mirror_zfs/include/linux/blkdev_compat.h
Brian Behlendorf 96801d2906 Linux 2.6.37 compat, WRITE_FLUSH_FUA
The WRITE_FLUSH, WRITE_FUA, and WRITE_FLUSH_FUA flags have been
introduced as a replacement for WRITE_BARRIER.  This was done
to allow richer semantics to be expressed to the block layer.
It is the block layers responsibility to choose the correct way
to implement these semantics.

This change simply updates the bio's to use the new kernel API
which should be absolutely safe.  However, since ZFS depends
entirely on this working as designed for correctness we do
want to be careful.

Closes #281
2011-06-17 14:37:26 -07:00

364 lines
10 KiB
C

/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (C) 2011 Lawrence Livermore National Security, LLC.
* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
* Written by Brian Behlendorf <behlendorf1@llnl.gov>.
* LLNL-CODE-403049.
*/
#ifndef _ZFS_BLKDEV_H
#define _ZFS_BLKDEV_H
#include <linux/blkdev.h>
#include <linux/elevator.h>
#ifndef HAVE_FMODE_T
typedef unsigned __bitwise__ fmode_t;
#endif /* HAVE_FMODE_T */
#ifndef HAVE_BLK_FETCH_REQUEST
static inline struct request *
blk_fetch_request(struct request_queue *q)
{
struct request *req;
req = elv_next_request(q);
if (req)
blkdev_dequeue_request(req);
return req;
}
#endif /* HAVE_BLK_FETCH_REQUEST */
#ifndef HAVE_BLK_REQUEUE_REQUEST
static inline void
blk_requeue_request(request_queue_t *q, struct request *req)
{
elv_requeue_request(q, req);
}
#endif /* HAVE_BLK_REQUEUE_REQUEST */
#ifndef HAVE_BLK_END_REQUEST
static inline bool
__blk_end_request(struct request *req, int error, unsigned int nr_bytes)
{
LIST_HEAD(list);
/*
* Request has already been dequeued but 2.6.18 version of
* end_request() unconditionally dequeues the request so we
* add it to a local list to prevent hitting the BUG_ON.
*/
list_add(&req->queuelist, &list);
/*
* The old API required the driver to end each segment and not
* the entire request. In our case we always need to end the
* entire request partial requests are not supported.
*/
req->hard_cur_sectors = nr_bytes >> 9;
end_request(req, ((error == 0) ? 1 : error));
return 0;
}
static inline bool
blk_end_request(struct request *req, int error, unsigned int nr_bytes)
{
struct request_queue *q = req->q;
bool rc;
spin_lock_irq(q->queue_lock);
rc = __blk_end_request(req, error, nr_bytes);
spin_unlock_irq(q->queue_lock);
return rc;
}
#else
# ifdef HAVE_BLK_END_REQUEST_GPL_ONLY
/*
* Define required to avoid conflicting 2.6.29 non-static prototype for a
* GPL-only version of the helper. As of 2.6.31 the helper is available
* to non-GPL modules and is not explicitly exported GPL-only.
*/
# define __blk_end_request __blk_end_request_x
# define blk_end_request blk_end_request_x
static inline bool
__blk_end_request_x(struct request *req, int error, unsigned int nr_bytes)
{
/*
* The old API required the driver to end each segment and not
* the entire request. In our case we always need to end the
* entire request partial requests are not supported.
*/
req->hard_cur_sectors = nr_bytes >> 9;
end_request(req, ((error == 0) ? 1 : error));
return 0;
}
static inline bool
blk_end_request_x(struct request *req, int error, unsigned int nr_bytes)
{
struct request_queue *q = req->q;
bool rc;
spin_lock_irq(q->queue_lock);
rc = __blk_end_request_x(req, error, nr_bytes);
spin_unlock_irq(q->queue_lock);
return rc;
}
# endif /* HAVE_BLK_END_REQUEST_GPL_ONLY */
#endif /* HAVE_BLK_END_REQUEST */
#ifndef HAVE_BLK_RQ_POS
static inline sector_t
blk_rq_pos(struct request *req)
{
return req->sector;
}
#endif /* HAVE_BLK_RQ_POS */
#ifndef HAVE_BLK_RQ_SECTORS
static inline unsigned int
blk_rq_sectors(struct request *req)
{
return req->nr_sectors;
}
#endif /* HAVE_BLK_RQ_SECTORS */
#if !defined(HAVE_BLK_RQ_BYTES) || defined(HAVE_BLK_RQ_BYTES_GPL_ONLY)
/*
* Define required to avoid conflicting 2.6.29 non-static prototype for a
* GPL-only version of the helper. As of 2.6.31 the helper is available
* to non-GPL modules in the form of a static inline in the header.
