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mirror_zfs/include/linux/blkdev_compat.h
Tim Chase a5e046eaac 4.10 compat - BIO flag changes and others 
[bio] The req_op enum was changed to req_opf.  Update the "Linux 4.8 API"
autotools checks to use an int to determine whether the various REQ_OP
values are defined.  This should work properly on kernels >= 4.8.

[bio] bio_set_op_attrs() is now an inline function and can't be detected
with #ifdef.  Add a configure check to determine whether bio_set_op_attrs()
is defined.  Move the local definition of it from vdev_disk.c to
blkdev_compat.h for consistency with other related compability shims.

[bio] The read/write flags and their modifiers, including WRITE_FLUSH,
WRITE_FUA and WRITE_FLUSH_FUA have been removed from fs.h.  Add the new
bio_set_flush() compatibility wrapper to replace VDEV_WRITE_FLUSH_FUA
and set the flags appropriately for each supported kernel version.

[vfs] The generic_readlink() function has been made static.  If .readlink
in inode_operations is NULL, generic_readlink() is used.

[zol typo] Completely unrelated to 4.10 compat, fix a typo in the check
for REQ_OP_SECURE_ERASE so that the proper macro is defined:

    s/HAVE_REQ_OP_SECURE_DISCARD/HAVE_REQ_OP_SECURE_ERASE/

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes #5499
2016-12-30 16:03:59 -06:00

