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 struct nd_blk_device {
  25         struct request_queue *queue;
  26         struct gendisk *disk;
  27         struct nd_namespace_blk *nsblk;
  28         struct nd_blk_region *ndbr;
  29         size_t disk_size;
  30         u32 sector_size;
  31         u32 internal_lbasize;
  32 };
  33
  34 static int nd_blk_major;
  35
  36 static u32 nd_blk_meta_size(struct nd_blk_device *blk_dev)
  37 {
  38         return blk_dev->nsblk->lbasize - blk_dev->sector_size;
  39 }
  40
  41 static resource_size_t to_dev_offset(struct nd_namespace_blk *nsblk,
  42                                 resource_size_t ns_offset, unsigned int len)
  43 {
  44         int i;
  45
  46         for (i = 0; i < nsblk->num_resources; i++) {
  47                 if (ns_offset < resource_size(nsblk->res[i])) {
  48                         if (ns_offset + len > resource_size(nsblk->res[i])) {
  49                                 dev_WARN_ONCE(&nsblk->common.dev, 1,
  50                                         "illegal request\n");
  51                                 return SIZE_MAX;
  52                         }
  53                         return nsblk->res[i]->start + ns_offset;
  54                 }
  55                 ns_offset -= resource_size(nsblk->res[i]);
  56         }
  57
  58         dev_WARN_ONCE(&nsblk->common.dev, 1, "request out of range\n");
  59         return SIZE_MAX;
  60 }
  61
  62 #ifdef CONFIG_BLK_DEV_INTEGRITY
  63 static int nd_blk_rw_integrity(struct nd_blk_device *blk_dev,
  64                                 struct bio_integrity_payload *bip, u64 lba,
  65                                 int rw)
  66 {
  67         unsigned int len = nd_blk_meta_size(blk_dev);
  68         resource_size_t dev_offset, ns_offset;
  69         struct nd_namespace_blk *nsblk;
  70         struct nd_blk_region *ndbr;
  71         int err = 0;
  72
  73         nsblk = blk_dev->nsblk;
  74         ndbr = blk_dev->ndbr;
  75         ns_offset = lba * blk_dev->internal_lbasize + blk_dev->sector_size;
  76         dev_offset = to_dev_offset(nsblk, ns_offset, len);
  77         if (dev_offset == SIZE_MAX)
  78                 return -EIO;
  79
  80         while (len) {
  81                 unsigned int cur_len;
  82                 struct bio_vec bv;
  83                 void *iobuf;
  84
  85                 bv = bvec_iter_bvec(bip->bip_vec, bip->bip_iter);
  86                 /*
  87                  * The 'bv' obtained from bvec_iter_bvec has its .bv_len and
  88                  * .bv_offset already adjusted for iter->bi_bvec_done, and we
  89                  * can use those directly
  90                  */
  91
  92                 cur_len = min(len, bv.bv_len);
  93                 iobuf = kmap_atomic(bv.bv_page);
  94                 err = ndbr->do_io(ndbr, dev_offset, iobuf + bv.bv_offset,
  95                                 cur_len, rw);
  96                 kunmap_atomic(iobuf);
  97                 if (err)
  98                         return err;
  99
 100                 len -= cur_len;
 101                 dev_offset += cur_len;
 102                 bvec_iter_advance(bip->bip_vec, &bip->bip_iter, cur_len);
 103         }
 104
 105         return err;
 106 }
 107
 108 #else /* CONFIG_BLK_DEV_INTEGRITY */
 109 static int nd_blk_rw_integrity(struct nd_blk_device *blk_dev,
 110                                 struct bio_integrity_payload *bip, u64 lba,
 111                                 int rw)
 112 {
 113         return 0;
 114 }
 115 #endif
 116
 117 static int nd_blk_do_bvec(struct nd_blk_device *blk_dev,
 118                         struct bio_integrity_payload *bip, struct page *page,
 119                         unsigned int len, unsigned int off, int rw,
 120                         sector_t sector)
 121 {
 122         struct nd_blk_region *ndbr = blk_dev->ndbr;
 123         resource_size_t dev_offset, ns_offset;
 124         int err = 0;
 125         void *iobuf;
 126         u64 lba;
 127
 128         while (len) {
 129                 unsigned int cur_len;
 130
 131                 /*
 132                  * If we don't have an integrity payload, we don't have to
 133                  * split the bvec into sectors, as this would cause unnecessary
 134                  * Block Window setup/move steps. the do_io routine is capable
 135                  * of handling len <= PAGE_SIZE.