*/
#define blk_rq_bytes __blk_rq_bytes
static inline unsigned int
__blk_rq_bytes(struct request *req)
{
return blk_rq_sectors(req) << 9;
}
#endif /* !HAVE_BLK_RQ_BYTES || HAVE_BLK_RQ_BYTES_GPL_ONLY */
/*
* Most of the blk_* macros were removed in 2.6.36. Ostensibly this was
* done to improve readability and allow easier grepping. However, from
* a portability stand point the macros are helpful. Therefore the needed
* macros are redefined here if they are missing from the kernel.
*/
#ifndef blk_fs_request
#define blk_fs_request(rq) ((rq)->cmd_type == REQ_TYPE_FS)
#endif
/*
* 2.6.27 API change,
* The blk_queue_stackable() queue flag was added in 2.6.27 to handle dm
* stacking drivers. Prior to this request stacking drivers were detected
* by checking (q->request_fn == NULL), for earlier kernels we revert to
* this legacy behavior.
*/
#ifndef blk_queue_stackable
#define blk_queue_stackable(q) ((q)->request_fn == NULL)
#endif
#ifndef HAVE_GET_DISK_RO
static inline int
get_disk_ro(struct gendisk *disk)
{
int policy = 0;
if (disk->part[0])
policy = disk->part[0]->policy;
return policy;
}
#endif /* HAVE_GET_DISK_RO */
#ifndef HAVE_RQ_IS_SYNC
static inline bool
rq_is_sync(struct request *req)
{
return (req->flags & REQ_RW_SYNC);
}
#endif /* HAVE_RQ_IS_SYNC */
#ifndef HAVE_RQ_FOR_EACH_SEGMENT
struct req_iterator {
int i;
struct bio *bio;
};
# define for_each_bio(_bio) \
for (; _bio; _bio = _bio->bi_next)
# define __rq_for_each_bio(_bio, rq) \
if ((rq->bio)) \
for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
# define rq_for_each_segment(bvl, _rq, _iter) \
__rq_for_each_bio(_iter.bio, _rq) \
bio_for_each_segment(bvl, _iter.bio, _iter.i)
#endif /* HAVE_RQ_FOR_EACH_SEGMENT */
/*
* Portable helper for correctly setting the FAILFAST flags. The
* correct usage has changed 3 times from 2.6.12 to 2.6.38.
*/
static inline void
bio_set_flags_failfast(struct block_device *bdev, int *flags)
{
#ifdef CONFIG_BUG
/*
* Disable FAILFAST for loopback devices because of the
* following incorrect BUG_ON() in loop_make_request().
* This support is also disabled for md devices because the
* test suite layers md devices on top of loopback devices.
* This may be removed when the loopback driver is fixed.
*
* BUG_ON(!lo || (rw != READ && rw != WRITE));
*/
if ((MAJOR(bdev->bd_dev) == LOOP_MAJOR) ||
(MAJOR(bdev->bd_dev) == MD_MAJOR))
return;
#ifdef BLOCK_EXT_MAJOR
if (MAJOR(bdev->bd_dev) == BLOCK_EXT_MAJOR)
return;
#endif /* BLOCK_EXT_MAJOR */
#endif /* CONFIG_BUG */
#ifdef HAVE_BIO_RW_FAILFAST_DTD
/* BIO_RW_FAILFAST_* preferred interface from 2.6.28 - 2.6.35 */
*flags |=
((1 << BIO_RW_FAILFAST_DEV) |
(1 << BIO_RW_FAILFAST_TRANSPORT) |
(1 << BIO_RW_FAILFAST_DRIVER));
#else
# ifdef HAVE_BIO_RW_FAILFAST
/* BIO_RW_FAILFAST preferred interface from 2.6.12 - 2.6.27 */
*flags |= (1 << BIO_RW_FAILFAST);
# else
# ifdef HAVE_REQ_FAILFAST_MASK
/* REQ_FAILFAST_* preferred interface from 2.6.36 - 2.6.xx,
* the BIO_* and REQ_* flags were unified under REQ_* flags. */
*flags |= REQ_FAILFAST_MASK;
# endif /* HAVE_REQ_FAILFAST_MASK */
# endif /* HAVE_BIO_RW_FAILFAST */
#endif /* HAVE_BIO_RW_FAILFAST_DTD */
}
/*
* Maximum disk label length, it may be undefined for some kernels.
