include/linux/blkdev_compat.h

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright (C) 2011 Lawrence Livermore National Security, LLC.
  24  * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
  25  * Written by Brian Behlendorf <behlendorf1@llnl.gov>.
  26  * LLNL-CODE-403049.
  27  */
  28
  29 #ifndef _ZFS_BLKDEV_H
  30 #define _ZFS_BLKDEV_H
  31
  32 #include <linux/blkdev.h>
  33 #include <linux/elevator.h>
  34
  35 #ifndef HAVE_FMODE_T
  36 typedef unsigned __bitwise__ fmode_t;
  37 #endif /* HAVE_FMODE_T */
  38
  39 #ifndef HAVE_BLK_FETCH_REQUEST
  40 static inline struct request *
  41 blk_fetch_request(struct request_queue *q)
  42 {
  43         struct request *req;
  44
  45         req = elv_next_request(q);
  46         if (req)
  47                 blkdev_dequeue_request(req);
  48
  49         return (req);
  50 }
  51 #endif /* HAVE_BLK_FETCH_REQUEST */
  52
  53 #ifndef HAVE_BLK_REQUEUE_REQUEST
  54 static inline void
  55 blk_requeue_request(request_queue_t *q, struct request *req)
  56 {
  57         elv_requeue_request(q, req);
  58 }
  59 #endif /* HAVE_BLK_REQUEUE_REQUEST */
  60
  61 #ifndef HAVE_BLK_END_REQUEST
  62 static inline bool
  63 __blk_end_request(struct request *req, int error, unsigned int nr_bytes)
  64 {
  65         LIST_HEAD(list);
  66
  67         /*
  68          * Request has already been dequeued but 2.6.18 version of
  69          * end_request() unconditionally dequeues the request so we
  70          * add it to a local list to prevent hitting the BUG_ON.
  71          */
  72         list_add(&req->queuelist, &list);
  73
  74         /*
  75          * The old API required the driver to end each segment and not
  76          * the entire request.  In our case we always need to end the
  77          * entire request partial requests are not supported.
  78          */
  79         req->hard_cur_sectors = nr_bytes >> 9;
  80         end_request(req, ((error == 0) ? 1 : error));
  81
  82         return (0);
  83 }
  84
  85 static inline bool
  86 blk_end_request(struct request *req, int error, unsigned int nr_bytes)
  87 {
  88         struct request_queue *q = req->q;
  89         bool rc;
  90
  91         spin_lock_irq(q->queue_lock);
  92         rc = __blk_end_request(req, error, nr_bytes);
  93         spin_unlock_irq(q->queue_lock);
  94
  95         return (rc);
  96 }
  97 #else
  98 #ifdef HAVE_BLK_END_REQUEST_GPL_ONLY
  99 /*
 100  * Define required to avoid conflicting 2.6.29 non-static prototype for a
 101  * GPL-only version of the helper.  As of 2.6.31 the helper is available
 102  * to non-GPL modules and is not explicitly exported GPL-only.
 103  */
 104 #define __blk_end_request __blk_end_request_x
 105 #define blk_end_request blk_end_request_x
 106
 107 static inline bool
 108 __blk_end_request_x(struct request *req, int error, unsigned int nr_bytes)
 109 {
 110         /*
 111          * The old API required the driver to end each segment and not
 112          * the entire request.  In our case we always need to end the
 113          * entire request partial requests are not supported.
 114          */
 115         req->hard_cur_sectors = nr_bytes >> 9;
 116         end_request(req, ((error == 0) ? 1 : error));
 117
 118         return (0);
 119 }
 120 static inline bool
 121 blk_end_request_x(struct request *req, int error, unsigned int nr_bytes)
 122 {
 123         struct request_queue *q = req->q;
 124         bool rc;
 125
 126         spin_lock_irq(q->queue_lock);
 127         rc = __blk_end_request_x(req, error, nr_bytes);
 128         spin_unlock_irq(q->queue_lock);
 129
 130         return (rc);
 131 }
 132 #endif /* HAVE_BLK_END_REQUEST_GPL_ONLY */
 133 #endif /* HAVE_BLK_END_REQUEST */
 134
 135 /*
 136  * 2.6.36 API change,
 137  * The blk_queue_flush() interface has replaced blk_queue_ordered()
 138  * interface.  However, while the old interface was available to all the
 139  * new one is GPL-only.   Thus if the GPL-only version is detected we
 140  * implement our own trivial helper compatibility funcion.   The hope is
 141  * that long term this function will be opened up.
