Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757297AbdIIAOD (ORCPT ); Fri, 8 Sep 2017 20:14:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:44222 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757247AbdIIAOB (ORCPT ); Fri, 8 Sep 2017 20:14:01 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B1E4E21B81 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=sstabellini@kernel.org Date: Fri, 8 Sep 2017 17:14:00 -0700 (PDT) From: Stefano Stabellini X-X-Sender: sstabellini@sstabellini-ThinkPad-X260 To: Boris Ostrovsky cc: Stefano Stabellini , xen-devel@lists.xen.org, linux-kernel@vger.kernel.org, jgross@suse.com, Stefano Stabellini Subject: Re: [PATCH v3 03/13] xen/pvcalls: connect to the backend In-Reply-To: <4fbe7300-8934-ed6b-3868-443ae96c2ecb@oracle.com> Message-ID: References: <1501541855-7354-1-git-send-email-sstabellini@kernel.org> <1501541855-7354-3-git-send-email-sstabellini@kernel.org> <4fbe7300-8934-ed6b-3868-443ae96c2ecb@oracle.com> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5787 Lines: 188 On Fri, 11 Aug 2017, Boris Ostrovsky wrote: > On 07/31/2017 06:57 PM, Stefano Stabellini wrote: > > Implement the probe function for the pvcalls frontend. Read the > > supported versions, max-page-order and function-calls nodes from > > xenstore. > > > > Only one frontend<->backend connection is supported at any given time > > for a guest. Store the active frontend device to a static pointer. > > > > Introduce a stub functions for the event handler. > > > > Signed-off-by: Stefano Stabellini > > CC: boris.ostrovsky@oracle.com > > CC: jgross@suse.com > > --- > > drivers/xen/pvcalls-front.c | 130 ++++++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 130 insertions(+) > > > > diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c > > index a126195..2afe36d 100644 > > --- a/drivers/xen/pvcalls-front.c > > +++ b/drivers/xen/pvcalls-front.c > > @@ -84,12 +84,142 @@ static int pvcalls_front_remove(struct xenbus_device *dev) > > static int pvcalls_front_probe(struct xenbus_device *dev, > > const struct xenbus_device_id *id) > > { > > + int ret = -ENOMEM, evtchn, i; > > + unsigned int max_page_order, function_calls, len; > > + char *versions; > > + grant_ref_t gref_head = 0; > > + struct xenbus_transaction xbt; > > + struct pvcalls_bedata *bedata = NULL; > > + struct xen_pvcalls_sring *sring; > > + > > + if (pvcalls_front_dev != NULL) { > > + dev_err(&dev->dev, "only one PV Calls connection supported\n"); > > + return -EINVAL; > > + } > > + > > + versions = xenbus_read(XBT_NIL, dev->otherend, "versions", &len); > > + if (!len) > > + return -EINVAL; > > + if (strcmp(versions, "1")) { > > + kfree(versions); > > + return -EINVAL; > > + } > > + kfree(versions); > > + max_page_order = xenbus_read_unsigned(dev->otherend, > > + "max-page-order", 0); > > + if (max_page_order < PVCALLS_RING_ORDER) > > + return -ENODEV; > > + function_calls = xenbus_read_unsigned(dev->otherend, > > + "function-calls", 0); > > + if (function_calls != 1) > > XENBUS_FUNCTIONS_CALLS XENBUS_FUNCTIONS_CALLS is actually defined as "1". I'll add a comment instead. > > + return -ENODEV; > > + pr_info("%s max-page-order is %u\n", __func__, max_page_order); > > + > > + bedata = kzalloc(sizeof(struct pvcalls_bedata), GFP_KERNEL); > > + if (!bedata) > > + return -ENOMEM; > > + > > + dev_set_drvdata(&dev->dev, bedata); > > + pvcalls_front_dev = dev; > > + init_waitqueue_head(&bedata->inflight_req); > > + for (i = 0; i < PVCALLS_NR_REQ_PER_RING; i++) > > + bedata->rsp[i].req_id = PVCALLS_INVALID_ID; > > + > > + sring = (struct xen_pvcalls_sring *) __get_free_page(GFP_KERNEL | > > + __GFP_ZERO); > > + if (!sring) > > + goto error; > > + SHARED_RING_INIT(sring); > > + FRONT_RING_INIT(&bedata->ring, sring, XEN_PAGE_SIZE); > > + > > + ret = xenbus_alloc_evtchn(dev, &evtchn); > > + if (ret) > > + goto error; > > + > > + bedata->irq = bind_evtchn_to_irqhandler(evtchn, > > + pvcalls_front_event_handler, > > + 0, "pvcalls-frontend", dev); > > + if (bedata->irq < 0) { > > In the previous patch you free up irq if it is strictly >0. Should have > been >=0. OK > > + ret = bedata->irq; > > + goto error; > > + } > > + > > + ret = gnttab_alloc_grant_references(1, &gref_head); > > + if (ret < 0) > > + goto error; > > + bedata->ref = gnttab_claim_grant_reference(&gref_head); > > + if (bedata->ref < 0) { > > + ret = bedata->ref; > > + goto error; > > + } > > + gnttab_grant_foreign_access_ref(bedata->ref, dev->otherend_id, > > + virt_to_gfn((void *)sring), 0); > > + > > + again: > > + ret = xenbus_transaction_start(&xbt); > > + if (ret) { > > + xenbus_dev_fatal(dev, ret, "starting transaction"); > > + goto error; > > + } > > + ret = xenbus_printf(xbt, dev->nodename, "version", "%u", 1); > > + if (ret) > > + goto error_xenbus; > > + ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", bedata->ref); > > + if (ret) > > + goto error_xenbus; > > + ret = xenbus_printf(xbt, dev->nodename, "port", "%u", > > + evtchn); > > + if (ret) > > + goto error_xenbus; > > + ret = xenbus_transaction_end(xbt, 0); > > + if (ret) { > > + if (ret == -EAGAIN) > > + goto again; > > + xenbus_dev_fatal(dev, ret, "completing transaction"); > > + goto error; > > + } > > + > > + INIT_LIST_HEAD(&bedata->socket_mappings); > > + INIT_LIST_HEAD(&bedata->socketpass_mappings); > > + spin_lock_init(&bedata->pvcallss_lock); > > + xenbus_switch_state(dev, XenbusStateInitialised); > > + > > return 0; > > + > > + error_xenbus: > > + xenbus_transaction_end(xbt, 1); > > + xenbus_dev_fatal(dev, ret, "writing xenstore"); > > + error: > > + pvcalls_front_remove(dev); > > Going back to the previous patch --- it seems to me that on some error > paths certain structures may not be usable in pvcalls_front_remove(). > For example, socket_mappings list is definitely not initialized. You are right, I'll fix that. > > + return ret; > > } > > > > static void pvcalls_front_changed(struct xenbus_device *dev, > > enum xenbus_state backend_state) > > { > > + switch (backend_state) { > > + case XenbusStateReconfiguring: > > + case XenbusStateReconfigured: > > + case XenbusStateInitialising: > > + case XenbusStateInitialised: > > + case XenbusStateUnknown: > > + break; > > + > > + case XenbusStateInitWait: > > + break; > > + > > + case XenbusStateConnected: > > + xenbus_switch_state(dev, XenbusStateConnected); > > + break; > > + > > + case XenbusStateClosed: > > + if (dev->state == XenbusStateClosed) > > + break; > > + /* Missed the backend's CLOSING state -- fallthrough */ > > + case XenbusStateClosing: > > + xenbus_frontend_closed(dev); > > + break; > > + } > > } > > > > static struct xenbus_driver pvcalls_front_driver = { >