Copies data from the fifo into user space
kfifo_to_user(fifo, to, len, copied);
fifo
address of the fifo to be used
to
where the data must be copied
len
the size of the destination buffer
copied
pointer to output variable to store the number of copied bytes
This macro copies at most len bytes from the fifo into the to buffer and returns -EFAULT/0.
Note that with only one concurrent reader and one concurrent writer, you don't need extra locking to use these macro.