Linux核心数据结构

2/9/2008来源:Oracle教程人气:4610


  本章列出了linux实用的主要数据结构。
  
  block_dev_strUCt
  
    此结构用于向核心登记块设备,它还被buffer cache实用。所有此类结构都位于blk_dev数组中。
  
  struct blk_dev_struct {
  void (*request_fn)(void);
  struct request * current_request;
  struct request plug;
  struct tq_struct plug_tq;
  };
  buffer_head
  
    此结构包含关于buffer cache中一块缓存的信息。
  
  /* bh state bits */
  #define BH_Uptodate 0 /* 1 if the buffer contains valid data */
  #define BH_Dirty 1 /* 1 if the buffer is dirty */
  #define BH_Lock 2 /* 1 if the buffer is locked */
  #define BH_Req 3 /* 0 if the buffer has been invalidated */
  #define BH_Touched 4 /* 1 if the buffer has been touched (aging) */
  #define BH_Has_aged 5 /* 1 if the buffer has been aged (aging) */
  #define BH_PRotected 6 /* 1 if the buffer is protected */
  #define BH_FreeOnIO 7 /* 1 to discard the buffer_head after IO */
  struct buffer_head {
  /* First cache line: */
  unsigned long b_blocknr; /* block number */
  kdev_t b_dev; /* device (B_FREE = free) */
  kdev_t b_rdev; /* Real device */
  unsigned long b_rsector; /* Real buffer location on disk */
  struct buffer_head *b_next; /* Hash queue list */
  struct buffer_head *b_this_page; /* circular list of buffers in one
  page */
  /* Second cache line: */
  unsigned long b_state; /* buffer state bitmap (above) */
  struct buffer_head *b_next_free;
  unsigned int b_count; /* users using this block */
  unsigned long b_size; /* block size */
  /* Non-performance-critical data follows. */
  char *b_data; /* pointer to data block */
  unsigned int b_list; /* List that this buffer appears */
  unsigned long b_flushtime; /* Time when this (dirty) buffer
  * should be written */
  unsigned long b_lru_time; /* Time when this buffer was
  * last used. */
  struct wait_queue *b_wait;
  struct buffer_head *b_prev; /* doubly linked hash list */
  struct buffer_head *b_prev_free; /* doubly linked list of buffers */
  struct buffer_head *b_reqnext; /* request queue */
  };
  device
  
