sr_raid1_set_chunk_state
void sr_raid1_set_chunk_state(struct sr_discipline *, int, int);
sd->sd_set_chunk_state = sr_raid1_set_chunk_state;
sd->sd_set_chunk_state = sr_raid1_set_chunk_state;
extern void sr_raid1_set_chunk_state(struct sr_discipline *, int, int);