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
  89         if (seed == dev || ndns || dev->driver)
  90                 return false;
  91         return true;
  92 }
  93
  94 static void nd_detach_and_reset(struct device *dev,
  95                 struct nd_namespace_common **_ndns)
  96 {
  97         /* detach the namespace and destroy / reset the device */
  98         nd_detach_ndns(dev, _ndns);
  99         if (is_idle(dev, *_ndns)) {
 100                 nd_device_unregister(dev, ND_ASYNC);
 101         } else if (is_nd_btt(dev)) {
 102                 struct nd_btt *nd_btt = to_nd_btt(dev);
 103
 104                 nd_btt->lbasize = 0;
 105                 kfree(nd_btt->uuid);
 106                 nd_btt->uuid = NULL;
 107         } else if (is_nd_pfn(dev)) {
 108                 struct nd_pfn *nd_pfn = to_nd_pfn(dev);
 109
 110                 kfree(nd_pfn->uuid);
 111                 nd_pfn->uuid = NULL;
 112                 nd_pfn->mode = PFN_MODE_NONE;
 113         }
 114 }
 115
 116 ssize_t nd_namespace_store(struct device *dev,
 117                 struct nd_namespace_common **_ndns, const char *buf,
 118                 size_t len)
 119 {
 120         struct nd_namespace_common *ndns;
 121         struct device *found;
 122         char *name;
 123
 124         if (dev->driver) {
 125                 dev_dbg(dev, "%s: -EBUSY\n", __func__);
 126                 return -EBUSY;
 127         }
 128
 129         name = kstrndup(buf, len, GFP_KERNEL);
 130         if (!name)
 131                 return -ENOMEM;
 132         strim(name);
 133
 134         if (strncmp(name, "namespace", 9) == 0 || strcmp(name, "") == 0)
 135                 /* pass */;
 136         else {
 137                 len = -EINVAL;
 138                 goto out;
 139         }
 140
 141         ndns = *_ndns;
 142         if (strcmp(name, "") == 0) {
 143                 nd_detach_and_reset(dev, _ndns);
 144                 goto out;
 145         } else if (ndns) {
 146                 dev_dbg(dev, "namespace already set to: %s\n",
 147                                 dev_name(&ndns->dev));
 148                 len = -EBUSY;
 149                 goto out;
 150         }
 151
 152         found = device_find_child(dev->parent, name, namespace_match);
 153         if (!found) {
 154                 dev_dbg(dev, "'%s' not found under %s\n", name,
 155                                 dev_name(dev->parent));
 156                 len = -ENODEV;
 157                 goto out;
 158         }
 159
 160         ndns = to_ndns(found);
 161         if (__nvdimm_namespace_capacity(ndns) < SZ_16M) {
 162                 dev_dbg(dev, "%s too small to host\n", name);
 163                 len = -ENXIO;
 164                 goto out_attach;
 165         }
 166
 167         WARN_ON_ONCE(!is_nvdimm_bus_locked(dev));
 168         if (!nd_attach_ndns(dev, ndns, _ndns)) {
 169                 dev_dbg(dev, "%s already claimed\n",
 170                                 dev_name(&ndns->dev));
 171                 len = -EBUSY;
 172         }
 173
 174  out_attach:
 175         put_device(&ndns->dev); /* from device_find_child */
 176  out:
 177         kfree(name);
 178         return len;
 179 }
 180
 181 /*
 182  * nd_sb_checksum: compute checksum for a generic info block
 183  *
 184  * Returns a fletcher64 checksum of everything in the given info block
 185  * except the last field (since that's where the checksum lives).
 186  */
 187 u64 nd_sb_checksum(struct nd_gen_sb *nd_gen_sb)
 188 {
 189         u64 sum;
 190         __le64 sum_save;
 191
 192         BUILD_BUG_ON(sizeof(struct btt_sb) != SZ_4K);
 193         BUILD_BUG_ON(sizeof(struct nd_pfn_sb) != SZ_4K);
 194         BUILD_BUG_ON(sizeof(struct nd_gen_sb) != SZ_4K);
 195
 196         sum_save = nd_gen_sb->checksum;
 197         nd_gen_sb->checksum = 0;
 198         sum = nd_fletcher64(nd_gen_sb, sizeof(*nd_gen_sb), 1);
 199         nd_gen_sb->checksum = sum_save;
 200         return sum;
 201 }
 202 EXPORT_SYMBOL(nd_sb_checksum);
 203
 204 static int nsio_rw_bytes(struct nd_namespace_common *ndns,
 205                 resource_size_t offset, void *buf, size_t size, int rw)
 206 {
 207         struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 208
 209         if (unlikely(offset + size > nsio->size)) {
 210                 dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
 211                 return -EFAULT;
 212         }
 213
 214         if (rw == READ) {
 215                 unsigned int sz_align = ALIGN(size + (offset & (512 - 1)), 512);
 216
 217                 if (unlikely(is_bad_pmem(&nsio->bb, offset / 512, sz_align)))
 218                         return -EIO;
 219                 return memcpy_from_pmem(buf, nsio->addr + offset, size);
 220         } else {
 221                 memcpy_to_pmem(nsio->addr + offset, buf, size);
 222                 wmb_pmem();
 223         }
 224
 225         return 0;
 226 }
 227
 228 int devm_nsio_enable(struct device *dev, struct nd_namespace_io *nsio)
 229 {
 230         struct resource *res = &nsio->res;
 231         struct nd_namespace_common *ndns = &nsio->common;
 232
 233         nsio->size = resource_size(res);
 234         if (!devm_request_mem_region(dev, res->start, resource_size(res),
 235                                 dev_name(dev))) {
 236                 dev_warn(dev, "could not reserve region %pR\n", res);
 237                 return -EBUSY;
 238         }
 239
 240         ndns->rw_bytes = nsio_rw_bytes;
 241         if (devm_init_badblocks(dev, &nsio->bb))
 242                 return -ENOMEM;
 243         nvdimm_badblocks_populate(to_nd_region(ndns->dev.parent), &nsio->bb,
 244                         &nsio->res);
 245
 246         nsio->addr = devm_memremap(dev, res->start, resource_size(res),
 247                         ARCH_MEMREMAP_PMEM);
 248         if (IS_ERR(nsio->addr))
 249                 return PTR_ERR(nsio->addr);
 250         return 0;
 251 }
 252 EXPORT_SYMBOL_GPL(devm_nsio_enable);
 253
 254 void devm_nsio_disable(struct device *dev, struct nd_namespace_io *nsio)
 255 {
 256         struct resource *res = &nsio->res;
 257
 258         devm_memunmap(dev, nsio->addr);
 259         devm_exit_badblocks(dev, &nsio->bb);
 260         devm_release_mem_region(dev, res->start, resource_size(res));
 261 }
 262 EXPORT_SYMBOL_GPL(devm_nsio_disable);