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mirror_zfs/include/linux/blkdev_compat.h
Chunwei Chen 2727b9d3b6 Use uio for zvol_{read,write} 
Since uio now supports bvec, we can convert bio into uio and reuse
dmu_{read,write}_uio. This way, we can remove some duplicate code.

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #4078
2015-12-15 16:21:43 -08:00

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/*
* 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 */
/*
* 2.6.36 API change,
* The blk_queue_flush() interface has replaced blk_queue_ordered()
* interface. However, while the old interface was available to all the
* new one is GPL-only. Thus if the GPL-only version is detected we
* implement our own trivial helper compatibility funcion. The hope is
* that long term this function will be opened up.
*/
#if defined(HAVE_BLK_QUEUE_FLUSH) && defined(HAVE_BLK_QUEUE_FLUSH_GPL_ONLY)
#define blk_queue_flush __blk_queue_flush
static inline void
__blk_queue_flush(struct request_queue *q, unsigned int flags)
{
q->flush_flags = flags & (REQ_FLUSH | REQ_FUA);
}
#endif /* HAVE_BLK_QUEUE_FLUSH && HAVE_BLK_QUEUE_FLUSH_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
/*
* 2.6.34 API change,
* The blk_queue_max_hw_sectors() function replaces blk_queue_max_sectors().
*/
#ifndef HAVE_BLK_QUEUE_MAX_HW_SECTORS
#define blk_queue_max_hw_sectors __blk_queue_max_hw_sectors
static inline void
__blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors)
{
blk_queue_max_sectors(q, max_hw_sectors);
}
#endif
/*
* 2.6.34 API change,
* The blk_queue_max_segments() function consolidates
* blk_queue_max_hw_segments() and blk_queue_max_phys_segments().
*/
#ifndef HAVE_BLK_QUEUE_MAX_SEGMENTS
#define blk_queue_max_segments __blk_queue_max_segments
static inline void
__blk_queue_max_segments(struct request_queue *q, unsigned short max_segments)
{
blk_queue_max_phys_segments(q, max_segments);
blk_queue_max_hw_segments(q, max_segments);
}
#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 */
#ifdef HAVE_BIO_BVEC_ITER
#define BIO_BI_SECTOR(bio) (bio)->bi_iter.bi_sector
#define BIO_BI_SIZE(bio) (bio)->bi_iter.bi_size
#define BIO_BI_IDX(bio) (bio)->bi_iter.bi_idx
#define BIO_BI_SKIP(bio) (bio)->bi_iter.bi_bvec_done
#define bio_for_each_segment4(bv, bvp, b, i) \
bio_for_each_segment((bv), (b), (i))
typedef struct bvec_iter bvec_iterator_t;
#else
#define BIO_BI_SECTOR(bio) (bio)->bi_sector
#define BIO_BI_SIZE(bio) (bio)->bi_size
#define BIO_BI_IDX(bio) (bio)->bi_idx
#define BIO_BI_SKIP(bio) (0)
#define bio_for_each_segment4(bv, bvp, b, i) \
bio_for_each_segment((bvp), (b), (i))
typedef int bvec_iterator_t;
#endif
/*
* 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 */
#if defined(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));
#elif defined(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;
#else
#error "Undefined block IO FAILFAST interface."
#endif
}
/*
* Maximum disk label length, it may be undefined for some kernels.
*/
#ifndef DISK_NAME_LEN
#define DISK_NAME_LEN 32
#endif /* DISK_NAME_LEN */
/*
* 4.3 API change
* The bio_endio() prototype changed slightly. These are helper
* macro's to ensure the prototype and invocation are handled.
*/
#ifdef HAVE_1ARG_BIO_END_IO_T
#define BIO_END_IO_PROTO(fn, x, z) static void fn(struct bio *x)
#define BIO_END_IO(bio, error) bio->bi_error = error; bio_endio(bio);
#else
#define BIO_END_IO_PROTO(fn, x, z) static void fn(struct bio *x, int z)
#define BIO_END_IO(bio, error) bio_endio(bio, error);
#endif /* HAVE_1ARG_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 */
/*
* 2.6.27 API change
* The function was exported for use, prior to this it existed by the
* symbol was not exported.
