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include/linux/pipe_fs_i.h 1.86 KB
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  #ifndef _LINUX_PIPE_FS_I_H
  #define _LINUX_PIPE_FS_I_H
  
  #define PIPEFS_MAGIC 0x50495045
  
  #define PIPE_BUFFERS (16)
  
  struct pipe_buffer {
  	struct page *page;
  	unsigned int offset, len;
  	struct pipe_buf_operations *ops;
  };
  
  struct pipe_buf_operations {
  	int can_merge;
  	void * (*map)(struct file *, struct pipe_inode_info *, struct pipe_buffer *);
  	void (*unmap)(struct pipe_inode_info *, struct pipe_buffer *);
  	void (*release)(struct pipe_inode_info *, struct pipe_buffer *);
  };
  
  struct pipe_inode_info {
  	wait_queue_head_t wait;
  	unsigned int nrbufs, curbuf;
  	struct pipe_buffer bufs[PIPE_BUFFERS];
  	struct page *tmp_page;
  	unsigned int start;
  	unsigned int readers;
  	unsigned int writers;
  	unsigned int waiting_writers;
  	unsigned int r_counter;
  	unsigned int w_counter;
  	struct fasync_struct *fasync_readers;
  	struct fasync_struct *fasync_writers;
  };
  
  /* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual
     memory allocation, whereas PIPE_BUF makes atomicity guarantees.  */
  #define PIPE_SIZE		PAGE_SIZE
  
  #define PIPE_SEM(inode)		(&(inode).i_sem)
  #define PIPE_WAIT(inode)	(&(inode).i_pipe->wait)
  #define PIPE_BASE(inode)	((inode).i_pipe->base)
  #define PIPE_START(inode)	((inode).i_pipe->start)
  #define PIPE_LEN(inode)		((inode).i_pipe->len)
  #define PIPE_READERS(inode)	((inode).i_pipe->readers)
  #define PIPE_WRITERS(inode)	((inode).i_pipe->writers)
  #define PIPE_WAITING_WRITERS(inode)	((inode).i_pipe->waiting_writers)
  #define PIPE_RCOUNTER(inode)	((inode).i_pipe->r_counter)
  #define PIPE_WCOUNTER(inode)	((inode).i_pipe->w_counter)
  #define PIPE_FASYNC_READERS(inode)     (&((inode).i_pipe->fasync_readers))
  #define PIPE_FASYNC_WRITERS(inode)     (&((inode).i_pipe->fasync_writers))
  
  /* Drop the inode semaphore and wait for a pipe event, atomically */
  void pipe_wait(struct inode * inode);
  
  struct inode* pipe_new(struct inode* inode);
  void free_pipe_info(struct inode* inode);
  
  #endif