pipe: add pipe_buf_steal() helper

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 5da47e2..8114744 100644 (file)
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -889,7 +889,7 @@ static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
                return 0;
 
        /* Try lock this page */
-       if (buf->ops->steal(pipe, buf) == 0) {
+       if (pipe_buf_steal(pipe, buf) == 0) {
                /* Get reference and unlock page for moving */
                get_page(buf->page);
                unlock_page(buf->page);

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index e5d5cc9..17a706d 100644 (file)
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -841,7 +841,7 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
        if (cs->len != PAGE_SIZE)
                goto out_fallback;
 
-       if (buf->ops->steal(cs->pipe, buf) != 0)
+       if (pipe_buf_steal(cs->pipe, buf) != 0)
                goto out_fallback;
 
        newpage = buf->page;

diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 6544133..bddccf0 100644 (file)
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -151,6 +151,17 @@ static inline int pipe_buf_confirm(struct pipe_inode_info *pipe,
        return buf->ops->confirm(pipe, buf);
 }
 
+/**
+ * pipe_buf_steal - attempt to take ownership of a pipe_buffer
+ * @pipe:      the pipe that the buffer belongs to
+ * @buf:       the buffer to attempt to steal
+ */
+static inline int pipe_buf_steal(struct pipe_inode_info *pipe,
+                                struct pipe_buffer *buf)
+{
+       return buf->ops->steal(pipe, buf);
+}
+
 /* 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