*/
#ifndef HAVE_LOOKUP_BDEV
#define lookup_bdev(path) ERR_PTR(-ENOTSUP)
#endif
/*
* 2.6.30 API change
* To ensure good performance preferentially use the physical block size
* for proper alignment. The physical size is supposed to be the internal
* sector size used by the device. This is often 4096 byte for AF devices,
* while a smaller 512 byte logical size is supported for compatibility.
*
* Unfortunately, many drives still misreport their physical sector size.
* For devices which are known to lie you may need to manually set this
* at pool creation time with 'zpool create -o ashift=12 ...'.
*
* When the physical block size interface isn't available, we fall back to
* the logical block size interface and then the older hard sector size.
*/
#ifdef HAVE_BDEV_PHYSICAL_BLOCK_SIZE
#define vdev_bdev_block_size(bdev) bdev_physical_block_size(bdev)
#else
#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 /* HAVE_BDEV_LOGICAL_BLOCK_SIZE */
#endif /* HAVE_BDEV_PHYSICAL_BLOCK_SIZE */
/*
* 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.
*
* The existence of these flags implies that REQ_FLUSH an REQ_FUA are
* defined. Thus we can safely define VDEV_REQ_FLUSH and VDEV_REQ_FUA
* compatibility macros.
*/
#ifdef WRITE_FLUSH_FUA
#define VDEV_WRITE_FLUSH_FUA WRITE_FLUSH_FUA
#define VDEV_REQ_FLUSH REQ_FLUSH
#define VDEV_REQ_FUA REQ_FUA
#else
#define VDEV_WRITE_FLUSH_FUA WRITE_BARRIER
#ifdef HAVE_BIO_RW_BARRIER
#define VDEV_REQ_FLUSH (1 << BIO_RW_BARRIER)
#define VDEV_REQ_FUA (1 << BIO_RW_BARRIER)
#else
#define VDEV_REQ_FLUSH REQ_HARDBARRIER
#define VDEV_REQ_FUA REQ_FUA
#endif
#endif
/*
* 2.6.32 API change
* Use the normal I/O patch for discards.
*/
#ifdef QUEUE_FLAG_DISCARD
#ifdef HAVE_BIO_RW_DISCARD
#define VDEV_REQ_DISCARD (1 << BIO_RW_DISCARD)
#else
#define VDEV_REQ_DISCARD REQ_DISCARD
#endif
#else
#error "Allowing the build will cause discard requests to become writes "
"potentially triggering the DMU_MAX_ACCESS assertion. Please file a "
"an issue report at: https://github.com/zfsonlinux/zfs/issues/new"
#endif
/*
* 2.6.33 API change
* Discard granularity and alignment restrictions may now be set. For
* older kernels which do not support this it is safe to skip it.
*/
#ifdef HAVE_DISCARD_GRANULARITY
static inline void
blk_queue_discard_granularity(struct request_queue *q, unsigned int dg)
{
q->limits.discard_granularity = dg;
}
#else
#define blk_queue_discard_granularity(x, dg) ((void)0)
#endif /* HAVE_DISCARD_GRANULARITY */
/*
* 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"
/*
* A common holder for vdev_bdev_open() is used to relax the exclusive open
* semantics slightly. Internal vdev disk callers may pass VDEV_HOLDER to
* allow them to open the device multiple times. Other kernel callers and
* user space processes which don't pass this value will get EBUSY. This is
* currently required for the correct operation of hot spares.
*/
#define VDEV_HOLDER ((void *)0x2401de7)
#ifndef HAVE_GENERIC_IO_ACCT
#define generic_start_io_acct(rw, slen, part) ((void)0)
#define generic_end_io_acct(rw, part, start_jiffies) ((void)0)
#endif
#endif /* _ZFS_BLKDEV_H */
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