kfifo_from_user_rec — puts some data from user space into the FIFO
__must_check unsigned int kfifo_from_user_rec ( | struct kfifo * fifo, |
const void __user * from, | |
unsigned int n, | |
unsigned int recsize) ; |
fifo
the fifo to be used.
from
pointer to the data to be added.
n
the length of the data to be added.
recsize
size of record field
This function copies n
bytes from the from
into the
FIFO and returns the number of bytes which cannot be copied.
If the returned value is equal or less the n
value, the copy_from_user
functions has failed. Otherwise the record doesn't fit into the buffer.
Note that with only one concurrent reader and one concurrent writer, you don't need extra locking to use these functions.