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