staging: unisys: visorbus: save_crash_message add error handling

Add proper error handling to the function save_crash_message.
Signed-off-by: David Kershner <david.kershner@unisys.com>
Reported-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/unisys/visorbus/visorchipset.c

@@ -579,57 +579,63 @@ enum crash_obj_type {
 	CRASH_BUS,
 };
 
-static void
+static int
 save_crash_message(struct controlvm_message *msg, enum crash_obj_type typ)
 {
 	u32 local_crash_msg_offset;
 	u16 local_crash_msg_count;
+	int err;
 
-	if (visorchannel_read(controlvm_channel,
-			      offsetof(struct spar_controlvm_channel_protocol,
-				       saved_crash_message_count),
-			      &local_crash_msg_count, sizeof(u16)) < 0) {
+	err = visorchannel_read(controlvm_channel,
+				offsetof(struct spar_controlvm_channel_protocol,
+					 saved_crash_message_count),
+				&local_crash_msg_count, sizeof(u16));
+	if (err) {
 		POSTCODE_LINUX_2(CRASH_DEV_CTRL_RD_FAILURE_PC,
 				 POSTCODE_SEVERITY_ERR);
-		return;
+		return err;
 	}
 
 	if (local_crash_msg_count != CONTROLVM_CRASHMSG_MAX) {
 		POSTCODE_LINUX_3(CRASH_DEV_COUNT_FAILURE_PC,
 				 local_crash_msg_count,
 				 POSTCODE_SEVERITY_ERR);
-		return;
+		return -EIO;
 	}
 
-	if (visorchannel_read(controlvm_channel,
-			      offsetof(struct spar_controlvm_channel_protocol,
-				       saved_crash_message_offset),
-			      &local_crash_msg_offset, sizeof(u32)) < 0) {
+	err = visorchannel_read(controlvm_channel,
+				offsetof(struct spar_controlvm_channel_protocol,
+					 saved_crash_message_offset),
+				&local_crash_msg_offset, sizeof(u32));
+	if (err) {
 		POSTCODE_LINUX_2(CRASH_DEV_CTRL_RD_FAILURE_PC,
 				 POSTCODE_SEVERITY_ERR);
-		return;
+		return err;
 	}
 
 	if (typ == CRASH_BUS) {
-		if (visorchannel_write(controlvm_channel,
-				       local_crash_msg_offset,
-				       msg,
-				       sizeof(struct controlvm_message)) < 0) {
+		err = visorchannel_write(controlvm_channel,
+					 local_crash_msg_offset,
+					 msg,
+					sizeof(struct controlvm_message));
+		if (err) {
 			POSTCODE_LINUX_2(SAVE_MSG_BUS_FAILURE_PC,
 					 POSTCODE_SEVERITY_ERR);
-			return;
+			return err;
 		}
 	} else {
 		local_crash_msg_offset += sizeof(struct controlvm_message);
-		if (visorchannel_write(controlvm_channel,
-				       local_crash_msg_offset,
-				       msg,
-				       sizeof(struct controlvm_message)) < 0) {
+		err = visorchannel_write(controlvm_channel,
+					 local_crash_msg_offset,
+					 msg,
+					 sizeof(struct controlvm_message));
+		if (err) {
 			POSTCODE_LINUX_2(SAVE_MSG_DEV_FAILURE_PC,
 					 POSTCODE_SEVERITY_ERR);
-			return;
+			return err;
 		}
 	}
+	return 0;
 }
 
 static void