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);


struct request * rq

the request to be setup

struct request * rq_src

original request to be cloned

struct bio_set * bs

bio_set that bios for clone are allocated from

gfp_t gfp_mask

memory allocation mask for bio

int (*)(struct bio *, struct bio *, void *) bio_ctr

setup function to be called for each clone bio. Returns 0 for success, non 0 for failure.

void * data

private data to be passed to bio_ctr


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.