kernel/drivers/nvdimm/region.c

   1 /*
   2  * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of version 2 of the GNU General Public License as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  */
  13 #include <linux/cpumask.h>
  14 #include <linux/module.h>
  15 #include <linux/device.h>
  16 #include <linux/nd.h>
  17 #include "nd.h"
  18
  19 static int nd_region_probe(struct device *dev)
  20 {
  21         int err, rc;
  22         static unsigned long once;
  23         struct nd_region_namespaces *num_ns;
  24         struct nd_region *nd_region = to_nd_region(dev);
  25
  26         if (nd_region->num_lanes > num_online_cpus()
  27                         && nd_region->num_lanes < num_possible_cpus()
  28                         && !test_and_set_bit(0, &once)) {
  29                 dev_info(dev, "online cpus (%d) < concurrent i/o lanes (%d) < possible cpus (%d)\n",
  30                                 num_online_cpus(), nd_region->num_lanes,
  31                                 num_possible_cpus());
  32                 dev_info(dev, "setting nr_cpus=%d may yield better libnvdimm device performance\n",
  33                                 nd_region->num_lanes);
  34         }
  35
  36         rc = nd_blk_region_init(nd_region);
  37         if (rc)
  38                 return rc;
  39
  40         rc = nd_region_register_namespaces(nd_region, &err);
  41         num_ns = devm_kzalloc(dev, sizeof(*num_ns), GFP_KERNEL);
  42         if (!num_ns)
  43                 return -ENOMEM;
  44
  45         if (rc < 0)
  46                 return rc;
  47
  48         num_ns->active = rc;
  49         num_ns->count = rc + err;
  50         dev_set_drvdata(dev, num_ns);
  51
  52         if (rc && err && rc == err)
  53                 return -ENODEV;
  54
  55         nd_region->btt_seed = nd_btt_create(nd_region);
  56         nd_region->pfn_seed = nd_pfn_create(nd_region);
  57         if (err == 0)
  58                 return 0;
  59
  60         /*
  61          * Given multiple namespaces per region, we do not want to
  62          * disable all the successfully registered peer namespaces upon
  63          * a single registration failure.  If userspace is missing a
  64          * namespace that it expects it can disable/re-enable the region
  65          * to retry discovery after correcting the failure.
  66          * <regionX>/namespaces returns the current
  67          * "<async-registered>/<total>" namespace count.
  68          */
  69         dev_err(dev, "failed to register %d namespace%s, continuing...\n",
  70                         err, err == 1 ? "" : "s");
  71         return 0;
  72 }
  73
  74 static int child_unregister(struct device *dev, void *data)
  75 {
  76         nd_device_unregister(dev, ND_SYNC);
  77         return 0;
  78 }
  79
  80 static int nd_region_remove(struct device *dev)
  81 {
  82         struct nd_region *nd_region = to_nd_region(dev);
  83
  84         /* flush attribute readers and disable */
  85         nvdimm_bus_lock(dev);
  86         nd_region->ns_seed = NULL;
  87         nd_region->btt_seed = NULL;
  88         nd_region->pfn_seed = NULL;
  89         dev_set_drvdata(dev, NULL);
  90         nvdimm_bus_unlock(dev);
  91
  92         device_for_each_child(dev, NULL, child_unregister);
  93         return 0;
  94 }
  95
  96 static struct nd_device_driver nd_region_driver = {
  97         .probe = nd_region_probe,
  98         .remove = nd_region_remove,
  99         .drv = {
 100                 .name = "nd_region",
 101         },
 102         .type = ND_DRIVER_REGION_BLK | ND_DRIVER_REGION_PMEM,
 103 };
 104
 105 int __init nd_region_init(void)
 106 {
 107         return nd_driver_register(&nd_region_driver);
 108 }
 109
 110 void nd_region_exit(void)
 111 {
 112         driver_unregister(&nd_region_driver.drv);
 113 }
 114
 115 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_REGION_PMEM);
 116 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_REGION_BLK);