BLK_RQ_PREP_CLONE(9) Block Devices BLK_RQ_PREP_CLONE(9)
NAME blk_rq_prep_clone - Helper function to setup clone request
SYNOPSIS int blk_rq_prep_clone(struct request * rq, struct request * rq_src, struct bio_set * bs, gfp_t gfp_mask, int (*bio_ctr) (struct bio *, struct bio *, void *), void * data);
ARGUMENTS rq the request to be setup
rq_src original request to be cloned
bs bio_set that bios for clone are allocated from
gfp_mask memory allocation mask for bio
bio_ctr setup function to be called for each clone bio. Returns 0 for success, non 0 for failure.
data private data to be passed to bio_ctr
DESCRIPTION Clones bios in rq_src to rq, and copies attributes of rq_src to rq. The actual data parts of rq_src (e.g. ->cmd, ->buffer, ->sense) are not copied, and copying such parts is the caller´s responsibility. Also, pages which the original bios are pointing to are not copied and the cloned bios just point same pages. So cloned bios must be completed before original bios, which means the caller must complete rq before rq_src.
COPYRIGHT Kernel Hackers Manual 2.6. November 2011 BLK_RQ_PREP_CLONE(9)