drivers/nvdimm/blk.c

   1 /*
   2  * NVDIMM Block Window Driver
   3  * Copyright (c) 2014, Intel Corporation.
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms and conditions of the GNU General Public License,
   7  * version 2, as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  */
  14
  15 #include <linux/blkdev.h>
  16 #include <linux/fs.h>
  17 #include <linux/genhd.h>
  18 #include <linux/module.h>
  19 #include <linux/moduleparam.h>
  20 #include <linux/nd.h>
  21 #include <linux/sizes.h>
  22 #include "nd.h"
  23
  24 static u32 nsblk_meta_size(struct nd_namespace_blk *nsblk)
  25 {
  26         return nsblk->lbasize - ((nsblk->lbasize >= 4096) ? 4096 : 512);
  27 }
  28
  29 static u32 nsblk_internal_lbasize(struct nd_namespace_blk *nsblk)
  30 {
  31         return roundup(nsblk->lbasize, INT_LBASIZE_ALIGNMENT);
  32 }
  33
  34 static u32 nsblk_sector_size(struct nd_namespace_blk *nsblk)
  35 {
  36         return nsblk->lbasize - nsblk_meta_size(nsblk);
  37 }
  38
  39 static resource_size_t to_dev_offset(struct nd_namespace_blk *nsblk,
  40                                 resource_size_t ns_offset, unsigned int len)
  41 {
  42         int i;
  43
  44         for (i = 0; i < nsblk->num_resources; i++) {
  45                 if (ns_offset < resource_size(nsblk->res[i])) {
  46                         if (ns_offset + len > resource_size(nsblk->res[i])) {
  47                                 dev_WARN_ONCE(&nsblk->common.dev, 1,
  48                                         "illegal request\n");
  49                                 return SIZE_MAX;
  50                         }
  51                         return nsblk->res[i]->start + ns_offset;
  52                 }
  53                 ns_offset -= resource_size(nsblk->res[i]);
  54         }
  55
  56         dev_WARN_ONCE(&nsblk->common.dev, 1, "request out of range\n");
  57         return SIZE_MAX;
  58 }
  59
  60 static struct nd_blk_region *to_ndbr(struct nd_namespace_blk *nsblk)
  61 {
  62         struct nd_region *nd_region;
  63         struct device *parent;
  64
  65         parent = nsblk->common.dev.parent;
  66         nd_region = container_of(parent, struct nd_region, dev);
  67         return container_of(nd_region, struct nd_blk_region, nd_region);
  68 }
  69
  70 #ifdef CONFIG_BLK_DEV_INTEGRITY
  71 static int nd_blk_rw_integrity(struct nd_namespace_blk *nsblk,
  72                 struct bio_integrity_payload *bip, u64 lba, int rw)
  73 {
  74         struct nd_blk_region *ndbr = to_ndbr(nsblk);
  75         unsigned int len = nsblk_meta_size(nsblk);
  76         resource_size_t dev_offset, ns_offset;
  77         u32 internal_lbasize, sector_size;
  78         int err = 0;
  79
  80         internal_lbasize = nsblk_internal_lbasize(nsblk);
  81         sector_size = nsblk_sector_size(nsblk);
  82         ns_offset = lba * internal_lbasize + sector_size;
  83         dev_offset = to_dev_offset(nsblk, ns_offset, len);
  84         if (dev_offset == SIZE_MAX)
  85                 return -EIO;
  86
  87         while (len) {
  88                 unsigned int cur_len;
  89                 struct bio_vec bv;
  90                 void *iobuf;
  91
  92                 bv = bvec_iter_bvec(bip->bip_vec, bip->bip_iter);
  93                 /*
  94                  * The 'bv' obtained from bvec_iter_bvec has its .bv_len and
  95                  * .bv_offset already adjusted for iter->bi_bvec_done, and we
  96                  * can use those directly
  97                  */
  98
  99                 cur_len = min(len, bv.bv_len);
 100                 iobuf = kmap_atomic(bv.bv_page);
 101                 err = ndbr->do_io(ndbr, dev_offset, iobuf + bv.bv_offset,
 102                                 cur_len, rw);
 103                 kunmap_atomic(iobuf);
 104                 if (err)
 105                         return err;
 106
 107                 len -= cur_len;
 108                 dev_offset += cur_len;
 109                 bvec_iter_advance(bip->bip_vec, &bip->bip_iter, cur_len);
 110         }
 111
 112         return err;
 113 }
 114
 115 #else /* CONFIG_BLK_DEV_INTEGRITY */
 116 static int nd_blk_rw_integrity(struct nd_namespace_blk *nsblk,
 117                 struct bio_integrity_payload *bip, u64 lba, int rw)
 118 {
 119         return 0;
 120 }
 121 #endif
 122
 123 static int nsblk_do_bvec(struct nd_namespace_blk *nsblk,
 124                 struct bio_integrity_payload *bip, struct page *page,
 125                 unsigned int len, unsigned int off, int rw, sector_t sector)
 126 {
 127         struct nd_blk_region *ndbr = to_ndbr(nsblk);
 128         resource_size_t dev_offset, ns_offset;
 129         u32 internal_lbasize, sector_size;
 130         int err = 0;
 131         void *iobuf;
 132         u64 lba;
 133
 134         internal_lbasize = nsblk_internal_lbasize(nsblk);
 135         sector_size = nsblk_sector_size(nsblk);
 136         while (len) {
 137                 unsigned int cur_len;
 138
 139                 /*
 140                  * If we don't have an integrity payload, we don't have to
 141                  * split the bvec into sectors, as this would cause unnecessary
 142                  * Block Window setup/move steps. the do_io routine is capable
 143                  * of handling len <= PAGE_SIZE.
