Attempt to fix EINTR errors during shutdown

For userspace the conventional wisdom appears to be to just run the syscall
that returned EINTR again. The same should work in kernelspace.

src/cmd.c

@@ -37,6 +37,31 @@ static int ipts_cmd_get_errno(struct ipts_response rsp, enum ipts_status expect)
 	return -EINVAL;
 }
 
+static ssize_t _mei_recv(struct mei_cl_device *cldev, u8 *buf, size_t length, bool blocking)
+{
+	ssize_t ret = 0;
+
+	do {
+		if (blocking)
+			ret = mei_cldev_recv(cldev, buf, length);
+		else
+			ret = mei_cldev_recv_nonblock(cldev, buf, length);
+	} while (ret == -EINTR);
+
+	return ret;
+}
+
+static ssize_t _mei_send(struct mei_cl_device *cldev, u8 *buf, size_t length)
+{
+	ssize_t ret = 0;
+
+	do {
+		ret = mei_cldev_send(cldev, buf, length);
+	} while (ret == -EINTR);
+
+	return ret;
+}
+
 static int _ipts_cmd_recv(struct ipts_context *ipts, enum ipts_command_code code, void *data,
 			  size_t size, bool block, enum ipts_status expect)
 {
@@ -49,11 +74,7 @@ static int _ipts_cmd_recv(struct ipts_context *ipts, enum ipts_command_code code
 	if (size > sizeof(rsp.payload))
 		return -EINVAL;
 
-	if (block)
-		ret = mei_cldev_recv(ipts->cldev, (u8 *)&rsp, sizeof(rsp));
-	else
-		ret = mei_cldev_recv_nonblock(ipts->cldev, (u8 *)&rsp, sizeof(rsp));
-
+	ret = _mei_recv(ipts->cldev, (u8 *)&rsp, sizeof(rsp), block);
 	if (ret == -EAGAIN)
 		return ret;
 
@@ -102,7 +123,7 @@ int ipts_cmd_send(struct ipts_context *ipts, enum ipts_command_code code, void *
 	if (data && size > 0)
 		memcpy(cmd.payload, data, size);
 
-	ret = mei_cldev_send(ipts->cldev, (u8 *)&cmd, sizeof(cmd.cmd) + size);
+	ret = _mei_send(ipts->cldev, (u8 *)&cmd, sizeof(cmd.cmd) + size);
 	if (ret >= 0)
 		return 0;