On Thu, 28 Jun 2012 13:37:34 +0100
Mel Gorman <mgorman@xxxxxxx> wrote:
> On Thu, Jun 28, 2012 at 08:27:25AM -0400, Jeff Layton wrote:
> > > <SNIP>
> > > @@ -2108,11 +2156,15 @@ static void xs_tcp_setup_socket(struct work_struct *work)
> > > container_of(work, struct sock_xprt, connect_worker.work);
> > > struct socket *sock = transport->sock;
> > > struct rpc_xprt *xprt = &transport->xprt;
> > > + unsigned long pflags = current->flags;
> > > int status = -EIO;
> > >
> > > if (xprt->shutdown)
> > > goto out;
> > >
> > > + if (xprt->swapper)
> > > + current->flags |= PF_MEMALLOC;
> > > +
> > > if (!sock) {
> > > clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
> > > sock = xs_create_sock(xprt, transport,
> > > @@ -2174,6 +2226,7 @@ out_eagain:
> > > out:
> > > xprt_clear_connecting(xprt);
> > > xprt_wake_pending_tasks(xprt, status);
> > > + tsk_restore_flags(current, pflags, PF_MEMALLOC);
> > > }
> > >
> > > /**
> >
> > Apologies if this is fixed in another patch and I didn't see it...
> >
>
> No apologies necessary. Even if it was fixed in another patch, it would
> still be wrong for bisection reasons and for being rude to reviewers.
>
> > There's a place in the above function that returns without going
> > through "out:". I think you also want to tsk_restore_flags() in that
> > spot too.
> >
>
> You're right. The case that it would trigger would be some corner case
> but very nicely spotted.
>
> diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
> index b84df34..3d58b92 100644
> --- a/net/sunrpc/xprtsock.c
> +++ b/net/sunrpc/xprtsock.c
> @@ -2214,6 +2214,7 @@ static void xs_tcp_setup_socket(struct work_struct *work)
> case -EINPROGRESS:
> case -EALREADY:
> xprt_clear_connecting(xprt);
> + tsk_restore_flags(current, pflags, PF_MEMALLOC);
> return;
> case -EINVAL:
> /* Happens, for instance, if the user specified a link
That looks correct.
Actually it's not obvious in this function, but it turns out that this
is the common case. xs_tcp_finish_connecting calls kernel_connect with
O_NONBLOCK set, and that almost always immediately returns with
-EINPROGRESS.
Cheers,
--
Jeff Layton <jlayton@xxxxxxxxxx>
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