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;
  22         static unsigned long once;
  23         struct nd_region_namespaces *num_ns;
  24         struct nd_region *nd_region = to_nd_region(dev);
  25         int rc = nd_region_register_namespaces(nd_region, &err);
  26
  27         if (nd_region->num_lanes > num_online_cpus()
  28                         && nd_region->num_lanes < num_possible_cpus()
  29                         && !test_and_set_bit(0, &once)) {
  30                 dev_info(dev, "online cpus (%d) < concurrent i/o lanes (%d) < possible cpus (%d)\n",
  31                                 num_online_cpus(), nd_region->num_lanes,
  32                                 num_possible_cpus());
  33                 dev_info(dev, "setting nr_cpus=%d may yield better libnvdimm device performance\n",
  34                                 nd_region->num_lanes);
  35         }
  36
  37         num_ns = devm_kzalloc(dev, sizeof(*num_ns), GFP_KERNEL);
  38         if (!num_ns)
  39                 return -ENOMEM;
  40
  41         if (rc < 0)
  42                 return rc;
  43
  44         num_ns->active = rc;
  45         num_ns->count = rc + err;
  46         dev_set_drvdata(dev, num_ns);
  47
  48         if (rc && err && rc == err)
  49                 return -ENODEV;
  50
  51         nd_region->btt_seed = nd_btt_create(nd_region);
  52         if (err == 0)
  53                 return 0;
  54
  55         /*
  56          * Given multiple namespaces per region, we do not want to
  57          * disable all the successfully registered peer namespaces upon
  58          * a single registration failure.  If userspace is missing a
  59          * namespace that it expects it can disable/re-enable the region
  60          * to retry discovery after correcting the failure.
  61          * <regionX>/namespaces returns the current
  62          * "<async-registered>/<total>" namespace count.
  63          */
  64         dev_err(dev, "failed to register %d namespace%s, continuing...\n",
  65                         err, err == 1 ? "" : "s");
  66         return 0;
  67 }
  68
  69 static int child_unregister(struct device *dev, void *data)
  70 {
  71         nd_device_unregister(dev, ND_SYNC);
  72         return 0;
  73 }
  74
  75 static int nd_region_remove(struct device *dev)
  76 {
  77         struct nd_region *nd_region = to_nd_region(dev);
  78
  79         /* flush attribute readers and disable */
  80         nvdimm_bus_lock(dev);
  81         nd_region->ns_seed = NULL;
  82         nd_region->btt_seed = NULL;
  83         dev_set_drvdata(dev, NULL);
  84         nvdimm_bus_unlock(dev);
  85
  86         device_for_each_child(dev, NULL, child_unregister);
  87         return 0;
  88 }
  89
  90 static struct nd_device_driver nd_region_driver = {
  91         .probe = nd_region_probe,
  92         .remove = nd_region_remove,
  93         .drv = {
  94                 .name = "nd_region",
  95         },
  96         .type = ND_DRIVER_REGION_BLK | ND_DRIVER_REGION_PMEM,
  97 };
  98
  99 int __init nd_region_init(void)
 100 {
 101         return nd_driver_register(&nd_region_driver);
 102 }
 103
 104 void nd_region_exit(void)
 105 {
 106         driver_unregister(&nd_region_driver.drv);
 107 }
 108
 109 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_REGION_PMEM);
 110 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_REGION_BLK);