1299 lines
56 KiB
C
1299 lines
56 KiB
C
/*
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* Copyright (c) 2000-2016 Apple Computer, Inc. All rights reserved.
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*
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* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
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*
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* This file contains Original Code and/or Modifications of Original Code
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* as defined in and that are subject to the Apple Public Source License
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* Version 2.0 (the 'License'). You may not use this file except in
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* compliance with the License. The rights granted to you under the License
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* may not be used to create, or enable the creation or redistribution of,
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* unlawful or unlicensed copies of an Apple operating system, or to
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* circumvent, violate, or enable the circumvention or violation of, any
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* terms of an Apple operating system software license agreement.
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*
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* Please obtain a copy of the License at
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* http://www.opensource.apple.com/apsl/ and read it before using this file.
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*
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* The Original Code and all software distributed under the License are
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* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
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* Please see the License for the specific language governing rights and
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* limitations under the License.
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*
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* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
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*/
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/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
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/*
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* Copyright (c) 1982, 1986, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)buf.h 8.9 (Berkeley) 3/30/95
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*/
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#ifndef _SYS_BUF_H_
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#define _SYS_BUF_H_
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#include <sys/cdefs.h>
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#include <sys/kernel_types.h>
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#include <sys/ucred.h>
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#include <mach/memory_object_types.h>
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#define B_WRITE 0x00000000 /* Write buffer (pseudo flag). */
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#define B_READ 0x00000001 /* Read buffer. */
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#define B_ASYNC 0x00000002 /* Start I/O, do not wait. */
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#define B_NOCACHE 0x00000004 /* Do not cache block after use. */
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#define B_DELWRI 0x00000008 /* Delay I/O until buffer reused. */
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#define B_LOCKED 0x00000010 /* Locked in core (not reusable). */
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#define B_PHYS 0x00000020 /* I/O to user memory. */
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#define B_CLUSTER 0x00000040 /* UPL based I/O generated by cluster layer */
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#define B_PAGEIO 0x00000080 /* Page in/out */
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#define B_META 0x00000100 /* buffer contains meta-data. */
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#define B_RAW 0x00000200 /* Set by physio for raw transfers. */
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#define B_FUA 0x00000400 /* Write-through disk cache(if supported) */
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#define B_PASSIVE 0x00000800 /* PASSIVE I/Os are ignored by THROTTLE I/O */
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#define B_IOSTREAMING 0x00001000 /* sequential access pattern detected */
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#define B_THROTTLED_IO 0x00002000 /* low priority I/O (deprecated) */
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#define B_ENCRYPTED_IO 0x00004000 /* Encrypted I/O */
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#define B_STATICCONTENT 0x00008000 /* Buffer is likely to remain unaltered */
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/*
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* make sure to check when adding flags that
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* that the new flags don't overlap the definitions
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* in buf_internal.h
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*/
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__BEGIN_DECLS
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/*!
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* @function buf_markaged
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* @abstract Mark a buffer as "aged," i.e. as a good candidate to be discarded and reused after buf_brelse().
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* @param bp Buffer to mark.
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*/
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void buf_markaged(buf_t bp);
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/*!
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* @function buf_markinvalid
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* @abstract Mark a buffer as not having valid data and being ready for immediate reuse after buf_brelse().
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* @param bp Buffer to mark.
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*/
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void buf_markinvalid(buf_t bp);
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/*!
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* @function buf_markdelayed
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* @abstract Mark a buffer as a delayed write: mark it dirty without actually scheduling I/O.
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* @discussion Data will be flushed to disk at some later time, not with brelse(). A sync()/fsync()
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* or pressure necessitating reuse of the buffer will cause it to be written back to disk.
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* @param bp Buffer to mark.
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*/
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void buf_markdelayed(buf_t bp);
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void buf_markclean(buf_t);
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/*!
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* @function buf_markeintr
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* @abstract Mark a buffer as having been interrupted during I/O.
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* @discussion Waiters for I/O to complete (buf_biowait()) will return with EINTR when woken up.
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* buf_markeintr does not itself do a wakeup.
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* @param bp Buffer to mark.
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*/
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void buf_markeintr(buf_t bp);
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/*!
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* @function buf_markfua
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* @abstract Mark a buffer for write through disk cache, if disk supports it.
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* @param bp Buffer to mark.
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*/
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void buf_markfua(buf_t bp);
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/*!
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* @function buf_fua
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* @abstract Check if a buffer is marked for write through disk caches.
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* @param bp Buffer to test.
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* @return Nonzero if buffer is marked for write-through, 0 if not.
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*/
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int buf_fua(buf_t bp);
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/*!
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* @function buf_valid
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* @abstract Check if a buffer contains valid data.
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* @param bp Buffer to test.
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* @return Nonzero if buffer has valid data, 0 if not.
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*/
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int buf_valid(buf_t bp);
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/*!
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* @function buf_fromcache
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* @abstract Check if a buffer's data was found in core.
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* @discussion Will return truth after a buf_getblk that finds a valid buffer in the cache or the relevant
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* data in core (but not in a buffer).
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* @param bp Buffer to test.
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* @return Nonzero if we got this buffer's data without doing I/O, 0 if not.
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*/
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int buf_fromcache(buf_t bp);
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/*!
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* @function buf_upl
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* @abstract Get the upl (Universal Page List) associated with a buffer.
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* @discussion Buffers allocated with buf_alloc() are not returned with a upl, and
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* traditional buffers only have a upl while an I/O is in progress.
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* @param bp Buffer whose upl to grab.
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* @return Buffer's upl if it has one, else NULL.
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*/
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void * buf_upl(buf_t bp);
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/*!
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* @function buf_uploffset
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* @abstract Get the offset into a UPL at which this buffer begins.
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* @discussion This function should only be called on iobufs, i.e. buffers allocated with buf_alloc().
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* @param bp Buffer whose uploffset to grab.
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* @return Buffer's uploffset--does not check whether that value makes sense for this buffer.
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*/
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uint32_t buf_uploffset(buf_t bp);
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/*!
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* @function buf_rcred
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* @abstract Get the credential associated with a buffer for reading.
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* @discussion No reference is taken; if the credential is to be held on to persistently, an additional
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* reference must be taken with kauth_cred_ref.
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* @param bp Buffer whose credential to grab.
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* @return Credential if it exists, else NULL.
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*/
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kauth_cred_t buf_rcred(buf_t bp);
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/*!
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* @function buf_wcred
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* @abstract Get the credential associated with a buffer for writing.
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* @discussion No reference is taken; if the credential is to be held on to persistently, an additional
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* reference must be taken with kauth_cred_ref.
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* @param bp Buffer whose credential to grab.
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* @return Credential if it exists, else NULL.
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*/
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kauth_cred_t buf_wcred(buf_t bp);
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/*!
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* @function buf_proc
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* @abstract Get the process associated with this buffer.
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* @discussion buf_proc() will generally return NULL; a process is currently only associated with
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* a buffer in the event of a physio() call.
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* @param bp Buffer whose associated process to find.
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* @return Associated process, possibly NULL.
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*/
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proc_t buf_proc(buf_t bp);
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/*!
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* @function buf_dirtyoff
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* @abstract Get the starting offset of the dirty region associated with a buffer.
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* @discussion The dirty offset is zero unless someone explicitly calls buf_setdirtyoff() (which the kernel does not).
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* @param bp Buffer whose dirty offset to get.
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* @return Dirty offset (0 if not explicitly changed).
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*/
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uint32_t buf_dirtyoff(buf_t bp);
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/*!
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* @function buf_dirtyend
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* @abstract Get the ending offset of the dirty region associated with a buffer.
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* @discussion If the buffer's data was found incore and dirty, the dirty end is the size of the block; otherwise, unless
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* someone outside of xnu explicitly changes it by calling buf_setdirtyend(), it will be zero.
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* @param bp Buffer whose dirty end to get.
