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