 142  */
 143 #if defined(HAVE_BLK_QUEUE_FLUSH) && defined(HAVE_BLK_QUEUE_FLUSH_GPL_ONLY)
 144 #define blk_queue_flush __blk_queue_flush
 145 static inline void
 146 __blk_queue_flush(struct request_queue *q, unsigned int flags)
 147 {
 148         q->flush_flags = flags & (REQ_FLUSH | REQ_FUA);
 149 }
 150 #endif /* HAVE_BLK_QUEUE_FLUSH && HAVE_BLK_QUEUE_FLUSH_GPL_ONLY */
 151
 152 #ifndef HAVE_BLK_RQ_POS
 153 static inline sector_t
 154 blk_rq_pos(struct request *req)
 155 {
 156         return (req->sector);
 157 }
 158 #endif /* HAVE_BLK_RQ_POS */
 159
 160 #ifndef HAVE_BLK_RQ_SECTORS
 161 static inline unsigned int
 162 blk_rq_sectors(struct request *req)
 163 {
 164         return (req->nr_sectors);
 165 }
 166 #endif /* HAVE_BLK_RQ_SECTORS */
 167
 168 #if !defined(HAVE_BLK_RQ_BYTES) || defined(HAVE_BLK_RQ_BYTES_GPL_ONLY)
 169 /*
 170  * Define required to avoid conflicting 2.6.29 non-static prototype for a
 171  * GPL-only version of the helper.  As of 2.6.31 the helper is available
 172  * to non-GPL modules in the form of a static inline in the header.
 173  */
 174 #define blk_rq_bytes __blk_rq_bytes
 175 static inline unsigned int
 176 __blk_rq_bytes(struct request *req)
 177 {
 178         return (blk_rq_sectors(req) << 9);
 179 }
 180 #endif /* !HAVE_BLK_RQ_BYTES || HAVE_BLK_RQ_BYTES_GPL_ONLY */
 181
 182 /*
 183  * Most of the blk_* macros were removed in 2.6.36.  Ostensibly this was
 184  * done to improve readability and allow easier grepping.  However, from
 185  * a portability stand point the macros are helpful.  Therefore the needed
 186  * macros are redefined here if they are missing from the kernel.
 187  */
 188 #ifndef blk_fs_request
 189 #define blk_fs_request(rq)      ((rq)->cmd_type == REQ_TYPE_FS)
 190 #endif
 191
 192 /*
 193  * 2.6.27 API change,
 194  * The blk_queue_stackable() queue flag was added in 2.6.27 to handle dm
 195  * stacking drivers.  Prior to this request stacking drivers were detected
 196  * by checking (q->request_fn == NULL), for earlier kernels we revert to
 197  * this legacy behavior.
 198  */
 199 #ifndef blk_queue_stackable
 200 #define blk_queue_stackable(q)  ((q)->request_fn == NULL)
 201 #endif
 202
 203 /*
 204  * 2.6.34 API change,
 205  * The blk_queue_max_hw_sectors() function replaces blk_queue_max_sectors().
 206  */
 207 #ifndef HAVE_BLK_QUEUE_MAX_HW_SECTORS
 208 #define blk_queue_max_hw_sectors __blk_queue_max_hw_sectors
 209 static inline void
 210 __blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors)
 211 {
 212         blk_queue_max_sectors(q, max_hw_sectors);
 213 }
 214 #endif
 215
 216 /*
 217  * 2.6.34 API change,
 218  * The blk_queue_max_segments() function consolidates
 219  * blk_queue_max_hw_segments() and blk_queue_max_phys_segments().
