kernel/drivers/nvdimm/claim.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/device.h>
  14 #include <linux/sizes.h>
  15 #include "nd-core.h"
  16 #include "pfn.h"
  17 #include "btt.h"
  18 #include "nd.h"
  19
  20 void __nd_detach_ndns(struct device *dev, struct nd_namespace_common **_ndns)
  21 {
  22         struct nd_namespace_common *ndns = *_ndns;
  23
  24         dev_WARN_ONCE(dev, !mutex_is_locked(&ndns->dev.mutex)
  25                         || ndns->claim != dev,
  26                         "%s: invalid claim\n", __func__);
  27         ndns->claim = NULL;
  28         *_ndns = NULL;
  29         put_device(&ndns->dev);
  30 }
  31
  32 void nd_detach_ndns(struct device *dev,
  33                 struct nd_namespace_common **_ndns)
  34 {
  35         struct nd_namespace_common *ndns = *_ndns;
  36
  37         if (!ndns)
  38                 return;
  39         get_device(&ndns->dev);
  40         device_lock(&ndns->dev);
  41         __nd_detach_ndns(dev, _ndns);
  42         device_unlock(&ndns->dev);
  43         put_device(&ndns->dev);
  44 }
  45
  46 bool __nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
  47                 struct nd_namespace_common **_ndns)
  48 {
  49         if (attach->claim)
  50                 return false;
  51         dev_WARN_ONCE(dev, !mutex_is_locked(&attach->dev.mutex)
  52                         || *_ndns,
  53                         "%s: invalid claim\n", __func__);
  54         attach->claim = dev;
  55         *_ndns = attach;
  56         get_device(&attach->dev);
  57         return true;
  58 }
  59
  60 bool nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
  61                 struct nd_namespace_common **_ndns)
  62 {
  63         bool claimed;
  64
  65         device_lock(&attach->dev);
  66         claimed = __nd_attach_ndns(dev, attach, _ndns);
  67         device_unlock(&attach->dev);
  68         return claimed;
  69 }
  70
  71 static int namespace_match(struct device *dev, void *data)
  72 {
  73         char *name = data;
  74
  75         return strcmp(name, dev_name(dev)) == 0;
  76 }
  77
  78 static bool is_idle(struct device *dev, struct nd_namespace_common *ndns)
  79 {
  80         struct nd_region *nd_region = to_nd_region(dev->parent);
  81         struct device *seed = NULL;
  82
  83         if (is_nd_btt(dev))
  84                 seed = nd_region->btt_seed;
  85         else if (is_nd_pfn(dev))
  86                 seed = nd_region->pfn_seed;
  87
  88         if (seed == dev || ndns || dev->driver)
  89                 return false;
  90         return true;
  91 }
  92
  93 static void nd_detach_and_reset(struct device *dev,
  94                 struct nd_namespace_common **_ndns)
  95 {
  96         /* detach the namespace and destroy / reset the device */
  97         nd_detach_ndns(dev, _ndns);
  98         if (is_idle(dev, *_ndns)) {
  99                 nd_device_unregister(dev, ND_ASYNC);
 100         } else if (is_nd_btt(dev)) {
 101                 struct nd_btt *nd_btt = to_nd_btt(dev);
 102
 103                 nd_btt->lbasize = 0;
 104                 kfree(nd_btt->uuid);
 105                 nd_btt->uuid = NULL;
 106         } else if (is_nd_pfn(dev)) {
 107                 struct nd_pfn *nd_pfn = to_nd_pfn(dev);
 108
 109                 kfree(nd_pfn->uuid);
 110                 nd_pfn->uuid = NULL;
 111                 nd_pfn->mode = PFN_MODE_NONE;
 112         }
 113 }
 114
 115 ssize_t nd_namespace_store(struct device *dev,
 116                 struct nd_namespace_common **_ndns, const char *buf,
 117                 size_t len)
 118 {
 119         struct nd_namespace_common *ndns;
 120         struct device *found;
 121         char *name;
 122
 123         if (dev->driver) {
 124                 dev_dbg(dev, "%s: -EBUSY\n", __func__);
 125                 return -EBUSY;
 126         }
 127
 128         name = kstrndup(buf, len, GFP_KERNEL);
 129         if (!name)
 130                 return -ENOMEM;
 131         strim(name);
 132
 133         if (strncmp(name, "namespace", 9) == 0 || strcmp(name, "") == 0)
 134                 /* pass */;
 135         else {
 136                 len = -EINVAL;
 137                 goto out;
 138         }
 139
 140         ndns = *_ndns;
 141         if (strcmp(name, "") == 0) {
 142                 nd_detach_and_reset(dev, _ndns);
 143                 goto out;
 144         } else if (ndns) {
 145                 dev_dbg(dev, "namespace already set to: %s\n",
 146                                 dev_name(&ndns->dev));
 147                 len = -EBUSY;
 148                 goto out;
 149         }
 150
 151         found = device_find_child(dev->parent, name, namespace_match);
 152         if (!found) {
 153                 dev_dbg(dev, "'%s' not found under %s\n", name,
 154                                 dev_name(dev->parent));
 155                 len = -ENODEV;
 156                 goto out;
 157         }
 158
 159         ndns = to_ndns(found);
 160         if (__nvdimm_namespace_capacity(ndns) < SZ_16M) {
 161                 dev_dbg(dev, "%s too small to host\n", name);
 162                 len = -ENXIO;
 163                 goto out_attach;
 164         }
 165
 166         WARN_ON_ONCE(!is_nvdimm_bus_locked(dev));
 167         if (!nd_attach_ndns(dev, ndns, _ndns)) {
 168                 dev_dbg(dev, "%s already claimed\n",
 169                                 dev_name(&ndns->dev));
 170                 len = -EBUSY;
 171         }
 172
 173  out_attach:
 174         put_device(&ndns->dev); /* from device_find_child */
 175  out:
 176         kfree(name);
 177         return len;
 178 }
 179
 180 /*
 181  * nd_sb_checksum: compute checksum for a generic info block
 182  *
 183  * Returns a fletcher64 checksum of everything in the given info block
 184  * except the last field (since that's where the checksum lives).
 185  */
 186 u64 nd_sb_checksum(struct nd_gen_sb *nd_gen_sb)
 187 {
 188         u64 sum;
 189         __le64 sum_save;
 190
 191         BUILD_BUG_ON(sizeof(struct btt_sb) != SZ_4K);
 192         BUILD_BUG_ON(sizeof(struct nd_pfn_sb) != SZ_4K);
 193         BUILD_BUG_ON(sizeof(struct nd_gen_sb) != SZ_4K);
 194
 195         sum_save = nd_gen_sb->checksum;
 196         nd_gen_sb->checksum = 0;
 197         sum = nd_fletcher64(nd_gen_sb, sizeof(*nd_gen_sb), 1);
 198         nd_gen_sb->checksum = sum_save;
 199         return sum;
 200 }
 201 EXPORT_SYMBOL(nd_sb_checksum);