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* @return 0 if buffer is found clean; size of buffer if found dirty. Can be set to any value by callers of buf_setdirtyend().
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*/
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uint32_t buf_dirtyend(buf_t bp);
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/*!
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* @function buf_setdirtyoff
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* @abstract Set the starting offset of the dirty region associated with a buffer.
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* @discussion This value is zero unless someone set it explicitly.
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* @param bp Buffer whose dirty end to set.
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*/
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void buf_setdirtyoff(buf_t bp, uint32_t);
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/*!
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* @function buf_setdirtyend
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* @abstract Set the ending offset of the dirty region associated with a buffer.
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* @discussion If the buffer's data was found incore and dirty, the dirty end is the size of the block; otherwise, unless
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* someone outside of xnu explicitly changes it by calling buf_setdirtyend(), it will be zero.
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* @param bp Buffer whose dirty end to set.
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*/
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void buf_setdirtyend(buf_t bp, uint32_t);
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/*!
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* @function buf_error
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* @abstract Get the error value associated with a buffer.
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* @discussion Errors are set with buf_seterror().
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* @param bp Buffer whose error value to retrieve.
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* @return Error value, directly.
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*/
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errno_t buf_error(buf_t bp);
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/*!
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* @function buf_seterror
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* @abstract Set an error value on a buffer.
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* @param bp Buffer whose error value to set.
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*/
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void buf_seterror(buf_t bp, errno_t);
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/*!
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* @function buf_setflags
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* @abstract Set flags on a buffer.
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* @discussion buffer_flags |= flags
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* @param bp Buffer whose flags to set.
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* @param flags Flags to add to buffer's mask. B_LOCKED/B_NOCACHE/B_ASYNC/B_READ/B_WRITE/B_PAGEIO/B_FUA
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*/
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void buf_setflags(buf_t bp, int32_t flags);
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/*!
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* @function buf_clearflags
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* @abstract Clear flags on a buffer.
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* @discussion buffer_flags &= ~flags
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* @param bp Buffer whose flags to clear.
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* @param flags Flags to remove from buffer's mask. B_LOCKED/B_NOCACHE/B_ASYNC/B_READ/B_WRITE/B_PAGEIO/B_FUA
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*/
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void buf_clearflags(buf_t bp, int32_t flags);
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/*!
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* @function buf_flags
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* @abstract Get flags set on a buffer.
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* @discussion Valid flags are B_LOCKED/B_NOCACHE/B_ASYNC/B_READ/B_WRITE/B_PAGEIO/B_FUA.
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* @param bp Buffer whose flags to grab.
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* @return flags.
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*/
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int32_t buf_flags(buf_t bp);
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/*!
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* @function buf_reset
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* @abstract Reset I/O flag state on a buffer.
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* @discussion Clears current flags on a buffer (internal and external) and allows some new flags to be set.
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* Used perhaps to prepare an iobuf for reuse.
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* @param bp Buffer whose flags to grab.
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* @param flags Flags to set on buffer: B_READ, B_WRITE, B_ASYNC, B_NOCACHE.
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*/
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void buf_reset(buf_t bp, int32_t flags);
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/*!
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* @function buf_map
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* @abstract Get virtual mappings for buffer data.
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* @discussion For buffers created through buf_getblk() (i.e. traditional buffer cache usage),
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* buf_map() just returns the address at which data was mapped by but_getblk(). For a B_CLUSTER buffer, i.e. an iobuf
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* whose upl state is managed manually, there are two possibilities. If the buffer was created
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* with an underlying "real" buffer through cluster_bp(), the mapping of the "real" buffer is returned.
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* Otherwise, the buffer was created with buf_alloc() and buf_setupl() was subsequently called; buf_map()
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* will call ubc_upl_map() to get a mapping for the buffer's upl and return the start of that mapping
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* plus the buffer's upl offset (set in buf_setupl()). In the last case, buf_unmap() must later be called
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* to tear down the mapping. NOTE: buf_map() does not set the buffer data pointer; this must be done with buf_setdataptr().
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* @param bp Buffer whose mapping to find or create.
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* @param io_addr Destination for mapping address.
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* @return 0 for success, ENOMEM if unable to map the buffer.
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*/
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errno_t buf_map(buf_t bp, caddr_t *io_addr);
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/*!
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* @function buf_map_range
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* @abstract Get virtual mappings for buffer data.
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* @discussion Similar to buf_map but the focus is on a range
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* of the UPL. The b_uploffset and b_count control what part of the UPL will be mapped.
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* @param bp Buffer whose mapping to find or create.
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* @param io_addr Destination for mapping address.
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* @return 0 for success, ENOMEM if unable to map the buffer.
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*/
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errno_t buf_map_range(buf_t bp, caddr_t *io_addr);
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/*!
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* @function buf_map_range_with_prot
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* @abstract Get virtual mappings for buffer data.
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* @discussion Similar to buf_map_range but also takes protection so that part of the UPL
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* will be mapped with the requested protection.
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* @param bp Buffer whose mapping to find or create.
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* @param io_addr Destination for mapping address.
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* @return 0 for success, ENOMEM if unable to map the buffer.
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*/
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errno_t buf_map_range_with_prot(buf_t bp, caddr_t *io_addr, vm_prot_t prot);
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/*!
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* @function buf_unmap
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* @abstract Release mappings for buffer data.
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* @discussion For buffers created through buf_getblk() (i.e. traditional buffer cache usage),
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* buf_unmap() does nothing; buf_brelse() will take care of unmapping. For a B_CLUSTER buffer, i.e. an iobuf
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* whose upl state is managed manually, there are two possibilities. If the buffer was created
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* with an underlying "real" buffer through cluster_bp(), buf_unmap() does nothing; buf_brelse() on the
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* underlying buffer will tear down the mapping. Otherwise, the buffer was created with buf_alloc() and
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* buf_setupl() was subsequently called; buf_map() created the mapping. In this case, buf_unmap() will
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* unmap the buffer.
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* @param bp Buffer whose mapping to find or create.
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* @return 0 for success, EINVAL if unable to unmap buffer.
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*/
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errno_t buf_unmap(buf_t bp);
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/*!
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* @function buf_unmap_range
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* @abstract Release mappings for buffer data.
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* @discussion Similar to buf_unmap but the focus is on a range
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* of the UPL. The b_uploffset and b_count control what part of the UPL will be unmapped.
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* @param bp Buffer whose mapping to find or create.
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* @return 0 for success, EINVAL if unable to unmap buffer.
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*/
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errno_t buf_unmap_range(buf_t bp);
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/*!
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* @function buf_setdrvdata
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* @abstract Set driver-specific data on a buffer.
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* @param bp Buffer whose driver-data to set.
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* @param drvdata Opaque driver data.
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*/
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void buf_setdrvdata(buf_t bp, void *drvdata);
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/*!
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* @function buf_setdrvdata
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* @abstract Get driver-specific data from a buffer.
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* @param bp Buffer whose driver data to get.
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* @return Opaque driver data.
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*/
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void * buf_drvdata(buf_t bp);
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/*!
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* @function buf_setfsprivate
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* @abstract Set filesystem-specific data on a buffer.
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* @param bp Buffer whose filesystem data to set.
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* @param fsprivate Opaque filesystem data.
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*/
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void buf_setfsprivate(buf_t bp, void *fsprivate);
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/*!
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* @function buf_fsprivate
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* @abstract Get filesystem-specific data from a buffer.
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* @param bp Buffer whose filesystem data to get.
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* @return Opaque filesystem data.
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*/
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void * buf_fsprivate(buf_t bp);
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/*!
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* @function buf_blkno
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* @abstract Get physical block number associated with a buffer, in the sense of VNOP_BLOCKMAP.
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* @discussion When a buffer's physical block number is the same is its logical block number, then the physical
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* block number is considered uninitialized. A physical block number of -1 indicates that there is no valid
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* physical mapping (e.g. the logical block is invalid or corresponds to a sparse region in a file). Physical
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* block number is normally set by the cluster layer or by buf_getblk().
