FROMGIT: virtio_pmem: Check device status before requesting flush

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>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com

Bug: 358391069
Change-Id: I325e6f0ea047c4c5fa82cf4b590cbf7240f39b7b
(cherry picked from commit e25fbcd97cf52c3c9824d44b5c56c19673c3dd50 https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master)
Signed-off-by: Philip Chen <philipchen@google.com>

drivers/nvdimm/nd_virtio.c

diff --git a/drivers/nvdimm/nd_virtio.c b/drivers/nvdimm/nd_virtio.c
index c6a648f..a78e17a4 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 activated.
+	 */
+	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)