On Mon, Feb 27, 2023 at 02:23:32PM +0000, David Howells wrote: > > Don't let parts of multipage folios be gifted by (vm)splice into a pipe as > the other end may only be expecting single-page gifts (fuse and virtio > console for example). > > replace_page_cache_folio(), for example, will do the wrong thing if it > tries to replace a single paged folio with a multipage folio. > > Try to avoid this by making add_to_pipe() remove the gift flag on multipage > folios. > > Signed-off-by: David Howells <[email protected]>
What should the Fixes: here be? This was already possible with THPs (both anon and tmpfs backed) long before I introduced folios. > cc: Matthew Wilcox <[email protected]> > cc: Miklos Szeredi <[email protected]> > cc: Amit Shah <[email protected]> > cc: [email protected] > cc: [email protected] > cc: [email protected] > --- > fs/splice.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/fs/splice.c b/fs/splice.c > index 2e76dbb81a8f..33caa28a86e4 100644 > --- a/fs/splice.c > +++ b/fs/splice.c > @@ -240,6 +240,8 @@ ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct > pipe_buffer *buf) > } else if (pipe_full(head, tail, pipe->max_usage)) { > ret = -EAGAIN; > } else { > + if (folio_nr_pages(page_folio(buf->page)) > 1) > + buf->flags &= ~PIPE_BUF_FLAG_GIFT; if (PageCompound(buf->page)) buf->flags &= ~PIPE_BUF_FLAG_GIFT; would be simpler and more backportable. _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
