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692e55b8fe
mirror_zfs/include/linux/blkdev_compat.h
Chunwei Chen 692e55b8fe Reinstate zvol_taskq to fix aio on zvol 
Commit 37f9dac removed the zvol_taskq for processing zvol requests.
This was removed as part of switching to make_request_fn and was
motivated by a concern at the time over dispatch latency.

However, this also made all bio request synchronous, and caused
serious performance issues as the bio submitter would wait for
every bio it submitted, effectively making the IO depth 1.

This patch reinstate zvol_taskq, and to make sure overlapped I/Os
are ordered properly, we take range lock in zvol_request, and pass
it along with bio to the I/O functions zvol_{write,discard,read}.

In order to facilitate benchmarks a zvol_request_sync module
option was added to switch between sync and async request handling.
For the moment, the default behavior is synchronous but this is
likely to change pending additional testing.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes #5824
2017-04-26 13:54:40 -07:00

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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(REQ_PREFLUSH) /* >= 4.10 */
bio_set_op_attrs(bio, 0, REQ_PREFLUSH);
#elif defined(WRITE_FLUSH_FUA) /* >= 2.6.37 and <= 4.9 */
bio_set_op_attrs(bio, 0, WRITE_FLUSH_FUA);
#elif defined(WRITE_BARRIER) /* < 2.6.37 */
bio_set_op_attrs(bio, 0, WRITE_BARRIER);
#else
#error "Allowing the build will cause bio_set_flush requests to be ignored."
#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.
*
*/
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(REQ_FLUSH)
return (bio->bi_rw & REQ_FLUSH);
#elif defined(HAVE_BIO_RW_BARRIER)
return (bio->bi_rw & (1 << BIO_RW_BARRIER));
#else
#error "Allowing the build will cause flush requests to be ignored."
#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."
#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
/* potentially triggering the DMU_MAX_ACCESS assertion. */
#error "Allowing the build will cause discard requests to become writes."
#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
static inline void
generic_start_io_acct(int rw, unsigned long sectors, struct hd_struct *part)
{
}
static inline void
generic_end_io_acct(int rw, struct hd_struct *part, unsigned long start_time)
{
}
#endif
#endif /* _ZFS_BLKDEV_H */
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