From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752539AbdGDIDM (ORCPT ); Tue, 4 Jul 2017 04:03:12 -0400 Received: from mx2.suse.de ([195.135.220.15]:52611 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752473AbdGDIDL (ORCPT ); Tue, 4 Jul 2017 04:03:11 -0400 Subject: Re: [PATCH v6 04/18] xen/pvcalls: xenbus state handling To: Stefano Stabellini , xen-devel@lists.xen.org Cc: linux-kernel@vger.kernel.org, boris.ostrovsky@oracle.com, Stefano Stabellini References: <1499116119-15638-1-git-send-email-sstabellini@kernel.org> <1499116119-15638-4-git-send-email-sstabellini@kernel.org> From: Juergen Gross Message-ID: <2dd8d8e1-4fc4-3d9e-0b74-b1704ac5e658@suse.com> Date: Tue, 4 Jul 2017 10:03:07 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <1499116119-15638-4-git-send-email-sstabellini@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Language: de-DE Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/07/17 23:08, Stefano Stabellini wrote: > Introduce the code to handle xenbus state changes. > > Implement the probe function for the pvcalls backend. Write the > supported versions, max-page-order and function-calls nodes to xenstore, > as required by the protocol. > > Introduce stub functions for disconnecting/connecting to a frontend. > > Signed-off-by: Stefano Stabellini > Reviewed-by: Boris Ostrovsky > CC: boris.ostrovsky@oracle.com > CC: jgross@suse.com > --- > drivers/xen/pvcalls-back.c | 152 +++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 152 insertions(+) > > diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c > index 9044cf2..7bce750 100644 > --- a/drivers/xen/pvcalls-back.c > +++ b/drivers/xen/pvcalls-back.c > @@ -25,20 +25,172 @@ > #include > #include > > +#define PVCALLS_VERSIONS "1" > +#define MAX_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER > + > struct pvcalls_back_global { > struct list_head frontends; > struct semaphore frontends_lock; > } pvcalls_back_global; > > +static int backend_connect(struct xenbus_device *dev) > +{ > + return 0; > +} > + > +static int backend_disconnect(struct xenbus_device *dev) > +{ > + return 0; > +} > + > static int pvcalls_back_probe(struct xenbus_device *dev, > const struct xenbus_device_id *id) > { > + int err, abort; > + struct xenbus_transaction xbt; > + > +again: > + abort = 1; > + > + err = xenbus_transaction_start(&xbt); > + if (err) { > + pr_warn("%s cannot create xenstore transaction\n", __func__); > + return err; > + } > + > + err = xenbus_printf(xbt, dev->nodename, "versions", "%s", > + PVCALLS_VERSIONS); > + if (err) { > + pr_warn("%s write out 'version' failed\n", __func__); s/version/versions/ ? > + goto abort; > + } > + > + err = xenbus_printf(xbt, dev->nodename, "max-page-order", "%u", > + MAX_RING_ORDER); > + if (err) { > + pr_warn("%s write out 'max-page-order' failed\n", __func__); > + goto abort; > + } > + > + err = xenbus_printf(xbt, dev->nodename, "function-calls", > + XENBUS_FUNCTIONS_CALLS); > + if (err) { > + pr_warn("%s write out 'function-calls' failed\n", __func__); > + goto abort; > + } > + > + abort = 0; > +abort: > + err = xenbus_transaction_end(xbt, abort); > + if (err) { > + if (err == -EAGAIN && !abort) Hmm, while I don't think xenbus_transaction_end() will ever return -EAGAIN in the abort case I'm not sure you should limit the retry loop to the non-abort case. > + goto again; > + pr_warn("%s cannot complete xenstore transaction\n", __func__); > + return err; > + } > + > + xenbus_switch_state(dev, XenbusStateInitWait); I don't think you should switch state in case of abort set, no? Juergen