In reply to cgales:
No, my question is how the driver getting the next packet when the previous packet still there in req_fifo. Peek is a mailbox method. Peek method will give copy of the packet but the packet will be left there inside req_fifo. When a packet is already there inside the req_fifo, how the driver is getting another new packet (using peek method we can’t get the packet out. It’s just takes the copy of packet).