Provided by:
linux-doc-2.6.15_2.6.15-23.39_all 
NAME
__kfifo_get - gets some data from the FIFO, no locking version
SYNOPSIS
unsigned int __kfifo_get (struct kfifo * fifo, unsigned char * buffer,
unsigned int len);
ARGUMENTS
fifo the fifo to be used.
buffer where the data must be copied.
len the size of the destination buffer.
DESCRIPTION
This function copies at most ’len’ bytes from the FIFO into the
’buffer’ and returns the number of copied bytes.
Note that with only one concurrent reader and one concurrent writer,
you don’t need extra locking to use these functions.