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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 19 Aug 2019 08:05:33 +0100 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x7J75WWR13107280 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 19 Aug 2019 07:05:32 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 95AFD52054; Mon, 19 Aug 2019 07:05:32 +0000 (GMT) Received: from skywalker.linux.ibm.com (unknown [9.124.35.64]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id B12A352051; Mon, 19 Aug 2019 07:05:31 +0000 (GMT) X-Mailer: emacs 26.2 (via feedmail 11-beta-1 I) From: "Aneesh Kumar K.V" To: Dan Williams Subject: Re: [PATCH v5 1/4] nvdimm: Consider probe return -EOPNOTSUPP as success In-Reply-To: References: <20190809074520.27115-1-aneesh.kumar@linux.ibm.com> <20190809074520.27115-2-aneesh.kumar@linux.ibm.com> Date: Mon, 19 Aug 2019 12:35:30 +0530 MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 x-cbid: 19081907-0008-0000-0000-0000030A9AB1 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19081907-0009-0000-0000-00004A28BCAB Message-Id: <87y2zp1vph.fsf@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-08-19_02:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908190081 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Linux MM , linuxppc-dev , linux-nvdimm Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Dan Williams writes: > On Tue, Aug 13, 2019 at 9:22 PM Dan Williams wrote: >> >> Hi Aneesh, logic looks correct but there are some cleanups I'd like to >> see and a lead-in patch that I attached. >> >> I've started prefixing nvdimm patches with: >> >> libnvdimm/$component: >> >> ...since this patch mostly impacts the pmem driver lets prefix it >> "libnvdimm/pmem: " >> >> On Fri, Aug 9, 2019 at 12:45 AM Aneesh Kumar K.V >> wrote: >> > >> > This patch add -EOPNOTSUPP as return from probe callback to >> >> s/This patch add/Add/ >> >> No need to say "this patch" it's obviously a patch. >> >> > indicate we were not able to initialize a namespace due to pfn superblock >> > feature/version mismatch. We want to consider this a probe success so that >> > we can create new namesapce seed and there by avoid marking the failed >> > namespace as the seed namespace. >> >> Please replace usage of "we" with the exact agent involved as which >> "we" is being referred to gets confusing for the reader. >> >> i.e. "indicate that the pmem driver was not..." "The nvdimm core wants >> to consider this...". >> >> > >> > Signed-off-by: Aneesh Kumar K.V >> > --- >> > drivers/nvdimm/bus.c | 2 +- >> > drivers/nvdimm/pmem.c | 26 ++++++++++++++++++++++---- >> > 2 files changed, 23 insertions(+), 5 deletions(-) >> > >> > diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c >> > index 798c5c4aea9c..16c35e6446a7 100644 >> > --- a/drivers/nvdimm/bus.c >> > +++ b/drivers/nvdimm/bus.c >> > @@ -95,7 +95,7 @@ static int nvdimm_bus_probe(struct device *dev) >> > rc = nd_drv->probe(dev); >> > debug_nvdimm_unlock(dev); >> > >> > - if (rc == 0) >> > + if (rc == 0 || rc == -EOPNOTSUPP) >> > nd_region_probe_success(nvdimm_bus, dev); >> >> This now makes the nd_region_probe_success() helper obviously misnamed >> since it now wants to take actions on non-probe success. I attached a >> lead-in cleanup that you can pull into your series that renames that >> routine to nd_region_advance_seeds(). >> >> When you rebase this needs a comment about why EOPNOTSUPP has special handling. >> >> > else >> > nd_region_disable(nvdimm_bus, dev); >> > diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c >> > index 4c121dd03dd9..3f498881dd28 100644 >> > --- a/drivers/nvdimm/pmem.c >> > +++ b/drivers/nvdimm/pmem.c >> > @@ -490,6 +490,7 @@ static int pmem_attach_disk(struct device *dev, >> > >> > static int nd_pmem_probe(struct device *dev) >> > { >> > + int ret; >> > struct nd_namespace_common *ndns; >> > >> > ndns = nvdimm_namespace_common_probe(dev); >> > @@ -505,12 +506,29 @@ static int nd_pmem_probe(struct device *dev) >> > if (is_nd_pfn(dev)) >> > return pmem_attach_disk(dev, ndns); >> > >> > - /* if we find a valid info-block we'll come back as that personality */ >> > - if (nd_btt_probe(dev, ndns) == 0 || nd_pfn_probe(dev, ndns) == 0 >> > - || nd_dax_probe(dev, ndns) == 0) >> >> Similar need for an updated comment here to explain the special >> translation of error codes. >> >> > + ret = nd_btt_probe(dev, ndns); >> > + if (ret == 0) >> > return -ENXIO; >> > + else if (ret == -EOPNOTSUPP) >> >> Are there cases where the btt driver needs to return EOPNOTSUPP? I'd >> otherwise like to keep this special casing constrained to the pfn / >> dax info block cases. > > In fact I think EOPNOTSUPP is only something that the device-dax case > would be concerned with because that's the only interface that > attempts to guarantee a given mapping granularity. We need to do similar error handling w.r.t fsdax when the pfn superblock indicates different PAGE_SIZE and struct page size? I don't think btt needs to support EOPNOTSUPP. But we can keep it for consistency? -aneesh