sync(&portdev->config_work);
list_for_each_entry_safe(port, port2, &portdev->ports, list)
unplug_port(port);
@@ -2165,6 +2180,7 @@ static int virtcons_freeze(struct virtio_device *vdev)
virtqueue_disable_cb(portdev->c_ivq);
cancel_work_sync(&portdev->control_work);
+ cancel_work_sync(&portdev->config_work);
/*
* Once more: if control_work_handler() was running, it would
* enable the cb as the last step.
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