vmsplice: add vmsplice-to-user support

A bit of a cheat, it actually just copies the data to userspace. But
this makes the interface nice and symmetric and enables people to build
on splice, with room for future improvement in performance.

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

1 files changed, 7 insertions, 1 deletions

diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 883ba9b78d3f..6e7bfc125425 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -88,7 +88,13 @@ int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *);
 struct splice_desc {
         unsigned int len, total_len;    /* current and remaining length */
         unsigned int flags;             /* splice flags */
-        struct file *file;              /* file to read/write */
+        /*
+         * actor() private data
+         */
+        union {
+                void __user *userptr;   /* memory to write to */
+                struct file *file;      /* file to read/write */
+        } u;
         loff_t pos;                     /* file position */
 };