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 #ifndef HAVE_GET_DISK_RO
 204 static inline int
 205 get_disk_ro(struct gendisk *disk)
 206 {
 207         int policy = 0;
 208
 209         if (disk->part[0])
 210                 policy = disk->part[0]->policy;
 211
 212         return policy;
 213 }
 214 #endif /* HAVE_GET_DISK_RO */
 215
 216 #ifndef HAVE_RQ_IS_SYNC
 217 static inline bool
 218 rq_is_sync(struct request *req)
 219 {
 220         return (req->flags & REQ_RW_SYNC);
 221 }
 222 #endif /* HAVE_RQ_IS_SYNC */
 223
 224 #ifndef HAVE_RQ_FOR_EACH_SEGMENT
 225 struct req_iterator {
 226         int i;
 227         struct bio *bio;
 228 };
 229
 230 # define for_each_bio(_bio)              \
 231         for (; _bio; _bio = _bio->bi_next)
 232
 233 # define __rq_for_each_bio(_bio, rq)    \
 234         if ((rq->bio))                  \
 235                 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
 236
 237 # define rq_for_each_segment(bvl, _rq, _iter)                   \
 238         __rq_for_each_bio(_iter.bio, _rq)                       \
 239                 bio_for_each_segment(bvl, _iter.bio, _iter.i)
 240 #endif /* HAVE_RQ_FOR_EACH_SEGMENT */
 241
 242 /*
 243  * Portable helper for correctly setting the FAILFAST flags.  The
 244  * correct usage has changed 3 times from 2.6.12 to 2.6.38.
 245  */
 246 static inline void
 247 bio_set_flags_failfast(struct block_device *bdev, int *flags)
 248 {
 249 #ifdef CONFIG_BUG
 250         /*
 251          * Disable FAILFAST for loopback devices because of the
 252          * following incorrect BUG_ON() in loop_make_request().
 253          * This support is also disabled for md devices because the
 254          * test suite layers md devices on top of loopback devices.
 255          * This may be removed when the loopback driver is fixed.
 256          *
 257          *   BUG_ON(!lo || (rw != READ && rw != WRITE));
 258          */
 259         if ((MAJOR(bdev->bd_dev) == LOOP_MAJOR) ||
 260             (MAJOR(bdev->bd_dev) == MD_MAJOR))
 261                 return;
 262
 263 #ifdef BLOCK_EXT_MAJOR
 264         if (MAJOR(bdev->bd_dev) == BLOCK_EXT_MAJOR)
 265                 return;
 266 #endif /* BLOCK_EXT_MAJOR */
 267 #endif /* CONFIG_BUG */
 268
 269 #ifdef HAVE_BIO_RW_FAILFAST_DTD
 270         /* BIO_RW_FAILFAST_* preferred interface from 2.6.28 - 2.6.35 */
 271         *flags |=
 272             ((1 << BIO_RW_FAILFAST_DEV) |
 273              (1 << BIO_RW_FAILFAST_TRANSPORT) |
 274              (1 << BIO_RW_FAILFAST_DRIVER));
 275 #else
 276 # ifdef HAVE_BIO_RW_FAILFAST
 277         /* BIO_RW_FAILFAST preferred interface from 2.6.12 - 2.6.27 */
 278         *flags |= (1 << BIO_RW_FAILFAST);
 279 # else
 280 #  ifdef HAVE_REQ_FAILFAST_MASK
 281         /* REQ_FAILFAST_* preferred interface from 2.6.36 - 2.6.xx,
 282          * the BIO_* and REQ_* flags were unified under REQ_* flags. */
 283         *flags |= REQ_FAILFAST_MASK;
 284 #  endif /* HAVE_REQ_FAILFAST_MASK */
 285 # endif /* HAVE_BIO_RW_FAILFAST */
 286 #endif /* HAVE_BIO_RW_FAILFAST_DTD */
 287 }
 288
 289 /*
 290  * Maximum disk label length, it may be undefined for some kernels.
 291  */
 292 #ifndef DISK_NAME_LEN
 293 #define DISK_NAME_LEN   32
 294 #endif /* DISK_NAME_LEN */
 295
 296 /*
 297  * 2.6.24 API change,
 298  * The bio_end_io() prototype changed slightly.  These are helper
 299  * macro's to ensure the prototype and return value are handled.
