Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1666229
| From | Stefano Stabellini <sstabellini@kernel.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v3 06/18] xen/pvcalls: handle commands from the frontend |
| Date | 2017-06-14 23:10 +0200 |
| Message-ID | <tSnI5-1Q7-3@gated-at.bofh.it> (permalink) |
| References | <tO0Ap-5nM-7@gated-at.bofh.it> <tO0Ap-5nM-9@gated-at.bofh.it> <tO0Aq-5nM-35@gated-at.bofh.it> <tRFH3-800-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Mon, 12 Jun 2017, Boris Ostrovsky wrote:
> > +
> > static void pvcalls_back_work(struct work_struct *work)
> > {
> > + struct pvcalls_fedata *priv = container_of(work,
> > + struct pvcalls_fedata, register_work);
> > + int notify, notify_all = 0, more = 1;
> > + struct xen_pvcalls_request req;
> > + struct xenbus_device *dev = priv->dev;
> > +
> > + while (more) {
> > + while (RING_HAS_UNCONSUMED_REQUESTS(&priv->ring)) {
> > + RING_COPY_REQUEST(&priv->ring,
> > + priv->ring.req_cons++,
> > + &req);
> > +
> > + if (!pvcalls_back_handle_cmd(dev, &req)) {
> > + RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(
> > + &priv->ring, notify);
> > + notify_all += notify;
> > + }
> > + }
> > +
> > + if (notify_all)
> > + notify_remote_via_irq(priv->irq);
> > +
> > + RING_FINAL_CHECK_FOR_REQUESTS(&priv->ring, more);
> > + }
> > }
> >
> > static irqreturn_t pvcalls_back_event(int irq, void *dev_id)
> > {
> > + struct xenbus_device *dev = dev_id;
> > + struct pvcalls_fedata *priv = NULL;
> > +
> > + if (dev == NULL)
> > + return IRQ_HANDLED;
> > +
> > + priv = dev_get_drvdata(&dev->dev);
> > + if (priv == NULL)
> > + return IRQ_HANDLED;
> > +
> > + /*
> > + * TODO: a small theoretical race exists if we try to queue work
> > + * after pvcalls_back_work checked for final requests and before
> > + * it returns. The queuing will fail, and pvcalls_back_work
> > + * won't do the work because it is about to return. In that
> > + * case, we lose the notification.
> > + */
> > + queue_work(priv->wq, &priv->register_work);
>
> Would queuing delayed work (if queue_work() failed) help? And canceling
> it on next invocation of pvcalls_back_event()?
Looking at the implementation of queue_delayed_work_on and
queue_work_on, it looks like that if queue_work fails then also
queue_delayed_work would fail: they both test on
WORK_STRUCT_PENDING_BIT.
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
Re: [PATCH v3 06/18] xen/pvcalls: handle commands from the frontend Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-06-13 00:10 +0200
Re: [PATCH v3 06/18] xen/pvcalls: handle commands from the frontend Stefano Stabellini <sstabellini@kernel.org> - 2017-06-14 23:10 +0200
Re: [PATCH v3 06/18] xen/pvcalls: handle commands from the frontend Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-06-15 16:40 +0200
Re: [PATCH v3 06/18] xen/pvcalls: handle commands from the frontend Stefano Stabellini <sstabellini@kernel.org> - 2017-06-15 21:00 +0200
csiph-web