kfifo_put - puts some data into the FIFO
unsigned int kfifo_put (struct kfifo * fifo, unsigned char * buffer, unsigned int len);
fifo the fifo to be used. buffer the data to be added. len the length of the data to be added.
This function copies at most ’len’ bytes from the ’buffer’ into the FIFO depending on the free space, and returns the number of bytes copied.