NVMe: Improve error messages

Help people diagnose what is going wrong at initialisation time by
printing out which command has gone wrong and what the device returned.
Also fix the error message printed while waiting for reset.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>

drivers/block/nvme-core.c

@@ -1354,7 +1354,8 @@ static int nvme_wait_ready(struct nvme_dev *dev, u64 cap, bool enabled)
 			return -EINTR;
 		if (time_after(jiffies, timeout)) {
 			dev_err(&dev->pci_dev->dev,
-				"Device not ready; aborting initialisation\n");
+				"Device not ready; aborting %s\n", enabled ?
+						"initialisation" : "reset");
 			return -ENODEV;
 		}
 	}
@@ -2058,8 +2059,13 @@ static int set_queue_count(struct nvme_dev *dev, int count)
 
 	status = nvme_set_features(dev, NVME_FEAT_NUM_QUEUES, q_count, 0,
 								&result);
-	if (status)
-		return status < 0 ? -EIO : -EBUSY;
+	if (status < 0)
+		return status;
+	if (status > 0) {
+		dev_err(&dev->pci_dev->dev, "Could not set queue count (%d)\n",
+									status);
+		return -EBUSY;
+	}
 	return min(result & 0xffff, result >> 16) + 1;
 }
 
@@ -2180,6 +2186,7 @@ static int nvme_dev_add(struct nvme_dev *dev)
 
 	res = nvme_identify(dev, 0, 1, dma_addr);
 	if (res) {
+		dev_err(&pdev->dev, "Identify Controller failed (%d)\n", res);
 		res = -EIO;
 		goto out;
 	}