On Wed, Jan 07, 2009 at 05:00:28PM -0500, bfields wrote:
> On Mon, Jan 05, 2009 at 03:21:19PM -0600, Tom Tucker wrote:
> > Bruce,
> >
> > This patch replaces 2/3 of Trond's deferral cleanup patch. This shouldn't
>
> By that you mean patches 2 and 3, right?
Must be. Anyway, applied.
> > come across with the white-spaced munged. Please let me know if it does.
It seems to have arrived with an extra space at the beginning of each
context line (each line not beginning with a +/-). With that fixed, it
applies cleanly.
--b.
> >
> > Thanks,
> > Tom
> >
> > A race between svc_revisit and svc_delete_xprt can result in
> > deferred requests holding references on a transport that can never be
> > recovered because dead transports are not enqueued for subsequent
> > processing.
> >
> > Check for XPT_DEAD in revisit to clean up completing deferrals on a dead
> > transport and sweep a transport's deferred queue to do the same for queued
> > but unprocessed deferrals.
> >
> > Signed-off-by: Tom Tucker <tom@xxxxxxxxxxxxxxxxxxxxx>
> >
> > ---
> > net/sunrpc/svc_xprt.c | 25 ++++++++++++++++++-------
> > 1 files changed, 18 insertions(+), 7 deletions(-)
> >
> > diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
> > index bf5b5cd..e6e7e25 100644
> > --- a/net/sunrpc/svc_xprt.c
> > +++ b/net/sunrpc/svc_xprt.c
> > @@ -837,6 +837,11 @@ static void svc_age_temp_xprts(unsigned long closure)
> > void svc_delete_xprt(struct svc_xprt *xprt)
> > {
> > struct svc_serv *serv = xprt->xpt_server;
> > + struct svc_deferred_req *dr;
> > +
> > + /* Only do this once */
> > + if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags))
> > + return;
> >
> > dprintk("svc: svc_delete_xprt(%p)\n", xprt);
> > xprt->xpt_ops->xpo_detach(xprt);
> > @@ -851,12 +856,16 @@ void svc_delete_xprt(struct svc_xprt *xprt)
> > * while still attached to a queue, the queue itself
> > * is about to be destroyed (in svc_destroy).
> > */
> > - if (!test_and_set_bit(XPT_DEAD, &xprt->xpt_flags)) {
> > - BUG_ON(atomic_read(&xprt->xpt_ref.refcount) < 2);
> > - if (test_bit(XPT_TEMP, &xprt->xpt_flags))
> > - serv->sv_tmpcnt--;
> > + if (test_bit(XPT_TEMP, &xprt->xpt_flags))
> > + serv->sv_tmpcnt--;
> > +
> > + for (dr = svc_deferred_dequeue(xprt); dr;
> > + dr = svc_deferred_dequeue(xprt)) {
> > svc_xprt_put(xprt);
> > + kfree(dr);
> > }
> > +
> > + svc_xprt_put(xprt);
> > spin_unlock_bh(&serv->sv_lock);
> > }
> >
> > @@ -902,17 +911,19 @@ static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
> > container_of(dreq, struct svc_deferred_req, handle);
> > struct svc_xprt *xprt = dr->xprt;
> >
> > - if (too_many) {
> > + spin_lock(&xprt->xpt_lock);
> > + set_bit(XPT_DEFERRED, &xprt->xpt_flags);
> > + if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
> > + spin_unlock(&xprt->xpt_lock);
> > + dprintk("revisit canceled\n");
> > svc_xprt_put(xprt);
> > kfree(dr);
> > return;
> > }
> > dprintk("revisit queued\n");
> > dr->xprt = NULL;
> > - spin_lock(&xprt->xpt_lock);
> > list_add(&dr->handle.recent, &xprt->xpt_deferred);
> > spin_unlock(&xprt->xpt_lock);
> > - set_bit(XPT_DEFERRED, &xprt->xpt_flags);
> > svc_xprt_enqueue(xprt);
> > svc_xprt_put(xprt);
> > }
--
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