From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 69030C433EF for ; Thu, 16 Jun 2022 15:04:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377831AbiFPPEW (ORCPT ); Thu, 16 Jun 2022 11:04:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43870 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1377776AbiFPPET (ORCPT ); Thu, 16 Jun 2022 11:04:19 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 70828326E2; Thu, 16 Jun 2022 08:04:17 -0700 (PDT) Received: from fraeml714-chm.china.huawei.com (unknown [172.18.147.207]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4LP56Y73MVz67KsG; Thu, 16 Jun 2022 23:04:05 +0800 (CST) Received: from lhreml710-chm.china.huawei.com (10.201.108.61) by fraeml714-chm.china.huawei.com (10.206.15.33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 16 Jun 2022 17:04:14 +0200 Received: from localhost (10.202.226.42) by lhreml710-chm.china.huawei.com (10.201.108.61) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 16 Jun 2022 16:04:14 +0100 Date: Thu, 16 Jun 2022 16:04:12 +0100 From: Jonathan Cameron To: CC: Dan Williams , Ira Weiny , Vishal Verma , Ben Widawsky , Steven Rostedt , Ingo Molnar , , Subject: Re: [PATCH 3/3] cxl/core: Add sysfs attribute get_poison for list retrieval Message-ID: <20220616160412.00000c34@Huawei.com> In-Reply-To: <57644934bb7af8e1c692735f53c2c415a1ba16d1.1655250669.git.alison.schofield@intel.com> References: <57644934bb7af8e1c692735f53c2c415a1ba16d1.1655250669.git.alison.schofield@intel.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.29; i686-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.226.42] X-ClientProxiedBy: lhreml723-chm.china.huawei.com (10.201.108.74) To lhreml710-chm.china.huawei.com (10.201.108.61) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 14 Jun 2022 17:10:28 -0700 alison.schofield@intel.com wrote: > From: Alison Schofield > > The sysfs attribute, get_poison, allows user space to request the > retrieval of a CXL devices poison list for its persistent memory. > > From Documentation/ABI/.../sysfs-bus-cxl > (WO) When a '1' is written to this attribute the memdev > driver retrieves the poison list from the device. The list > includes addresses that are poisoned or would result in > poison if accessed, and the source of the poison. This > attribute is only visible for devices supporting the > capability. The retrieved errors are logged as kernel > trace events with the label: cxl_poison_list. > > Signed-off-by: Alison Schofield Hi Alison, I'm planning to throw together QEMU support for this and test it. In meantime a few quick comments / suggestions inline. Thanks, Jonathan > --- > Documentation/ABI/testing/sysfs-bus-cxl | 13 ++++++++++ > drivers/cxl/core/memdev.c | 32 +++++++++++++++++++++++++ > 2 files changed, 45 insertions(+) > > diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl > index 7c2b846521f3..9d0c3988fdd2 100644 > --- a/Documentation/ABI/testing/sysfs-bus-cxl > +++ b/Documentation/ABI/testing/sysfs-bus-cxl > @@ -163,3 +163,16 @@ Description: > memory (type-3). The 'target_type' attribute indicates the > current setting which may dynamically change based on what > memory regions are activated in this decode hierarchy. > + > +What: /sys/bus/cxl/devices/memX/get_poison > +Date: June, 2022 > +KernelVersion: v5.20 > +Contact: linux-cxl@vger.kernel.org > +Description: > + (WO) When a '1' is written to this attribute the memdev > + driver retrieves the poison list from the device. The list > + includes addresses that are poisoned or would result in > + poison if accessed, and the source of the poison. This > + attribute is only visible for devices supporting the > + capability. The retrieved errors are logged as kernel > + trace events with the label: cxl_poison_list. > diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c > index f7cdcd33504a..5ef9ffaa934a 100644 > --- a/drivers/cxl/core/memdev.c > +++ b/drivers/cxl/core/memdev.c > @@ -106,12 +106,34 @@ static ssize_t numa_node_show(struct device *dev, struct device_attribute *attr, > } > static DEVICE_ATTR_RO(numa_node); > > +static ssize_t get_poison_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t len) > + > +{ > + int rc; > + > + if (!sysfs_streq(buf, "1")) { Maybe kstrtobool? If you do then fine to leave the documentation claiming it's tighter as that'll tell people who actually read it to expect to write a 1. > + dev_err(dev, "%s: unknown value: %s\n", attr->attr.name, buf); Feels noisy when I'd expect -EINVAL to be enough info to indicate an invalid parameter. > + return -EINVAL; > + } > + > + rc = cxl_mem_get_poison_list(dev); > + if (rc) { > + dev_err(dev, "Failed to retrieve poison list %d\n", rc); Here I'd expect the error code to returned on the write to probably be enough info so not sure this error print is useful either. > + return rc; > + } > + return len; > +} > +static DEVICE_ATTR_WO(get_poison); > + > static struct attribute *cxl_memdev_attributes[] = { > &dev_attr_serial.attr, > &dev_attr_firmware_version.attr, > &dev_attr_payload_max.attr, > &dev_attr_label_storage_size.attr, > &dev_attr_numa_node.attr, > + &dev_attr_get_poison.attr, > NULL, > }; > > @@ -130,6 +152,16 @@ static umode_t cxl_memdev_visible(struct kobject *kobj, struct attribute *a, > { > if (!IS_ENABLED(CONFIG_NUMA) && a == &dev_attr_numa_node.attr) > return 0; > + > + if (a == &dev_attr_get_poison.attr) { > + struct device *dev = container_of(kobj, struct device, kobj); > + struct cxl_memdev *cxlmd = to_cxl_memdev(dev); > + struct cxl_dev_state *cxlds = cxlmd->cxlds; > + > + if (!test_bit(CXL_MEM_COMMAND_ID_GET_POISON, > + cxlds->enabled_cmds)) to_cxl_memdev(dev)->enabled_cmds)) and drop the local variable is shorter and I don't htink it loses any readability. > + return 0; > + } > return a->mode; > } >