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* @param bp Buffer whose physical block number to get.
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* @return Block number.
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*/
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daddr64_t buf_blkno(buf_t bp);
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/*!
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* @function buf_lblkno
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* @abstract Get logical block number associated with a buffer.
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* @discussion Logical block number is set on traditionally-used buffers by an argument passed to buf_getblk(),
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* for example by buf_bread().
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* @param bp Buffer whose logical block number to get.
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* @return Block number.
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*/
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daddr64_t buf_lblkno(buf_t bp);
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/*!
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* @function buf_lblksize
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* @abstract Get the block size used to calculate the logical block number associated with a buffer.
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* @discussion Logical block number is set on traditionally-used buffers by an argument passed to buf_getblk(),
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* for example by buf_bread(). Block size is the block size used to calculate the file offset.
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* @param bp Buffer whose logical block size to get.
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* @return Block size.
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*/
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uint32_t buf_lblksize(buf_t bp);
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|
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/*!
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* @function buf_setblkno
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* @abstract Set physical block number associated with a buffer.
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* @discussion Physical block number is generally set by the cluster layer or by buf_getblk().
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* @param bp Buffer whose physical block number to set.
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* @param blkno Block number to set.
|
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*/
|
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void buf_setblkno(buf_t bp, daddr64_t blkno);
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|
|
|
/*!
|
|
* @function buf_setlblkno
|
|
* @abstract Set logical block number associated with a buffer.
|
|
* @discussion Logical block number is set on traditionally-used buffers by an argument passed to buf_getblk(),
|
|
* for example by buf_bread().
|
|
* @param bp Buffer whose logical block number to set.
|
|
* @param lblkno Block number to set.
|
|
*/
|
|
void buf_setlblkno(buf_t bp, daddr64_t lblkno);
|
|
|
|
/*!
|
|
* @function buf_setlblksize
|
|
* @abstract Set block size used to set the logical block number associated with a buffer.
|
|
* @discussion Logical block number is set on traditionally-used buffers by an argument passed to buf_getblk(),
|
|
* for example by buf_bread().
|
|
* @param bp Buffer whose logical block size to set.
|
|
* @param lblksize Block size to set.
|
|
*/
|
|
void buf_setlblksize(buf_t bp, uint32_t lblksize);
|
|
|
|
/*!
|
|
* @function buf_count
|
|
* @abstract Get count of valid bytes in a buffer. This may be less than the space allocated to the buffer.
|
|
* @param bp Buffer whose byte count to get.
|
|
* @return Byte count.
|
|
*/
|
|
uint32_t buf_count(buf_t bp);
|
|
|
|
/*!
|
|
* @function buf_size
|
|
* @abstract Get size of data region allocated to a buffer.
|
|
* @discussion May be larger than amount of valid data in buffer.
|
|
* @param bp Buffer whose size to get.
|
|
* @return Size.
|
|
*/
|
|
uint32_t buf_size(buf_t bp);
|
|
|
|
/*!
|
|
* @function buf_resid
|
|
* @abstract Get a count of bytes which were not consumed by an I/O on a buffer.
|
|
* @discussion Set when an I/O operations completes.
|
|
* @param bp Buffer whose outstanding count to get.
|
|
* @return Count of unwritten/unread bytes.
|
|
*/
|
|
uint32_t buf_resid(buf_t bp);
|
|
|
|
/*!
|
|
* @function buf_setcount
|
|
* @abstract Set count of valid bytes in a buffer. This may be less than the space allocated to the buffer.
|
|
* @param bp Buffer whose byte count to set.
|
|
* @param bcount Count to set.
|
|
*/
|
|
void buf_setcount(buf_t bp, uint32_t bcount);
|
|
|
|
/*!
|
|
* @function buf_setsize
|
|
* @abstract Set size of data region allocated to a buffer.
|
|
* @discussion May be larger than amount of valid data in buffer. Should be used by
|
|
* code which is manually providing storage for an iobuf, one allocated with buf_alloc().
|
|
* @param bp Buffer whose size to set.
|
|
*/
|
|
void buf_setsize(buf_t bp, uint32_t);
|
|
|
|
/*!
|
|
* @function buf_setresid
|
|
* @abstract Set a count of bytes outstanding for I/O in a buffer.
|
|
* @discussion Set when an I/O operations completes. Examples: called by IOStorageFamily when I/O
|
|
* completes, often called on an "original" buffer when using a manipulated buffer to perform I/O
|
|
* on behalf of the first.
|
|
* @param bp Buffer whose outstanding count to set.
|
|
*/
|
|
void buf_setresid(buf_t bp, uint32_t resid);
|
|
|
|
/*!
|
|
* @function buf_setdataptr
|
|
* @abstract Set the address at which a buffer's data will be stored.
|
|
* @discussion In traditional buffer use, the data pointer will be set automatically. This routine is
|
|
* useful with iobufs (allocated with buf_alloc()).
|
|
* @param bp Buffer whose data pointer to set.
|
|
* @param data Pointer to data region.
|
|
*/
|
|
void buf_setdataptr(buf_t bp, uintptr_t data);
|
|
|
|
/*!
|
|
* @function buf_dataptr
|
|
* @abstract Get the address at which a buffer's data is stored; for iobufs, this must
|
|
* be set with buf_setdataptr(). See buf_map().
|
|
* @param bp Buffer whose data pointer to retrieve.
|
|
* @return Data pointer; NULL if unset.
|
|
*/
|
|
uintptr_t buf_dataptr(buf_t bp);
|
|
|
|
/*!
|
|
* @function buf_vnode
|
|
* @abstract Get the vnode associated with a buffer.
|
|
* @discussion Every buffer is associated with a file. Because there is an I/O in flight,
|
|
* there is an iocount on this vnode; it is returned WITHOUT an extra iocount, and vnode_put()
|
|
* need NOT be called.
|
|
* @param bp Buffer whose vnode to retrieve.
|
|
* @return Buffer's vnode.
|
|
*/
|
|
vnode_t buf_vnode(buf_t bp);
|
|
|
|
/*!
|
|
* @function buf_setvnode
|
|
* @abstract Set the vnode associated with a buffer.
|
|
* @discussion This call need not be used on traditional buffers; it is for use with iobufs.
|
|
* @param bp Buffer whose vnode to set.
|
|
* @param vp The vnode to attach to the buffer.
|
|
*/
|
|
void buf_setvnode(buf_t bp, vnode_t vp);
|
|
|
|
/*!
|
|
* @function buf_device
|
|
* @abstract Get the device ID associated with a buffer.
|
|
* @discussion In traditional buffer use, this value is NODEV until buf_strategy() is called unless
|
|
* buf_getblk() was passed a device vnode. It is set on an iobuf if buf_alloc() is passed a device
|
|
* vnode or if buf_setdevice() is called.
|
|
* @param bp Buffer whose device ID to retrieve.
|
|
* @return Device id.
|
|
*/
|
|
dev_t buf_device(buf_t bp);
|
|
|
|
/*!
|
|
* @function buf_setdevice
|
|
* @abstract Set the device associated with a buffer.
|
|
* @discussion A buffer's device is set in buf_strategy() (or in buf_getblk() if the file is a device).
|
|
* It is also set on an iobuf if buf_alloc() is passed a device vnode.
|
|
* @param bp Buffer whose device ID to set.
|
|
* @param vp Device to set on the buffer.
|
|
* @return 0 for success, EINVAL if vp is not a device file.
|
|
*/
|
|
errno_t buf_setdevice(buf_t bp, vnode_t vp);
|
|
|
|
/*!
|
|
* @function buf_strategy
|
|
* @abstract Pass an I/O request for a buffer down to the device layer.
