prev               47 bio.c            bcache.head.prev = &bcache.head;
prev               51 bio.c              b->prev = &bcache.head;
prev               53 bio.c              bcache.head.next->prev = b;
prev               81 bio.c            for(b = bcache.head.prev; b != &bcache.head; b = b->prev){
prev              132 bio.c              b->next->prev = b->prev;
prev              133 bio.c              b->prev->next = b->next;
prev              135 bio.c              b->prev = &bcache.head;
prev              136 bio.c              bcache.head.next->prev = b;
prev                7 buf.h            struct buf *prev; // LRU cache list