suse man page for kfifo_from_user_rec

KFIFO_FROM_USER_REC(9)						    FIFO Buffer 					    KFIFO_FROM_USER_REC(9)

NAME
       kfifo_from_user_rec - puts some data from user space into the FIFO

SYNOPSIS
       __must_check unsigned int kfifo_from_user_rec(struct kfifo * fifo, const void __user * from, unsigned int n, unsigned int recsize);

ARGUMENTS
       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

DESCRIPTION
       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.

COPYRIGHT
Kernel Hackers Manual 2.6.					     July 2010						    KFIFO_FROM_USER_REC(9)