[PATCH v2] virtio_pmem: Check device status before requesting flush

[Philip Chen <philipchen@chromium.org>]

If a pmem device is in a bad status, the driver side could wait for
host ack forever in virtio_pmem_flush(), causing the system to hang.

So add a status check in the beginning of virtio_pmem_flush() to return
early if the device is not activated.

Signed-off-by: Philip Chen <philipchen@chromium.org>
---

v2:
- Remove change id from the patch description
- Add more details to the patch description

 drivers/nvdimm/nd_virtio.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/nvdimm/nd_virtio.c b/drivers/nvdimm/nd_virtio.c
index 35c8fbbba10e..97addba06539 100644
--- a/drivers/nvdimm/nd_virtio.c
+++ b/drivers/nvdimm/nd_virtio.c
@@ -44,6 +44,15 @@ static int virtio_pmem_flush(struct nd_region *nd_region)
 	unsigned long flags;
 	int err, err1;
 
+	/*
+	 * Don't bother to submit the request to the device if the device is
+	 * not acticated.
+	 */
+	if (vdev->config->get_status(vdev) & VIRTIO_CONFIG_S_NEEDS_RESET) {
+		dev_info(&vdev->dev, "virtio pmem device needs a reset\n");
+		return -EIO;
+	}
+
 	might_sleep();
 	req_data = kmalloc(sizeof(*req_data), GFP_KERNEL);
 	if (!req_data)
-- 
2.46.0.184.g6999bdac58-goog