summaryrefslogtreecommitdiff
path: root/drivers/nvdimm/region.c
AgeCommit message (Collapse)AuthorFilesLines
2021-02-17libnvdimm: Make remove callback return voidUwe Kleine-König1-3/+1
All drivers return 0 in their remove callback and the driver core ignores the return value of nvdimm_bus_remove() anyhow. So simplify by changing the driver remove callback to return void and return 0 unconditionally to the upper layer. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/20210212171043.2136580-2-u.kleine-koenig@pengutronix.de Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2020-10-14mm/memremap_pages: convert to 'struct range'Dan Williams1-9/+12
The 'struct resource' in 'struct dev_pagemap' is only used for holding resource span information. The other fields, 'name', 'flags', 'desc', 'parent', 'sibling', and 'child' are all unused wasted space. This is in preparation for introducing a multi-range extension of devm_memremap_pages(). The bulk of this change is unwinding all the places internal to libnvdimm that used 'struct resource' unnecessarily, and replacing instances of 'struct dev_pagemap'.res with 'struct dev_pagemap'.range. P2PDMA had a minor usage of the resource flags field, but only to report failures with "%pR". That is replaced with an open coded print of the range. [dan.carpenter@oracle.com: mm/hmm/test: use after free in dmirror_allocate_chunk()] Link: https://lkml.kernel.org/r/20200926121402.GA7467@kadam Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> [xen] Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Ben Skeggs <bskeggs@redhat.com> Cc: David Airlie <airlied@linux.ie> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Juergen Gross <jgross@suse.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brice Goglin <Brice.Goglin@inria.fr> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Hulk Robot <hulkci@huawei.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Jason Yan <yanaijie@huawei.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Jia He <justin.he@arm.com> Cc: Joao Martins <joao.m.martins@oracle.com> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: kernel test robot <lkp@intel.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Will Deacon <will@kernel.org> Link: https://lkml.kernel.org/r/159643103173.4062302.768998885691711532.stgit@dwillia2-desk3.amr.corp.intel.com Link: https://lkml.kernel.org/r/160106115761.30709.13539840236873663620.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-24libnvdimm/region: Initialize bad block for volatile namespacesAneesh Kumar K.V1-2/+2
We do check for a bad block during namespace init and that use region bad block list. We need to initialize the bad block for volatile regions for this to work. We also observe a lockdep warning as below because the lock is not initialized correctly since we skip bad block init for volatile regions. INFO: trying to register non-static key. the code is fine but needs lockdep annotation. turning off the locking correctness validator. CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.3.0-rc1-15699-g3dee241c937e #149 Call Trace: [c0000000f95cb250] [c00000000147dd84] dump_stack+0xe8/0x164 (unreliable) [c0000000f95cb2a0] [c00000000022ccd8] register_lock_class+0x308/0xa60 [c0000000f95cb3a0] [c000000000229cc0] __lock_acquire+0x170/0x1ff0 [c0000000f95cb4c0] [c00000000022c740] lock_acquire+0x220/0x270 [c0000000f95cb580] [c000000000a93230] badblocks_check+0xc0/0x290 [c0000000f95cb5f0] [c000000000d97540] nd_pfn_validate+0x5c0/0x7f0 [c0000000f95cb6d0] [c000000000d98300] nd_dax_probe+0xd0/0x1f0 [c0000000f95cb760] [c000000000d9b66c] nd_pmem_probe+0x10c/0x160 [c0000000f95cb790] [c000000000d7f5ec] nvdimm_bus_probe+0x10c/0x240 [c0000000f95cb820] [c000000000d0f844] really_probe+0x254/0x4e0 [c0000000f95cb8b0] [c000000000d0fdfc] driver_probe_device+0x16c/0x1e0 [c0000000f95cb930] [c000000000d10238] device_driver_attach+0x68/0xa0 [c0000000f95cb970] [c000000000d1040c] __driver_attach+0x19c/0x1c0 [c0000000f95cb9f0] [c000000000d0c4c4] bus_for_each_dev+0x94/0x130 [c0000000f95cba50] [c000000000d0f014] driver_attach+0x34/0x50 [c0000000f95cba70] [c000000000d0e208] bus_add_driver+0x178/0x2f0 [c0000000f95cbb00] [c000000000d117c8] driver_register+0x108/0x170 [c0000000f95cbb70] [c000000000d7edb0] __nd_driver_register+0xe0/0x100 [c0000000f95cbbd0] [c000000001a6baa4] nd_pmem_driver_init+0x34/0x48 [c0000000f95cbbf0] [c0000000000106f4] do_one_initcall+0x1d4/0x4b0 [c0000000f95cbcd0] [c0000000019f499c] kernel_init_freeable+0x544/0x65c [c0000000f95cbdb0] [c000000000010d6c] kernel_init+0x2c/0x180 [c0000000f95cbe20] [c00000000000b954] ret_from_kernel_thread+0x5c/0x68 Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Link: https://lore.kernel.org/r/20190919083355.26340-1-aneesh.kumar@linux.ibm.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2019-07-19driver-core, libnvdimm: Let device subsystems add local lockdep coverageDan Williams1-1/+1
