LXR linux-bk/include/linux/pipe_fs

   1#ifndef _LINUX_PIPE_FS_I_H
   2#define _LINUX_PIPE_FS_I_H
   3
   4#define PIPEFS_MAGIC 0x50495045
   5struct pipe_inode_info {
   6        wait_queue_head_t wait;
   7        char *base;
   8        unsigned int len;
   9        unsigned int start;
  10        unsigned int readers;
  11        unsigned int writers;
  12        unsigned int waiting_writers;
  13        unsigned int r_counter;
  14        unsigned int w_counter;
  15        struct fasync_struct *fasync_readers;
  16        struct fasync_struct *fasync_writers;
  17};
  18
  19/* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual
  20   memory allocation, whereas PIPE_BUF makes atomicity guarantees.  */
  21#define PIPE_SIZE               PAGE_SIZE
  22
  23#define PIPE_SEM(inode)         (&(inode).i_sem)
  24#define PIPE_WAIT(inode)        (&(inode).i_pipe->wait)
  25#define PIPE_BASE(inode)        ((inode).i_pipe->base)
  26#define PIPE_START(inode)       ((inode).i_pipe->start)
  27#define PIPE_LEN(inode)         ((inode).i_pipe->len)
  28#define PIPE_READERS(inode)     ((inode).i_pipe->readers)
  29#define PIPE_WRITERS(inode)     ((inode).i_pipe->writers)
  30#define PIPE_WAITING_WRITERS(inode)     ((inode).i_pipe->waiting_writers)
  31#define PIPE_RCOUNTER(inode)    ((inode).i_pipe->r_counter)
  32#define PIPE_WCOUNTER(inode)    ((inode).i_pipe->w_counter)
  33#define PIPE_FASYNC_READERS(inode)     (&((inode).i_pipe->fasync_readers))
  34#define PIPE_FASYNC_WRITERS(inode)     (&((inode).i_pipe->fasync_writers))
  35
  36#define PIPE_EMPTY(inode)       (PIPE_LEN(inode) == 0)
  37#define PIPE_FULL(inode)        (PIPE_LEN(inode) == PIPE_SIZE)
  38#define PIPE_FREE(inode)        (PIPE_SIZE - PIPE_LEN(inode))
  39#define PIPE_END(inode) ((PIPE_START(inode) + PIPE_LEN(inode)) & (PIPE_SIZE-1))
  40#define PIPE_MAX_RCHUNK(inode)  (PIPE_SIZE - PIPE_START(inode))
  41#define PIPE_MAX_WCHUNK(inode)  (PIPE_SIZE - PIPE_END(inode))
  42
  43/* Drop the inode semaphore and wait for a pipe event, atomically */
  44void pipe_wait(struct inode * inode);
  45
  46struct inode* pipe_new(struct inode* inode);
  47
  48#endif
  49