- struct bio * bio_copy_kern(struct request_queue * q, void * data, unsigned int len, gfp_t gfp_mask, int reading);
- the struct request_queue for the bio
- pointer to buffer to copy
- length in bytes
- allocation flags for bio and page allocation
- data direction is READ
copy the kernel address into a bio suitable for io to a block device. Returns an error pointer in case of error.