pipe: add pipe_buf_steal() helper

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Miklos Szeredi 2016-09-27 10:45:12 +02:00 committed by Al Viro
parent fba597db42
commit ca76f5b6bd
3 changed files with 13 additions and 2 deletions

View File

@ -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);

View File

@ -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;

View File

@ -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