On Fri, Jun 15, 2007 at 10:43:18AM +0200, Jens Axboe ([EMAIL PROTECTED]) wrote:
> > So, things turned down to be not in the __splice_from_pipe(), but
> > splice_to_pipe(). Attached patch fixes a leak for me.
> > It was tested with different data files and all were received correctly.
> >
> > Signed-off-by: Evgeniy Polyakov <[EMAIL PROTECTED]>
> >
> > diff --git a/fs/splice.c b/fs/splice.c
> > index bc481f1..365bfd9 100644
> > --- a/fs/splice.c
> > +++ b/fs/splice.c
> > @@ -211,8 +211,6 @@ ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
> > break;
> > if (pipe->nrbufs < PIPE_BUFFERS)
> > continue;
> > -
> > - break;
> > }
> >
> > if (spd->flags & SPLICE_F_NONBLOCK) {
> >
>
> Hmm, curious. If we hit that location, then two conditions are true:
>
> - Pipe is full
> - We transferred some data
Yep.
> if you remove the break, then you'll end up blocking in pipe_wait()
> (unless you have SPLICE_F_NONBLOCK also set). And we don't want to block
> waiting for more room, if we already transferred some data. In that case
> we just want to return a short splice. Looking at pipe_write(), it'll
> block as well though. Just doesn't seem optimal to me, but...
>
> So the question is why would doing the break there cause a leak? I just
> don't yet see how it can happen, I'd love to fix that condition instead.
> For the case you describe, we should have page_nr == 1 and spd->nr_pages
> == 2. Is the:
>
> while (page_nr < spd->nr_pages)
> spd->spd_release(spd, page_nr++);
>
> not dropping the right reference?
Both spd->nr_pages and page_nr are equal to 1. When spd->nr_pages
was 2 there was only 1 free slot in pipe_buffer.
spd_fill_page: allocated: 89, freed: 73, data: ffff81003d606d28
spd_fill_page: allocated: 90, freed: 73, data: ffff81003d606d28
splice_to_pipe: priv: ffff81003d606d28, spd_nrpages: 1, pipe_nrbufs: 16,
page_nr: 1.
spd_fill_page: allocated: 91, freed: 73, data: fff81003d6549c8 // next data
...
__splice_from_pipe: process: sd_len: 0, buf_len: 0, buf_priv: ffff81003d606d28.
__splice_from_pipe: release ffff81003d606d28.
sock_pipe_buf_release: allocated: 91, freed: 89, ptr: ffff81003d606d28
splice_to_pipe: priv: ffff81003d6549c8, spd_nrpages: 0, pipe_nrbufs: 1,
page_nr: 1. // next data
> --
> Jens Axboe
--
Evgeniy Polyakov
-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
