nvme-pci: Rate limit the nvme timeout warnings

The block layer's timeout handling currently prevents drivers from
completing commands outside the timeout callback once blk-mq decides
they've expired. If a device breaks, this could potentially create many
thousands of timed out commands. There's nothing of value to be gleaned
from observing each of those messages, so this patch adds a rate limit
on them.
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

drivers/nvme/host/pci.c

@@ -1227,7 +1227,7 @@ static enum blk_eh_timer_return nvme_timeout(struct request *req, bool reserved)
 	switch (dev->ctrl.state) {
 	case NVME_CTRL_CONNECTING:
 	case NVME_CTRL_RESETTING:
-		dev_warn(dev->ctrl.device,
+		dev_warn_ratelimited(dev->ctrl.device,
 			 "I/O %d QID %d timeout, disable controller\n",
 			 req->tag, nvmeq->qid);
 		nvme_dev_disable(dev, false);