540 	struct bio *tail;  member
550 	bl->head = bl->tail = NULL;  in bio_list_init()
573 	if (bl->tail)  in bio_list_add()
574 		bl->tail->bi_next = bio;  in bio_list_add()
578 	bl->tail = bio;  in bio_list_add()
587 	if (!bl->tail)  in bio_list_add_head()
588 		bl->tail = bio;  in bio_list_add_head()
596 	if (bl->tail)  in bio_list_merge()
597 		bl->tail->bi_next = bl2->head;  in bio_list_merge()
601 	bl->tail = bl2->tail;  in bio_list_merge()
611 		bl2->tail->bi_next = bl->head;  in bio_list_merge_head()
613 		bl->tail = bl2->tail;  in bio_list_merge_head()
630 			bl->tail = NULL;  in bio_list_pop()
642 	bl->head = bl->tail = NULL;  in bio_list_get()