copies data from the fifo into user space
| fifo, |
| || to, |
| || len, |
| || copied|
address of the fifo to be used
where the data must be copied
the size of the destination buffer
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.