 300  */
 301 #ifdef HAVE_2ARGS_BIO_END_IO_T
 302 # define BIO_END_IO_PROTO(fn, x, y, z)  static void fn(struct bio *x, int z)
 303 # define BIO_END_IO_RETURN(rc)          return
 304 #else
 305 # define BIO_END_IO_PROTO(fn, x, y, z)  static int fn(struct bio *x, \
 306                                                       unsigned int y, int z)
 307 # define BIO_END_IO_RETURN(rc)          return rc
 308 #endif /* HAVE_2ARGS_BIO_END_IO_T */
 309
 310 /*
 311  * 2.6.38 - 2.6.x API,
 312  *   blkdev_get_by_path()
 313  *   blkdev_put()
 314  *
 315  * 2.6.28 - 2.6.37 API,
 316  *   open_bdev_exclusive()
 317  *   close_bdev_exclusive()
 318  *
 319  * 2.6.12 - 2.6.27 API,
 320  *   open_bdev_excl()
 321  *   close_bdev_excl()
 322  *
 323  * Used to exclusively open a block device from within the kernel.
 324  */
 325 #if defined(HAVE_BLKDEV_GET_BY_PATH)
 326 # define vdev_bdev_open(path, md, hld)  blkdev_get_by_path(path, \
 327                                             (md) | FMODE_EXCL, hld)
 328 # define vdev_bdev_close(bdev, md)      blkdev_put(bdev, (md) | FMODE_EXCL)
 329 #elif defined(HAVE_OPEN_BDEV_EXCLUSIVE)
 330 # define vdev_bdev_open(path, md, hld)  open_bdev_exclusive(path, md, hld)
 331 # define vdev_bdev_close(bdev, md)      close_bdev_exclusive(bdev, md)
 332 #else
 333 # define vdev_bdev_open(path, md, hld)  open_bdev_excl(path, md, hld)
 334 # define vdev_bdev_close(bdev, md)      close_bdev_excl(bdev)
 335 #endif /* HAVE_BLKDEV_GET_BY_PATH | HAVE_OPEN_BDEV_EXCLUSIVE */
 336
 337 /*
 338  * 2.6.22 API change
 339  * The function invalidate_bdev() lost it's second argument because
 340  * it was unused.
 341  */
 342 #ifdef HAVE_1ARG_INVALIDATE_BDEV
 343 # define vdev_bdev_invalidate(bdev)     invalidate_bdev(bdev)
 344 #else
 345 # define vdev_bdev_invalidate(bdev)     invalidate_bdev(bdev, 1)
 346 #endif /* HAVE_1ARG_INVALIDATE_BDEV */
 347
 348 /*
 349  * 2.6.30 API change
 350  * Change to make it explicit there this is the logical block size.
 351  */
 352 #ifdef HAVE_BDEV_LOGICAL_BLOCK_SIZE
 353 # define vdev_bdev_block_size(bdev)     bdev_logical_block_size(bdev)
 354 #else
 355 # define vdev_bdev_block_size(bdev)     bdev_hardsect_size(bdev)
 356 #endif
 357
 358 /*
 359  * 2.6.37 API change
 360  * The WRITE_FLUSH, WRITE_FUA, and WRITE_FLUSH_FUA flags have been
 361  * introduced as a replacement for WRITE_BARRIER.  This was done to
 362  * allow richer semantics to be expressed to the block layer.  It is
 363  * the block layers responsibility to choose the correct way to
 364  * implement these semantics.
 365  *
 366  * The existence of these flags implies that REQ_FLUSH an REQ_FUA are
 367  * defined.  Thus we can safely define VDEV_REQ_FLUSH and VDEV_REQ_FUA
 368  * compatibility macros.
 369  */
 370 #ifdef WRITE_FLUSH_FUA
 371 # define VDEV_WRITE_FLUSH_FUA           WRITE_FLUSH_FUA
 372 # define VDEV_REQ_FLUSH                 REQ_FLUSH
 373 # define VDEV_REQ_FUA                   REQ_FUA
 374 #else
 375 # define VDEV_WRITE_FLUSH_FUA           WRITE_BARRIER
 376 # define VDEV_REQ_FLUSH                 REQ_HARDBARRIER
 377 # define VDEV_REQ_FUA                   REQ_HARDBARRIER
 378 #endif
 379
 380 /*
 381  * Default Linux IO Scheduler,
 382  * Setting the scheduler to noop will allow the Linux IO scheduler to
 383  * still perform front and back merging, while leaving the request
 384  * ordering and prioritization to the ZFS IO scheduler.
 385  */
 386 #define VDEV_SCHEDULER                  "noop"
 387
 388 #endif /* _ZFS_BLKDEV_H */