TTY之struct tty_buffer

struct tty_buffer { union {  struct tty_buffer *next;  struct llist_node free; }; int used; int size; int commit; int read; int flags; /* Data points here */ unsigned long data[0];};

struct tty_bufhead { struct tty_buffer *head; /* Queue head */ struct work_struct work; struct mutex    lock; atomic_t    priority; struct tty_buffer sentinel; struct llist_head free;  /* Free queue head */ atomic_t    mem_used;    /* In-use buffers excluding free list */ int     mem_limit; struct tty_buffer *tail; /* Active buffer */};