bio_add_vmalloc_chunk
EXPORT_SYMBOL_GPL(bio_add_vmalloc_chunk);
unsigned int added = bio_add_vmalloc_chunk(bio, vaddr, len);
added = bio_add_vmalloc_chunk(bio, data + done, size - done);
added = bio_add_vmalloc_chunk(bio, data + done, count - done);
unsigned int bio_add_vmalloc_chunk(struct bio *bio, void *vaddr, unsigned len);