Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751493AbdFBTfz (ORCPT ); Fri, 2 Jun 2017 15:35:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:55996 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751238AbdFBTb7 (ORCPT ); Fri, 2 Jun 2017 15:31:59 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 44AD523A23 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 From: Stefano Stabellini To: xen-devel@lists.xen.org Cc: linux-kernel@vger.kernel.org, sstabellini@kernel.org, jgross@suse.com, boris.ostrovsky@oracle.com, Stefano Stabellini Subject: [PATCH v3 04/18] xen/pvcalls: xenbus state handling Date: Fri, 2 Jun 2017 12:31:41 -0700 Message-Id: <1496431915-20774-4-git-send-email-sstabellini@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1496431915-20774-1-git-send-email-sstabellini@kernel.org> References: <1496431915-20774-1-git-send-email-sstabellini@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4669 Lines: 194 Introduce the code to handle xenbus state changes. Implement the probe function for the pvcalls backend. Write the supported versions, max-page-order and function-calls nodes to xenstore, as required by the protocol. Introduce stub functions for disconnecting/connecting to a frontend. Signed-off-by: Stefano Stabellini CC: boris.ostrovsky@oracle.com CC: jgross@suse.com --- drivers/xen/pvcalls-back.c | 152 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 152 insertions(+) diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c index 9044cf2..7bce750 100644 --- a/drivers/xen/pvcalls-back.c +++ b/drivers/xen/pvcalls-back.c @@ -25,20 +25,172 @@ #include #include +#define PVCALLS_VERSIONS "1" +#define MAX_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER + struct pvcalls_back_global { struct list_head frontends; struct semaphore frontends_lock; } pvcalls_back_global; +static int backend_connect(struct xenbus_device *dev) +{ + return 0; +} + +static int backend_disconnect(struct xenbus_device *dev) +{ + return 0; +} + static int pvcalls_back_probe(struct xenbus_device *dev, const struct xenbus_device_id *id) { + int err, abort; + struct xenbus_transaction xbt; + +again: + abort = 1; + + err = xenbus_transaction_start(&xbt); + if (err) { + pr_warn("%s cannot create xenstore transaction\n", __func__); + return err; + } + + err = xenbus_printf(xbt, dev->nodename, "versions", "%s", + PVCALLS_VERSIONS); + if (err) { + pr_warn("%s write out 'version' failed\n", __func__); + goto abort; + } + + err = xenbus_printf(xbt, dev->nodename, "max-page-order", "%u", + MAX_RING_ORDER); + if (err) { + pr_warn("%s write out 'max-page-order' failed\n", __func__); + goto abort; + } + + err = xenbus_printf(xbt, dev->nodename, "function-calls", + XENBUS_FUNCTIONS_CALLS); + if (err) { + pr_warn("%s write out 'function-calls' failed\n", __func__); + goto abort; + } + + abort = 0; +abort: + err = xenbus_transaction_end(xbt, abort); + if (err) { + if (err == -EAGAIN && !abort) + goto again; + pr_warn("%s cannot complete xenstore transaction\n", __func__); + return err; + } + + xenbus_switch_state(dev, XenbusStateInitWait); + return 0; } +static void set_backend_state(struct xenbus_device *dev, + enum xenbus_state state) +{ + while (dev->state != state) { + switch (dev->state) { + case XenbusStateClosed: + switch (state) { + case XenbusStateInitWait: + case XenbusStateConnected: + xenbus_switch_state(dev, XenbusStateInitWait); + break; + case XenbusStateClosing: + xenbus_switch_state(dev, XenbusStateClosing); + break; + default: + __WARN(); + } + break; + case XenbusStateInitWait: + case XenbusStateInitialised: + switch (state) { + case XenbusStateConnected: + backend_connect(dev); + xenbus_switch_state(dev, XenbusStateConnected); + break; + case XenbusStateClosing: + case XenbusStateClosed: + xenbus_switch_state(dev, XenbusStateClosing); + break; + default: + __WARN(); + } + break; + case XenbusStateConnected: + switch (state) { + case XenbusStateInitWait: + case XenbusStateClosing: + case XenbusStateClosed: + down(&pvcalls_back_global.frontends_lock); + backend_disconnect(dev); + up(&pvcalls_back_global.frontends_lock); + xenbus_switch_state(dev, XenbusStateClosing); + break; + default: + __WARN(); + } + break; + case XenbusStateClosing: + switch (state) { + case XenbusStateInitWait: + case XenbusStateConnected: + case XenbusStateClosed: + xenbus_switch_state(dev, XenbusStateClosed); + break; + default: + __WARN(); + } + break; + default: + __WARN(); + } + } +} + static void pvcalls_back_changed(struct xenbus_device *dev, enum xenbus_state frontend_state) { + switch (frontend_state) { + case XenbusStateInitialising: + set_backend_state(dev, XenbusStateInitWait); + break; + + case XenbusStateInitialised: + case XenbusStateConnected: + set_backend_state(dev, XenbusStateConnected); + break; + + case XenbusStateClosing: + set_backend_state(dev, XenbusStateClosing); + break; + + case XenbusStateClosed: + set_backend_state(dev, XenbusStateClosed); + if (xenbus_dev_is_online(dev)) + break; + device_unregister(&dev->dev); + break; + case XenbusStateUnknown: + set_backend_state(dev, XenbusStateClosed); + device_unregister(&dev->dev); + break; + + default: + xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", + frontend_state); + break; + } } static int pvcalls_back_remove(struct xenbus_device *dev) -- 1.9.1