For good reason, the standard device_lock() is marked lockdep_set_novalidate_class() because there is simply no sane way to describe the myriad ways the device_lock() ordered with other locks. However, that leaves subsystems that know their own local device_lock() ordering rules to find lock ordering mistakes manually. Instead, introduce an optional / additional lockdep-enabled lock that a subsystem can acquire in all the same paths that the device_lock() is acquired. A conversion of the NFIT driver and NVDIMM subsystem to a lockdep-validate device_lock() scheme is included. The debug_nvdimm_lock() implementation implements the correct lock-class and stacking order for the libnvdimm device topology hierarchy. Yes, this is a hack, but hopefully it is a useful hack for other subsystems device_lock() debug sessions. Quoting Greg: "Yeah, it feels a bit hacky but it's really up to a subsystem to mess up using it as much as anything else, so user beware :) I don't object to it if it makes things easier for you to debug." Cc: Ingo Molnar <mingo@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Link: https://lore.kernel.org/r/156341210661.292348.7014034644265455704.stgit@dwillia2-desk3.amr.corp.intel.com
2019-07-19libnvdimm/region: Register badblocks before namespacesDan Williams1-11/+11
Namespace activation expects to be able to reference region badblocks. The following warning sometimes triggers when asynchronous namespace activation races in front of the completion of namespace probing. Move all possible namespace probing after region badblocks initialization. Otherwise, lockdep sometimes catches the uninitialized state of the badblocks seqlock with stack trace signatures like: INFO: trying to register non-static key. pmem2: detected capacity change from 0 to 136365211648 the code is fine but needs lockdep annotation. turning off the locking correctness validator. CPU: 9 PID: 358 Comm: kworker/u80:5 Tainted: G OE 5.2.0-rc4+ #3382 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 Workqueue: events_unbound async_run_entry_fn Call Trace: dump_stack+0x85/0xc0 pmem1.12: detected capacity change from 0 to 8589934592 register_lock_class+0x56a/0x570 ? check_object+0x140/0x270 __lock_acquire+0x80/0x1710 ? __mutex_lock+0x39d/0x910 lock_acquire+0x9e/0x180 ? nd_pfn_validate+0x28f/0x440 [libnvdimm] badblocks_check+0x93/0x1f0 ? nd_pfn_validate+0x28f/0x440 [libnvdimm] nd_pfn_validate+0x28f/0x440 [libnvdimm] ? lockdep_hardirqs_on+0xf0/0x180 nd_dax_probe+0x9a/0x120 [libnvdimm] nd_pmem_probe+0x6d/0x180 [nd_pmem] nvdimm_bus_probe+0x90/0x2c0 [libnvdimm] Fixes: 48af2f7e52f4 ("libnvdimm, pfn: during init, clear errors...") Cc: <stable@vger.kernel.org> Cc: Vishal Verma <vishal.l.verma@intel.com> Reviewed-by: Vishal Verma <vishal.l.verma@intel.com> Link: https://lore.kernel.org/r/156341208365.292348.1547528796026249120.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2019-06-05treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295Thomas Gleixner1-9/+1
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of version 2 of the gnu general public license as published by the free software foundation this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 64 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141901.894819585@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-07libnvdimm, region: quiet region probeDan Williams1-2/+2
The message about constraining number of online cpus to be less than or equal to ND_MAX_LANES (256) is only useful for block-aperture configurations and BTT. Make it debug since it is only relevant when debugging performance. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-07-01libnvdimm, region, pmem: fix 'badblocks' sysfs_get_dirent() reference lifetimeDan Williams1-4/+9
We need to hold a reference on the 'dirent' until we are sure there are no more notifications that will be sent. As noted in the new comments we take advantage of the fact that the references are taken and dropped under device_lock() and that nd_device_notify() holds device_lock() over new badblocks notifications. The notifications that happen when badblocks are cleared only occur while the device is active. Also take the opportunity to fix up the error messages to report the user visible effect of a sysfs_get_dirent() failure. Fixes: 975750a98c26 ("libnvdimm, pmem: Add sysfs notifications to badblocks") Cc: Toshi Kani <toshi.kani@hpe.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-06-16libnvdimm, pmem: Add sysfs notifications to badblocksToshi Kani1-2/+10
Sysfs "badblocks" information may be updated during run-time that: - MCE, SCI, and sysfs "scrub" may add new bad blocks - Writes and ioctl() may clear bad blocks Add support to send sysfs notifications to sysfs "badblocks" file under region and pmem directories when their badblocks information is re-evaluated (but is not necessarily changed) during run-time. Signed-off-by: Toshi Kani <toshi.kani@hpe.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Linda Knippers <linda.knippers@hpe.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-04-30libnvdimm: rework region badblocks clearingDan Williams1-25/+0
