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 "pmem.h"
  18 #include "pfn.h"
  19 #include "btt.h"
  20 #include "nd.h"
  21
  22 void __nd_detach_ndns(struct device *dev, struct nd_namespace_common **_ndns)
  23 {
  24         struct nd_namespace_common *ndns = *_ndns;
  25         struct nvdimm_bus *nvdimm_bus;
  26
  27         if (!ndns)
  28                 return;
  29
  30         nvdimm_bus = walk_to_nvdimm_bus(&ndns->dev);
  31         lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
  32         dev_WARN_ONCE(dev, ndns->claim != dev, "%s: invalid claim\n", __func__);
  33         ndns->claim = NULL;
  34         *_ndns = NULL;
  35         put_device(&ndns->dev);
  36 }
  37
  38 void nd_detach_ndns(struct device *dev,
  39                 struct nd_namespace_common **_ndns)
  40 {
  41         struct nd_namespace_common *ndns = *_ndns;
  42
  43         if (!ndns)
  44                 return;
  45         get_device(&ndns->dev);
  46         nvdimm_bus_lock(&ndns->dev);
  47         __nd_detach_ndns(dev, _ndns);
  48         nvdimm_bus_unlock(&ndns->dev);
  49         put_device(&ndns->dev);
  50 }
  51
  52 bool __nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
  53                 struct nd_namespace_common **_ndns)
  54 {
  55         struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(&attach->dev);
  56
  57         if (attach->claim)
  58                 return false;
  59         lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
  60         dev_WARN_ONCE(dev, *_ndns, "%s: invalid claim\n", __func__);
  61         attach->claim = dev;
  62         *_ndns = attach;
  63         get_device(&attach->dev);
  64         return true;
  65 }
  66
  67 bool nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
  68                 struct nd_namespace_common **_ndns)
  69 {
  70         bool claimed;
  71
  72         nvdimm_bus_lock(&attach->dev);
  73         claimed = __nd_attach_ndns(dev, attach, _ndns);
  74         nvdimm_bus_unlock(&attach->dev);
  75         return claimed;
  76 }
  77
  78 static int namespace_match(struct device *dev, void *data)
  79 {
  80         char *name = data;
  81
  82         return strcmp(name, dev_name(dev)) == 0;
  83 }
  84
  85 static bool is_idle(struct device *dev, struct nd_namespace_common *ndns)
  86 {
  87         struct nd_region *nd_region = to_nd_region(dev->parent);
  88         struct device *seed = NULL;
  89
  90         if (is_nd_btt(dev))
  91                 seed = nd_region->btt_seed;
  92         else if (is_nd_pfn(dev))
  93                 seed = nd_region->pfn_seed;
  94         else if (is_nd_dax(dev))
  95                 seed = nd_region->dax_seed;
  96
  97         if (seed == dev || ndns || dev->driver)
  98                 return false;
  99         return true;
 100 }
 101
 102 struct nd_pfn *to_nd_pfn_safe(struct device *dev)
 103 {
 104         /*
 105          * pfn device attributes are re-used by dax device instances, so we
 106          * need to be careful to correct device-to-nd_pfn conversion.