 220  */
 221 #ifndef HAVE_BLK_QUEUE_MAX_SEGMENTS
 222 #define blk_queue_max_segments __blk_queue_max_segments
 223 static inline void
 224 __blk_queue_max_segments(struct request_queue *q, unsigned short max_segments)
 225 {
 226         blk_queue_max_phys_segments(q, max_segments);
 227         blk_queue_max_hw_segments(q, max_segments);
 228 }
 229 #endif
 230
 231 /*
 232  * 2.6.30 API change,
 233  * The blk_queue_physical_block_size() function was introduced to
 234  * indicate the smallest I/O the device can write without incurring
 235  * a read-modify-write penalty.  For older kernels this is a no-op.
 236  */
 237 #ifndef HAVE_BLK_QUEUE_PHYSICAL_BLOCK_SIZE
 238 #define blk_queue_physical_block_size(q, x)     ((void)(0))
 239 #endif
 240
 241 /*
 242  * 2.6.30 API change,
 243  * The blk_queue_io_opt() function was added to indicate the optimal
 244  * I/O size for the device.  For older kernels this is a no-op.
 245  */
 246 #ifndef HAVE_BLK_QUEUE_IO_OPT
 247 #define blk_queue_io_opt(q, x)                  ((void)(0))
 248 #endif
 249
 250 #ifndef HAVE_GET_DISK_RO
 251 static inline int
 252 get_disk_ro(struct gendisk *disk)
 253 {
 254         int policy = 0;
 255
 256         if (disk->part[0])
 257                 policy = disk->part[0]->policy;
 258
 259         return (policy);
 260 }
 261 #endif /* HAVE_GET_DISK_RO */
 262
 263 #ifndef HAVE_RQ_IS_SYNC
 264 static inline bool
 265 rq_is_sync(struct request *req)
 266 {
 267         return (req->flags & REQ_RW_SYNC);
 268 }
 269 #endif /* HAVE_RQ_IS_SYNC */
 270
 271 #ifndef HAVE_RQ_FOR_EACH_SEGMENT
 272 struct req_iterator {
 273         int i;
 274         struct bio *bio;
 275 };
 276
 277 #define for_each_bio(_bio)              \
 278         for (; _bio; _bio = _bio->bi_next)
 279
 280 #define __rq_for_each_bio(_bio, rq)     \
 281         if ((rq->bio))                  \
 282                 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
 283
 284 #define rq_for_each_segment(bvl, _rq, _iter)                    \
 285         __rq_for_each_bio(_iter.bio, _rq)                       \
 286                 bio_for_each_segment(bvl, _iter.bio, _iter.i)
 287 #endif /* HAVE_RQ_FOR_EACH_SEGMENT */
 288
 289 /*
 290  * Portable helper for correctly setting the FAILFAST flags.  The
 291  * correct usage has changed 3 times from 2.6.12 to 2.6.38.
 292  */
 293 static inline void
 294 bio_set_flags_failfast(struct block_device *bdev, int *flags)
 295 {
 296 #ifdef CONFIG_BUG
 297         /*
 298          * Disable FAILFAST for loopback devices because of the
 299          * following incorrect BUG_ON() in loop_make_request().
 300          * This support is also disabled for md devices because the
 301          * test suite layers md devices on top of loopback devices.
 302          * This may be removed when the loopback driver is fixed.
 303          *
 304          *   BUG_ON(!lo || (rw != READ && rw != WRITE));
 305          */
 306         if ((MAJOR(bdev->bd_dev) == LOOP_MAJOR) ||
 307             (MAJOR(bdev->bd_dev) == MD_MAJOR))
 308                 return;
 309
 310 #ifdef BLOCK_EXT_MAJOR
 311         if (MAJOR(bdev->bd_dev) == BLOCK_EXT_MAJOR)
 312                 return;
 313 #endif /* BLOCK_EXT_MAJOR */
 314 #endif /* CONFIG_BUG */
 315
 316 #ifdef HAVE_BIO_RW_FAILFAST_DTD
 317         /* BIO_RW_FAILFAST_* preferred interface from 2.6.28 - 2.6.35 */
 318         *flags |= (
 319             (1 << BIO_RW_FAILFAST_DEV) |
 320             (1 << BIO_RW_FAILFAST_TRANSPORT) |
 321             (1 << BIO_RW_FAILFAST_DRIVER));
 322 #else
 323 #ifdef HAVE_BIO_RW_FAILFAST
 324         /* BIO_RW_FAILFAST preferred interface from 2.6.12 - 2.6.27 */
 325         *flags |= (1 << BIO_RW_FAILFAST);
 326 #else
 327 #ifdef HAVE_REQ_FAILFAST_MASK
 328         /*
 329          * REQ_FAILFAST_* preferred interface from 2.6.36 - 2.6.xx,
 330          * the BIO_* and REQ_* flags were unified under REQ_* flags.