    系统中每个网络设备都用一个设备数据结构来表示。
  
  struct device
  {
  /*
  * This is the first field of the "visible" part of this structure
  * (i.e. as seen by users in the "Space.c" file). It is the name
  * the interface.
  */
  char *name;
  /* I/O specific fields */
  unsigned long rmem_end; /* shmem "recv" end */
  unsigned long rmem_start; /* shmem "recv" start */
  unsigned long mem_end; /* shared mem end */
  unsigned long mem_start; /* shared mem start */
  unsigned long base_addr; /* device I/O address */
  unsigned char irq; /* device IRQ number */
  /* Low-level status flags. */
  volatile unsigned char start, /* start an Operation */
  interrupt; /* interrupt arrived */
  unsigned long tbusy; /* transmitter busy */
  struct device *next;
  /* The device initialization function. Called only once. */
  int (*init)(struct device *dev);
  /* Some hardware also needs these fields, but they are not part of
  the usual set specified in Space.c. */
  unsigned char if_port; /* Selectable AUI,TP, */
  unsigned char dma; /* DMA channel */
  struct enet_statistics* (*get_stats)(struct device *dev);
  /*
  * This marks the end of the "visible" part of the structure. All
  * fields hereafter are internal to the system, and may change at
  * will (read: may be cleaned up at will).
  */
  /* These may be needed for future network-power-down code. */
  unsigned long trans_start; /* Time (jiffies) of last transmit */
  unsigned long last_rx; /* Time of last Rx */
  unsigned short flags; /* interface flags (BSD)*/
  unsigned short family; /* address family ID */
  unsigned short metric; /* routing metric */
  unsigned short mtu; /* MTU value */
  unsigned short type; /* hardware type */
  unsigned short hard_header_len; /* hardware hdr len */
  void *priv; /* private data */
  /* Interface address info. */
  unsigned char broadcast[MAX_ADDR_LEN];
  unsigned char pad;
  unsigned char dev_addr[MAX_ADDR_LEN];
  unsigned char addr_len; /* hardware addr len */
  unsigned long pa_addr; /* protocol address */
  unsigned long pa_brdaddr; /* protocol broadcast addr*/
  unsigned long pa_dstaddr; /* protocol P-P other addr*/
  unsigned long pa_mask; /* protocol netmask */
  unsigned short pa_alen; /* protocol address len */
  struct dev_mc_list *mc_list; /* M'cast mac addrs */
  int mc_count; /* No installed mcasts */
  struct ip_mc_list *ip_mc_list; /* IP m'cast filter chain */
  __u32 tx_queue_len; /* Max frames per queue */
  /* For load balancing driver pair support */
  unsigned long pkt_queue; /* Packets queued */
  struct device *slave; /* Slave device */
  struct net_alias_info *alias_info; /* main dev alias info */
  struct net_alias *my_alias; /* alias devs */
  /* Pointer to the interface buffers. */
  struct sk_buff_head buffs[DEV_NUMBUFFS];
  /* Pointers to interface service routines. */
  int (*open)(struct device *dev);
  int (*stop)(struct device *dev);
  int (*hard_start_xmit) (struct sk_buff *skb,
  struct device *dev);
  int (*hard_header) (struct sk_buff *skb,
  struct device *dev,
  unsigned short type,
  void *daddr,
  void *saddr,
  unsigned len);
  int (*rebuild_header)(void *eth,
  struct device *dev,
  unsigned long raddr,
  struct sk_buff *skb);
  void (*set_multicast_list)(struct device *dev);
  int (*set_mac_address)(struct device *dev,
  void *addr);
  int (*do_ioctl)(struct device *dev,
  struct ifreq *ifr,
  int cmd);
  int (*set_config)(struct device *dev,
  struct ifmap *map);
  void (*header_cache_bind)(struct hh_cache **hhp,
  struct device *dev,
  unsigned short htype,
  __u32 daddr);
  void (*header_cache_update)(struct hh_cache *hh,
  struct device *dev,
  unsigned char * haddr);
  int (*change_mtu)(struct device *dev,
  int new_mtu);
  struct iw_statistics* (*get_wireless_stats)(struct device *dev);
  };
  device_struct
  
    此结构被块设备和字符设备用来向核心登记(包含设备名称以及可对此设备进行的文件操作)。
chrdevs和blkdevs中的每个有效分别表示一个字符设备和块设备。
  
  struct device_struct {
  const char * name;
  struct file_operations * fops;
  };
  file
  
    每个打开的文件、套接口都用此结构表示。
  
  struct file {
  mode_t f_mode;
  loff_t f_pos;
  unsigned short f_flags;
  unsigned short f_count;
  unsigned long f_reada, f_ramax, f_raend, f_ralen, f_rawin;
  struct file *f_next, *f_prev;
  int f_owner; /* pid or -pgrp where SIGIO should be sent */
  struct inode * f_inode;
  struct file_operations * f_op;
  unsigned long f_version;
  void *private_data; /* needed for tty driver, and maybe others */
  };
  files_struct
  
   描叙被某进程打开的所有文件。
  
  struct files_struct {
  int count;
  fd_set close_on_exec;
  fd_set open_fds;
  struct file * fd[NR_OPEN];
  };
  fs_struct
  struct fs_struct {
  int count;
  unsigned short umask;
  struct inode * root, * pwd;
  };
  gendisk
  
    包含关于某个硬盘的信息。用于磁盘初始化与分区检查时。
  
  struct hd_struct {
  long start_sect;
  long nr_sects;
  };
  struct gendisk {