[PATCH] vmsplice: restrict stealing a little more

Apply the same rules as the anon pipe pages, only allow stealing
if no one else is using the page.

Signed-off-by: Jens Axboe <axboe@suse.de>

3 files changed, 5 insertions, 4 deletions

diff --git a/fs/pipe.c b/fs/pipe.c
index 3941a7f78b5d..5acd8954aaa0 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -184,8 +184,8 @@ void generic_pipe_buf_unmap(struct pipe_inode_info *pipe,
                 kunmap(buf->page);
 }
 
-static int anon_pipe_buf_steal(struct pipe_inode_info *pipe,
-                               struct pipe_buffer *buf)
+int generic_pipe_buf_steal(struct pipe_inode_info *pipe,
+                           struct pipe_buffer *buf)
 {
         struct page *page = buf->page;
 
@@ -213,7 +213,7 @@ static struct pipe_buf_operations anon_pipe_buf_ops = {
         .unmap = generic_pipe_buf_unmap,
         .pin = generic_pipe_buf_pin,
         .release = anon_pipe_buf_release,
-        .steal = anon_pipe_buf_steal,
+        .steal = generic_pipe_buf_steal,
         .get = generic_pipe_buf_get,
 };
 
diff --git a/fs/splice.c b/fs/splice.c
index 3318b965c10b..7fb04970c72d 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -141,7 +141,7 @@ static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe,
         if (!(buf->flags & PIPE_BUF_FLAG_GIFT))
                 return 1;
 
-        return 0;
+        return generic_pipe_buf_steal(pipe, buf);
 }
 
 static struct pipe_buf_operations user_page_pipe_buf_ops = {
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 070954f05947..ba73108cbf8b 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -69,6 +69,7 @@ void *generic_pipe_buf_map(struct pipe_inode_info *, struct pipe_buffer *, int);
 void generic_pipe_buf_unmap(struct pipe_inode_info *, struct pipe_buffer *, void *);
 void generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *);
 int generic_pipe_buf_pin(struct pipe_inode_info *, struct pipe_buffer *);
+int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *);
 
 /*
  * splice is tied to pipes as a transport (at least for now), so we'll just