18  *	struct pipe_buffer - a linux kernel pipe buffer
19  *	@page: the page containing the data for the pipe buffer
23  *	@flags: pipe buffer flags. See above.
35  *	struct pipe_inode_info - a linux kernel pipe
37  *	@rd_wait: reader wait point in case of empty pipe
38  *	@wr_wait: writer wait point in case of full pipe
44  *	@nr_accounted: The amount this pipe accounts for in user->pipe_bufs
46  *	@readers: number of current readers of this pipe
47  *	@writers: number of current writers of this pipe
48  *	@files: number of struct file referring this pipe (protected by ->i_lock)
51  *	@poll_usage: is this pipe used for epoll, which has crazy wakeups?
54  *	@bufs: the circular array of pipe buffers
55  *	@user: the user who created this pipe
56  *	@watch_queue: If this pipe is a watch_queue, this is the stuff for that
92  * the meaning of each operation.  Also see the kerneldoc in fs/pipe.c for the
93  * pipe and generic variants of these hooks.
97 	 * ->confirm() verifies that the data in the pipe buffer is there
98 	 * and that the contents are good. If the pages in the pipe belong
106 	 * When the contents of this pipe buffer has been completely
112 	 * Attempt to take ownership of the pipe buffer and its contents.
114 	 * of the pipe (the buf->page) is locked and now completely owned by the
122 	 * Get a reference to the pipe buffer.
128  * pipe_empty - Return true if the pipe is empty
129  * @head: The pipe ring head pointer
130  * @tail: The pipe ring tail pointer
138  * pipe_occupancy - Return number of slots used in the pipe
139  * @head: The pipe ring head pointer
140  * @tail: The pipe ring tail pointer
148  * pipe_full - Return true if the pipe is full
149  * @head: The pipe ring head pointer
150  * @tail: The pipe ring tail pointer
161  * @head: The pipe ring head pointer
162  * @tail: The pipe ring tail pointer
163  * @pipe: The pipe info structure
166 					       struct pipe_inode_info *pipe)  in pipe_space_for_user()  argument
171 	if (p_occupancy >= pipe->max_usage)  in pipe_space_for_user()
173 	p_space = pipe->ring_size - p_occupancy;  in pipe_space_for_user()
174 	if (p_space > pipe->max_usage)  in pipe_space_for_user()
175 		p_space = pipe->max_usage;  in pipe_space_for_user()
181  * @pipe:	the pipe that the buffer belongs to
186 static inline __must_check bool pipe_buf_get(struct pipe_inode_info *pipe,  in pipe_buf_get()  argument
189 	return buf->ops->get(pipe, buf);  in pipe_buf_get()
194  * @pipe:	the pipe that the buffer belongs to
197 static inline void pipe_buf_release(struct pipe_inode_info *pipe,  in pipe_buf_release()  argument
203 	ops->release(pipe, buf);  in pipe_buf_release()
207  * pipe_buf_confirm - verify contents of the pipe buffer
208  * @pipe:	the pipe that the buffer belongs to
211 static inline int pipe_buf_confirm(struct pipe_inode_info *pipe,  in pipe_buf_confirm()  argument
216 	return buf->ops->confirm(pipe, buf);  in pipe_buf_confirm()
221  * @pipe:	the pipe that the buffer belongs to
224 static inline bool pipe_buf_try_steal(struct pipe_inode_info *pipe,  in pipe_buf_try_steal()  argument
229 	return buf->ops->try_steal(pipe, buf);  in pipe_buf_try_steal()
236 /* Pipe lock and unlock operations */
245 /* Wait for a pipe to be readable/writable while dropping the pipe lock */
252 /* Generic pipe buffer ops functions */
269 int pipe_resize_ring(struct pipe_inode_info *pipe, unsigned int nr_slots);