From 0e20a057e0fa6245f8437ba763a66c8cc0b9fdf3 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Thu, 5 Mar 2015 10:45:49 +1030 Subject: [PATCH] virtio_console: avoid config access from irq commit eeb8a7e8bb123e84daeef84f5a2eab99ad2839a2 upstream. 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 Reviewed-by: Amit Shah Signed-off-by: Rusty Russell [bwh: Backported to 3.2: - Adjust context - Drop changes to virtcons_freeze()] Signed-off-by: Ben Hutchings --- drivers/char/virtio_console.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index c68b8ad957f9..e9d18aa4e337 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -124,6 +124,7 @@ struct ports_device { * notification */ struct work_struct control_work; + struct work_struct config_work; struct list_head ports; @@ -1556,10 +1557,21 @@ 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; vdev->config->get(vdev, offsetof(struct virtio_console_config, cols), &cols, sizeof(u16)); @@ -1731,6 +1743,8 @@ static int __devinit virtcons_probe(struct virtio_device *vdev) spin_lock_init(&portdev->ports_lock); INIT_LIST_HEAD(&portdev->ports); + INIT_WORK(&portdev->config_work, &config_work_handler); + if (multiport) { unsigned int nr_added_bufs; @@ -1806,6 +1820,8 @@ 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); -- 2.39.5