 144                  */
 145                 cur_len = bip ? min(len, sector_size) : len;
 146
 147                 lba = div_u64(sector << SECTOR_SHIFT, sector_size);
 148                 ns_offset = lba * internal_lbasize;
 149                 dev_offset = to_dev_offset(nsblk, ns_offset, cur_len);
 150                 if (dev_offset == SIZE_MAX)
 151                         return -EIO;
 152
 153                 iobuf = kmap_atomic(page);
 154                 err = ndbr->do_io(ndbr, dev_offset, iobuf + off, cur_len, rw);
 155                 kunmap_atomic(iobuf);
 156                 if (err)
 157                         return err;
 158
 159                 if (bip) {
 160                         err = nd_blk_rw_integrity(nsblk, bip, lba, rw);
 161                         if (err)
 162                                 return err;
 163                 }
 164                 len -= cur_len;
 165                 off += cur_len;
 166                 sector += sector_size >> SECTOR_SHIFT;
 167         }
 168
 169         return err;
 170 }
 171
 172 static blk_qc_t nd_blk_make_request(struct request_queue *q, struct bio *bio)
 173 {
 174         struct bio_integrity_payload *bip;
 175         struct nd_namespace_blk *nsblk;
 176         struct bvec_iter iter;
 177         unsigned long start;
 178         struct bio_vec bvec;
 179         int err = 0, rw;
 180         bool do_acct;
 181
 182         /*
 183          * bio_integrity_enabled also checks if the bio already has an
 184          * integrity payload attached. If it does, we *don't* do a
 185          * bio_integrity_prep here - the payload has been generated by
 186          * another kernel subsystem, and we just pass it through.
 187          */
 188         if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
 189                 bio->bi_error = -EIO;
 190                 goto out;
 191         }
 192
 193         bip = bio_integrity(bio);
 194         nsblk = q->queuedata;
 195         rw = bio_data_dir(bio);
 196         do_acct = nd_iostat_start(bio, &start);
 197         bio_for_each_segment(bvec, bio, iter) {
 198                 unsigned int len = bvec.bv_len;
 199
 200                 BUG_ON(len > PAGE_SIZE);
 201                 err = nsblk_do_bvec(nsblk, bip, bvec.bv_page, len,
 202                                 bvec.bv_offset, rw, iter.bi_sector);
 203                 if (err) {
 204                         dev_dbg(&nsblk->common.dev,
 205                                         "io error in %s sector %lld, len %d,\n",
 206                                         (rw == READ) ? "READ" : "WRITE",
 207                                         (unsigned long long) iter.bi_sector, len);
 208                         bio->bi_error = err;
 209                         break;
 210                 }
 211         }
 212         if (do_acct)
 213                 nd_iostat_end(bio, start);
 214
 215  out:
 216         bio_endio(bio);
 217         return BLK_QC_T_NONE;
 218 }
 219
 220 static int nsblk_rw_bytes(struct nd_namespace_common *ndns,
 221                 resource_size_t offset, void *iobuf, size_t n, int rw)
 222 {
 223         struct nd_namespace_blk *nsblk = to_nd_namespace_blk(&ndns->dev);
 224         struct nd_blk_region *ndbr = to_ndbr(nsblk);
 225         resource_size_t dev_offset;
 226
 227         dev_offset = to_dev_offset(nsblk, offset, n);
 228
 229         if (unlikely(offset + n > nsblk->size)) {
 230                 dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
 231                 return -EFAULT;
 232         }
 233
 234         if (dev_offset == SIZE_MAX)
 235                 return -EIO;
 236
 237         return ndbr->do_io(ndbr, dev_offset, iobuf, n, rw);
 238 }
 239
 240 static const struct block_device_operations nd_blk_fops = {
 241         .owner = THIS_MODULE,
 242         .revalidate_disk = nvdimm_revalidate_disk,
 243 };
 244
 245 static void nd_blk_release_queue(void *q)
 246 {
