Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755422AbdCGPEL (ORCPT ); Tue, 7 Mar 2017 10:04:11 -0500 Received: from aserp1050.oracle.com ([141.146.126.70]:19863 "EHLO aserp1050.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754319AbdCGPEB (ORCPT ); Tue, 7 Mar 2017 10:04:01 -0500 From: Boris Ostrovsky Subject: Re: [PATCH 4/7] xen/9pfs: connect to the backend To: Stefano Stabellini , xen-devel@lists.xenproject.org References: <1488830488-18506-1-git-send-email-sstabellini@kernel.org> <1488830488-18506-4-git-send-email-sstabellini@kernel.org> Cc: linux-kernel@vger.kernel.org, Stefano Stabellini , jgross@suse.com, Eric Van Hensbergen , Ron Minnich , Latchesar Ionkov , v9fs-developer@lists.sourceforge.net Message-ID: Date: Tue, 7 Mar 2017 10:03:03 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.6.0 MIME-Version: 1.0 In-Reply-To: <1488830488-18506-4-git-send-email-sstabellini@kernel.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Source-IP: aserp1040.oracle.com [141.146.126.69] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5426 Lines: 192 > > +static int xen_9pfs_front_free(struct xen_9pfs_front_priv *priv) > +{ > + int i, j; > + > + list_del(&priv->list); > + > + for (i = 0; i < priv->num_rings; i++) { > + if (priv->rings[i].intf == NULL) > + break; Are we guaranteed that all subsequent entries are not allocated (i.e. this shouldn't be 'continue')? > + if (priv->rings[i].irq > 0) > + unbind_from_irqhandler(priv->rings[i].irq, priv->dev); > + if (priv->rings[i].bytes != NULL) { > + for (j = 0; j < (1 << XEN_9PFS_RING_ORDER); j++) > + gnttab_end_foreign_access(priv->rings[i].intf->ref[j], 0, 0); > + free_pages((unsigned long)priv->rings[i].bytes, XEN_9PFS_RING_ORDER); > + } > + gnttab_end_foreign_access(priv->rings[i].ref, 0, 0); > + free_page((unsigned long)priv->rings[i].intf); > + } > + kfree(priv->rings); > + kfree(priv); > + > + return 0; > +} > + > static int xen_9pfs_front_remove(struct xenbus_device *dev) > { > + int ret; > + struct xen_9pfs_front_priv *priv = dev_get_drvdata(&dev->dev); > + > + dev_set_drvdata(&dev->dev, NULL); > + ret = xen_9pfs_front_free(priv); > + return ret; > +} > + > +static int xen_9pfs_front_alloc_dataring(struct xenbus_device *dev, > + struct xen_9pfs_dataring *ring) > +{ > + int i; > + int ret = -ENOMEM; > + > + init_waitqueue_head(&ring->wq); > + spin_lock_init(&ring->lock); > + INIT_WORK(&ring->work, p9_xen_response); > + > + ring->intf = (struct xen_9pfs_data_intf *) __get_free_page(GFP_KERNEL | __GFP_ZERO); > + if (!ring->intf) > + goto error; > + memset(ring->intf, 0, XEN_PAGE_SIZE); get_zeroed_page()? (especially given that __get_free_page() returns PAGE_SIZE, not XEN_PAGE_SIZE) > + ring->bytes = (void*)__get_free_pages(GFP_KERNEL | __GFP_ZERO, XEN_9PFS_RING_ORDER); > + if (ring->bytes == NULL) > + goto error; > + for (i = 0; i < (1 << XEN_9PFS_RING_ORDER); i++) > + ring->intf->ref[i] = gnttab_grant_foreign_access(dev->otherend_id, pfn_to_gfn(virt_to_pfn((void*)ring->bytes) + i), 0); > + ring->ref = gnttab_grant_foreign_access(dev->otherend_id, pfn_to_gfn(virt_to_pfn((void*)ring->intf)), 0); > + ring->ring.in = ring->bytes; > + ring->ring.out = ring->bytes + XEN_9PFS_RING_SIZE; > + > + ret = xenbus_alloc_evtchn(dev, &ring->evtchn); > + if (ret) > + goto error; > + ring->irq = bind_evtchn_to_irqhandler(ring->evtchn, xen_9pfs_front_event_handler, > + 0, "xen_9pfs-frontend", ring); > + if (ring->irq < 0) { > + xenbus_free_evtchn(dev, ring->evtchn); > + ret = ring->irq; > + goto error; > + } > return 0; > + > +error: You may need to gnttab_end_foreign_access(). > + if (ring->intf != NULL) > + kfree(ring->intf); > + if (ring->bytes != NULL) > + kfree(ring->bytes); > + return ret; > } > > static int xen_9pfs_front_probe(struct xenbus_device *dev, > const struct xenbus_device_id *id) > { > + int ret = -EFAULT, i; Unnecessary initialization. > + struct xenbus_transaction xbt; > + struct xen_9pfs_front_priv *priv = NULL; > + char *versions; > + unsigned int max_rings, max_ring_order, len; > + > + versions = xenbus_read(XBT_NIL, dev->otherend, "versions", &len); > + if (!len || strcmp(versions, "1")) > + return -EINVAL; > + kfree(versions); > + ret = xenbus_scanf(XBT_NIL, dev->otherend, "max-rings", "%u", &max_rings); > + if (ret < 0 || max_rings < XEN_9PFS_NUM_RINGS) > + return -EINVAL; > + ret = xenbus_scanf(XBT_NIL, dev->otherend, "max-ring-page-order", "%u", &max_ring_order); > + if (ret < 0|| max_ring_order < XEN_9PFS_RING_ORDER) > + return -EINVAL; > + > + > + priv = kzalloc(sizeof(struct xen_9pfs_front_priv), GFP_KERNEL); > + if (!priv) > + return -ENOMEM; > + > + priv->dev = dev; > + priv->num_rings = XEN_9PFS_NUM_RINGS; > + priv->rings = kzalloc(sizeof(struct xen_9pfs_dataring) * priv->num_rings, > + GFP_KERNEL); > + if (!priv->rings) { > + kfree(priv); > + return -ENOMEM; > + } > + > + 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, "num-rings", "%u", priv->num_rings); > + if (ret) > + goto error_xenbus; > + for (i = 0; i < priv->num_rings; i++) { > + char str[16]; > + > + priv->rings[i].priv = priv; > + ret = xen_9pfs_front_alloc_dataring(dev, &priv->rings[i]); Not for -EAGAIN, I think. -boris > + if (ret < 0) > + goto error_xenbus; > + > + sprintf(str, "ring-ref%u", i); > + ret = xenbus_printf(xbt, dev->nodename, str, "%d", priv->rings[i].ref); > + if (ret) > + goto error_xenbus; > + > + sprintf(str, "event-channel-%u", i); > + ret = xenbus_printf(xbt, dev->nodename, str, "%u", priv->rings[i].evtchn); > + if (ret) > + goto error_xenbus; > + } > + priv->tag = xenbus_read(xbt, dev->nodename, "tag", NULL); > + 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; > + } > + > + > + list_add_tail(&priv->list, &xen_9pfs_devs); > + dev_set_drvdata(&dev->dev, priv); > + xenbus_switch_state(dev, XenbusStateInitialised); > + > return 0; > + > + error_xenbus: > + xenbus_transaction_end(xbt, 1); > + xenbus_dev_fatal(dev, ret, "writing xenstore"); > + error: > + dev_set_drvdata(&dev->dev, NULL); > + xen_9pfs_front_free(priv); > + return ret; > } >