 107          */
 108         if (is_nd_pfn(dev))
 109                 return to_nd_pfn(dev);
 110
 111         if (is_nd_dax(dev)) {
 112                 struct nd_dax *nd_dax = to_nd_dax(dev);
 113
 114                 return &nd_dax->nd_pfn;
 115         }
 116
 117         WARN_ON(1);
 118         return NULL;
 119 }
 120
 121 static void nd_detach_and_reset(struct device *dev,
 122                 struct nd_namespace_common **_ndns)
 123 {
 124         /* detach the namespace and destroy / reset the device */
 125         __nd_detach_ndns(dev, _ndns);
 126         if (is_idle(dev, *_ndns)) {
 127                 nd_device_unregister(dev, ND_ASYNC);
 128         } else if (is_nd_btt(dev)) {
 129                 struct nd_btt *nd_btt = to_nd_btt(dev);
 130
 131                 nd_btt->lbasize = 0;
 132                 kfree(nd_btt->uuid);
 133                 nd_btt->uuid = NULL;
 134         } else if (is_nd_pfn(dev) || is_nd_dax(dev)) {
 135                 struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 136
 137                 kfree(nd_pfn->uuid);
 138                 nd_pfn->uuid = NULL;
 139                 nd_pfn->mode = PFN_MODE_NONE;
 140         }
 141 }
 142
 143 ssize_t nd_namespace_store(struct device *dev,
 144                 struct nd_namespace_common **_ndns, const char *buf,
 145                 size_t len)
 146 {
 147         struct nd_namespace_common *ndns;
 148         struct device *found;
 149         char *name;
 150
 151         if (dev->driver) {
 152                 dev_dbg(dev, "%s: -EBUSY\n", __func__);
 153                 return -EBUSY;
 154         }
 155
 156         name = kstrndup(buf, len, GFP_KERNEL);
 157         if (!name)
 158                 return -ENOMEM;
 159         strim(name);
 160
 161         if (strncmp(name, "namespace", 9) == 0 || strcmp(name, "") == 0)
 162                 /* pass */;
 163         else {
 164                 len = -EINVAL;
 165                 goto out;
 166         }
 167
 168         ndns = *_ndns;
 169         if (strcmp(name, "") == 0) {
 170                 nd_detach_and_reset(dev, _ndns);
 171                 goto out;
 172         } else if (ndns) {
 173                 dev_dbg(dev, "namespace already set to: %s\n",
 174                                 dev_name(&ndns->dev));
 175                 len = -EBUSY;
 176                 goto out;
 177         }
 178
 179         found = device_find_child(dev->parent, name, namespace_match);
 180         if (!found) {
 181                 dev_dbg(dev, "'%s' not found under %s\n", name,
 182                                 dev_name(dev->parent));
 183                 len = -ENODEV;
 184                 goto out;
 185         }
 186
 187         ndns = to_ndns(found);
 188         if (__nvdimm_namespace_capacity(ndns) < SZ_16M) {
 189                 dev_dbg(dev, "%s too small to host\n", name);
 190                 len = -ENXIO;
 191                 goto out_attach;
 192         }
 193
 194         WARN_ON_ONCE(!is_nvdimm_bus_locked(dev));
 195         if (!__nd_attach_ndns(dev, ndns, _ndns)) {
 196                 dev_dbg(dev, "%s already claimed\n",
 197                                 dev_name(&ndns->dev));
 198                 len = -EBUSY;
 199         }
 200
 201  out_attach:
 202         put_device(&ndns->dev); /* from device_find_child */
 203  out:
 204         kfree(name);
 205         return len;
 206 }
 207
 208 /*
 209  * nd_sb_checksum: compute checksum for a generic info block
 210  *
 211  * Returns a fletcher64 checksum of everything in the given info block
 212  * except the last field (since that's where the checksum lives).
