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Sun, 13 Sep 2020 16:11:57 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 08DG5vgQ160957; Sun, 13 Sep 2020 16:11:57 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserp3030.oracle.com with ESMTP id 33h7wjtmd7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 13 Sep 2020 16:11:57 +0000 Received: from abhmp0004.oracle.com (abhmp0004.oracle.com [141.146.116.10]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 08DGBrTb013868; Sun, 13 Sep 2020 16:11:53 GMT Received: from [10.74.86.192] (/10.74.86.192) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Sun, 13 Sep 2020 16:11:53 +0000 Subject: Re: [PATCH v3 02/11] xenbus: add freeze/thaw/restore callbacks support To: Anchal Agarwal , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org, jgross@suse.com, linux-pm@vger.kernel.org, linux-mm@kvack.org, kamatam@amazon.com, sstabellini@kernel.org, konrad.wilk@oracle.com, roger.pau@citrix.com, axboe@kernel.dk, davem@davemloft.net, rjw@rjwysocki.net, len.brown@intel.com, pavel@ucw.cz, peterz@infradead.org, eduval@amazon.com, sblbir@amazon.com, xen-devel@lists.xenproject.org, vkuznets@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, dwmw@amazon.co.uk, benh@kernel.crashing.org References: <2d3a7ed32bf38e13e0141a631a453b6e4c7ba5dc.1598042152.git.anchalag@amazon.com> From: boris.ostrovsky@oracle.com Organization: Oracle Corporation Message-ID: Date: Sun, 13 Sep 2020 12:11:47 -0400 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.2.1 MIME-Version: 1.0 In-Reply-To: <2d3a7ed32bf38e13e0141a631a453b6e4c7ba5dc.1598042152.git.anchalag@amazon.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9743 signatures=668679 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=2 malwarescore=0 adultscore=0 bulkscore=0 phishscore=0 mlxlogscore=999 mlxscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009130145 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9743 signatures=668679 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 mlxlogscore=999 adultscore=0 malwarescore=0 clxscore=1015 lowpriorityscore=0 phishscore=0 spamscore=0 priorityscore=1501 suspectscore=2 impostorscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009130145 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 8/21/20 6:26 PM, Anchal Agarwal wrote: > From: Munehisa Kamata > > Since commit b3e96c0c7562 ("xen: use freeze/restore/thaw PM events for > suspend/resume/chkpt"), xenbus uses PMSG_FREEZE, PMSG_THAW and > PMSG_RESTORE events for Xen suspend. However, they're actually assigned > to xenbus_dev_suspend(), xenbus_dev_cancel() and xenbus_dev_resume() > respectively, and only suspend and resume callbacks are supported at > driver level. To support PM suspend and PM hibernation, modify the bus > level PM callbacks to invoke not only device driver's suspend/resume but > also freeze/thaw/restore. > > Note that we'll use freeze/restore callbacks even for PM suspend whereas > suspend/resume callbacks are normally used in the case, becausae the > existing xenbus device drivers already have suspend/resume callbacks > specifically designed for Xen suspend. Something is wrong with this sentence. Or with my brain --- I can't quite parse this. And please be consistent with "PM suspend" vs. "PM hibernation". > So we can allow the device > drivers to keep the existing callbacks wihtout modification. > > @@ -599,16 +600,33 @@ int xenbus_dev_suspend(struct device *dev) > struct xenbus_driver *drv; > struct xenbus_device *xdev > = container_of(dev, struct xenbus_device, dev); > + bool xen_suspend = is_xen_suspend(); > > DPRINTK("%s", xdev->nodename); > > if (dev->driver == NULL) > return 0; > drv = to_xenbus_driver(dev->driver); > - if (drv->suspend) > - err = drv->suspend(xdev); > - if (err) > - dev_warn(dev, "suspend failed: %i\n", err); > + if (xen_suspend) { > + if (drv->suspend) > + err = drv->suspend(xdev); > + } else { > + if (drv->freeze) { 'else if' (to avoid extra indent level).  In xenbus_dev_resume() too. > + err = drv->freeze(xdev); > + if (!err) { > + free_otherend_watch(xdev); > + free_otherend_details(xdev); > + return 0; > + } > + } > + } > + > + if (err) { > + dev_warn(&xdev->dev, Is there a reason why you replaced dev with xdev->dev (here and elsewhere)? > "%s %s failed: %d\n", xen_suspend ? > + "suspend" : "freeze", xdev->nodename, err); > + return err; > + } > + > > @@ -653,8 +683,44 @@ EXPORT_SYMBOL_GPL(xenbus_dev_resume); > > int xenbus_dev_cancel(struct device *dev) > { > - /* Do nothing */ > - DPRINTK("cancel"); > + int err; > + struct xenbus_driver *drv; > + struct xenbus_device *xendev = to_xenbus_device(dev); xdev for consistency please. > + bool xen_suspend = is_xen_suspend(); No need for this, you use it only once anyway. -boris