splice: divorce the splice structure/function definitions from the pipe header

We need to move even more stuff into the header so that folks can use
the splice_to_pipe() implementation instead of open-coding a lot of
pipe knowledge (see relay implementation), so move to our own header
file finally.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 72 insertions, 0 deletions

diff --git a/include/linux/splice.h b/include/linux/splice.h
new file mode 100644
index 000000000000..f8cc97f71cd0
--- /dev/null
+++ b/include/linux/splice.h
@@ -0,0 +1,72 @@
+/*
+ * Function declerations and data structures related to the splice
+ * implementation.
+ *
+ * Copyright (C) 2007 Jens Axboe <jens.axboe@oracle.com>
+ *
+ */
+#ifndef SPLICE_H
+#define SPLICE_H
+
+#include <linux/pipe_fs_i.h>
+
+/*
+ * splice is tied to pipes as a transport (at least for now), so we'll just
+ * add the splice flags here.
+ */
+#define SPLICE_F_MOVE   (0x01)  /* move pages instead of copying */
+#define SPLICE_F_NONBLOCK (0x02) /* don't block on the pipe splicing (but */
+                                 /* we may still block on the fd we splice */
+                                 /* from/to, of course */
+#define SPLICE_F_MORE   (0x04)  /* expect more data */
+#define SPLICE_F_GIFT   (0x08)  /* pages passed in are a gift */
+
+/*
+ * Passed to the actors
+ */
+struct splice_desc {
+        unsigned int len, total_len;    /* current and remaining length */
+        unsigned int flags;             /* splice flags */
+        /*
+         * actor() private data
+         */
+        union {
+                void __user *userptr;   /* memory to write to */
+                struct file *file;      /* file to read/write */
+                void *data;             /* cookie */
+        } u;
+        loff_t pos;                     /* file position */
+};
+
+struct partial_page {
+        unsigned int offset;
+        unsigned int len;
+};
+
+/*
+ * Passed to splice_to_pipe
+ */
+struct splice_pipe_desc {
+        struct page **pages;            /* page map */
+        struct partial_page *partial;   /* pages[] may not be contig */
+        int nr_pages;                   /* number of pages in map */
+        unsigned int flags;             /* splice flags */
+        const struct pipe_buf_operations *ops;/* ops associated with output pipe */
+};
+
+typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *,
+                           struct splice_desc *);
+typedef int (splice_direct_actor)(struct pipe_inode_info *,
+                                  struct splice_desc *);
+
+extern ssize_t splice_from_pipe(struct pipe_inode_info *, struct file *,
+                                loff_t *, size_t, unsigned int,
+                                splice_actor *);
+extern ssize_t __splice_from_pipe(struct pipe_inode_info *,
+                                  struct splice_desc *, splice_actor *);
+extern ssize_t splice_to_pipe(struct pipe_inode_info *,
+                              struct splice_pipe_desc *);
+extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
+                                      splice_direct_actor *);
+
+#endif