 213  */
 214 u64 nd_sb_checksum(struct nd_gen_sb *nd_gen_sb)
 215 {
 216         u64 sum;
 217         __le64 sum_save;
 218
 219         BUILD_BUG_ON(sizeof(struct btt_sb) != SZ_4K);
 220         BUILD_BUG_ON(sizeof(struct nd_pfn_sb) != SZ_4K);
 221         BUILD_BUG_ON(sizeof(struct nd_gen_sb) != SZ_4K);
 222
 223         sum_save = nd_gen_sb->checksum;
 224         nd_gen_sb->checksum = 0;
 225         sum = nd_fletcher64(nd_gen_sb, sizeof(*nd_gen_sb), 1);
 226         nd_gen_sb->checksum = sum_save;
 227         return sum;
 228 }
 229 EXPORT_SYMBOL(nd_sb_checksum);
 230
 231 static int nsio_rw_bytes(struct nd_namespace_common *ndns,
 232                 resource_size_t offset, void *buf, size_t size, int rw,
 233                 unsigned long flags)
 234 {
 235         struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 236         unsigned int sz_align = ALIGN(size + (offset & (512 - 1)), 512);
 237         sector_t sector = offset >> 9;
 238         int rc = 0;
 239
 240         if (unlikely(!size))
 241                 return 0;
 242
 243         if (unlikely(offset + size > nsio->size)) {
 244                 dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
 245                 return -EFAULT;
 246         }
 247
 248         if (rw == READ) {
 249                 if (unlikely(is_bad_pmem(&nsio->bb, sector, sz_align)))
 250                         return -EIO;
 251                 return memcpy_mcsafe(buf, nsio->addr + offset, size);
 252         }
 253
 254         if (unlikely(is_bad_pmem(&nsio->bb, sector, sz_align))) {
 255                 /*
 256                  * FIXME: nsio_rw_bytes() may be called from atomic
 257                  * context in the btt case and the ACPI DSM path for
 258                  * clearing the error takes sleeping locks and allocates
 259                  * memory. An explicit error clearing path, and support
 260                  * for tracking badblocks in BTT metadata is needed to
 261                  * work around this collision.
 262                  */
 263                 if (IS_ALIGNED(offset, 512) && IS_ALIGNED(size, 512)
 264                                 && !(flags & NVDIMM_IO_ATOMIC)
 265                                 && !ndns->claim) {
 266                         long cleared;
 267
 268                         cleared = nvdimm_clear_poison(&ndns->dev,
 269                                         nsio->res.start + offset, size);
 270                         if (cleared < size)
 271                                 rc = -EIO;
 272                         if (cleared > 0 && cleared / 512) {
 273                                 cleared /= 512;
 274                                 badblocks_clear(&nsio->bb, sector, cleared);
 275                         }
 276                         arch_invalidate_pmem(nsio->addr + offset, size);
 277                 } else
 278                         rc = -EIO;
 279         }
 280
 281         memcpy_flushcache(nsio->addr + offset, buf, size);
 282         nvdimm_flush(to_nd_region(ndns->dev.parent));
 283
 284         return rc;
 285 }
 286
 287 int devm_nsio_enable(struct device *dev, struct nd_namespace_io *nsio)
 288 {
 289         struct resource *res = &nsio->res;
 290         struct nd_namespace_common *ndns = &nsio->common;
 291
 292         nsio->size = resource_size(res);
 293         if (!devm_request_mem_region(dev, res->start, resource_size(res),
 294                                 dev_name(&ndns->dev))) {
 295                 dev_warn(dev, "could not reserve region %pR\n", res);
 296                 return -EBUSY;
 297         }
 298
 299         ndns->rw_bytes = nsio_rw_bytes;
 300         if (devm_init_badblocks(dev, &nsio->bb))
 301                 return -ENOMEM;
 302         nvdimm_badblocks_populate(to_nd_region(ndns->dev.parent), &nsio->bb,
 303                         &nsio->res);
 304
 305         nsio->addr = devm_memremap(dev, res->start, resource_size(res),
 306                         ARCH_MEMREMAP_PMEM);
 307
 308         return PTR_ERR_OR_ZERO(nsio->addr);
 309 }
 310 EXPORT_SYMBOL_GPL(devm_nsio_enable);
 311
 312 void devm_nsio_disable(struct device *dev, struct nd_namespace_io *nsio)
 313 {
 314         struct resource *res = &nsio->res;
 315
 316         devm_memunmap(dev, nsio->addr);
 317         devm_exit_badblocks(dev, &nsio->bb);
 318         devm_release_mem_region(dev, res->start, resource_size(res));
 319 }
 320 EXPORT_SYMBOL_GPL(devm_nsio_disable);