*/
#ifndef DISK_NAME_LEN
#define DISK_NAME_LEN 32
#endif /* DISK_NAME_LEN */
/*
* 2.6.24 API change,
* The bio_end_io() prototype changed slightly. These are helper
* macro's to ensure the prototype and return value are handled.
*/
#ifdef HAVE_2ARGS_BIO_END_IO_T
# define BIO_END_IO_PROTO(fn, x, y, z) static void fn(struct bio *x, int z)
# define BIO_END_IO_RETURN(rc) return
#else
# define BIO_END_IO_PROTO(fn, x, y, z) static int fn(struct bio *x, \
unsigned int y, int z)
# define BIO_END_IO_RETURN(rc) return rc
#endif /* HAVE_2ARGS_BIO_END_IO_T */
/*
* 2.6.38 - 2.6.x API,
* blkdev_get_by_path()
* blkdev_put()
*
* 2.6.28 - 2.6.37 API,
* open_bdev_exclusive()
* close_bdev_exclusive()
*
* 2.6.12 - 2.6.27 API,
* open_bdev_excl()
* close_bdev_excl()
*
* Used to exclusively open a block device from within the kernel.
*/
#if defined(HAVE_BLKDEV_GET_BY_PATH)
# define vdev_bdev_open(path, md, hld) blkdev_get_by_path(path, \
(md) | FMODE_EXCL, hld)
# define vdev_bdev_close(bdev, md) blkdev_put(bdev, (md) | FMODE_EXCL)
#elif defined(HAVE_OPEN_BDEV_EXCLUSIVE)
# define vdev_bdev_open(path, md, hld) open_bdev_exclusive(path, md, hld)
# define vdev_bdev_close(bdev, md) close_bdev_exclusive(bdev, md)
#else
# define vdev_bdev_open(path, md, hld) open_bdev_excl(path, md, hld)
# define vdev_bdev_close(bdev, md) close_bdev_excl(bdev)
#endif /* HAVE_BLKDEV_GET_BY_PATH | HAVE_OPEN_BDEV_EXCLUSIVE */
/*
* 2.6.22 API change
* The function invalidate_bdev() lost it's second argument because
* it was unused.
*/
#ifdef HAVE_1ARG_INVALIDATE_BDEV
# define vdev_bdev_invalidate(bdev) invalidate_bdev(bdev)
#else
# define vdev_bdev_invalidate(bdev) invalidate_bdev(bdev, 1)
#endif /* HAVE_1ARG_INVALIDATE_BDEV */
/*
* 2.6.30 API change
* Change to make it explicit there this is the logical block size.
*/
#ifdef HAVE_BDEV_LOGICAL_BLOCK_SIZE
# define vdev_bdev_block_size(bdev) bdev_logical_block_size(bdev)
#else
# define vdev_bdev_block_size(bdev) bdev_hardsect_size(bdev)
#endif
/*
* 2.6.37 API change
* The WRITE_FLUSH, WRITE_FUA, and WRITE_FLUSH_FUA flags have been
* introduced as a replacement for WRITE_BARRIER. This was done to
* allow richer semantics to be expressed to the block layer. It is
* the block layers responsibility to choose the correct way to
* implement these semantics.
*/
#ifdef WRITE_FLUSH_FUA
# define VDEV_WRITE_FLUSH_FUA WRITE_FLUSH_FUA
#else
# define VDEV_WRITE_FLUSH_FUA WRITE_BARRIER
#endif
/*
* Default Linux IO Scheduler,
* Setting the scheduler to noop will allow the Linux IO scheduler to
* still perform front and back merging, while leaving the request
* ordering and prioritization to the ZFS IO scheduler.
*/
#define VDEV_SCHEDULER "noop"
#endif /* _ZFS_BLKDEV_H */