include/linux/pipe_fs_i.h

   1 #ifndef _LINUX_PIPE_FS_I_H
   2 #define _LINUX_PIPE_FS_I_H
   3
   4 #define PIPEFS_MAGIC 0x50495045
   5 struct 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 */
  44 void pipe_wait(struct inode * inode);
  45
  46 struct inode* pipe_new(struct inode* inode);
  47
  48 #endif