int mem_flags,
unsigned mem_flags,
void *usb_buffer_alloc (	struct usb_device *dev,	size_t size,	int mem_flags,	dma_addr_t *dma){	if (!dev || !dev->bus || !dev->bus->op || !dev->bus->op->buffer_alloc)		return NULL;	return dev->bus->op->buffer_alloc (dev->bus, size, mem_flags, dma);}