1 #ifndef _LINUX_PIPE_FS_I_H
2 #define _LINUX_PIPE_FS_I_H
4 #define PIPEFS_MAGIC 0x50495045
5 struct pipe_inode_info {
6 wait_queue_head_t wait;
12 unsigned int waiting_readers;
13 unsigned int waiting_writers;
14 unsigned int r_counter;
15 unsigned int w_counter;
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
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)
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))
41 /* Drop the inode semaphore and wait for a pipe event, atomically */
42 void pipe_wait(struct inode * inode);
44 struct inode* pipe_new(struct inode* inode);