[PATCH] splice: add support for SPLICE_F_MOVE flag

This enables the caller to migrate pages from one address space page
cache to another.  In buzz word marketing, you can do zero-copy file
copies!

Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index b12e59c75752..75c7f55023ab 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -9,6 +9,7 @@ struct pipe_buffer {
         struct page *page;
         unsigned int offset, len;
         struct pipe_buf_operations *ops;
+        unsigned int stolen;
 };
 
 struct pipe_buf_operations {
@@ -16,6 +17,7 @@ struct pipe_buf_operations {
         void * (*map)(struct file *, struct pipe_inode_info *, struct pipe_buffer *);
         void (*unmap)(struct pipe_inode_info *, struct pipe_buffer *);
         void (*release)(struct pipe_inode_info *, struct pipe_buffer *);
+        int (*steal)(struct pipe_inode_info *, struct pipe_buffer *);
 };
 
 struct pipe_inode_info {
@@ -53,4 +55,10 @@ void pipe_wait(struct inode * inode);
 struct inode* pipe_new(struct inode* inode);
 void free_pipe_info(struct inode* inode);
 
+/*
+ * 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 */
+
 #endif