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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 */
/*
* 4.7 - 4.x API,
* The blk_queue_write_cache() interface has replaced blk_queue_flush()
* interface. However, the new interface is GPL-only thus we implement
* our own trivial wrapper when the GPL-only version is detected.
*
* 2.6.36 - 4.6 API,
* 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.
*
* 2.6.x - 2.6.35
* Legacy blk_queue_ordered() interface.
*/
static inline void
blk_queue_set_write_cache(struct request_queue *q, bool wc, bool fua)
{
#if defined(HAVE_BLK_QUEUE_WRITE_CACHE_GPL_ONLY)
spin_lock_irq(q->queue_lock);
if (wc)
queue_flag_set(QUEUE_FLAG_WC, q);
else
queue_flag_clear(QUEUE_FLAG_WC, q);
if (fua)
queue_flag_set(QUEUE_FLAG_FUA, q);
else
queue_flag_clear(QUEUE_FLAG_FUA, q);
spin_unlock_irq(q->queue_lock);
#elif defined(HAVE_BLK_QUEUE_WRITE_CACHE)
blk_queue_write_cache(q, wc, fua);
#elif defined(HAVE_BLK_QUEUE_FLUSH_GPL_ONLY)
if (wc)
q->flush_flags |= REQ_FLUSH;
if (fua)
q->flush_flags |= REQ_FUA;
#elif defined(HAVE_BLK_QUEUE_FLUSH)
blk_queue_flush(q, (wc ? REQ_FLUSH : 0) | (fua ? REQ_FUA : 0));
#else
blk_queue_ordered(q, QUEUE_ORDERED_DRAIN, NULL);
#endif
}
/*
* 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 but the
* symbol was not exported.
*
* 4.4.0-6.21 API change for Ubuntu
* lookup_bdev() gained a second argument, FMODE_*, to check inode permissions.
*/
#ifdef HAVE_1ARG_LOOKUP_BDEV
#define vdev_lookup_bdev(path) lookup_bdev(path)
#else
#ifdef HAVE_2ARGS_LOOKUP_BDEV
#define vdev_lookup_bdev(path) lookup_bdev(path, 0)
#else
#define vdev_lookup_bdev(path) ERR_PTR(-ENOTSUP)
#endif /* HAVE_2ARGS_LOOKUP_BDEV */
#endif /* HAVE_1ARG_LOOKUP_BDEV */
/*
* 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 */
#ifndef HAVE_BIO_SET_OP_ATTRS
/*
* Kernels without bio_set_op_attrs use bi_rw for the bio flags.
*/
static inline void
bio_set_op_attrs(struct bio *bio, unsigned rw, unsigned flags)
{
bio->bi_rw |= rw | flags;
}
#endif
/*
* bio_set_flush - Set the appropriate flags in a bio to guarantee
* data are on non-volatile media on completion.
*
* 2.6.X - 2.6.36 API,
* WRITE_BARRIER - Tells the block layer to commit all previously submitted
* writes to stable storage before this one is started and that the current
* write is on stable storage upon completion. Also prevents reordering
* on both sides of the current operation.
*
* 2.6.37 - 4.8 API,
* Introduce WRITE_FLUSH, WRITE_FUA, and WRITE_FLUSH_FUA flags as a
* replacement for WRITE_BARRIER to allow expressing richer semantics
* to the block layer. It's up to the block layer to implement the
* semantics correctly. Use the WRITE_FLUSH_FUA flag combination.
*
* 4.8 - 4.9 API,
* REQ_FLUSH was renamed to REQ_PREFLUSH. For consistency with previous
* ZoL releases, prefer the WRITE_FLUSH_FUA flag set if it's available.
*
* 4.10 API,
* The read/write flags and their modifiers, including WRITE_FLUSH,
* WRITE_FUA and WRITE_FLUSH_FUA were removed from fs.h in
* torvalds/linux@70fd7614 and replaced by direct flag modification
* of the REQ_ flags in bio->bi_opf. Use REQ_PREFLUSH.
*/
static inline void
bio_set_flush(struct bio *bio)
{
#if defined(WRITE_BARRIER) /* < 2.6.37 */
bio_set_op_attrs(bio, 0, WRITE_BARRIER);
#elif defined(WRITE_FLUSH_FUA) /* >= 2.6.37 and <= 4.9 */
bio_set_op_attrs(bio, 0, WRITE_FLUSH_FUA);
#elif defined(REQ_PREFLUSH) /* >= 4.10 */
bio_set_op_attrs(bio, 0, REQ_PREFLUSH);
#else
#error "Allowing the build will cause bio_set_flush requests to be ignored."
"Please file an issue report at: "
"https://github.com/zfsonlinux/zfs/issues/new"
#endif
}
/*
* 4.8 - 4.x API,
* REQ_OP_FLUSH
*
* 4.8-rc0 - 4.8-rc1,
* REQ_PREFLUSH
*
* 2.6.36 - 4.7 API,
* REQ_FLUSH
*
* 2.6.x - 2.6.35 API,
* HAVE_BIO_RW_BARRIER
*
* Used to determine if a cache flush has been requested. This check has
* been left intentionally broad in order to cover both a legacy flush
* and the new preflush behavior introduced in Linux 4.8. This is correct
* in all cases but may have a performance impact for some kernels. It
* has the advantage of minimizing kernel specific changes in the zvol code.
*
* Note that 2.6.32 era kernels provide both BIO_RW_BARRIER and REQ_FLUSH,
* where BIO_RW_BARRIER is the correct interface. Therefore, it is important
* that the HAVE_BIO_RW_BARRIER check occur before the REQ_FLUSH check.
*/
static inline boolean_t
bio_is_flush(struct bio *bio)
{
#if defined(HAVE_REQ_OP_FLUSH) && defined(HAVE_BIO_BI_OPF)
return ((bio_op(bio) == REQ_OP_FLUSH) || (bio->bi_opf & REQ_PREFLUSH));
#elif defined(REQ_PREFLUSH) && defined(HAVE_BIO_BI_OPF)
return (bio->bi_opf & REQ_PREFLUSH);
#elif defined(REQ_PREFLUSH) && !defined(HAVE_BIO_BI_OPF)
return (bio->bi_rw & REQ_PREFLUSH);
#elif defined(HAVE_BIO_RW_BARRIER)
return (bio->bi_rw & (1 << BIO_RW_BARRIER));
#elif defined(REQ_FLUSH)
return (bio->bi_rw & REQ_FLUSH);
#else
#error "Allowing the build will cause flush requests to be ignored. Please "
"file an issue report at: https://github.com/zfsonlinux/zfs/issues/new"
#endif
}
/*
* 4.8 - 4.x API,
* REQ_FUA flag moved to bio->bi_opf
*
* 2.6.x - 4.7 API,
* REQ_FUA
*/
static inline boolean_t
bio_is_fua(struct bio *bio)
{
#if defined(HAVE_BIO_BI_OPF)
return (bio->bi_opf & REQ_FUA);
#elif defined(REQ_FUA)
return (bio->bi_rw & REQ_FUA);
#else
#error "Allowing the build will cause fua requests to be ignored. Please "
"file an issue report at: https://github.com/zfsonlinux/zfs/issues/new"
#endif
}
/*
* 4.8 - 4.x API,
* REQ_OP_DISCARD
*
* 2.6.36 - 4.7 API,
* REQ_DISCARD
*
* 2.6.28 - 2.6.35 API,
* BIO_RW_DISCARD
*
* In all cases the normal I/O path is used for discards. The only
* difference is how the kernel tags individual I/Os as discards.
*
* Note that 2.6.32 era kernels provide both BIO_RW_DISCARD and REQ_DISCARD,
* where BIO_RW_DISCARD is the correct interface. Therefore, it is important
* that the HAVE_BIO_RW_DISCARD check occur before the REQ_DISCARD check.
*/
static inline boolean_t
bio_is_discard(struct bio *bio)
{
#if defined(HAVE_REQ_OP_DISCARD)
return (bio_op(bio) == REQ_OP_DISCARD);
#elif defined(HAVE_BIO_RW_DISCARD)
return (bio->bi_rw & (1 << BIO_RW_DISCARD));
#elif defined(REQ_DISCARD)
return (bio->bi_rw & REQ_DISCARD);
#else
#error "Allowing the build will cause discard requests to become writes "
"potentially triggering the DMU_MAX_ACCESS assertion. Please file "
"an issue report at: https://github.com/zfsonlinux/zfs/issues/new"
#endif
}
/*
* 4.8 - 4.x API,
* REQ_OP_SECURE_ERASE
*
* 2.6.36 - 4.7 API,
* REQ_SECURE
*
* 2.6.x - 2.6.35 API,
* Unsupported by kernel
*/
static inline boolean_t
bio_is_secure_erase(struct bio *bio)
{
#if defined(HAVE_REQ_OP_SECURE_ERASE)
return (bio_op(bio) == REQ_OP_SECURE_ERASE);
#elif defined(REQ_SECURE)
return (bio->bi_rw & REQ_SECURE);
#else
return (0);
#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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