 247         blk_cleanup_queue(q);
 248 }
 249
 250 static void nd_blk_release_disk(void *disk)
 251 {
 252         del_gendisk(disk);
 253         put_disk(disk);
 254 }
 255
 256 static int nsblk_attach_disk(struct nd_namespace_blk *nsblk)
 257 {
 258         struct device *dev = &nsblk->common.dev;
 259         resource_size_t available_disk_size;
 260         struct request_queue *q;
 261         struct gendisk *disk;
 262         u64 internal_nlba;
 263
 264         internal_nlba = div_u64(nsblk->size, nsblk_internal_lbasize(nsblk));
 265         available_disk_size = internal_nlba * nsblk_sector_size(nsblk);
 266
 267         q = blk_alloc_queue(GFP_KERNEL);
 268         if (!q)
 269                 return -ENOMEM;
 270         if (devm_add_action(dev, nd_blk_release_queue, q)) {
 271                 blk_cleanup_queue(q);
 272                 return -ENOMEM;
 273         }
 274
 275         blk_queue_make_request(q, nd_blk_make_request);
 276         blk_queue_max_hw_sectors(q, UINT_MAX);
 277         blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
 278         blk_queue_logical_block_size(q, nsblk_sector_size(nsblk));
 279         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
 280         q->queuedata = nsblk;
 281
 282         disk = alloc_disk(0);
 283         if (!disk)
 284                 return -ENOMEM;
 285         if (devm_add_action(dev, nd_blk_release_disk, disk)) {
 286                 put_disk(disk);
 287                 return -ENOMEM;
 288         }
 289
 290         disk->driverfs_dev      = dev;
 291         disk->first_minor       = 0;
 292         disk->fops              = &nd_blk_fops;
 293         disk->queue             = q;
 294         disk->flags             = GENHD_FL_EXT_DEVT;
 295         nvdimm_namespace_disk_name(&nsblk->common, disk->disk_name);
 296         set_capacity(disk, 0);
 297         add_disk(disk);
 298
 299         if (nsblk_meta_size(nsblk)) {
 300                 int rc = nd_integrity_init(disk, nsblk_meta_size(nsblk));
 301
 302                 if (rc)
 303                         return rc;
 304         }
 305
 306         set_capacity(disk, available_disk_size >> SECTOR_SHIFT);
 307         revalidate_disk(disk);
 308         return 0;
 309 }
 310
 311 static int nd_blk_probe(struct device *dev)
 312 {
 313         struct nd_namespace_common *ndns;
 314         struct nd_namespace_blk *nsblk;
 315
 316         ndns = nvdimm_namespace_common_probe(dev);
 317         if (IS_ERR(ndns))
 318                 return PTR_ERR(ndns);
 319
 320         nsblk = to_nd_namespace_blk(&ndns->dev);
 321         nsblk->size = nvdimm_namespace_capacity(ndns);
 322         dev_set_drvdata(dev, nsblk);
 323
 324         ndns->rw_bytes = nsblk_rw_bytes;
 325         if (is_nd_btt(dev))
 326                 return nvdimm_namespace_attach_btt(ndns);
 327         else if (nd_btt_probe(dev, ndns) == 0) {
 328                 /* we'll come back as btt-blk */
 329                 return -ENXIO;
 330         } else
 331                 return nsblk_attach_disk(nsblk);
 332 }
 333
 334 static int nd_blk_remove(struct device *dev)
 335 {
 336         if (is_nd_btt(dev))
 337                 nvdimm_namespace_detach_btt(to_nd_btt(dev));
 338         return 0;
 339 }
 340
 341 static struct nd_device_driver nd_blk_driver = {
 342         .probe = nd_blk_probe,
 343         .remove = nd_blk_remove,
 344         .drv = {
 345                 .name = "nd_blk",
 346         },
 347         .type = ND_DRIVER_NAMESPACE_BLK,
 348 };
 349
 350 static int __init nd_blk_init(void)
 351 {
 352         return nd_driver_register(&nd_blk_driver);
 353 }
 354
 355 static void __exit nd_blk_exit(void)
 356 {
 357         driver_unregister(&nd_blk_driver.drv);
 358 }
 359
 360 MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
 361 MODULE_LICENSE("GPL v2");
 362 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_BLK);
 363 module_init(nd_blk_init);
 364 module_exit(nd_blk_exit);