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.
62  *	struct pipe_inode_info - a linux kernel pipe
64  *	@rd_wait: reader wait point in case of empty pipe
65  *	@wr_wait: writer wait point in case of full pipe
72  *	@nr_accounted: The amount this pipe accounts for in user->pipe_bufs
74  *	@readers: number of current readers of this pipe
75  *	@writers: number of current writers of this pipe
76  *	@files: number of struct file referring this pipe (protected by ->i_lock)
79  *	@poll_usage: is this pipe used for epoll, which has crazy wakeups?
82  *	@bufs: the circular array of pipe buffers
83  *	@user: the user who created this pipe
84  *	@watch_queue: If this pipe is a watch_queue, this is the stuff for that
128  * the meaning of each operation.  Also see the kerneldoc in fs/pipe.c for the
129  * pipe and generic variants of these hooks.
133 	 * ->confirm() verifies that the data in the pipe buffer is there
134 	 * and that the contents are good. If the pages in the pipe belong
142 	 * When the contents of this pipe buffer has been completely
148 	 * Attempt to take ownership of the pipe buffer and its contents.
150 	 * of the pipe (the buf->page) is locked and now completely owned by the
158 	 * Get a reference to the pipe buffer.
164  * pipe_has_watch_queue - Check whether the pipe is a watch_queue,
166  * @pipe: The pipe to check
168  * Return: true if pipe is a watch queue, false otherwise.
170 static inline bool pipe_has_watch_queue(const struct pipe_inode_info *pipe)  in pipe_has_watch_queue()  argument
173 	return pipe->watch_queue != NULL;  in pipe_has_watch_queue()
180  * pipe_occupancy - Return number of slots used in the pipe
181  * @head: The pipe ring head pointer
182  * @tail: The pipe ring tail pointer
190  * pipe_empty - Return true if the pipe is empty
191  * @head: The pipe ring head pointer
192  * @tail: The pipe ring tail pointer
200  * pipe_full - Return true if the pipe is full
201  * @head: The pipe ring head pointer
202  * @tail: The pipe ring tail pointer
212  * pipe_is_full - Return true if the pipe is full
213  * @pipe: the pipe
215 static inline bool pipe_is_full(const struct pipe_inode_info *pipe)  in pipe_is_full()  argument
217 	return pipe_full(pipe->head, pipe->tail, pipe->max_usage);  in pipe_is_full()
221  * pipe_is_empty - Return true if the pipe is empty
222  * @pipe: the pipe
224 static inline bool pipe_is_empty(const struct pipe_inode_info *pipe)  in pipe_is_empty()  argument
226 	return pipe_empty(pipe->head, pipe->tail);  in pipe_is_empty()
230  * pipe_buf_usage - Return how many pipe buffers are in use
231  * @pipe: the pipe
233 static inline unsigned int pipe_buf_usage(const struct pipe_inode_info *pipe)  in pipe_buf_usage()  argument
235 	return pipe_occupancy(pipe->head, pipe->tail);  in pipe_buf_usage()
239  * pipe_buf - Return the pipe buffer for the specified slot in the pipe ring
240  * @pipe: The pipe to access
243 static inline struct pipe_buffer *pipe_buf(const struct pipe_inode_info *pipe,  in pipe_buf()  argument
246 	return &pipe->bufs[slot & (pipe->ring_size - 1)];  in pipe_buf()
250  * pipe_head_buf - Return the pipe buffer at the head of the pipe ring
251  * @pipe: The pipe to access
253 static inline struct pipe_buffer *pipe_head_buf(const struct pipe_inode_info *pipe)  in pipe_head_buf()  argument
255 	return pipe_buf(pipe, pipe->head);  in pipe_head_buf()
260  * @pipe:	the pipe that the buffer belongs to
265 static inline __must_check bool pipe_buf_get(struct pipe_inode_info *pipe,  in pipe_buf_get()  argument
268 	return buf->ops->get(pipe, buf);  in pipe_buf_get()
273  * @pipe:	the pipe that the buffer belongs to
276 static inline void pipe_buf_release(struct pipe_inode_info *pipe,  in pipe_buf_release()  argument
282 	ops->release(pipe, buf);  in pipe_buf_release()
286  * pipe_buf_confirm - verify contents of the pipe buffer
287  * @pipe:	the pipe that the buffer belongs to
290 static inline int pipe_buf_confirm(struct pipe_inode_info *pipe,  in pipe_buf_confirm()  argument
295 	return buf->ops->confirm(pipe, buf);  in pipe_buf_confirm()
300  * @pipe:	the pipe that the buffer belongs to
303 static inline bool pipe_buf_try_steal(struct pipe_inode_info *pipe,  in pipe_buf_try_steal()  argument
308 	return buf->ops->try_steal(pipe, buf);  in pipe_buf_try_steal()
315 /* Pipe lock and unlock operations */
320 /* Wait for a pipe to be readable/writable while dropping the pipe lock */
327 /* Generic pipe buffer ops functions */
341 int pipe_resize_ring(struct pipe_inode_info *pipe, unsigned int nr_slots);