|
|
* @discussion This is one of the most important routines in the buffer cache layer. For buffers obtained
|
|
* through buf_getblk, it handles finding physical block numbers for the I/O (with VNOP_BLKTOOFF and
|
|
* VNOP_BLOCKMAP), packaging the I/O into page-sized chunks, and initiating I/O on the disk by calling
|
|
* the device's strategy routine. If a buffer's UPL has been set manually with buf_setupl(), it assumes
|
|
* that the request is already correctly configured with a block number and a size divisible by page size
|
|
* and will just call directly to the device.
|
|
* @param devvp Device on which to perform I/O
|
|
* @param ap vnop_strategy_args structure (most importantly, a buffer).
|
|
* @return 0 for success, or errors from filesystem or device layers.
|
|
*/
|
|
errno_t buf_strategy(vnode_t devvp, void *ap);
|
|
|
|
/*
|
|
* Flags for buf_invalblkno()
|
|
*/
|
|
#define BUF_WAIT 0x01
|
|
|
|
/*!
|
|
* @function buf_invalblkno
|
|
* @abstract Invalidate a filesystem logical block in a file.
|
|
* @discussion buf_invalblkno() tries to make the data for a given block in a file
|
|
* invalid; if the buffer for that block is found in core and is not busy, we mark it
|
|
* invalid and call buf_brelse() (see "flags" param for what happens if the buffer is busy).
|
|
* buf_brelse(), noticing that it is invalid, will
|
|
* will return the buffer to the empty-buffer list and tell the VM subsystem to abandon
|
|
* the relevant pages. Data will not be written to backing store--it will be cast aside.
|
|
* Note that this function will only work if the block in question has been
|
|
* obtained with a buf_getblk(). If data has been read into core without using
|
|
* traditional buffer cache routines, buf_invalblkno() will not be able to invalidate it--this
|
|
* includes the use of iobufs.
|
|
* @param vp vnode whose block to invalidate.
|
|
* @param lblkno Logical block number.
|
|
* @param flags BUF_WAIT: wait for busy buffers to become unbusy and invalidate them then. Otherwise,
|
|
* just return EBUSY for busy blocks.
|
|
* @return 0 for success, EINVAL if vp is not a device file.
|
|
*/
|
|
errno_t buf_invalblkno(vnode_t vp, daddr64_t lblkno, int flags);
|
|
|
|
/*!
|
|
* @function buf_callback
|
|
* @abstract Get the function set to be called when I/O on a buffer completes.
|
|
* @discussion A function returned by buf_callback was originally set with buf_setcallback().
|
|
* @param bp Buffer whose callback to get.
|
|
* @return 0 for success, or errors from filesystem or device layers.
|
|
*/
|
|
void * buf_callback(buf_t bp);
|
|
|
|
/*!
|
|
* @function buf_setcallback
|
|
* @abstract Set a function to be called once when I/O on a buffer completes.
|
|
* @discussion A one-shot callout set with buf_setcallback() will be called from buf_biodone()
|
|
* when I/O completes. It will be passed the "transaction" argument as well as the buffer.
|
|
* buf_setcallback() also marks the buffer as B_ASYNC.
|
|
* @param bp Buffer whose callback to set.
|
|
* @param callback function to use as callback.
|
|
* @param transaction Additional argument to callback function.
|
|
* @return 0; always succeeds.
|
|
*/
|
|
errno_t buf_setcallback(buf_t bp, void (*callback)(buf_t, void *), void *transaction);
|
|
|
|
/*!
|
|
* @function buf_setupl
|
|
* @abstract Set the UPL (Universal Page List), and offset therein, on a buffer.
|
|
* @discussion buf_setupl() should only be called on buffers allocated with buf_alloc().
|
|
* A subsequent call to buf_map() will map the UPL and give back the address at which data
|
|
* begins. After buf_setupl() is called, a buffer is marked B_CLUSTER; when this is the case,
|
|
* buf_strategy() assumes that a buffer is correctly configured to be passed to the device
|
|
* layer without modification. Passing a NULL upl will clear the upl and the B_CLUSTER flag on the
|
|
* buffer.
|
|
* @param bp Buffer whose upl to set.
|
|
* @param upl UPL to set in the buffer.
|
|
* @param offset Offset within upl at which relevant data begin.
|
|
* @return 0 for success, EINVAL if the buffer was not allocated with buf_alloc().
|
|
*/
|
|
errno_t buf_setupl(buf_t bp, upl_t upl, uint32_t offset);
|
|
|
|
/*!
|
|
* @function buf_clone
|
|
* @abstract Clone a buffer with a restricted range and an optional callback.
|
|
* @discussion Generates a buffer which is identical to its "bp" argument except that
|
|
* it spans a subset of the data of the original. The buffer to be cloned should
|
|
* have been allocated with buf_alloc(). Checks its arguments to make sure
|
|
* that the data subset is coherent. Optionally, adds a callback function and argument to it
|
|
* to be called when I/O completes (as with buf_setcallback(), but B_ASYNC is not set). If the original buffer had
|
|
* a upl set through buf_setupl(), this upl is copied to the new buffer; otherwise, the original's
|
|
* data pointer is used raw. The buffer must be released with buf_free().
|
|
* @param bp Buffer to clone.
|
|
* @param io_offset Offset, relative to start of data in original buffer, at which new buffer's data will begin.
|
|
* @param io_size Size of buffer region in new buffer, in the sense of buf_count().
|
|
* @param iodone Callback to be called from buf_biodone() when I/O completes, in the sense of buf_setcallback().
|
|
* @param arg Argument to pass to iodone() callback.
|
|
* @return NULL if io_offset/io_size combination is invalid for the buffer to be cloned; otherwise, the new buffer.
|
|
*/
|
|
buf_t buf_clone(buf_t bp, int io_offset, int io_size, void (*iodone)(buf_t, void *), void *arg);
|
|
|
|
|
|
/*!
|
|
* @function buf_create_shadow
|
|
* @abstract Create a shadow buffer with optional private storage and an optional callback.
|
|
* @param bp Buffer to shadow.
|
|
* @param force_copy If TRUE, do not link the shadaow to 'bp' and if 'external_storage' == NULL,
|
|
* force a copy of the data associated with 'bp'.
|
|
* @param external_storage If non-NULL, associate it with the new buffer as its storage instead of the
|
|
* storage currently associated with 'bp'.
|
|
* @param iodone Callback to be called from buf_biodone() when I/O completes, in the sense of buf_setcallback().
|
|
* @param arg Argument to pass to iodone() callback.
|
|
* @return NULL if the buffer to be shadowed is not B_META or a primary buffer (i.e. not a shadow buffer); otherwise, the new buffer.
|
|
*/
|
|
|
|
buf_t buf_create_shadow(buf_t bp, boolean_t force_copy, uintptr_t external_storage, void (*iodone)(buf_t, void *), void *arg);
|
|
|
|
|
|
/*!
|
|
* @function buf_shadow
|
|
* @abstract returns true if 'bp' is a shadow of another buffer.
|
|
* @param bp Buffer to query.
|
|
* @return 1 if 'bp' is a shadow, 0 otherwise.
|
|
*/
|
|
int buf_shadow(buf_t bp);
|
|
|
|
|
|
/*!
|
|
* @function buf_alloc
|
|
* @abstract Allocate an uninitialized buffer.
|
|
* @discussion A buffer returned by buf_alloc() is marked as busy and as an iobuf; it has no storage set up and must be
|
|
* set up using buf_setdataptr() or buf_setupl()/buf_map().
|
|
* @param vp vnode to associate with the buffer: optionally NULL. If vp is a device file, then
|
|
* the buffer's associated device will be set. If vp is NULL, it can be set later with buf_setvnode().
|
|
* @return New buffer.
|
|
*/
|
|
buf_t buf_alloc(vnode_t vp);
|
|
|
|
/*!
|
|
* @function buf_free
|
|
* @abstract Free a buffer that was allocated with buf_alloc().
|
|
* @discussion The storage (UPL, data pointer) associated with an iobuf must be freed manually.
|
|
* @param bp The buffer to free.
