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virtio_console: free buffers after reset

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Console driver is out of spec. The spec says:
	A driver MUST NOT decrement the available idx on a live
	virtqueue (ie. there is no way to “unexpose” buffers).
and it does exactly that by trying to detach unused buffers
without doing a device reset first.

Defer detaching the buffers until device unplug.

Of course this means we might get an interrupt for
a vq without an attached port now. Handle that by
discarding the consumed buffer.

Reported-by: Tiwei Bie <tiwei.bie@intel.com>
Fixes: b3258ff1d6 ("virtio: Decrement avail idx on buffer detach")
Cc: stable@vger.kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Michael S. Tsirkin 2018-04-20 20:24:23 +03:00
parent 24a7e4d207
commit a7a69ec0d8
1 changed files with 24 additions and 25 deletions
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49
drivers/char/virtio_console.c
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@ -1402,7 +1402,6 @@ static int add_port(struct ports_device *portdev, u32 id)
{
char debugfs_name[16];
struct port *port;
struct port_buffer *buf;
dev_t devt;
unsigned int nr_added_bufs;
int err;
@ -1513,8 +1512,6 @@ static int add_port(struct ports_device *portdev, u32 id)
return 0;
free_inbufs:
while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
free_buf(buf, true);
free_device:
device_destroy(pdrvdata.class, port->dev->devt);
free_cdev:
@ -1539,34 +1536,14 @@ static void remove_port(struct kref *kref)
static void remove_port_data(struct port *port)
{
struct port_buffer *buf;
spin_lock_irq(&port->inbuf_lock);
/* Remove unused data this port might have received. */
discard_port_data(port);
spin_unlock_irq(&port->inbuf_lock);
/* Remove buffers we queued up for the Host to send us data in. */
do {
spin_lock_irq(&port->inbuf_lock);
buf = virtqueue_detach_unused_buf(port->in_vq);
spin_unlock_irq(&port->inbuf_lock);
if (buf)
free_buf(buf, true);
} while (buf);
spin_lock_irq(&port->outvq_lock);
reclaim_consumed_buffers(port);
spin_unlock_irq(&port->outvq_lock);
/* Free pending buffers from the out-queue. */
do {
spin_lock_irq(&port->outvq_lock);
buf = virtqueue_detach_unused_buf(port->out_vq);
spin_unlock_irq(&port->outvq_lock);
if (buf)
free_buf(buf, true);
} while (buf);
}
/*
@ -1791,13 +1768,24 @@ static void control_work_handler(struct work_struct *work)
spin_unlock(&portdev->c_ivq_lock);
}
static void flush_bufs(struct virtqueue *vq, bool can_sleep)
{
struct port_buffer *buf;
unsigned int len;
while ((buf = virtqueue_get_buf(vq, &len)))
free_buf(buf, can_sleep);
}
static void out_intr(struct virtqueue *vq)
{
struct port *port;
port = find_port_by_vq(vq->vdev->priv, vq);
if (!port)
if (!port) {
flush_bufs(vq, false);
return;
}
wake_up_interruptible(&port->waitqueue);
}
@ -1808,8 +1796,10 @@ static void in_intr(struct virtqueue *vq)
unsigned long flags;
port = find_port_by_vq(vq->vdev->priv, vq);
if (!port)
if (!port) {
flush_bufs(vq, false);
return;
}
spin_lock_irqsave(&port->inbuf_lock, flags);
port->inbuf = get_inbuf(port);
@ -1984,6 +1974,15 @@ static const struct file_operations portdev_fops = {
static void remove_vqs(struct ports_device *portdev)
{
struct virtqueue *vq;
virtio_device_for_each_vq(portdev->vdev, vq) {
struct port_buffer *buf;
flush_bufs(vq, true);
while ((buf = virtqueue_detach_unused_buf(vq)))
free_buf(buf, true);
}
portdev->vdev->config->del_vqs(portdev->vdev);
kfree(portdev->in_vqs);
kfree(portdev->out_vqs);