Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751872AbdGaVz0 (ORCPT ); Mon, 31 Jul 2017 17:55:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:44946 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751799AbdGaVzY (ORCPT ); Mon, 31 Jul 2017 17:55:24 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0E1EE22B5D 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: Mon, 31 Jul 2017 14:55:21 -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: <3cb294af-51cb-897a-8d20-bc3504daaa92@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> <3cb294af-51cb-897a-8d20-bc3504daaa92@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: 4416 Lines: 132 On Thu, 27 Jul 2017, Boris Ostrovsky wrote: > >>> 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? > > bedata there is read from dev_get_drvdata() and here you assign drvdata > at the very end. > > Come think of it, pvcalls_front_remove() should probably first check > whether bedata is valid. Or drvdata should be assigned right away in > this routine, before any 'got error/error_xenbus'. Yes, I'll do that