|
|
*/
|
|
void buf_free(buf_t bp);
|
|
|
|
/*
|
|
* flags for buf_invalidateblks
|
|
*/
|
|
#define BUF_WRITE_DATA 0x0001 /* write data blocks first */
|
|
#define BUF_SKIP_META 0x0002 /* skip over metadata blocks */
|
|
#define BUF_INVALIDATE_LOCKED 0x0004 /* force B_LOCKED blocks to be invalidated */
|
|
|
|
/*!
|
|
* @function buf_invalidateblks
|
|
* @abstract Invalidate all the blocks associated with a vnode.
|
|
* @discussion This function does for all blocks associated with a vnode what buf_invalblkno does for one block.
|
|
* Again, it will only be able to invalidate data which were populated with traditional buffer cache routines,
|
|
* i.e. by buf_getblk() and callers thereof. Unlike buf_invalblkno(), it can be made to write dirty data to disk
|
|
* rather than casting it aside.
|
|
* @param vp The vnode whose data to invalidate.
|
|
* @param flags BUF_WRITE_DATA: write dirty data to disk with VNOP_BWRITE() before kicking buffer cache entries out.
|
|
* BUF_SKIP_META: do not invalidate metadata blocks.
|
|
* @param slpflag Flags to pass to "msleep" while waiting to acquire busy buffers.
|
|
* @param slptimeo Timeout in "hz" (1/100 second) to wait for a buffer to become unbusy before waking from sleep
|
|
* and re-starting the scan.
|
|
* @return 0 for success, error values from msleep().
|
|
*/
|
|
int buf_invalidateblks(vnode_t vp, int flags, int slpflag, int slptimeo);
|
|
|
|
/*
|
|
* flags for buf_flushdirtyblks and buf_iterate
|
|
*/
|
|
#define BUF_SKIP_NONLOCKED 0x01
|
|
#define BUF_SKIP_LOCKED 0x02
|
|
#define BUF_SCAN_CLEAN 0x04 /* scan the clean buffers */
|
|
#define BUF_SCAN_DIRTY 0x08 /* scan the dirty buffers */
|
|
#define BUF_NOTIFY_BUSY 0x10 /* notify the caller about the busy pages during the scan */
|
|
|
|
|
|
#define BUF_RETURNED 0
|
|
#define BUF_RETURNED_DONE 1
|
|
#define BUF_CLAIMED 2
|
|
#define BUF_CLAIMED_DONE 3
|
|
/*!
|
|
* @function buf_flushdirtyblks
|
|
* @abstract Write dirty file blocks to disk.
|
|
* @param vp The vnode whose blocks to flush.
|
|
* @param wait Wait for writes to complete before returning.
|
|
* @param flags Can pass zero, meaning "flush all dirty buffers."
|
|
* BUF_SKIP_NONLOCKED: Skip buffers which are not busy when we encounter them.
|
|
* BUF_SKIP_LOCKED: Skip buffers which are busy when we encounter them.
|
|
* @param msg String to pass to msleep().
|
|
*/
|
|
void buf_flushdirtyblks(vnode_t vp, int wait, int flags, const char *msg);
|
|
|
|
/*!
|
|
* @function buf_iterate
|
|
* @abstract Perform some operation on all buffers associated with a vnode.
|
|
* @param vp The vnode whose buffers to scan.
|
|
* @param callout Function to call on each buffer. Should return one of:
|
|
* BUF_RETURNED: buf_iterate() should call buf_brelse() on the buffer.
|
|
* BUF_RETURNED_DONE: buf_iterate() should call buf_brelse() on the buffer and then stop iterating.
|
|
* BUF_CLAIMED: buf_iterate() should continue iterating (and not call buf_brelse()).
|
|
* BUF_CLAIMED_DONE: buf_iterate() should stop iterating (and not call buf_brelse()).
|
|
* @param flags
|
|
* BUF_SKIP_NONLOCKED: Skip buffers which are not busy when we encounter them. BUF_SKIP_LOCKED: Skip buffers which are busy when we encounter them.
|
|
* BUF_SCAN_CLEAN: Call out on clean buffers.
|
|
* BUF_SCAN_DIRTY: Call out on dirty buffers.
|
|
* BUF_NOTIFY_BUSY: If a buffer cannot be acquired, pass a NULL buffer to callout; otherwise,
|
|
* that buffer will be silently skipped.
|
|
* @param arg Argument to pass to callout in addition to buffer.
|
|
*/
|
|
void buf_iterate(vnode_t vp, int (*callout)(buf_t, void *), int flags, void *arg);
|
|
|
|
/*!
|
|
* @function buf_clear
|
|
* @abstract Zero out the storage associated with a buffer.
|
|
* @discussion Calls buf_map() to get the buffer's data address; for a B_CLUSTER
|
|
* buffer (one which has had buf_setupl() called on it), it tries to map the buffer's
|
|
* UPL into memory; should only be called once during the life cycle of an iobuf (one allocated
|
|
* with buf_alloc()).
|
|
* @param bp The buffer to zero out.
|
|
*/
|
|
void buf_clear(buf_t bp);
|
|
|
|
/*!
|
|
* @function buf_bawrite
|
|
* @abstract Start an asychronous write on a buffer.
|
|
* @discussion Calls VNOP_BWRITE to start the process of propagating an asynchronous write down to the device layer.
|
|
* Callers can wait for writes to complete at their discretion using buf_biowait(). When this function is called,
|
|
* data should already have been written to the buffer's data region.
|
|
* @param bp The buffer on which to initiate I/O.
|
|
* @return EWOULDBLOCK if write count is high and "throttle" is zero; otherwise, errors from VNOP_BWRITE.
|
|
*/
|
|
errno_t buf_bawrite(buf_t bp);
|
|
|
|
/*!
|
|
* @function buf_bdwrite
|
|
* @abstract Mark a buffer for delayed write.
|
|
* @discussion Marks a buffer as waiting for delayed write and the current I/O as complete; data will be written to backing store
|
|
* before the buffer is reused, but it will not be queued for I/O immediately. Note that for buffers allocated
|
|
* with buf_alloc(), there are no such guarantees; you must take care of your own flushing to disk. If
|
|
* the number of delayed writes pending on the system is greater than an internal limit and the caller has not
|
|
* requested otherwise [see return_error] , buf_bdwrite() will unilaterally launch an asynchronous I/O with buf_bawrite() to keep the pile of
|
|
* delayed writes from getting too large.
|
|
* @param bp The buffer to mark for delayed write.
|
|
* @return EAGAIN for return_error != 0 case, 0 for succeess, errors from buf_bawrite.
|
|
*/
|
|
errno_t buf_bdwrite(buf_t bp);
|
|
|
|
/*!
|
|
* @function buf_bwrite
|
|
* @abstract Write a buffer's data to backing store.
|
|
* @discussion Once the data in a buffer has been modified, buf_bwrite() starts sending it to disk by calling
|
|
* VNOP_STRATEGY. Unless B_ASYNC has been set on the buffer (by buf_setflags() or otherwise), data will have
|
|
* been written to disk when buf_bwrite() returns. See Bach (p 56).
|
|
* @param bp The buffer to write to disk.
|
|
* @return 0 for success; errors from buf_biowait().
|
|
*/
|
|
errno_t buf_bwrite(buf_t bp);
|
|
|
|
/*!
|
|
* @function buf_biodone
|
|
* @abstract Mark an I/O as completed.
|
|
* @discussion buf_biodone() should be called by whosoever decides that an I/O on a buffer is complete; for example,
|
|
* IOStorageFamily. It clears the dirty flag on a buffer and signals on the vnode that a write has completed
|
|
* with vnode_writedone(). If a callout or filter has been set on the buffer, that function is called. In the case
|
|
* of a callout, that function is expected to take care of cleaning up and freeing the buffer.
|
|
* Otherwise, if the buffer is marked B_ASYNC (e.g. it was passed to buf_bawrite()), then buf_biodone()
|
|
* considers itself justified in calling buf_brelse() to return it to free lists--no one is waiting for it. Finally,
|
|
* waiters on the bp (e.g. in buf_biowait()) are woken up.
