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 <linux/pmem.h>
  16 #include "nd-core.h"
  17 #include "pfn.h"
  18 #include "btt.h"
  19 #include "nd.h"
  20
  21 void __nd_detach_ndns(struct device *dev, struct nd_namespace_common **_ndns)
  22 {
  23         struct nd_namespace_common *ndns = *_ndns;
  24
  25         lockdep_assert_held(&ndns->dev.mutex);
  26         dev_WARN_ONCE(dev, ndns->claim != dev, "%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         lockdep_assert_held(&attach->dev.mutex);
  52         dev_WARN_ONCE(dev, *_ndns, "%s: invalid claim\n", __func__);
  53         attach->claim = dev;
  54         *_ndns = attach;
  55         get_device(&attach->dev);
  56         return true;
  57 }
  58
  59 bool nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
  60                 struct nd_namespace_common **_ndns)
  61 {
  62         bool claimed;
  63
  64         device_lock(&attach->dev);
  65         claimed = __nd_attach_ndns(dev, attach, _ndns);
  66         device_unlock(&attach->dev);
  67         return claimed;
  68 }
  69
  70 static int namespace_match(struct device *dev, void *data)
  71 {
  72         char *name = data;
  73
  74         return strcmp(name, dev_name(dev)) == 0;
  75 }
  76
  77 static bool is_idle(struct device *dev, struct nd_namespace_common *ndns)
  78 {
  79         struct nd_region *nd_region = to_nd_region(dev->parent);
  80         struct device *seed = NULL;
  81
  82         if (is_nd_btt(dev))
  83                 seed = nd_region->btt_seed;
  84         else if (is_nd_pfn(dev))
  85                 seed = nd_region->pfn_seed;
  86         else if (is_nd_dax(dev))
  87                 seed = nd_region->dax_seed;
  88
  89         if (seed == dev || ndns || dev->driver)
  90                 return false;
  91         return true;
  92 }
  93
  94 struct nd_pfn *to_nd_pfn_safe(struct device *dev)
  95 {
  96         /*
  97          * pfn device attributes are re-used by dax device instances, so we
  98          * need to be careful to correct device-to-nd_pfn conversion.
  99          */
 100         if (is_nd_pfn(dev))
 101                 return to_nd_pfn(dev);
 102
 103         if (is_nd_dax(dev)) {
 104                 struct nd_dax *nd_dax = to_nd_dax(dev);
 105
 106                 return &nd_dax->nd_pfn;
 107         }
 108
 109         WARN_ON(1);
 110         return NULL;
 111 }
 112
 113 static void nd_detach_and_reset(struct device *dev,
 114                 struct nd_namespace_common **_ndns)
 115 {
 116         /* detach the namespace and destroy / reset the device */
 117         nd_detach_ndns(dev, _ndns);
 118         if (is_idle(dev, *_ndns)) {
 119                 nd_device_unregister(dev, ND_ASYNC);
 120         } else if (is_nd_btt(dev)) {
 121                 struct nd_btt *nd_btt = to_nd_btt(dev);
 122
 123                 nd_btt->lbasize = 0;
 124                 kfree(nd_btt->uuid);
 125                 nd_btt->uuid = NULL;
 126         } else if (is_nd_pfn(dev) || is_nd_dax(dev)) {
 127                 struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 128
 129                 kfree(nd_pfn->uuid);
 130                 nd_pfn->uuid = NULL;
 131                 nd_pfn->mode = PFN_MODE_NONE;
 132         }
 133 }
 134
 135 ssize_t nd_namespace_store(struct device *dev,
 136                 struct nd_namespace_common **_ndns, const char *buf,
 137                 size_t len)
 138 {
 139         struct nd_namespace_common *ndns;
 140         struct device *found;
 141         char *name;
 142
 143         if (dev->driver) {
 144                 dev_dbg(dev, "%s: -EBUSY\n", __func__);
 145                 return -EBUSY;
 146         }
 147
 148         name = kstrndup(buf, len, GFP_KERNEL);
 149         if (!name)
 150                 return -ENOMEM;
 151         strim(name);
 152
 153         if (strncmp(name, "namespace", 9) == 0 || strcmp(name, "") == 0)
 154                 /* pass */;
 155         else {
 156                 len = -EINVAL;
 157                 goto out;
 158         }
 159
 160         ndns = *_ndns;
 161         if (strcmp(name, "") == 0) {
 162                 nd_detach_and_reset(dev, _ndns);
 163                 goto out;
 164         } else if (ndns) {
 165                 dev_dbg(dev, "namespace already set to: %s\n",
 166                                 dev_name(&ndns->dev));
 167                 len = -EBUSY;
 168                 goto out;
 169         }
 170
 171         found = device_find_child(dev->parent, name, namespace_match);
 172         if (!found) {
 173                 dev_dbg(dev, "'%s' not found under %s\n", name,
 174                                 dev_name(dev->parent));
 175                 len = -ENODEV;
 176                 goto out;
 177         }
 178
 179         ndns = to_ndns(found);
 180         if (__nvdimm_namespace_capacity(ndns) < SZ_16M) {
 181                 dev_dbg(dev, "%s too small to host\n", name);
 182                 len = -ENXIO;
 183                 goto out_attach;
 184         }
 185
 186         WARN_ON_ONCE(!is_nvdimm_bus_locked(dev));
 187         if (!nd_attach_ndns(dev, ndns, _ndns)) {
 188                 dev_dbg(dev, "%s already claimed\n",
 189                                 dev_name(&ndns->dev));
 190                 len = -EBUSY;
 191         }
 192
 193  out_attach:
 194         put_device(&ndns->dev); /* from device_find_child */
 195  out:
 196         kfree(name);
 197         return len;
 198 }
 199
 200 /*
 201  * nd_sb_checksum: compute checksum for a generic info block
 202  *
 203  * Returns a fletcher64 checksum of everything in the given info block
 204  * except the last field (since that's where the checksum lives).