 331          */
 332         *flags |= REQ_FAILFAST_MASK;
 333 #endif /* HAVE_REQ_FAILFAST_MASK */
 334 #endif /* HAVE_BIO_RW_FAILFAST */
 335 #endif /* HAVE_BIO_RW_FAILFAST_DTD */
 336 }
 337
 338 /*
 339  * Maximum disk label length, it may be undefined for some kernels.
 340  */
 341 #ifndef DISK_NAME_LEN
 342 #define DISK_NAME_LEN   32
 343 #endif /* DISK_NAME_LEN */
 344
 345 /*
 346  * 2.6.24 API change,
 347  * The bio_end_io() prototype changed slightly.  These are helper
 348  * macro's to ensure the prototype and return value are handled.
 349  */
 350 #ifdef HAVE_2ARGS_BIO_END_IO_T
 351 #define BIO_END_IO_PROTO(fn, x, y, z)   static void fn(struct bio *x, int z)
 352 #define BIO_END_IO_RETURN(rc)           return
 353 #else
 354 #define BIO_END_IO_PROTO(fn, x, y, z)   static int fn( \
 355                                             struct bio *x, \
 356                                             unsigned int y, \
 357                                             int z)
 358 #define BIO_END_IO_RETURN(rc)           return rc
 359 #endif /* HAVE_2ARGS_BIO_END_IO_T */
 360
 361 /*
 362  * 2.6.38 - 2.6.x API,
 363  *   blkdev_get_by_path()
 364  *   blkdev_put()
 365  *
 366  * 2.6.28 - 2.6.37 API,
 367  *   open_bdev_exclusive()
 368  *   close_bdev_exclusive()
 369  *
 370  * 2.6.12 - 2.6.27 API,
 371  *   open_bdev_excl()
 372  *   close_bdev_excl()
 373  *
 374  * Used to exclusively open a block device from within the kernel.
 375  */
 376 #if defined(HAVE_BLKDEV_GET_BY_PATH)
 377 #define vdev_bdev_open(path, md, hld)   blkdev_get_by_path(path, \
 378                                             (md) | FMODE_EXCL, hld)
 379 #define vdev_bdev_close(bdev, md)       blkdev_put(bdev, (md) | FMODE_EXCL)
 380 #elif defined(HAVE_OPEN_BDEV_EXCLUSIVE)
 381 #define vdev_bdev_open(path, md, hld)   open_bdev_exclusive(path, md, hld)
 382 #define vdev_bdev_close(bdev, md)       close_bdev_exclusive(bdev, md)
 383 #else
 384 #define vdev_bdev_open(path, md, hld)   open_bdev_excl(path, md, hld)
 385 #define vdev_bdev_close(bdev, md)       close_bdev_excl(bdev)
 386 #endif /* HAVE_BLKDEV_GET_BY_PATH | HAVE_OPEN_BDEV_EXCLUSIVE */
 387
 388 /*
 389  * 2.6.22 API change
 390  * The function invalidate_bdev() lost it's second argument because
 391  * it was unused.
 392  */
 393 #ifdef HAVE_1ARG_INVALIDATE_BDEV
 394 #define vdev_bdev_invalidate(bdev)      invalidate_bdev(bdev)
 395 #else
 396 #define vdev_bdev_invalidate(bdev)      invalidate_bdev(bdev, 1)
 397 #endif /* HAVE_1ARG_INVALIDATE_BDEV */
 398
 399 /*
 400  * 2.6.27 API change
 401  * The function was exported for use, prior to this it existed by the
 402  * symbol was not exported.
 403  */
 404 #ifndef HAVE_LOOKUP_BDEV
 405 #define lookup_bdev(path)               ERR_PTR(-ENOTSUP)
 406 #endif
 407
 408 /*
 409  * 2.6.30 API change
 410  * To ensure good performance preferentially use the physical block size
 411  * for proper alignment.  The physical size is supposed to be the internal
 412  * sector size used by the device.  This is often 4096 byte for AF devices,
 413  * while a smaller 512 byte logical size is supported for compatibility.
