A lot of busy waiting in STM32F4 HAL USB libraries? Not RTOS friendly?

[bernieserver]

I want to implement an USB host MSC class for concurrent log transfer to an USB stick inside an RTOS context. I have seen the newest USB host device librarie implements an RTOS / CMSIS interface. But I have seen in code that there are still a lot of busy waitings. For example: In function

USBH_MSC_Write

in usbh_msc.c

there is the following wile loop:

 while (USBH_MSC_RdWrProcess(phost, lun) == USBH_BUSY)
 {
 if(((phost->Timer - timeout) > (10000U * length)) || (phost->device.is_connected == 0U))
 {
 MSC_Handle->state = MSC_IDLE;
 return USBH_FAIL;
 }
 }

Inside this loop in the function

static USBH_StatusTypeDef USBH_MSC_RdWrProcess(USBH_HandleTypeDef *phost, uint8_t lun)

there is a state machine which checks some inner states.

Does this while Loop blocks the whole CPU during transfer preventing lower priorized task to run?

Thanks and kindly regards

Bernhard.