Path: csiph.com!aioe.org!bofh.it!news.nic.it!robomod From: Boris Ostrovsky Newsgroups: linux.kernel Subject: Re: [PATCH v3 02/13] xen/pvcalls: implement frontend disconnect Date: Sat, 12 Aug 2017 00:50:02 +0200 Message-ID: References: X-Original-To: Stefano Stabellini , xen-devel@lists.xen.org User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 104 Organization: linux.* mail to news gateway X-Original-Cc: linux-kernel@vger.kernel.org, jgross@suse.com, Stefano Stabellini X-Original-Date: Fri, 11 Aug 2017 18:43:43 -0400 X-Original-Message-ID: X-Original-References: <1501541855-7354-1-git-send-email-sstabellini@kernel.org> <1501541855-7354-2-git-send-email-sstabellini@kernel.org> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: csiph.com linux.kernel:1710074 On 07/31/2017 06:57 PM, Stefano Stabellini wrote: > 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. > > Implement pvcalls frontend removal function. Go through the list of > active and passive sockets and free them all, one at a time. > > Signed-off-by: Stefano Stabellini > CC: boris.ostrovsky@oracle.com > CC: jgross@suse.com > --- > drivers/xen/pvcalls-front.c | 51 +++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 51 insertions(+) > > diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c > index a8d38c2..a126195 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 > +#define PVCALLS_RING_ORDER XENBUS_MAX_RING_GRANT_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; In the backend this is called socket_lock and (subjectively) it would sound as a better name here too. > + > + wait_queue_head_t inflight_req; > + struct xen_pvcalls_response rsp[PVCALLS_NR_REQ_PER_RING]; > +}; > +static struct xenbus_device *pvcalls_front_dev; > + > +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" }, > { "" } > @@ -27,6 +50,34 @@ > > static int pvcalls_front_remove(struct xenbus_device *dev) > { > + struct pvcalls_bedata *bedata; > + struct sock_mapping *map = NULL, *n; > + > + bedata = dev_get_drvdata(&pvcalls_front_dev->dev); > + > + list_for_each_entry_safe(map, n, &bedata->socket_mappings, list) { > + mutex_lock(&map->active.in_mutex); > + mutex_lock(&map->active.out_mutex); > + pvcalls_front_free_map(bedata, map); > + mutex_unlock(&map->active.out_mutex); > + mutex_unlock(&map->active.in_mutex); > + kfree(map); I think this is the same issue as the one discussed for some other patch --- unlocking and then immediately freeing a lock. > + } > + list_for_each_entry_safe(map, n, &bedata->socketpass_mappings, list) { > + spin_lock(&bedata->pvcallss_lock); > + list_del_init(&map->list); > + spin_unlock(&bedata->pvcallss_lock); > + kfree(map); > + } > + if (bedata->irq > 0) > + unbind_from_irqhandler(bedata->irq, dev); > + if (bedata->ref >= 0) > + gnttab_end_foreign_access(bedata->ref, 0, 0); > + kfree(bedata->ring.sring); > + kfree(bedata); > + dev_set_drvdata(&dev->dev, NULL); > + xenbus_switch_state(dev, XenbusStateClosed); Should we first move the state to Closed and then free things up? Or it doesn't matter? -boris > + pvcalls_front_dev = NULL; > return 0; > } >