centos man page for bio_copy_user

BIO_COPY_USER(9)						   The Linux VFS						  BIO_COPY_USER(9)

NAME
       bio_copy_user - copy user data to bio

SYNOPSIS
       struct bio * bio_copy_user(struct request_queue * q, struct rq_map_data * map_data, unsigned long uaddr, unsigned int len, int write_to_vm,
				  gfp_t gfp_mask);

ARGUMENTS
       q
	   destination block queue

       map_data
	   pointer to the rq_map_data holding pages (if necessary)

       uaddr
	   start of user address

       len
	   length in bytes

       write_to_vm
	   bool indicating writing to pages or not

       gfp_mask
	   memory allocation flags

DESCRIPTION
       Prepares and returns a bio for indirect user io, bouncing data to/from kernel pages as necessary. Must be paired with call bio_uncopy_user
       on io completion.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014							  BIO_COPY_USER(9)