megaraid_sas: do not process IOCTLs and SCSI commands during driver removal

Do not process any SCSI and IOCTL command further (return them with
appropriate return values to callers), while driver removal is in
progress or PCI shutdown is invoked.

Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: Kashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/scsi/megaraid/megaraid_sas_base.c

@@ -1571,6 +1571,12 @@ megasas_queue_command(struct Scsi_Host *shost, struct scsi_cmnd *scmd)
 	instance = (struct megasas_instance *)
 	    scmd->device->host->hostdata;
 
+	if (instance->unload == 1) {
+		scmd->result = DID_NO_CONNECT << 16;
+		scmd->scsi_done(scmd);
+		return 0;
+	}
+
 	if (instance->issuepend_done == 0)
 		return SCSI_MLQUEUE_HOST_BUSY;
 
@@ -5011,10 +5017,6 @@ static int megasas_io_attach(struct megasas_instance *instance)
 		return -ENODEV;
 	}
 
-	/*
-	 * Trigger SCSI to scan our drives
-	 */
-	scsi_scan_host(host);
 	return 0;
 }
 
@@ -5344,6 +5346,10 @@ retry_irq_register:
 		goto fail_io_attach;
 
 	instance->unload = 0;
+	/*
+	 * Trigger SCSI to scan our drives
+	 */
+	scsi_scan_host(host);
 
 	/*
 	 * Initiate AEN (Asynchronous Event Notification)
@@ -6107,6 +6113,11 @@ megasas_mgmt_fw_ioctl(struct megasas_instance *instance,
 	megasas_issue_blocked_cmd(instance, cmd, 0);
 	cmd->sync_cmd = 0;
 
+	if (instance->unload == 1) {
+		dev_info(&instance->pdev->dev, "Driver unload is in progress "
+			"don't submit data to application\n");
+		goto out;
+	}
 	/*
 	 * copy out the kernel buffers to user buffers
 	 */