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