blk_rq_prep_clone - Helper function to setup clone request
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);
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, ->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.
|January 2017||Kernel Hackers Manual 4.8.|