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); |
rqthe request to be setup
rq_srcoriginal request to be cloned
bsbio_set that bios for clone are allocated from
gfp_maskmemory 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
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.