|
|
* @param bp The buffer to mark as done with I/O.
|
|
*/
|
|
void buf_biodone(buf_t bp);
|
|
|
|
/*!
|
|
* @function buf_biowait
|
|
* @abstract Wait for I/O on a buffer to complete.
|
|
* @discussion Waits for I/O on a buffer to finish, as marked by a buf_biodone() call.
|
|
* @param bp The buffer to wait on.
|
|
* @return 0 for a successful wait; nonzero the buffer has been marked as EINTR or had an error set on it.
|
|
*/
|
|
errno_t buf_biowait(buf_t bp);
|
|
|
|
/*!
|
|
* @function buf_brelse
|
|
* @abstract Release any claim to a buffer, sending it back to free lists.
|
|
* @discussion buf_brelse() cleans up buffer state and releases a buffer to the free lists. If the buffer
|
|
* is not marked invalid and its pages are dirty (e.g. a delayed write was made), its data will be commited
|
|
* to backing store. If it is marked invalid, its data will be discarded completely.
|
|
* A valid, cacheable buffer will be put on a list and kept in the buffer hash so it
|
|
* can be found again; otherwise, it will be dissociated from its vnode and treated as empty. Which list a valid
|
|
* buffer is placed on depends on the use of buf_markaged(), whether it is metadata, and the B_LOCKED flag. A
|
|
* B_LOCKED buffer will not be available for reuse by other files, though its data may be paged out.
|
|
* Note that buf_brelse() is intended for use with traditionally allocated buffers.
|
|
* @param bp The buffer to release.
|
|
*/
|
|
void buf_brelse(buf_t bp);
|
|
|
|
/*!
|
|
* @function buf_bread
|
|
* @abstract Synchronously read a block of a file.
|
|
* @discussion buf_bread() is the traditional way to read a single logical block of a file through the buffer cache.
|
|
* It tries to find the buffer and corresponding page(s) in core, calls VNOP_STRATEGY if necessary to bring the data
|
|
* into memory, and waits for I/O to complete. It should not be used to read blocks of greater than 4K (one VM page)
|
|
* in size; use cluster routines for large reads. Indeed, the cluster layer is a more efficient choice for reading DATA
|
|
* unless you need some finely-tuned semantics that it cannot provide.
|
|
* @param vp The file from which to read.
|
|
* @param blkno The logical (filesystem) block number to read.
|
|
* @param size Size of block; do not use for sizes > 4K.
|
|
* @param cred Credential to store and use for reading from disk if data are not already in core.
|
|
* @param bpp Destination pointer for buffer.
|
|
* @return 0 for success, or an error from buf_biowait().
|
|
*/
|
|
errno_t buf_bread(vnode_t vp, daddr64_t blkno, int size, kauth_cred_t cred, buf_t *bpp);
|
|
|
|
/*!
|
|
* @function buf_breadn
|
|
* @abstract Read a block from a file with read-ahead.
|
|
* @discussion buf_breadn() reads one block synchronously in the style of buf_bread() and fires
|
|
* off a specified set of asynchronous reads to improve the likelihood of future cache hits.
|
|
* It should not be used to read blocks of greater than 4K (one VM page) in size; use cluster
|
|
* routines for large reads. Indeed, the cluster layer is a more efficient choice for reading DATA
|
|
* unless you need some finely-tuned semantics that it cannot provide.
|
|
* @param vp The file from which to read.
|
|
* @param blkno The logical (filesystem) block number to read synchronously.
|
|
* @param size Size of block; do not use for sizes > 4K.
|
|
* @param rablks Array of logical block numbers for asynchronous read-aheads.
|
|
* @param rasizes Array of block sizes for asynchronous read-aheads, each index corresponding to same index in "rablks."
|
|
* @param nrablks Number of entries in read-ahead arrays.
|
|
* @param cred Credential to store and use for reading from disk if data are not already in core.
|
|
* @param bpp Destination pointer for buffer.
|
|
* @return 0 for success, or an error from buf_biowait().
|
|
*/
|
|
errno_t buf_breadn(vnode_t vp, daddr64_t blkno, int size, daddr64_t *rablks, int *rasizes, int nrablks, kauth_cred_t cred, buf_t *bpp);
|
|
|
|
/*!
|
|
* @function buf_meta_bread
|
|
* @abstract Synchronously read a metadata block of a file.
|
|
* @discussion buf_meta_bread() is the traditional way to read a single logical block of a file through the buffer cache.
|
|
* It tries to find the buffer and corresponding page(s) in core, calls VNOP_STRATEGY if necessary to bring the data
|
|
* into memory, and waits for I/O to complete. It should not be used to read blocks of greater than 4K (one VM page)
|
|
* in size; use cluster routines for large reads. Reading meta-data through the traditional buffer cache, unlike
|
|
* reading data, is efficient and encouraged, especially if the blocks being read are significantly smaller than page size.
|
|
* @param vp The file from which to read.
|
|
* @param blkno The logical (filesystem) block number to read.
|
|
* @param size Size of block; do not use for sizes > 4K.
|
|
* @param cred Credential to store and use for reading from disk if data are not already in core.
|
|
* @param bpp Destination pointer for buffer.
|
|
* @return 0 for success, or an error from buf_biowait().
|
|
*/
|
|
errno_t buf_meta_bread(vnode_t vp, daddr64_t blkno, int size, kauth_cred_t cred, buf_t *bpp);
|
|
|
|
/*!
|
|
* @function buf_meta_breadn
|
|
* @abstract Read a metadata block from a file with read-ahead.
|
|
* @discussion buf_meta_breadn() reads one block synchronously in the style of buf_meta_bread() and fires
|
|
* off a specified set of asynchronous reads to improve the likelihood of future cache hits.
|
|
* It should not be used to read blocks of greater than 4K (one VM page) in size; use cluster
|
|
* routines for large reads.
|
|
* @param vp The file from which to read.
|
|
* @param blkno The logical (filesystem) block number to read synchronously.
|
|
* @param size Size of block; do not use for sizes > 4K.
|
|
* @param rablks Array of logical block numbers for asynchronous read-aheads.
|
|
* @param rasizes Array of block sizes for asynchronous read-aheads, each index corresponding to same index in "rablks."
|
|
* @param nrablks Number of entries in read-ahead arrays.
|
|
* @param cred Credential to store and use for reading from disk if data are not already in core.
|
|
* @param bpp Destination pointer for buffer.
|
|
* @return 0 for success, or an error from buf_biowait().
|
|
*/
|
|
errno_t buf_meta_breadn(vnode_t vp, daddr64_t blkno, int size, daddr64_t *rablks, int *rasizes, int nrablks, kauth_cred_t cred, buf_t *bpp);
|
|
|
|
/*!
|
|
* @function minphys
|
|
* @abstract Adjust a buffer's count to be no more than maximum physical I/O transfer size for the host architecture.
|
|
* @discussion physio() takes as a parameter a function to bound transfer sizes for each VNOP_STRATEGY() call. minphys()
|
|
* is a default implementation. It calls buf_setcount() to make the buffer's count the min() of its current count
|
|
* and the max I/O size for the host architecture.
|
|
* @param bp The buffer whose byte count to modify.
|
|
* @return New byte count.
|
|
*/
|
|
u_int minphys(buf_t bp);
|
|
|
|
/*!
|
|
* @function physio
|
|
* @abstract Perform I/O on a device to/from target memory described by a uio.
|
|
* @discussion physio() allows I/O directly from a device to user-space memory. It waits
|
|
* for all I/O to complete before returning.
|
|
* @param f_strategy Strategy routine to call to initiate I/O.
|
|
* @param bp Buffer to configure and pass to strategy routine; can be NULL.
|
|
* @param dev Device on which to perform I/O.
|
|
* @param flags B_READ or B_WRITE.
