head               35 bio.c            struct buf head;
head               47 bio.c            bcache.head.prev = &bcache.head;
head               48 bio.c            bcache.head.next = &bcache.head;
head               50 bio.c              b->next = bcache.head.next;
head               51 bio.c              b->prev = &bcache.head;
head               53 bio.c              bcache.head.next->prev = b;
head               54 bio.c              bcache.head.next = b;
head               69 bio.c            for(b = bcache.head.next; b != &bcache.head; b = b->next){
head               81 bio.c            for(b = bcache.head.prev; b != &bcache.head; b = b->prev){
head              134 bio.c              b->next = bcache.head.next;
head              135 bio.c              b->prev = &bcache.head;
head              136 bio.c              bcache.head.next->prev = b;
head              137 bio.c              bcache.head.next = b;