 414  *
 415  * Unfortunately, many drives still misreport their physical sector size.
 416  * For devices which are known to lie you may need to manually set this
 417  * at pool creation time with 'zpool create -o ashift=12 ...'.
 418  *
 419  * When the physical block size interface isn't available, we fall back to
 420  * the logical block size interface and then the older hard sector size.
 421  */
 422 #ifdef HAVE_BDEV_PHYSICAL_BLOCK_SIZE
 423 #define vdev_bdev_block_size(bdev)      bdev_physical_block_size(bdev)
 424 #else
 425 #ifdef HAVE_BDEV_LOGICAL_BLOCK_SIZE
 426 #define vdev_bdev_block_size(bdev)      bdev_logical_block_size(bdev)
 427 #else
 428 #define vdev_bdev_block_size(bdev)      bdev_hardsect_size(bdev)
 429 #endif /* HAVE_BDEV_LOGICAL_BLOCK_SIZE */
 430 #endif /* HAVE_BDEV_PHYSICAL_BLOCK_SIZE */
 431
 432 /*
 433  * 2.6.37 API change
 434  * The WRITE_FLUSH, WRITE_FUA, and WRITE_FLUSH_FUA flags have been
 435  * introduced as a replacement for WRITE_BARRIER.  This was done to
 436  * allow richer semantics to be expressed to the block layer.  It is
 437  * the block layers responsibility to choose the correct way to
 438  * implement these semantics.
 439  *
 440  * The existence of these flags implies that REQ_FLUSH an REQ_FUA are
 441  * defined.  Thus we can safely define VDEV_REQ_FLUSH and VDEV_REQ_FUA
 442  * compatibility macros.
 443  */
 444 #ifdef WRITE_FLUSH_FUA
 445 #define VDEV_WRITE_FLUSH_FUA            WRITE_FLUSH_FUA
 446 #define VDEV_REQ_FLUSH                  REQ_FLUSH
 447 #define VDEV_REQ_FUA                    REQ_FUA
 448 #else
 449 #define VDEV_WRITE_FLUSH_FUA            WRITE_BARRIER
 450 #define VDEV_REQ_FLUSH                  REQ_HARDBARRIER
 451 #define VDEV_REQ_FUA                    REQ_HARDBARRIER
 452 #endif
 453
 454 /*
 455  * 2.6.32 API change
 456  * Use the normal I/O patch for discards.
 457  */
 458 #ifdef REQ_DISCARD
 459 #define VDEV_REQ_DISCARD                REQ_DISCARD
 460 #endif
 461
 462 /*
 463  * 2.6.33 API change
 464  * Discard granularity and alignment restrictions may now be set.  For
 465  * older kernels which do not support this it is safe to skip it.
 466  */
 467 #ifdef HAVE_DISCARD_GRANULARITY
 468 static inline void
 469 blk_queue_discard_granularity(struct request_queue *q, unsigned int dg)
 470 {
 471         q->limits.discard_granularity = dg;
 472 }
 473 #else
 474 #define blk_queue_discard_granularity(x, dg)    ((void)0)
 475 #endif /* HAVE_DISCARD_GRANULARITY */
 476
 477 /*
 478  * Default Linux IO Scheduler,
 479  * Setting the scheduler to noop will allow the Linux IO scheduler to
 480  * still perform front and back merging, while leaving the request
 481  * ordering and prioritization to the ZFS IO scheduler.
 482  */
 483 #define VDEV_SCHEDULER                  "noop"
 484
 485 /*
 486  * A common holder for vdev_bdev_open() is used to relax the exclusive open
 487  * semantics slightly.  Internal vdev disk callers may pass VDEV_HOLDER to
 488  * allow them to open the device multiple times.  Other kernel callers and
 489  * user space processes which don't pass this value will get EBUSY.  This is
 490  * currently required for the correct operation of hot spares.
 491  */
 492 #define VDEV_HOLDER                     ((void *)0x2401de7)
 493
 494 #endif /* _ZFS_BLKDEV_H */