 205  */
 206 u64 nd_sb_checksum(struct nd_gen_sb *nd_gen_sb)
 207 {
 208         u64 sum;
 209         __le64 sum_save;
 210
 211         BUILD_BUG_ON(sizeof(struct btt_sb) != SZ_4K);
 212         BUILD_BUG_ON(sizeof(struct nd_pfn_sb) != SZ_4K);
 213         BUILD_BUG_ON(sizeof(struct nd_gen_sb) != SZ_4K);
 214
 215         sum_save = nd_gen_sb->checksum;
 216         nd_gen_sb->checksum = 0;
 217         sum = nd_fletcher64(nd_gen_sb, sizeof(*nd_gen_sb), 1);
 218         nd_gen_sb->checksum = sum_save;
 219         return sum;
 220 }
 221 EXPORT_SYMBOL(nd_sb_checksum);
 222
 223 static int nsio_rw_bytes(struct nd_namespace_common *ndns,
 224                 resource_size_t offset, void *buf, size_t size, int rw)
 225 {
 226         struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 227         unsigned int sz_align = ALIGN(size + (offset & (512 - 1)), 512);
 228         sector_t sector = offset >> 9;
 229         int rc = 0;
 230
 231         if (unlikely(!size))
 232                 return 0;
 233
 234         if (unlikely(offset + size > nsio->size)) {
 235                 dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
 236                 return -EFAULT;
 237         }
 238
 239         if (rw == READ) {
 240                 if (unlikely(is_bad_pmem(&nsio->bb, sector, sz_align)))
 241                         return -EIO;
 242                 return memcpy_from_pmem(buf, nsio->addr + offset, size);
 243         }
 244
 245         if (unlikely(is_bad_pmem(&nsio->bb, sector, sz_align))) {
 246                 /*
 247                  * FIXME: nsio_rw_bytes() may be called from atomic
 248                  * context in the btt case and nvdimm_clear_poison()
 249                  * takes a sleeping lock. Until the locking can be
 250                  * reworked this capability requires that the namespace
 251                  * is not claimed by btt.
 252                  */
 253                 if (IS_ALIGNED(offset, 512) && IS_ALIGNED(size, 512)
 254                                 && (!ndns->claim || !is_nd_btt(ndns->claim))) {
 255                         long cleared;
 256
 257                         cleared = nvdimm_clear_poison(&ndns->dev, offset, size);
 258                         if (cleared < size)
 259                                 rc = -EIO;
 260                         if (cleared > 0 && cleared / 512) {
 261                                 cleared /= 512;
 262                                 badblocks_clear(&nsio->bb, sector, cleared);
 263                         }
 264                         invalidate_pmem(nsio->addr + offset, size);
 265                 } else
 266                         rc = -EIO;
 267         }
 268
 269         memcpy_to_pmem(nsio->addr + offset, buf, size);
 270         nvdimm_flush(to_nd_region(ndns->dev.parent));
 271
 272         return rc;
 273 }
 274
 275 int devm_nsio_enable(struct device *dev, struct nd_namespace_io *nsio)
 276 {
 277         struct resource *res = &nsio->res;
 278         struct nd_namespace_common *ndns = &nsio->common;
 279
 280         nsio->size = resource_size(res);
 281         if (!devm_request_mem_region(dev, res->start, resource_size(res),
 282                                 dev_name(&ndns->dev))) {
 283                 dev_warn(dev, "could not reserve region %pR\n", res);
 284                 return -EBUSY;
 285         }
 286
 287         ndns->rw_bytes = nsio_rw_bytes;
 288         if (devm_init_badblocks(dev, &nsio->bb))
 289                 return -ENOMEM;
 290         nvdimm_badblocks_populate(to_nd_region(ndns->dev.parent), &nsio->bb,
 291                         &nsio->res);
 292
 293         nsio->addr = devm_memremap(dev, res->start, resource_size(res),
 294                         ARCH_MEMREMAP_PMEM);
 295
 296         return PTR_ERR_OR_ZERO(nsio->addr);
 297 }
 298 EXPORT_SYMBOL_GPL(devm_nsio_enable);
 299
 300 void devm_nsio_disable(struct device *dev, struct nd_namespace_io *nsio)
 301 {
 302         struct resource *res = &nsio->res;
 303
 304         devm_memunmap(dev, nsio->addr);
 305         devm_exit_badblocks(dev, &nsio->bb);
 306         devm_release_mem_region(dev, res->start, resource_size(res));
 307 }
 308 EXPORT_SYMBOL_GPL(devm_nsio_disable);