|
|
* @param f_minphys Function which calls buf_setcount() to set a byte count which is suitably
|
|
* small for the device in question. Returns byte count that has been set (or unchanged) on the buffer.
|
|
* @param uio UIO describing the I/O operation.
|
|
* @param blocksize Logical block size for this vnode.
|
|
* @return 0 for success; EFAULT for an invalid uio; errors from buf_biowait().
|
|
*/
|
|
int physio(void (*f_strategy)(buf_t), buf_t bp, dev_t dev, int flags, u_int (*f_minphys)(buf_t), struct uio *uio, int blocksize);
|
|
|
|
|
|
/*
|
|
* Flags for operation type in getblk()
|
|
*/
|
|
#define BLK_READ 0x01 /* buffer for read */
|
|
#define BLK_WRITE 0x02 /* buffer for write */
|
|
#define BLK_META 0x10 /* buffer for metadata */
|
|
/*
|
|
* modifier for above flags... if set, getblk will only return
|
|
* a bp that is already valid... i.e. found in the cache
|
|
*/
|
|
#define BLK_ONLYVALID 0x80000000
|
|
|
|
/*!
|
|
* @function buf_getblk
|
|
* @abstract Traditional buffer cache routine to get a buffer corresponding to a logical block in a file.
|
|
* @discussion buf_getblk() gets a buffer, not necessarily containing valid data, representing a block in a file.
|
|
* A metadata buffer will be returned with its own zone-allocated storage, managed by the traditional buffer-cache
|
|
* layer, whereas data buffers will be returned hooked into backing by the UBC (which in fact controls the caching of data).
|
|
* buf_getblk() first looks for the buffer header in cache; if the buffer is in-core but busy, buf_getblk() will wait for it to become
|
|
* unbusy, depending on the slpflag and slptimeo parameters. If the buffer is found unbusy and is a metadata buffer,
|
|
* it must already contain valid data and will be returned directly; data buffers will have a UPL configured to
|
|
* prepare for interaction with the underlying UBC. If the buffer is found in core, it will be marked as such
|
|
* and buf_fromcache() will return truth. A buffer is allocated and initialized (but not filled with data)
|
|
* if none is found in core. buf_bread(), buf_breadn(), buf_meta_bread(), and buf_meta_breadn() all
|
|
* return buffers obtained with buf_getblk().
|
|
* @param vp File for which to get block.
|
|
* @param blkno Logical block number.
|
|
* @param size Size of block.
|
|
* @param slpflag Flag to pass to msleep() while waiting for buffer to become unbusy.
|
|
* @param slptimeo Time, in milliseconds, to wait for buffer to become unbusy. 0 means to wait indefinitely.
|
|
* @param operation BLK_READ: want a read buffer. BLK_WRITE: want a write buffer. BLK_META: want a metadata buffer. BLK_ONLYVALID:
|
|
* only return buffers which are found in core (do not allocate anew), and do not change buffer size. The last remark means
|
|
* that if a given logical block is found in core with a different size than what is requested, the buffer size will not be modified.
|
|
* @return Buffer found in core or newly allocated, either containing valid data or ready for I/O.
|
|
*/
|
|
buf_t buf_getblk(vnode_t vp, daddr64_t blkno, int size, int slpflag, int slptimeo, int operation);
|
|
|
|
/*!
|
|
* @function buf_geteblk
|
|
* @abstract Get a metadata buffer which is marked invalid and not associated with any vnode.
|
|
* @discussion A buffer is returned with zone-allocated storage of the specified size, marked B_META and invalid.
|
|
* It has no vnode and is not visible in the buffer hash.
|
|
* @param size Size of buffer.
|
|
* @return Always returns a new buffer.
|
|
*/
|
|
buf_t buf_geteblk(int size);
|
|
|
|
/*!
|
|
* @function buf_clear_redundancy_flags
|
|
* @abstract Clear flags on a buffer.
|
|
* @discussion buffer_redundancy_flags &= ~flags
|
|
* @param bp Buffer whose flags to clear.
|
|
* @param flags Flags to remove from buffer's mask
|
|
*/
|
|
void buf_clear_redundancy_flags(buf_t bp, uint32_t flags);
|
|
|
|
/*!
|
|
* @function buf_redundancyflags
|
|
* @abstract Get redundancy flags set on a buffer.
|
|
* @param bp Buffer whose redundancy flags to grab.
|
|
* @return flags.
|
|
*/
|
|
uint32_t buf_redundancy_flags(buf_t bp);
|
|
|
|
/*!
|
|
* @function buf_setredundancyflags
|
|
* @abstract Set redundancy flags on a buffer.
|
|
* @discussion buffer_redundancy_flags |= flags
|
|
* @param bp Buffer whose flags to set.
|
|
* @param flags Flags to add to buffer's redundancy flags
|
|
*/
|
|
void buf_set_redundancy_flags(buf_t bp, uint32_t flags);
|
|
|
|
/*!
|
|
* @function buf_attr
|
|
* @abstract Gets the attributes for this buf.
|
|
* @param bp Buffer whose attributes to get.
|
|
* @return bufattr_t.
|
|
*/
|
|
bufattr_t buf_attr(buf_t bp);
|
|
|
|
/*!
|
|
* @function buf_markstatic
|
|
* @abstract Mark a buffer as being likely to contain static data.
|
|
* @param bp Buffer to mark.
|
|
*/
|
|
void buf_markstatic(buf_t bp);
|
|
|
|
/*!
|
|
* @function buf_static
|
|
* @abstract Check if a buffer contains static data.
|
|
* @param bp Buffer to test.
|
|
* @return Nonzero if buffer has static data, 0 otherwise.
|
|
*/
|
|
int buf_static(buf_t bp);
|
|
|
|
/*!
|
|
* @function bufattr_markiosched
|
|
* @abstract Mark a buffer as belonging to an io scheduled mount point
|
|
* @param bap Buffer attributes to mark.
|
|
* @discussion Marks the buffer so that spec_strategy() will know that it belongs to an io scheduled mount point
|
|
*/
|
|
void bufattr_markioscheduled(bufattr_t bap);
|
|
|
|
/*!
|
|
* @function bufattr_iosched
|
|
* @abstract Check if a buffer is marked as io scheduled
|
|
* @param bap Buffer attributes to test.
|
|
* @return Nonzero if the buffer is marked io scheduled, 0 otherwise.
|
|
*/
|
|
int bufattr_ioscheduled(bufattr_t bap);
|
|
|
|
/*!
|
|
* @function bufattr_markexpeditedmeta
|
|
* @abstract Mark a metadata I/O buffer as expedited (i.e. requires a high I/O tier).
|
|
* @param bap Buffer attributes to mark.
|
|
* @discussion Marks the buffer so that spec_strategy() will know that it should be expedited
|
|
*/
|
|
void bufattr_markexpeditedmeta(bufattr_t bap);
|
|
|
|
/*!
|
|
* @function bufattr_expeditedmeta
|
|
* @abstract Check if a buffer is marked as expedited metadata I/O.
|
|
* @param bap Buffer attributes to test.
|
|
* @return Nonzero if the buffer is marked expedited metadata I/O, 0 otherwise.
|
|
*/
|
|
int bufattr_expeditedmeta(bufattr_t bap);
|
|
|
|
#ifdef KERNEL_PRIVATE
|
|
void buf_setfilter(buf_t, void (*)(buf_t, void *), void *, void(**)(buf_t, void *), void **);
|
|
|
|
/* bufattr allocation/duplication/deallocation functions */
|
|
bufattr_t bufattr_alloc(void);
|
|
bufattr_t bufattr_dup(bufattr_t bap);
|
|
void bufattr_free(bufattr_t bap);
|
|
|
|
/*!
|
|
* @function bufattr_cpx
|
|
* @abstract Returns a pointer to a cpx_t structure.
|
|
* @param bap Buffer Attribute whose cpx_t structure you wish to get.
