Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751788AbdGZNgC (ORCPT ); Wed, 26 Jul 2017 09:36:02 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:37132 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751748AbdGZNfp (ORCPT ); Wed, 26 Jul 2017 09:35:45 -0400 Subject: Re: [PATCH v2 02/13] xen/pvcalls: connect to the backend To: Stefano Stabellini , xen-devel@lists.xen.org References: <1501017730-12797-1-git-send-email-sstabellini@kernel.org> <1501017730-12797-2-git-send-email-sstabellini@kernel.org> Cc: linux-kernel@vger.kernel.org, jgross@suse.com, Stefano Stabellini From: Boris Ostrovsky Organization: Oracle Corporation Message-ID: <59789AA1.2050505@oracle.com> Date: Wed, 26 Jul 2017 09:35:29 -0400 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.8.0 MIME-Version: 1.0 In-Reply-To: <1501017730-12797-2-git-send-email-sstabellini@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: userv0021.oracle.com [156.151.31.71] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6455 Lines: 225 On 7/25/2017 5:21 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. > > Introduce a data structure named pvcalls_bedata. It contains pointers to > the command ring, the event channel, a list of active sockets and a list > of passive sockets. Lists accesses are protected by a spin_lock. > > Introduce a waitqueue to allow waiting for a response on commands sent > to the backend. > > Introduce an array of struct xen_pvcalls_response to store commands > responses. > > 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 | 153 ++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 153 insertions(+) > > diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c > index a8d38c2..5e0b265 100644 > --- a/drivers/xen/pvcalls-front.c > +++ b/drivers/xen/pvcalls-front.c > @@ -20,6 +20,29 @@ > #include > #include > > +#define PVCALLS_INVALID_ID (UINT_MAX) Unnecessary parentheses > +#define RING_ORDER XENBUS_MAX_RING_GRANT_ORDER PVCALLS_RING_ORDER? > +#define PVCALLS_NR_REQ_PER_RING __CONST_RING_SIZE(xen_pvcalls, XEN_PAGE_SIZE) > + > +struct pvcalls_bedata { > + struct xen_pvcalls_front_ring ring; > + grant_ref_t ref; > + int irq; > + > + struct list_head socket_mappings; > + struct list_head socketpass_mappings; > + spinlock_t pvcallss_lock; > + > + wait_queue_head_t inflight_req; > + struct xen_pvcalls_response rsp[PVCALLS_NR_REQ_PER_RING]; > +}; > +struct xenbus_device *pvcalls_front_dev; static > + > +static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id) > +{ > + return IRQ_HANDLED; > +} > + > static const struct xenbus_device_id pvcalls_front_ids[] = { > { "pvcalls" }, > { "" } > @@ -33,12 +56,142 @@ 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 = -EFAULT, evtchn, ref = -1, 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); > + ret = xenbus_scanf(XBT_NIL, dev->otherend, > + "max-page-order", "%u", &max_page_order); > + if (ret <= 0) > + return -ENODEV; > + if (max_page_order < RING_ORDER) > + return -ENODEV; > + ret = xenbus_scanf(XBT_NIL, dev->otherend, > + "function-calls", "%u", &function_calls); > + if (ret <= 0 || function_calls != 1) > + 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; > + > + 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) { > + ret = bedata->irq; > + goto error; > + } > + > + ret = gnttab_alloc_grant_references(1, &gref_head); > + if (ret < 0) > + goto error; > + bedata->ref = ref = gnttab_claim_grant_reference(&gref_head); Is ref really needed? > + if (ref < 0) > + goto error; > + gnttab_grant_foreign_access_ref(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", 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); > + dev_set_drvdata(&dev->dev, bedata); > + pvcalls_front_dev = dev; > + 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); I think patch 12 (where you implement cleanup) could be moved before this one. I also think you are leaking bedata on error paths. -boris > + 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 = {