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virtio_scsi: fix race on device removal

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We cancel event work on device removal, but an interrupt
could trigger immediately after this, and queue it
again.

To fix, set a flag.

Loosely based on patch by Paolo Bonzini

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Michael S. Tsirkin 2014-10-15 10:22:33 +10:30 committed by Rusty Russell
parent 1fa5b2a784
commit e67423c7b4
1 changed files with 10 additions and 1 deletions
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11
drivers/scsi/virtio_scsi.c
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@ -110,6 +110,9 @@ struct virtio_scsi {
/* CPU hotplug notifier */
struct notifier_block nb;
/* Protected by event_vq lock */
bool stop_events;
struct virtio_scsi_vq ctrl_vq;
struct virtio_scsi_vq event_vq;
struct virtio_scsi_vq req_vqs[];
@ -303,6 +306,11 @@ static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi)
{
int i;
/* Stop scheduling work before calling cancel_work_sync. */
spin_lock_irq(&vscsi->event_vq.vq_lock);
vscsi->stop_events = true;
spin_unlock_irq(&vscsi->event_vq.vq_lock);
for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++)
cancel_work_sync(&vscsi->event_list[i].work);
}
@ -390,7 +398,8 @@ static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf)
{
struct virtio_scsi_event_node *event_node = buf;
queue_work(system_freezable_wq, &event_node->work);
if (!vscsi->stop_events)
queue_work(system_freezable_wq, &event_node->work);
}
static void virtscsi_event_done(struct virtqueue *vq)