[PATCH 4/4] nvdimm: virtio_pmem: drain requests in freeze

[Li Chen <me@linux.beauty>]

virtio_pmem_freeze() deletes virtqueues and resets the device without
waking threads waiting for a virtqueue descriptor or a host completion.

Mark the request virtqueue broken and drain outstanding requests under
pmem_lock before teardown so waiters can make progress and return -EIO.

Signed-off-by: Li Chen <me@linux.beauty>
---
 drivers/nvdimm/virtio_pmem.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/nvdimm/virtio_pmem.c b/drivers/nvdimm/virtio_pmem.c
index aa07328e3ff9..5c60a7b459d4 100644
--- a/drivers/nvdimm/virtio_pmem.c
+++ b/drivers/nvdimm/virtio_pmem.c
@@ -152,6 +152,13 @@ static void virtio_pmem_remove(struct virtio_device *vdev)
 
 static int virtio_pmem_freeze(struct virtio_device *vdev)
 {
+	struct virtio_pmem *vpmem = vdev->priv;
+	unsigned long flags;
+
+	spin_lock_irqsave(&vpmem->pmem_lock, flags);
+	virtio_pmem_mark_broken_and_drain(vpmem);
+	spin_unlock_irqrestore(&vpmem->pmem_lock, flags);
+
 	vdev->config->del_vqs(vdev);
 	virtio_reset_device(vdev);
 
-- 
2.51.0