block: sunvdc: don't run hw queue synchronously from irq context

vdc_blk_queue_start() may be called from irq context, so we can't run
queue via blk_mq_start_hw_queues() since we never allow to run queue
from irq context. Use blk_mq_start_stopped_hw_queues(q, true) to fix
this issue.

Fixes: fa182a1f ("sunvdc: convert to blk-mq")
Reported-by: NAnatoly Pugachev <matorola@gmail.com>
Tested-by: NAnatoly Pugachev <matorola@gmail.com>
Cc: Anatoly Pugachev <matorola@gmail.com>
Cc: sparclinux@vger.kernel.org
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

drivers/block/sunvdc.c

@@ -181,7 +181,7 @@ static void vdc_blk_queue_start(struct vdc_port *port)
 	 * allocated a disk.
 	 */
 	if (port->disk && vdc_tx_dring_avail(dr) * 100 / VDC_TX_RING_SIZE >= 50)
-		blk_mq_start_hw_queues(port->disk->queue);
+		blk_mq_start_stopped_hw_queues(port->disk->queue, true);
 }
 
 static void vdc_finish(struct vio_driver_state *vio, int err, int waiting_for)