Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751762AbdFTQAl (ORCPT ); Tue, 20 Jun 2017 12:00:41 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:36702 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751002AbdFTQAj (ORCPT ); Tue, 20 Jun 2017 12:00:39 -0400 Subject: Re: [PATCH v4 11/18] xen/pvcalls: implement accept command To: Stefano Stabellini , xen-devel@lists.xen.org References: <1497553787-3709-1-git-send-email-sstabellini@kernel.org> <1497553787-3709-11-git-send-email-sstabellini@kernel.org> Cc: linux-kernel@vger.kernel.org, jgross@suse.com, Stefano Stabellini From: Boris Ostrovsky Message-ID: Date: Tue, 20 Jun 2017 12:02:15 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <1497553787-3709-11-git-send-email-sstabellini@kernel.org> Content-Type: text/plain; charset=windows-1252 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: 3690 Lines: 134 > static void __pvcalls_back_accept(struct work_struct *work) > { > + struct sockpass_mapping *mappass = container_of( > + work, struct sockpass_mapping, register_work); > + struct sock_mapping *map; > + struct pvcalls_ioworker *iow; > + struct pvcalls_fedata *fedata; > + struct socket *sock; > + struct xen_pvcalls_response *rsp; > + struct xen_pvcalls_request *req; > + int notify; > + int ret = -EINVAL; > + unsigned long flags; > + > + fedata = mappass->fedata; > + /* > + * __pvcalls_back_accept can race against pvcalls_back_accept. > + * We only need to check the value of "cmd" on read. It could be > + * done atomically, but to simplify the code on the write side, we > + * use a spinlock. > + */ > + spin_lock_irqsave(&mappass->copy_lock, flags); > + req = &mappass->reqcopy; > + if (req->cmd != PVCALLS_ACCEPT) { > + spin_unlock_irqrestore(&mappass->copy_lock, flags); > + return; > + } > + spin_unlock_irqrestore(&mappass->copy_lock, flags); > + > + sock = sock_alloc(); > + if (sock == NULL) > + goto out_error; > + sock->type = mappass->sock->type; > + sock->ops = mappass->sock->ops; > + > + ret = inet_accept(mappass->sock, sock, O_NONBLOCK, true); > + if (ret == -EAGAIN) { > + sock_release(sock); > + goto out_error; > + } > + > + map = pvcalls_new_active_socket(fedata, > + req->u.accept.id_new, > + req->u.accept.ref, > + req->u.accept.evtchn, > + sock); > + if (!map) { > + sock_release(sock); > + goto out_error; Again, lost ret value. > + } > + > + map->sockpass = mappass; > + iow = &map->ioworker; > + atomic_inc(&map->read); > + atomic_inc(&map->io); > + queue_work(iow->wq, &iow->register_work); > + > +out_error: > + rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); > + rsp->req_id = req->req_id; > + rsp->cmd = req->cmd; > + rsp->u.accept.id = req->u.accept.id; > + rsp->ret = ret; > + RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify); > + if (notify) > + notify_remote_via_irq(fedata->irq); > + > + mappass->reqcopy.cmd = 0; > } > > static void pvcalls_pass_sk_data_ready(struct sock *sock) > { > + struct sockpass_mapping *mappass = sock->sk_user_data; > + > + if (mappass == NULL) > + return; > + > + queue_work(mappass->wq, &mappass->register_work); > } > > static int pvcalls_back_bind(struct xenbus_device *dev, > @@ -383,6 +456,43 @@ static int pvcalls_back_listen(struct xenbus_device *dev, > static int pvcalls_back_accept(struct xenbus_device *dev, > struct xen_pvcalls_request *req) > { > + struct pvcalls_fedata *fedata; > + struct sockpass_mapping *mappass; > + int ret = -EINVAL; Unnecessary initialization. -boris > + struct xen_pvcalls_response *rsp; > + unsigned long flags; > + > + fedata = dev_get_drvdata(&dev->dev); > + > + mappass = radix_tree_lookup(&fedata->socketpass_mappings, > + req->u.accept.id); > + if (mappass == NULL) > + goto out_error; > + > + /* > + * Limitation of the current implementation: only support one > + * concurrent accept or poll call on one socket. > + */ > + spin_lock_irqsave(&mappass->copy_lock, flags); > + if (mappass->reqcopy.cmd != 0) { > + spin_unlock_irqrestore(&mappass->copy_lock, flags); > + ret = -EINTR; > + goto out_error; > + } > + > + mappass->reqcopy = *req; > + spin_unlock_irqrestore(&mappass->copy_lock, flags); > + queue_work(mappass->wq, &mappass->register_work); > + > + /* Tell the caller we don't need to send back a notification yet */ > + return -1; > + > +out_error: > + rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); > + rsp->req_id = req->req_id; > + rsp->cmd = req->cmd; > + rsp->u.accept.id = req->u.accept.id; > + rsp->ret = ret; > return 0; > } >