Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751471AbdG0A0g (ORCPT ); Wed, 26 Jul 2017 20:26:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:45856 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751078AbdG0A0f (ORCPT ); Wed, 26 Jul 2017 20:26:35 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1A40322CAA 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: Wed, 26 Jul 2017 17:26:34 -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 v2 02/13] xen/pvcalls: connect to the backend In-Reply-To: <59789AA1.2050505@oracle.com> Message-ID: References: <1501017730-12797-1-git-send-email-sstabellini@kernel.org> <1501017730-12797-2-git-send-email-sstabellini@kernel.org> <59789AA1.2050505@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: 7083 Lines: 242 On Wed, 26 Jul 2017, Boris Ostrovsky wrote: > 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 OK > > +#define RING_ORDER XENBUS_MAX_RING_GRANT_ORDER > > PVCALLS_RING_ORDER? Sure > > +#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 good point, I'll fix > > + > > +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? No, I'll remove it > > + 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'll move the patch > I also think you are leaking bedata on error paths. bedata is freed by pvcalls_front_remove (kfree(bedata)), why do you say so? > > + 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 = {