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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>
115 lines
3.0 KiB
C
115 lines
3.0 KiB
C
/*
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* Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#include <linux/cpumask.h>
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/nd.h>
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#include "nd.h"
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static int nd_region_probe(struct device *dev)
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{
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int err, rc;
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static unsigned long once;
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struct nd_region_namespaces *num_ns;
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struct nd_region *nd_region = to_nd_region(dev);
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if (nd_region->num_lanes > num_online_cpus()
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&& nd_region->num_lanes < num_possible_cpus()
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&& !test_and_set_bit(0, &once)) {
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dev_info(dev, "online cpus (%d) < concurrent i/o lanes (%d) < possible cpus (%d)\n",
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num_online_cpus(), nd_region->num_lanes,
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num_possible_cpus());
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dev_info(dev, "setting nr_cpus=%d may yield better libnvdimm device performance\n",
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nd_region->num_lanes);
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}
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rc = nd_blk_region_init(nd_region);
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if (rc)
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return rc;
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rc = nd_region_register_namespaces(nd_region, &err);
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num_ns = devm_kzalloc(dev, sizeof(*num_ns), GFP_KERNEL);
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if (!num_ns)
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return -ENOMEM;
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if (rc < 0)
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return rc;
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num_ns->active = rc;
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num_ns->count = rc + err;
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dev_set_drvdata(dev, num_ns);
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if (rc && err && rc == err)
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return -ENODEV;
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nd_region->btt_seed = nd_btt_create(nd_region);
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if (err == 0)
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return 0;
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/*
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* Given multiple namespaces per region, we do not want to
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* disable all the successfully registered peer namespaces upon
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* a single registration failure. If userspace is missing a
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* namespace that it expects it can disable/re-enable the region
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* to retry discovery after correcting the failure.
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* <regionX>/namespaces returns the current
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* "<async-registered>/<total>" namespace count.
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*/
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dev_err(dev, "failed to register %d namespace%s, continuing...\n",
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err, err == 1 ? "" : "s");
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return 0;
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}
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static int child_unregister(struct device *dev, void *data)
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{
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nd_device_unregister(dev, ND_SYNC);
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return 0;
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}
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static int nd_region_remove(struct device *dev)
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{
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struct nd_region *nd_region = to_nd_region(dev);
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/* flush attribute readers and disable */
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nvdimm_bus_lock(dev);
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nd_region->ns_seed = NULL;
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nd_region->btt_seed = NULL;
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dev_set_drvdata(dev, NULL);
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nvdimm_bus_unlock(dev);
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device_for_each_child(dev, NULL, child_unregister);
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return 0;
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}
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static struct nd_device_driver nd_region_driver = {
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.probe = nd_region_probe,
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.remove = nd_region_remove,
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.drv = {
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.name = "nd_region",
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},
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.type = ND_DRIVER_REGION_BLK | ND_DRIVER_REGION_PMEM,
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};
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int __init nd_region_init(void)
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{
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return nd_driver_register(&nd_region_driver);
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}
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void nd_region_exit(void)
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{
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driver_unregister(&nd_region_driver.drv);
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}
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MODULE_ALIAS_ND_DEVICE(ND_DEVICE_REGION_PMEM);
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MODULE_ALIAS_ND_DEVICE(ND_DEVICE_REGION_BLK);
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