 136                  */
 137                 cur_len = bip ? min(len, blk_dev->sector_size) : len;
 138
 139                 lba = div_u64(sector << SECTOR_SHIFT, blk_dev->sector_size);
 140                 ns_offset = lba * blk_dev->internal_lbasize;
 141                 dev_offset = to_dev_offset(blk_dev->nsblk, ns_offset, cur_len);
 142                 if (dev_offset == SIZE_MAX)
 143                         return -EIO;
 144
 145                 iobuf = kmap_atomic(page);
 146                 err = ndbr->do_io(ndbr, dev_offset, iobuf + off, cur_len, rw);
 147                 kunmap_atomic(iobuf);
 148                 if (err)
 149                         return err;
 150
 151                 if (bip) {
 152                         err = nd_blk_rw_integrity(blk_dev, bip, lba, rw);
 153                         if (err)
 154                                 return err;
 155                 }
 156                 len -= cur_len;
 157                 off += cur_len;
 158                 sector += blk_dev->sector_size >> SECTOR_SHIFT;
 159         }
 160
 161         return err;
 162 }
 163
 164 static void nd_blk_make_request(struct request_queue *q, struct bio *bio)
 165 {
 166         struct block_device *bdev = bio->bi_bdev;
 167         struct gendisk *disk = bdev->bd_disk;
 168         struct bio_integrity_payload *bip;
 169         struct nd_blk_device *blk_dev;
 170         struct bvec_iter iter;
 171         unsigned long start;
 172         struct bio_vec bvec;
 173         int err = 0, rw;
 174         bool do_acct;
 175
 176         /*
 177          * bio_integrity_enabled also checks if the bio already has an
 178          * integrity payload attached. If it does, we *don't* do a
 179          * bio_integrity_prep here - the payload has been generated by
 180          * another kernel subsystem, and we just pass it through.
 181          */
 182         if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
 183                 bio->bi_error = -EIO;
 184                 goto out;
 185         }
 186
 187         bip = bio_integrity(bio);
 188         blk_dev = disk->private_data;
 189         rw = bio_data_dir(bio);
 190         do_acct = nd_iostat_start(bio, &start);
 191         bio_for_each_segment(bvec, bio, iter) {
 192                 unsigned int len = bvec.bv_len;
 193
 194                 BUG_ON(len > PAGE_SIZE);
 195                 err = nd_blk_do_bvec(blk_dev, bip, bvec.bv_page, len,
 196                                         bvec.bv_offset, rw, iter.bi_sector);
 197                 if (err) {
 198                         dev_info(&blk_dev->nsblk->common.dev,
 199                                         "io error in %s sector %lld, len %d,\n",
 200                                         (rw == READ) ? "READ" : "WRITE",
 201                                         (unsigned long long) iter.bi_sector, len);
 202                         bio->bi_error = err;
 203                         break;
 204                 }
 205         }
 206         if (do_acct)
 207                 nd_iostat_end(bio, start);
 208
 209  out:
 210         bio_endio(bio);
 211 }
 212
 213 static int nd_blk_rw_bytes(struct nd_namespace_common *ndns,
 214                 resource_size_t offset, void *iobuf, size_t n, int rw)
 215 {
 216         struct nd_blk_device *blk_dev = dev_get_drvdata(ndns->claim);
 217         struct nd_namespace_blk *nsblk = blk_dev->nsblk;
 218         struct nd_blk_region *ndbr = blk_dev->ndbr;
 219         resource_size_t dev_offset;
 220
 221         dev_offset = to_dev_offset(nsblk, offset, n);
 222
 223         if (unlikely(offset + n > blk_dev->disk_size)) {
 224                 dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
 225                 return -EFAULT;
 226         }
 227
 228         if (dev_offset == SIZE_MAX)
 229                 return -EIO;
 230
 231         return ndbr->do_io(ndbr, dev_offset, iobuf, n, rw);
 232 }
 233
 234 static const struct block_device_operations nd_blk_fops = {
 235         .owner = THIS_MODULE,
 236         .revalidate_disk = nvdimm_revalidate_disk,
 237 };
 238
 239 static int nd_blk_attach_disk(struct nd_namespace_common *ndns,
 240                 struct nd_blk_device *blk_dev)
 241 {
 242         resource_size_t available_disk_size;
 243         struct gendisk *disk;
 244         u64 internal_nlba;
 245
 246         internal_nlba = div_u64(blk_dev->disk_size, blk_dev->internal_lbasize);
 247         available_disk_size = internal_nlba * blk_dev->sector_size;
 248
 249         blk_dev->queue = blk_alloc_queue(GFP_KERNEL);
 250         if (!blk_dev->queue)
 251                 return -ENOMEM;
 252