Toshi noticed that the new support for a region-level badblocks missed the case where errors are cleared due to BTT I/O. An initial attempt to fix this ran into a "sleeping while atomic" warning due to taking the nvdimm_bus_lock() in the BTT I/O path to satisfy the locking requirements of __nvdimm_bus_badblocks_clear(). However, that lock is not needed since we are not acting on any data that is subject to change under that lock. The badblocks instance has its own internal lock to handle mutations of the error list. So, in order to make it clear that we are just acting on region devices, rename __nvdimm_bus_badblocks_clear() to nvdimm_clear_badblocks_regions(). Eliminate the lock and consolidate all support routines for the new nvdimm_account_cleared_poison() in drivers/nvdimm/bus.c. Finally, to the opportunity to cleanup to some unnecessary casts, make the calling convention of nvdimm_clear_badblocks_regions() clearer by replacing struct resource with the minimal struct clear_badblocks_context, and use the DEVICE_ATTR macro. Cc: Dave Jiang <dave.jiang@intel.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Reported-by: Toshi Kani <toshi.kani@hpe.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-04-13libnvdimm: add support for clear poison list and badblocks for device daxDave Jiang1-0/+25
Providing mechanism to clear poison list via the ndctl ND_CMD_CLEAR_ERROR call. We will update the poison list and also the badblocks at region level if the region is in dax mode or in pmem mode and not active. In other words we force badblocks to be cleared through write requests if the address is currently accessed through a block device, otherwise it can only be done via the ioctl+dsm path. Signed-off-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-04-13libnvdimm: add mechanism to publish badblocks at the region levelDave Jiang1-0/+24
badblocks sysfs file will be export at region level. When nvdimm event notifier happens for NVDIMM_REVALIATE_POISON, the badblocks in the region will be updated. Signed-off-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-07-12libnvdimm: keep region data alive over namespace removalDan Williams1-1/+2
nd_region device driver data will be used in the namespace i/o path. Re-order nd_region_remove() to ensure this data stays live across namespace device removal Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-07-12libnvdimm, nfit: move flush hint mapping to region-device driver-dataDan Williams1-8/+8
In preparation for triggering flushes of a DIMM's writes-posted-queue (WPQ) via the pmem driver move mapping of flush hint addresses to the region driver. Since this uses devm_nvdimm_memremap() the flush addresses will remain mapped while any region to which the dimm belongs is active. We need to communicate more information to the nvdimm core to facilitate this mapping, namely each dimm object now carries an array of flush hint address resources. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-05-10libnvdimm, dax: introduce device-dax infrastructureDan Williams1-0/+2
Device DAX is the device-centric analogue of Filesystem DAX (CONFIG_FS_DAX). It allows persistent memory ranges to be allocated and mapped without need of an intervening file system. This initial infrastructure arranges for a libnvdimm pfn-device to be represented as a different device-type so that it can be attached to a driver other than the pmem driver. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-03-05libnvdimm: async notification supportDan Williams1-0/+12
In preparation for asynchronous address range scrub support add an ability for the pmem driver to dynamically consume address range scrub results. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-08-29libnvdimm, pfn: 'struct page' provider infrastructureDan Williams1-0/+2
Implement the base infrastructure for libnvdimm PFN devices. Similar to BTT devices they take a namespace as a backing device and layer functionality on top. In this case the functionality is reserving space for an array of 'struct page' entries to be handed out through pfn_to_page(). For now this is just the basic libnvdimm-device-model for configuring the base PFN device. As the namespace claiming mechanism for PFN devices is mostly identical to BTT devices drivers/nvdimm/claim.c is created to house the common bits. Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-06-26libnvdimm, nfit, nd_blk: driver for BLK-mode access persistent memoryRoss Zwisler1-2/+6
The libnvdimm implementation handles allocating dimm address space (DPA) between PMEM and BLK mode interfaces. After DPA has been allocated from a BLK-region to a BLK-namespace the nd_blk driver attaches to handle I/O as a struct bio based block device. Unlike PMEM, BLK is required to handle platform specific details like mmio register formats and memory controller interleave. For this reason the libnvdimm generic nd_blk driver calls back into the bus provider to carry out the I/O. This initial implementation handles the BLK interface defined by the ACPI 6 NFIT [1] and the NVDIMM DSM Interface Example [2] composed from DCR (dimm control region), BDW (block data window), IDT (interleave descriptor) NFIT structures and the hardware register format. [1]: http://www.uefi.org/sites/default/files/resources/ACPI_6.0.pdf [2]: http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdf Cc: Andy Lutomirski <luto@amacapital.net> Cc: Boaz Harrosh <boaz@plexistor.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jens Axboe <axboe@fb.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-06-26nd_btt: atomic sector updatesVishal Verma1-0/+12
