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_readers;
13	unsigned int waiting_writers;
14	unsigned int r_counter;
15	unsigned int w_counter;
16};
17
18/* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual
19   memory allocation, whereas PIPE_BUF makes atomicity guarantees.  */
20#define PIPE_SIZE		PAGE_SIZE
21
22#define PIPE_SEM(inode)		(&(inode).i_sem)
23#define PIPE_WAIT(inode)	(&(inode).i_pipe->wait)
24#define PIPE_BASE(inode)	((inode).i_pipe->base)
25#define PIPE_START(inode)	((inode).i_pipe->start)
26#define PIPE_LEN(inode)		((inode).i_pipe->len)
27#define PIPE_READERS(inode)	((inode).i_pipe->readers)
28#define PIPE_WRITERS(inode)	((inode).i_pipe->writers)
29#define PIPE_WAITING_READERS(inode)	((inode).i_pipe->waiting_readers)
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
34#define PIPE_EMPTY(inode)	(PIPE_LEN(inode) == 0)
35#define PIPE_FULL(inode)	(PIPE_LEN(inode) == PIPE_SIZE)
36#define PIPE_FREE(inode)	(PIPE_SIZE - PIPE_LEN(inode))
37#define PIPE_END(inode)	((PIPE_START(inode) + PIPE_LEN(inode)) & (PIPE_SIZE-1))
38#define PIPE_MAX_RCHUNK(inode)	(PIPE_SIZE - PIPE_START(inode))
39#define PIPE_MAX_WCHUNK(inode)	(PIPE_SIZE - PIPE_END(inode))
40
41/* Drop the inode semaphore and wait for a pipe event, atomically */
42void pipe_wait(struct inode * inode);
43
44struct inode* pipe_new(struct inode* inode);
45
46#endif
47