|
|
* @return Returns a cpx_t structure, or NULL if not valid
|
|
*/
|
|
struct cpx *bufattr_cpx(bufattr_t bap);
|
|
|
|
/*!
|
|
* @function bufattr_setcpx
|
|
* @abstract Set the cp_ctx on a buffer attribute.
|
|
* @param bap Buffer Attribute that you wish to change
|
|
*/
|
|
void bufattr_setcpx(bufattr_t bap, struct cpx *cpx);
|
|
|
|
/*!
|
|
* @function bufattr_cpoff
|
|
* @abstract Gets the file offset on the buffer.
|
|
* @param bap Buffer Attribute whose file offset value is used
|
|
*/
|
|
uint64_t bufattr_cpoff(bufattr_t bap);
|
|
|
|
/*!
|
|
* @function bufattr_setcpoff
|
|
* @abstract Set the file offset for a content protected I/O on
|
|
* a buffer attribute.
|
|
* @param bap Buffer Attribute whose cp file offset has to be set
|
|
*/
|
|
void bufattr_setcpoff(bufattr_t bap, uint64_t);
|
|
|
|
/*!
|
|
* @function bufattr_rawencrypted
|
|
* @abstract Check if a buffer contains raw encrypted data.
|
|
* @param bap Buffer attribute to test.
|
|
* @return Nonzero if buffer has raw encrypted data, 0 otherwise.
|
|
*/
|
|
int bufattr_rawencrypted(bufattr_t bap);
|
|
|
|
/*!
|
|
* @function bufattr_markgreedymode
|
|
* @abstract Mark a buffer to use the greedy mode for writing.
|
|
* @param bap Buffer attributes to mark.
|
|
* @discussion Greedy Mode: request improved write performance from the underlying device at the expense of storage efficiency
|
|
*/
|
|
void bufattr_markgreedymode(bufattr_t bap);
|
|
|
|
/*!
|
|
* @function bufattr_greedymode
|
|
* @abstract Check if a buffer is written using the Greedy Mode
|
|
* @param bap Buffer attributes to test.
|
|
* @discussion Greedy Mode: request improved write performance from the underlying device at the expense of storage efficiency
|
|
* @return Nonzero if buffer uses greedy mode, 0 otherwise.
|
|
*/
|
|
int bufattr_greedymode(bufattr_t bap);
|
|
|
|
/*!
|
|
* @function bufattr_markisochronous
|
|
* @abstract Mark a buffer to use the isochronous throughput mode for writing.
|
|
* @param bap Buffer attributes to mark.
|
|
* @discussion isochronous mode: request improved write performance from the underlying device at the expense of storage efficiency
|
|
*/
|
|
void bufattr_markisochronous(bufattr_t bap);
|
|
|
|
/*!
|
|
* @function bufattr_isochronous
|
|
* @abstract Check if a buffer is written using the isochronous
|
|
* @param bap Buffer attributes to test.
|
|
* @discussion isochronous mode: request improved write performance from the underlying device at the expense of storage efficiency
|
|
* @return Nonzero if buffer uses isochronous mode, 0 otherwise.
|
|
*/
|
|
int bufattr_isochronous(bufattr_t bap);
|
|
|
|
|
|
/*!
|
|
* @function bufattr_throttled
|
|
* @abstract Check if a buffer is throttled.
|
|
* @param bap Buffer attribute to test.
|
|
* @return Nonzero if the buffer is throttled, 0 otherwise.
|
|
*/
|
|
int bufattr_throttled(bufattr_t bap);
|
|
|
|
/*!
|
|
* @function bufattr_willverify
|
|
* @abstract Check if a buffer is verified by the cluster layer.
|
|
* @param bap Buffer attribute to test.
|
|
* @return Nonzero if the buffer will be verified, 0 otherwise.
|
|
*/
|
|
int bufattr_willverify(bufattr_t bap);
|
|
|
|
/*!
|
|
* @function bufattr_passive
|
|
* @abstract Check if a buffer is marked passive.
|
|
* @param bap Buffer attribute to test.
|
|
* @return Nonzero if the buffer is marked passive, 0 otherwise.
|
|
*/
|
|
int bufattr_passive(bufattr_t bap);
|
|
|
|
/*!
|
|
* @function bufattr_nocache
|
|
* @abstract Check if a buffer has nocache attribute.
|
|
* @param bap Buffer attribute to test.
|
|
* @return Nonzero if the buffer is not cached, 0 otherwise.
|
|
*/
|
|
int bufattr_nocache(bufattr_t bap);
|
|
|
|
/*!
|
|
* @function bufattr_meta
|
|
* @abstract Check if a buffer has the bufattr meta attribute.
|
|
* @param bap Buffer attribute to test.
|
|
* @return Nonzero if the buffer has meta attribute, 0 otherwise.
|
|
*/
|
|
|
|
int bufattr_meta(bufattr_t bap);
|
|
|
|
/*!
|
|
* @function bufattr_markmeta
|
|
* @abstract Set the bufattr meta attribute.
|
|
* @param bap Buffer attribute to manipulate.
|
|
*/
|
|
void bufattr_markmeta(bufattr_t bap);
|
|
|
|
|
|
/*!
|
|
* @function bufattr_delayidlesleep
|
|
* @abstract Check if a buffer is marked to delay idle sleep on disk IO.
|
|
* @param bap Buffer attribute to test.
|
|
* @return Nonzero if the buffer is marked to delay idle sleep on disk IO, 0 otherwise.
|
|
*/
|
|
int bufattr_delayidlesleep(bufattr_t bap);
|
|
|
|
/*!
|
|
* @function buf_kernel_addrperm_addr
|
|
* @abstract Obfuscate the buf pointers.
|
|
* @param addr Buf_t pointer.
|
|
* @return Obfuscated pointer if addr is non zero, 0 otherwise.
|
|
*/
|
|
vm_offset_t buf_kernel_addrperm_addr(void * addr);
|
|
|
|
/*!
|
|
* @function bufattr_markquickcomplete
|
|
* @abstract Mark a buffer to hint quick completion to the driver.
|
|
* @discussion This flag hints the storage driver that some thread is waiting for this I/O to complete.
|
|
* It should therefore attempt to complete it as soon as possible at the cost of device efficiency.
|
|
* @param bap Buffer attributes to mark.
|
|
*/
|
|
void bufattr_markquickcomplete(bufattr_t bap);
|
|
|
|
/*!
|
|
* @function bufattr_quickcomplete
|
|
* @abstract Check if a buffer is marked for quick completion
|
|
* @discussion This flag hints the storage driver that some thread is waiting for this I/O to complete.
|
|
* It should therefore attempt to complete it as soon as possible at the cost of device efficiency.
|
|
* @param bap Buffer attribute to test.
|
|
* @return Nonzero if the buffer is marked for quick completion, 0 otherwise.
|
|
*/
|
|
int bufattr_quickcomplete(bufattr_t bap);
|
|
|
|
int count_lock_queue(void);
|
|
|
|
/*
|
|
* Flags for buf_acquire
|
|
*/
|
|
#define BAC_NOWAIT 0x01 /* Don't wait if buffer is busy */
|
|
#define BAC_REMOVE 0x02 /* Remove from free list once buffer is acquired */
|
|
#define BAC_SKIP_NONLOCKED 0x04 /* Don't return LOCKED buffers */
|
|
#define BAC_SKIP_LOCKED 0x08 /* Only return LOCKED buffers */
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errno_t buf_acquire(buf_t, int, int, int);
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buf_t buf_create_shadow_priv(buf_t bp, boolean_t force_copy, uintptr_t external_storage, void (*iodone)(buf_t, void *), void *arg);
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void buf_drop(buf_t);
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#endif /* KERNEL_PRIVATE */
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__END_DECLS
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/* Macros to clear/set/test flags. */
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#define SET(t, f) (t) |= (f)
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#define CLR(t, f) (t) &= ~(f)
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#define ISSET(t, f) ((t) & (f))
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#endif /* !_SYS_BUF_H_ */
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