BTT stands for Block Translation Table, and is a way to provide power fail sector atomicity semantics for block devices that have the ability to perform byte granularity IO. It relies on the capability of libnvdimm namespace devices to do byte aligned IO. The BTT works as a stacked blocked device, and reserves a chunk of space from the backing device for its accounting metadata. It is a bio-based driver because all IO is done synchronously, and there is no queuing or asynchronous completions at either the device or the driver level. The BTT uses 'lanes' to index into various 'on-disk' data structures, and lanes also act as a synchronization mechanism in case there are more CPUs than available lanes. We did a comparison between two lane lock strategies - first where we kept an atomic counter around that tracked which was the last lane that was used, and 'our' lane was determined by atomically incrementing that. That way, for the nr_cpus > nr_lanes case, theoretically, no CPU would be blocked waiting for a lane. The other strategy was to use the cpu number we're scheduled on to and hash it to a lane number. Theoretically, this could block an IO that could've otherwise run using a different, free lane. But some fio workloads showed that the direct cpu -> lane hash performed faster than tracking 'last lane' - my reasoning is the cache thrash caused by moving the atomic variable made that approach slower than simply waiting out the in-progress IO. This supports the conclusion that the driver can be a very simple bio-based one that does synchronous IOs instead of queuing. Cc: Andy Lutomirski <luto@amacapital.net> Cc: Boaz Harrosh <boaz@plexistor.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jens Axboe <axboe@fb.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Neil Brown <neilb@suse.de> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Greg KH <gregkh@linuxfoundation.org> [jmoyer: fix nmi watchdog timeout in btt_map_init] [jmoyer: move btt initialization to module load path] [jmoyer: fix memory leak in the btt initialization path] [jmoyer: Don't overwrite corrupted arenas] Signed-off-by: Vishal Verma <vishal.l.verma@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-06-25libnvdimm: infrastructure for btt devicesDan Williams1-3/+5
NVDIMM namespaces, in addition to accepting "struct bio" based requests, also have the capability to perform byte-aligned accesses. By default only the bio/block interface is used. However, if another driver can make effective use of the byte-aligned capability it can claim namespace interface and use the byte-aligned ->rw_bytes() interface. The BTT driver is the initial first consumer of this mechanism to allow adding atomic sector update semantics to a pmem or blk namespace. This patch is the sysfs infrastructure to allow configuring a BTT instance for a namespace. Enabling that BTT and performing i/o is in a subsequent patch. Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-06-25libnvdimm: pmem label sets and namespace instantiation.Dan Williams1-0/+3
A complete label set is a PMEM-label per-dimm per-interleave-set where all the UUIDs match and the interleave set cookie matches the hosting interleave set. Present sysfs attributes for manipulation of a PMEM-namespace's 'alt_name', 'uuid', and 'size' attributes. A later patch will make these settings persistent by writing back the label. Note that PMEM allocations grow forwards from the start of an interleave set (lowest dimm-physical-address (DPA)). BLK-namespaces that alias with a PMEM interleave set will grow allocations backward from the highest DPA. Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Neil Brown <neilb@suse.de> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-06-25libnvdimm: support for legacy (non-aliasing) nvdimmsDan Williams1-0/+93
The libnvdimm region driver is an intermediary driver that translates non-volatile "region"s into "namespace" sub-devices that are surfaced by persistent memory block-device drivers (PMEM and BLK). ACPI 6 introduces the concept that a given nvdimm may simultaneously offer multiple access modes to its media through direct PMEM load/store access, or windowed BLK mode. Existing nvdimms mostly implement a PMEM interface, some offer a BLK-like mode, but never both as ACPI 6 defines. If an nvdimm is single interfaced, then there is no need for dimm metadata labels. For these devices we can take the region boundaries directly to create a child namespace device (nd_namespace_io). Acked-by: Christoph Hellwig <hch@lst.de> Tested-by: Toshi Kani <toshi.kani@hp.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>