1 #ifndef _LINUX_PIPE_FS_I_H
2 #define _LINUX_PIPE_FS_I_H
4 #define PIPEFS_MAGIC 0x50495045
6 #define PIPE_BUFFERS (16)
8 #define PIPE_BUF_FLAG_LRU 0x01 /* page is on the LRU */
9 #define PIPE_BUF_FLAG_ATOMIC 0x02 /* was atomically mapped */
10 #define PIPE_BUF_FLAG_GIFT 0x04 /* page is a gift */
14 unsigned int offset, len;
15 const struct pipe_buf_operations *ops;
19 struct pipe_inode_info {
20 wait_queue_head_t wait;
21 unsigned int nrbufs, curbuf;
22 struct page *tmp_page;
25 unsigned int waiting_writers;
26 unsigned int r_counter;
27 unsigned int w_counter;
28 struct fasync_struct *fasync_readers;
29 struct fasync_struct *fasync_writers;
31 struct pipe_buffer bufs[PIPE_BUFFERS];
35 * Note on the nesting of these functions:
44 * That is, ->map() must be called on a pinned buffer, same goes for ->steal().
46 struct pipe_buf_operations {
48 void * (*map)(struct pipe_inode_info *, struct pipe_buffer *, int);
49 void (*unmap)(struct pipe_inode_info *, struct pipe_buffer *, void *);
50 int (*pin)(struct pipe_inode_info *, struct pipe_buffer *);
51 void (*release)(struct pipe_inode_info *, struct pipe_buffer *);
52 int (*steal)(struct pipe_inode_info *, struct pipe_buffer *);
53 void (*get)(struct pipe_inode_info *, struct pipe_buffer *);
56 /* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual
57 memory allocation, whereas PIPE_BUF makes atomicity guarantees. */
58 #define PIPE_SIZE PAGE_SIZE
60 /* Drop the inode semaphore and wait for a pipe event, atomically */
61 void pipe_wait(struct pipe_inode_info *pipe);
63 struct pipe_inode_info * alloc_pipe_info(struct inode * inode);
64 void free_pipe_info(struct inode * inode);
65 void __free_pipe_info(struct pipe_inode_info *);
67 /* Generic pipe buffer ops functions */
68 void *generic_pipe_buf_map(struct pipe_inode_info *, struct pipe_buffer *, int);
69 void generic_pipe_buf_unmap(struct pipe_inode_info *, struct pipe_buffer *, void *);
70 void generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *);
71 int generic_pipe_buf_pin(struct pipe_inode_info *, struct pipe_buffer *);
72 int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *);