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2017-06-27libnvdimm, pmem: fix persistence warningDan Williams1-2/+3
The pmem driver assumes if platform firmware describes the memory devices associated with a persistent memory range and CONFIG_ARCH_HAS_PMEM_API=y that it has all the mechanism necessary to flush data to a power-fail safe zone. We warn if the firmware does not describe memory devices, but we also need to warn if the architecture does not claim pmem support. Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-06-27x86, libnvdimm, pmem: remove global pmem apiDan Williams1-1/+0
Now that all callers of the pmem api have been converted to dax helpers that call back to the pmem driver, we can remove include/linux/pmem.h and asm/pmem.h. Cc: <x86@kernel.org> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Oliver O'Halloran <oohall@gmail.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-06-15libnvdimm, label: add v1.2 interleave-set-cookie algorithmDan Williams1-5/+38
The interleave-set-cookie algorithm is extended to incorporate all the same components that are used to generate an nvdimm unique-id. For backwards compatibility we still maintain the old v1.1 definition. Reported-by: Nicholas Moulin <nicholas.w.moulin@intel.com> Reported-by: Kaushik Kanetkar <kaushik.a.kanetkar@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-06-09x86, uaccess: introduce copy_from_iter_flushcache for pmem / cache-bypass operationsDan Williams1-2/+2
The pmem driver has a need to transfer data with a persistent memory destination and be able to rely on the fact that the destination writes are not cached. It is sufficient for the writes to be flushed to a cpu-store-buffer (non-temporal / "movnt" in x86 terms), as we expect userspace to call fsync() to ensure data-writes have reached a power-fail-safe zone in the platform. The fsync() triggers a REQ_FUA or REQ_FLUSH to the pmem driver which will turn around and fence previous writes with an "sfence". Implement a __copy_from_user_inatomic_flushcache, memcpy_page_flushcache, and memcpy_flushcache, that guarantee that the destination buffer is not dirty in the cpu cache on completion. The new copy_from_iter_flushcache and sub-routines will be used to replace the "pmem api" (include/linux/pmem.h + arch/x86/include/asm/pmem.h). The availability of copy_from_iter_flushcache() and memcpy_flushcache() are gated by the CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE config symbol, and fallback to copy_from_iter_nocache() and plain memcpy() otherwise. This is meant to satisfy the concern from Linus that if a driver wants to do something beyond the normal nocache semantics it should be something private to that driver [1], and Al's concern that anything uaccess related belongs with the rest of the uaccess code [2]. The first consumer of this interface is a new 'copy_from_iter' dax operation so that pmem can inject cache maintenance operations without imposing this overhead on other dax-capable drivers. [1]: https://lists.01.org/pipermail/linux-nvdimm/2017-January/008364.html [2]: https://lists.01.org/pipermail/linux-nvdimm/2017-April/009942.html Cc: <x86@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Matthew Wilcox <mawilcox@microsoft.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-05-04libnvdimm: convert NDD_ flags to use bitops, introduce NDD_LOCKEDDan Williams1-2/+2
This is a preparation patch for handling locked nvdimm label regions, a new concept as introduced by the latest DSM document on pmem.io [1]. A future patch will leverage nvdimm_set_locked() at DIMM probe time to flag regions that can not be enabled. There should be no functional difference resulting from this change. [1]: http://pmem.io/documents/NVDIMM_DSM_Interface_Example-V1.3.pdf Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-04-29libnvdimm: rework region badblocks clearingDan Williams1-10/+5
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>
2017-04-28libnvdimm, region: sysfs trigger for nvdimm_flush()Dan Williams1-0/+41
The nvdimm_flush() mechanism helps to reduce the impact of an ADR (asynchronous-dimm-refresh) failure. The ADR mechanism handles flushing platform WPQ (write-pending-queue) buffers when power is removed. The nvdimm_flush() mechanism performs that same function on-demand. When a pmem namespace is associated with a block device, an nvdimm_flush() is triggered with every block-layer REQ_FUA, or REQ_FLUSH request. These requests are typically associated with filesystem metadata updates. However, when a namespace is in device-dax mode, userspace (think database metadata) needs another path to perform the same flushing. In other words this is not required to make data persistent, but in the case of metadata it allows for a smaller failure domain in the unlikely event of an ADR failure. The new 'deep_flush' attribute is visible when the individual DIMMs backing a given interleave-set are described by platform firmware. In ACPI terms this is "NVDIMM Region Mapping Structures" and associated "Flush Hint Address Structures". Reads return "1" if the region supports triggering WPQ flushes on all DIMMs. Reads return "0" the flush operation is a platform nop, and in that case the attribute is read-only. Why sysfs and not an ioctl? An ioctl requires establishing a new ioctl function number space for device-dax. Given that this would be called on a device-dax fd an application could be forgiven for accidentally calling this on a filesystem-dax fd. Placing this interface in libnvdimm sysfs removes that potential for collision with a filesystem ioctl, and it keeps ioctls out of the generic device-dax implementation. Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-04-24libnvdimm, region: fix flush hint detection crashDan Williams1-4/+7
In the case where a dimm does not have any associated flush hints the ndrd->flush_wpq array may be uninitialized leading to crashes with the following signature: BUG: unable to handle kernel NULL pointer dereference at 0000000000000010 IP: region_visible+0x10f/0x160 [libnvdimm] Call Trace: internal_create_group+0xbe/0x2f0 sysfs_create_groups+0x40/0x80 device_add+0x2d8/0x650 nd_async_device_register+0x12/0x40 [libnvdimm] async_run_entry_fn+0x39/0x170 process_one_work+0x212/0x6c0 ? process_one_work+0x197/0x6c0 worker_thread+0x4e/0x4a0 kthread+0x10c/0x140 ? process_one_work+0x6c0/0x6c0 ? kthread_create_on_node+0x60/0x60 ret_from_fork+0x31/0x40 Cc: <stable@vger.kernel.org> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Fixes: f284a4f23752 ("libnvdimm: introduce nvdimm_flush() and nvdimm_has_flush()") Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-04-12libnvdimm: Add 'resource' sysfs attribute to regionsDave Jiang1-0/+13
Adding sysfs attribute in order to export the physical address of the region. This is for supporting of user app poison clear via ND_IOCTL_CLEAR_ERROR. 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>
2017-04-12libnvdimm: add mechanism to publish badblocks at the region levelDave Jiang1-0/+19
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>
2017-03-01nfit, libnvdimm: fix interleave set cookie calculationDan Williams1-0/+9
The interleave-set cookie is a sum that sanity checks the composition of an interleave set has not changed from when the namespace was initially created. The checksum is calculated by sorting the DIMMs by their location in the interleave-set. The comparison for the sort must be 64-bit wide, not byte-by-byte as performed by memcmp() in the broken case. Fix the implementation to accept correct cookie values in addition to the Linux "memcmp" order cookies, but only allow correct cookies to be generated going forward. It does mean that namespaces created by third-party-tooling, or created by newer kernels with this fix, will not validate on older kernels. However, there are a couple mitigating conditions: 1/ platforms with namespace-label capable NVDIMMs are not widely available. 2/ interleave-sets with a single-dimm are by definition not affected (nothing to sort). This covers the QEMU-KVM NVDIMM emulation case. The cookie stored in the namespace label will be fixed by any write the namespace label, the most straightforward way to achieve this is to write to the "alt_name" attribute of a namespace in sysfs. Cc: <stable@vger.kernel.org> Fixes: eaf961536e16 ("libnvdimm, nfit: add interleave-set state-tracking infrastructure") Reported-by: Nicholas Moulin <nicholas.w.moulin@linux.intel.com> Tested-by: Nicholas Moulin <nicholas.w.moulin@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-12-15libnvdimm: replace mutex_is_locked() warnings with lockdep_assert_heldDan Williams1-1/+1
For warnings that should only ever trigger during development and testing replace WARN statements with lockdep_assert_held. The lockdep pattern is prevalent, and these paths are are well covered by libnvdimm unit tests. Reported-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-10-07Merge branch 'for-4.9/libnvdimm' into libnvdimm-for-nextDan Williams1-17/+41
2016-10-07libnvdimm, namespace: allow creation of multiple pmem-namespaces per regionDan Williams1-5/+13
Similar to BLK regions, publish new seed namespace devices to allow unused PMEM region capacity to be consumed by additional namespaces. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-10-07libnvdimm, region: update nd_region_available_dpa() for multi-pmem supportDan Williams1-3/+2
The free dpa (dimm-physical-address) space calculation reports how much free space is available with consideration for aliased BLK + PMEM regions. Recall that BLK capacity is allocated from high addresses and PMEM is allocated from low addresses in their respective regions. nd_region_available_dpa() accounts for the fact that the largest encroachment (lowest starting address) into PMEM capacity by a BLK allocation limits the available capacity to that point, regardless if there is BLK allocation hole at a higher address. Similarly, for the multi-pmem case we need to track the largest encroachment (highest ending address) of a PMEM allocation in BLK capacity regardless of whether there is an allocation hole that a BLK allocation could fill at a lower address. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-09-30libnvdimm, label: convert label tracking to a linked listDan Williams1-2/+17
In preparation for enabling multiple namespaces per pmem region, convert the label tracking to use a linked list. In particular this will allow select_pmem_id() to move labels from the unvalidated state to the validated state. Currently we only track one validated set per-region. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-09-30libnvdimm, region: move region-mapping input-paramters to nd_mapping_descDan Williams1-7/+9
Before we add more libnvdimm-private fields to nd_mapping make it clear which parameters are input vs libnvdimm internals. Use struct nd_mapping_desc instead of struct nd_mapping in nd_region_desc and make struct nd_mapping private to libnvdimm. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-09-30nvdimm: reduce duplicated wpq flushesDave Jiang1-1/+16
Existing implemenetation writes to all the flush hint addresses for a given ND region. This is not necessary as the flushes are per imc and not per DIMM. Search the mappings and clear out the duplicates at init to avoid multiple flush to the same imc. Signed-off-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-09-24libnvdimm, region: fix flush hint table thinkoDan Williams1-8/+12
The definition of the flush hint table as: void __iomem *flush_wpq[0][0]; ...passed the unit test, but is broken as flush_wpq[0][1] and flush_wpq[1][0] refer to the same entry. Fix this to use a helper that calculates a slot in the table based on the geometry of flush hints in the region. This is important to get right since virtualization solutions use this mechanism to trigger hypervisor flushes to platform persistence. Reported-by: Dave Jiang <dave.jiang@intel.com> Tested-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-09-19nvdimm: fix PHYS_PFN/PFN_PHYS mixupOliver O'Halloran1-1/+1
nd_activate_region() iomaps any hint addresses required when activating a region. To prevent duplicate mappings it checks the PFN of the hint to be mapped against the PFNs of the already mapped hints. Unfortunately it doesn't convert the PFN back into a physical address before passing it to devm_nvdimm_ioremap(). Instead it applies PHYS_PFN a second time which ends about as well as you would imagine. Signed-off-by: Oliver O'Halloran <oohall@gmail.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-07-11libnvdimm: cycle flush hintsDan Williams1-3/+14
When the NFIT provides multiple flush hint addresses per-dimm it is expressing that the platform is capable of processing multiple flush requests in parallel. There is some fixed cost per flush request, let the cost be shared in parallel on multiple cpus. Since there may not be enough flush hint addresses for each cpu to have one, keep a per-cpu index of the last used hint, hash it with current pid, and assume that access pattern and scheduler randomness will keep the flush-hint usage somewhat staggered across cpus. Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-07-11libnvdimm: introduce nvdimm_flush() and nvdimm_has_flush()Dan Williams1-0/+61
nvdimm_flush() is a replacement for the x86 'pcommit' instruction. It is an optional write flushing mechanism that an nvdimm bus can provide for the pmem driver to consume. In the case of the NFIT nvdimm-bus-provider nvdimm_flush() is implemented as a series of flush-hint-address [1] writes to each dimm in the interleave set (region) that backs the namespace. The nvdimm_has_flush() routine relies on platform firmware to describe the flushing capabilities of a platform. It uses the heuristic of whether an nvdimm bus provider provides flush address data to return a ternary result: 1: flush addresses defined 0: dimm topology described without flush addresses (assume ADR) -errno: no topology information, unable to determine flush mechanism The pmem driver is expected to take the following actions on this ternary result: 1: nvdimm_flush() in response to REQ_FUA / REQ_FLUSH and shutdown 0: do not set, WC or FUA on the queue, take no further action -errno: warn and then operate as if nvdimm_has_flush() returned '0' The caveat of this heuristic is that it can not distinguish the "dimm does not have flush address" case from the "platform firmware is broken and failed to describe a flush address". Given we are already explicitly trusting the NFIT there's not much more we can do beyond blacklisting broken firmwares if they are ever encountered. Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-07-11libnvdimm, nfit: move flush hint mapping to region-device driver-dataDan Williams1-3/+76
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>
2016-07-11libnvdimm, nfit: remove nfit_spa_map() infrastructureDan Williams1-3/+0
Now that all shared mappings are handled by devm_nvdimm_memremap() we no longer need nfit_spa_map() nor do we need to trigger a callback to the bus provider at region disable time. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-05-20libnvdimm: release ida resourcesDan Williams1-0/+5
ida instances allocate some internal memory for ->free_bitmap in addition to the base 'struct ida'. Use ida_destroy() to release that memory at module_exit(). Reported-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-05-09libnvdimm, dax: introduce device-dax infrastructureDan Williams1-0/+29
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>
2016-01-05libnvdimm: fix namespace object confusion in is_uuid_busy()Dan Williams1-56/+0
When btt devices were re-worked to be child devices of regions this routine was overlooked. It mistakenly attempts to_nd_namespace_pmem() or to_nd_namespace_blk() conversions on btt and pfn devices. By luck to date we have happened to be hitting valid memory leading to a uuid miscompare, but a recent change to struct nd_namespace_common causes: BUG: unable to handle kernel NULL pointer dereference at 0000000000000001 IP: [<ffffffff814610dc>] memcmp+0xc/0x40 [..] Call Trace: [<ffffffffa0028631>] is_uuid_busy+0xc1/0x2a0 [libnvdimm] [<ffffffffa0028570>] ? to_nd_blk_region+0x50/0x50 [libnvdimm] [<ffffffff8158c9c0>] device_for_each_child+0x50/0x90 Cc: <stable@vger.kernel.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-12-13libnvdimm, pfn: fix pfn seed creationDan Williams1-0/+7
Similar to btt, plant a new pfn seed when the existing one is activated. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-12-08nvdimm: do not show pfn_seed for non pmem regionsDmitry Krivenok1-0/+3
This simple change hides pfn_seed attribute for non pmem regions because they don't support pfn anyway. Signed-off-by: Dmitry V. Krivenok <krivenok.dmitry@gmail.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-08-28libnvdimm, pmem: direct map legacy pmem by defaultDan Williams1-0/+1
The expectation is that the legacy / non-standard pmem discovery method (e820 type-12) will only ever be used to describe small quantities of persistent memory. Larger capacities will be described via the ACPI NFIT. When "allocate struct page from pmem" support is added this default policy can be overridden by assigning a legacy pmem namespace to a pfn device, however this would be only be necessary if a platform used the legacy mechanism to define a very large range. Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-08-28libnvdimm, pfn: 'struct page' provider infrastructureDan Williams1-0/+19
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>
2015-07-25libnvdimm: fix namespace seed creationDan Williams1-0/+5
A new BLK namespace "seed" device is created whenever the current seed is successfully probed. However, if that namespace is assigned to a BTT it may never directly experience a successful probe as it is a subordinate device to a BTT configuration. The effect of the current code is that no new namespaces can be instantiated, after the seed namespace, to consume available BLK DPA capacity. Fix this by treating a successful BTT probe event as a successful probe event for the backing namespace. Reported-by: Nicholas Moulin <nicholas.w.moulin@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-06-26libnvdimm: Set numa_node to NVDIMM devicesToshi Kani1-0/+1
ACPI NFIT table has System Physical Address Range Structure entries that describe a proximity ID of each range when ACPI_NFIT_PROXIMITY_VALID is set in the flags. Change acpi_nfit_register_region() to map a proximity ID to its node ID, and set it to a new numa_node field of nd_region_desc, which is then conveyed to the nd_region device. The device core arranges for btt and namespace devices to inherit their node from their parent region. Signed-off-by: Toshi Kani <toshi.kani@hp.com> [djbw: move set_dev_node() from region.c to bus.c] Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-06-26libnvdimm, nfit: handle unarmed dimms, mark namespaces read-onlyDan Williams1-0/+29
Upon detection of an unarmed dimm in a region, arrange for descendant BTT, PMEM, or BLK instances to be read-only. A dimm is primarily marked "unarmed" via flags passed by platform firmware (NFIT). The flags in the NFIT memory device sub-structure indicate the state of the data on the nvdimm relative to its energy source or last "flush to persistence". For the most part there is nothing the driver can do but advertise the state of these flags in sysfs and emit a message if firmware indicates that the contents of the device may be corrupted. However, for the case of ACPI_NFIT_MEM_ARMED, the driver can arrange for the block devices incorporating that nvdimm to be marked read-only. This is a safe default as the data is still available and new writes are held off until the administrator either forces read-write mode, or the energy source becomes armed. A 'read_only' attribute is added to REGION devices to allow for overriding the default read-only policy of all descendant block devices. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-06-26libnvdimm, nfit, nd_blk: driver for BLK-mode access persistent memoryRoss Zwisler1-11/+80
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 Verma1-4/+78
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 Williams1-5/+34
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>
2015-06-24libnvdimm: blk labels and namespace instantiationDan Williams1-2/+15
A blk label set describes a namespace comprised of one or more discontiguous dpa ranges on a single dimm. They may alias with one or more pmem interleave sets that include the given dimm. This is the runtime/volatile configuration infrastructure for sysfs manipulation of 'alt_name', 'uuid', 'size', and 'sector_size'. A later patch will make these settings persistent by writing back the label(s). Unlike pmem namespaces, multiple blk namespaces can be created per region. Once a blk namespace has been created a new seed device (unconfigured child of a parent blk region) is instantiated. As long as a region has 'available_size' != 0 new child namespaces may be created. 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>
2015-06-24libnvdimm: pmem label sets and namespace instantiation.Dan Williams1-8/+150
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>
2015-06-24libnvdimm, nfit: add interleave-set state-tracking infrastructureDan Williams1-0/+69
On platforms that have firmware support for reading/writing per-dimm label space, a portion of the dimm may be accessible via an interleave set PMEM mapping in addition to the dimm's BLK (block-data-window aperture(s)) interface. A label, stored in a "configuration data region" on the dimm, disambiguates which dimm addresses are accessed through which exclusive interface. Add infrastructure that allows the kernel to block modifications to a label in the set while any member dimm is active. Note that this is meant only for enforcing "no modifications of active labels" via the coarse ioctl command. Adding/deleting namespaces from an active interleave set is always possible via sysfs. Another aspect of tracking interleave sets is tracking their integrity when DIMMs in a set are physically re-ordered. For this purpose we generate an "interleave-set cookie" that can be recorded in a label and validated against the current configuration. It is the bus provider implementation's responsibility to calculate the interleave set cookie and attach it to a given region. Cc: Neil Brown <neilb@suse.de> Cc: <linux-acpi@vger.kernel.org> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Robert Moore <robert.moore@intel.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Christoph Hellwig <hch@lst.de> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-06-24libnvdimm: support for legacy (non-aliasing) nvdimmsDan Williams1-1/+65
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>
2015-06-24libnvdimm, nfit: regions (block-data-window, persistent memory, volatile memory)Dan Williams1-0/+297
A "region" device represents the maximum capacity of a BLK range (mmio block-data-window(s)), or a PMEM range (DAX-capable persistent memory or volatile memory), without regard for aliasing. Aliasing, in the dimm-local address space (DPA), is resolved by metadata on a dimm to designate which exclusive interface will access the aliased DPA ranges. Support for the per-dimm metadata/label arrvies is in a subsequent patch. The name format of "region" devices is "regionN" where, like dimms, N is a global ida index assigned at discovery time. This id is not reliable across reboots nor in the presence of hotplug. Look to attributes of the region or static id-data of the sub-namespace to generate a persistent name. However, if the platform configuration does not change it is reasonable to expect the same region id to be assigned at the next boot. "region"s have 2 generic attributes "size", and "mapping"s where: - size: the BLK accessible capacity or the span of the system physical address range in the case of PMEM. - mappingN: a tuple describing a dimm's contribution to the region's capacity in the format (<nmemX>,<dpa>,<size>). For a PMEM-region there will be at least one mapping per dimm in the interleave set. For a BLK-region there is only "mapping0" listing the starting DPA of the BLK-region and the available DPA capacity of that space (matches "size" above). The max number of mappings per "region" is hard coded per the constraints of sysfs attribute groups. That said the number of mappings per region should never exceed the maximum number of possible dimms in the system. If the current number turns out to not be enough then the "mappings" attribute clarifies how many there are supposed to be. "32 should be enough for anybody...". Cc: Neil Brown <neilb@suse.de> Cc: <linux-acpi@vger.kernel.org> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Robert Moore <robert.moore@intel.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Christoph Hellwig <hch@lst.de> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Toshi Kani <toshi.kani@hp.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>