Initial import

1 files changed, 149 insertions, 0 deletions

diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
new file mode 100644
index 000000000..eb8b8ac6d
--- /dev/null
+++ b/include/linux/pipe_fs_i.h
@@ -0,0 +1,149 @@
+#ifndef _LINUX_PIPE_FS_I_H
+#define _LINUX_PIPE_FS_I_H
+
+#define PIPE_DEF_BUFFERS	16
+
+#define PIPE_BUF_FLAG_LRU	0x01	/* page is on the LRU */
+#define PIPE_BUF_FLAG_ATOMIC	0x02	/* was atomically mapped */
+#define PIPE_BUF_FLAG_GIFT	0x04	/* page is a gift */
+#define PIPE_BUF_FLAG_PACKET	0x08	/* read() as a packet */
+
+/**
+ *	struct pipe_buffer - a linux kernel pipe buffer
+ *	@page: the page containing the data for the pipe buffer
+ *	@offset: offset of data inside the @page
+ *	@len: length of data inside the @page
+ *	@ops: operations associated with this buffer. See @pipe_buf_operations.
+ *	@flags: pipe buffer flags. See above.
+ *	@private: private data owned by the ops.
+ **/
+struct pipe_buffer {
+	struct page *page;
+	unsigned int offset, len;
+	const struct pipe_buf_operations *ops;
+	unsigned int flags;
+	unsigned long private;
+};
+
+/**
+ *	struct pipe_inode_info - a linux kernel pipe
+ *	@mutex: mutex protecting the whole thing
+ *	@wait: reader/writer wait point in case of empty/full pipe
+ *	@nrbufs: the number of non-empty pipe buffers in this pipe
+ *	@buffers: total number of buffers (should be a power of 2)
+ *	@curbuf: the current pipe buffer entry
+ *	@tmp_page: cached released page
+ *	@readers: number of current readers of this pipe
+ *	@writers: number of current writers of this pipe
+ *	@files: number of struct file referring this pipe (protected by ->i_lock)
+ *	@waiting_writers: number of writers blocked waiting for room
+ *	@r_counter: reader counter
+ *	@w_counter: writer counter
+ *	@fasync_readers: reader side fasync
+ *	@fasync_writers: writer side fasync
+ *	@bufs: the circular array of pipe buffers
+ **/
+struct pipe_inode_info {
+	struct mutex mutex;
+	wait_queue_head_t wait;
+	unsigned int nrbufs, curbuf, buffers;
+	unsigned int readers;
+	unsigned int writers;
+	unsigned int files;
+	unsigned int waiting_writers;
+	unsigned int r_counter;
+	unsigned int w_counter;
+	struct page *tmp_page;
+	struct fasync_struct *fasync_readers;
+	struct fasync_struct *fasync_writers;
+	struct pipe_buffer *bufs;
+};
+
+/*
+ * Note on the nesting of these functions:
+ *
+ * ->confirm()
+ *	->steal()
+ *	...
+ *	->map()
+ *	...
+ *	->unmap()
+ *
+ * That is, ->map() must be called on a confirmed buffer,
+ * same goes for ->steal(). See below for the meaning of each
+ * operation. Also see kerneldoc in fs/pipe.c for the pipe
+ * and generic variants of these hooks.
+ */
+struct pipe_buf_operations {
+	/*
+	 * This is set to 1, if the generic pipe read/write may coalesce
+	 * data into an existing buffer. If this is set to 0, a new pipe
+	 * page segment is always used for new data.
+	 */
+	int can_merge;
+
+	/*
+	 * ->confirm() verifies that the data in the pipe buffer is there
+	 * and that the contents are good. If the pages in the pipe belong
+	 * to a file system, we may need to wait for IO completion in this
+	 * hook. Returns 0 for good, or a negative error value in case of
+	 * error.
+	 */
+	int (*confirm)(struct pipe_inode_info *, struct pipe_buffer *);
+
+	/*
+	 * When the contents of this pipe buffer has been completely
+	 * consumed by a reader, ->release() is called.
+	 */
+	void (*release)(struct pipe_inode_info *, struct pipe_buffer *);
+
+	/*
+	 * Attempt to take ownership of the pipe buffer and its contents.
+	 * ->steal() returns 0 for success, in which case the contents
+	 * of the pipe (the buf->page) is locked and now completely owned
+	 * by the caller. The page may then be transferred to a different
+	 * mapping, the most often used case is insertion into different
+	 * file address space cache.
+	 */
+	int (*steal)(struct pipe_inode_info *, struct pipe_buffer *);
+
+	/*
+	 * Get a reference to the pipe buffer.
+	 */
+	void (*get)(struct pipe_inode_info *, struct pipe_buffer *);
+};
+
+/* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual
+   memory allocation, whereas PIPE_BUF makes atomicity guarantees.  */
+#define PIPE_SIZE		PAGE_SIZE
+
+/* Pipe lock and unlock operations */
+void pipe_lock(struct pipe_inode_info *);
+void pipe_unlock(struct pipe_inode_info *);
+void pipe_double_lock(struct pipe_inode_info *, struct pipe_inode_info *);
+
+extern unsigned int pipe_max_size, pipe_min_size;
+int pipe_proc_fn(struct ctl_table *, int, void __user *, size_t *, loff_t *);
+
+
+/* Drop the inode semaphore and wait for a pipe event, atomically */
+void pipe_wait(struct pipe_inode_info *pipe);
+
+struct pipe_inode_info *alloc_pipe_info(void);
+void free_pipe_info(struct pipe_inode_info *);
+
+/* Generic pipe buffer ops functions */
+void generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *);
+int generic_pipe_buf_confirm(struct pipe_inode_info *, struct pipe_buffer *);
+int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *);
+void generic_pipe_buf_release(struct pipe_inode_info *, struct pipe_buffer *);
+
+extern const struct pipe_buf_operations nosteal_pipe_buf_ops;
+
+/* for F_SETPIPE_SZ and F_GETPIPE_SZ */
+long pipe_fcntl(struct file *, unsigned int, unsigned long arg);
+struct pipe_inode_info *get_pipe_info(struct file *file);
+
+int create_pipe_files(struct file **, int);
+
+#endif