 253         blk_queue_make_request(blk_dev->queue, nd_blk_make_request);
 254         blk_queue_max_hw_sectors(blk_dev->queue, UINT_MAX);
 255         blk_queue_bounce_limit(blk_dev->queue, BLK_BOUNCE_ANY);
 256         blk_queue_logical_block_size(blk_dev->queue, blk_dev->sector_size);
 257         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, blk_dev->queue);
 258
 259         disk = blk_dev->disk = alloc_disk(0);
 260         if (!disk) {
 261                 blk_cleanup_queue(blk_dev->queue);
 262                 return -ENOMEM;
 263         }
 264
 265         disk->driverfs_dev      = &ndns->dev;
 266         disk->major             = nd_blk_major;
 267         disk->first_minor       = 0;
 268         disk->fops              = &nd_blk_fops;
 269         disk->private_data      = blk_dev;
 270         disk->queue             = blk_dev->queue;
 271         disk->flags             = GENHD_FL_EXT_DEVT;
 272         nvdimm_namespace_disk_name(ndns, disk->disk_name);
 273         set_capacity(disk, 0);
 274         add_disk(disk);
 275
 276         if (nd_blk_meta_size(blk_dev)) {
 277                 int rc = nd_integrity_init(disk, nd_blk_meta_size(blk_dev));
 278
 279                 if (rc) {
 280                         del_gendisk(disk);
 281                         put_disk(disk);
 282                         blk_cleanup_queue(blk_dev->queue);
 283                         return rc;
 284                 }
 285         }
 286
 287         set_capacity(disk, available_disk_size >> SECTOR_SHIFT);
 288         revalidate_disk(disk);
 289         return 0;
 290 }
 291
 292 static int nd_blk_probe(struct device *dev)
 293 {
 294         struct nd_namespace_common *ndns;
 295         struct nd_namespace_blk *nsblk;
 296         struct nd_blk_device *blk_dev;
 297         int rc;
 298
 299         ndns = nvdimm_namespace_common_probe(dev);
 300         if (IS_ERR(ndns))
 301                 return PTR_ERR(ndns);
 302
 303         blk_dev = kzalloc(sizeof(*blk_dev), GFP_KERNEL);
 304         if (!blk_dev)
 305                 return -ENOMEM;
 306
 307         nsblk = to_nd_namespace_blk(&ndns->dev);
 308         blk_dev->disk_size = nvdimm_namespace_capacity(ndns);
 309         blk_dev->ndbr = to_nd_blk_region(dev->parent);
 310         blk_dev->nsblk = to_nd_namespace_blk(&ndns->dev);
 311         blk_dev->internal_lbasize = roundup(nsblk->lbasize,
 312                                                 INT_LBASIZE_ALIGNMENT);
 313         blk_dev->sector_size = ((nsblk->lbasize >= 4096) ? 4096 : 512);
 314         dev_set_drvdata(dev, blk_dev);
 315
 316         ndns->rw_bytes = nd_blk_rw_bytes;
 317         if (is_nd_btt(dev))
 318                 rc = nvdimm_namespace_attach_btt(ndns);
 319         else if (nd_btt_probe(ndns, blk_dev) == 0) {
 320                 /* we'll come back as btt-blk */
 321                 rc = -ENXIO;
 322         } else
 323                 rc = nd_blk_attach_disk(ndns, blk_dev);
 324         if (rc)
 325                 kfree(blk_dev);
 326         return rc;
 327 }
 328
 329 static void nd_blk_detach_disk(struct nd_blk_device *blk_dev)
 330 {
 331         del_gendisk(blk_dev->disk);
 332         put_disk(blk_dev->disk);
 333         blk_cleanup_queue(blk_dev->queue);
 334 }
 335
 336 static int nd_blk_remove(struct device *dev)
 337 {
 338         struct nd_blk_device *blk_dev = dev_get_drvdata(dev);
 339
 340         if (is_nd_btt(dev))
 341                 nvdimm_namespace_detach_btt(to_nd_btt(dev)->ndns);
 342         else
 343                 nd_blk_detach_disk(blk_dev);
 344         kfree(blk_dev);
 345
 346         return 0;
 347 }
 348
 349 static struct nd_device_driver nd_blk_driver = {
 350         .probe = nd_blk_probe,
 351         .remove = nd_blk_remove,
 352         .drv = {
 353                 .name = "nd_blk",
 354         },
 355         .type = ND_DRIVER_NAMESPACE_BLK,
 356 };
 357
 358 static int __init nd_blk_init(void)
 359 {
 360         int rc;
 361
 362         rc = register_blkdev(0, "nd_blk");
 363         if (rc < 0)
 364                 return rc;
 365
 366         nd_blk_major = rc;
 367         rc = nd_driver_register(&nd_blk_driver);
 368
 369         if (rc < 0)
 370                 unregister_blkdev(nd_blk_major, "nd_blk");
 371
 372         return rc;
 373 }
 374
 375 static void __exit nd_blk_exit(void)
 376 {
 377         driver_unregister(&nd_blk_driver.drv);
 378         unregister_blkdev(nd_blk_major, "nd_blk");
 379 }
 380
 381 MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
 382 MODULE_LICENSE("GPL v2");
 383 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_BLK);
 384 module_init(nd_blk_init);
 385 module_exit(nd_blk_exit);