prev               48 bio.c            bcache.head.prev = &bcache.head;
prev               52 bio.c              b->prev = &bcache.head;
prev               54 bio.c              bcache.head.next->prev = b;
prev               86 bio.c            for(b = bcache.head.prev; b != &bcache.head; b = b->prev){
prev              131 bio.c            b->next->prev = b->prev;
prev              132 bio.c            b->prev->next = b->next;
prev              134 bio.c            b->prev = &bcache.head;
prev              135 bio.c            bcache.head.next->prev = b;
prev                5 buf.h            struct buf *prev; // LRU cache list