[apple/xnu.git] / bsd / kern / kern_physio.c

/*
 * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*-
 * Copyright (c) 1982, 1986, 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	from: @(#)kern_physio.c	8.1 (Berkeley) 6/10/93
 */
/*
 * HISTORY
 * 27-July-97  Umesh Vaishampayan  (umeshv@apple.com)
 *	Allow physio() to kernel space.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/buf_internal.h>
#include <sys/conf.h>
#include <sys/proc_internal.h>
#include <sys/uio_internal.h>
#include <kern/assert.h>

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)
{
	struct proc *p = current_proc();
	int error, i, buf_allocated, todo, iosize;
	int orig_bflags = 0;
#if LP64KERN
	int64_t done;
#else
	int done;
#endif

	error = 0;
	flags &= B_READ | B_WRITE;
	buf_allocated = 0;

	/*
	 * [check user read/write access to the data buffer]
	 *
	 * Check each iov one by one.  Note that we know if we're reading or
	 * writing, so we ignore the uio's rw parameter.  Also note that if
	 * we're doing a read, that's a *write* to user-space.
	 */
	for (i = 0; i < uio->uio_iovcnt; i++) {
		if (UIO_SEG_IS_USER_SPACE(uio->uio_segflg)) {
			user_addr_t base;
			user_size_t len;
			
			if (uio_getiov(uio, i, &base, &len) ||
				!useracc(base,
					len,
		    		(flags == B_READ) ? B_WRITE : B_READ))
			return (EFAULT);
		}
	}
	/*
	 * Make sure we have a buffer, creating one if necessary.
	 */
	if (bp == NULL) {
		bp = buf_alloc((vnode_t)0);
		buf_allocated = 1;
	} else
	        orig_bflags = buf_flags(bp);
	/*
	 * at this point we should have a buffer
	 * that is marked BL_BUSY... we either 
	 * acquired it via buf_alloc, or it was
	 * passed into us... if it was passed
	 * in, it needs to already be owned by
	 * the caller (i.e. BL_BUSY is set)
	 */
	assert(bp->b_lflags & BL_BUSY);

	/*
	 * [set up the fixed part of the buffer for a transfer]
	 */
	bp->b_dev = dev;
	bp->b_proc = p;

	/*
	 * [mark the buffer busy for physical I/O]
	 * (i.e. set B_PHYS (because it's an I/O to user
	 * memory, and B_RAW, because B_RAW is to be
	 * "Set by physio for raw transfers.", in addition
	 * to the read/write flag.)
	 */
        buf_setflags(bp, B_PHYS | B_RAW);

	/*
	 * [while there is data to transfer and no I/O error]
	 * Note that I/O errors are handled with a 'goto' at the bottom
	 * of the 'while' loop.
	 */
	while (uio_resid(uio) > 0) {
			
			if ( (iosize = uio_curriovlen(uio)) > MAXPHYSIO_WIRED)
			        iosize = MAXPHYSIO_WIRED;
			/*
			 * make sure we're set to issue a fresh I/O
			 * in the right direction
			 */
			buf_reset(bp, flags);

			/* [set up the buffer for a maximum-sized transfer] */
 			buf_setblkno(bp, uio_offset(uio) / blocksize);
			buf_setcount(bp, iosize);
			buf_setdataptr(bp, (uintptr_t)CAST_DOWN(caddr_t, uio_curriovbase(uio)));
			
			/*
			 * [call f_minphys to bound the tranfer size]
			 * and remember the amount of data to transfer,
			 * for later comparison.
			 */
			(*f_minphys)(bp);
			todo = buf_count(bp);

			/*
			 * [lock the part of the user address space involved
			 *    in the transfer]
			 */

			if(UIO_SEG_IS_USER_SPACE(uio->uio_segflg)) {
				error = vslock(CAST_USER_ADDR_T(buf_dataptr(bp)),
					       (user_size_t)todo);
				if (error)
					goto done;
			}
			
			/* [call f_strategy to start the transfer] */
			(*f_strategy)(bp);


			/* [wait for the transfer to complete] */
			error = (int)buf_biowait(bp);

			/*
			 * [unlock the part of the address space previously
			 *    locked]
			 */
			if(UIO_SEG_IS_USER_SPACE(uio->uio_segflg))
				vsunlock(CAST_USER_ADDR_T(buf_dataptr(bp)),
					 (user_size_t)todo,
					 (flags & B_READ));

			/*
			 * [deduct the transfer size from the total number
			 *    of data to transfer]
			 */
			done = buf_count(bp) - buf_resid(bp);
			uio_update(uio, done);

			/*
			 * Now, check for an error.
			 * Also, handle weird end-of-disk semantics.
			 */
			if (error || done < todo)
				goto done;
	}

done:
	if (buf_allocated)
	        buf_free(bp);
	else
		buf_setflags(bp, orig_bflags);

	return (error);
}

/*
 * Leffler, et al., says on p. 231:
 * "The minphys() routine is called by physio() to adjust the
 * size of each I/O transfer before the latter is passed to
 * the strategy routine..." 
 *
 * so, just adjust the buffer's count accounting to MAXPHYS here,
 * and return the new count;
 */
u_int
minphys(struct buf *bp)
{

	buf_setcount(bp, min(MAXPHYS, buf_count(bp)));
        return buf_count(bp);
}
Commit	Line	Data
1c79356b	1	/*
5d5c5d0d A	2	* Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
5d5c5d0d A	3	*
2d21ac55	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
1c79356b	5	*
2d21ac55 A	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the License
	10	* may not be used to create, or enable the creation or redistribution of,
	11	* unlawful or unlicensed copies of an Apple operating system, or to
	12	* circumvent, violate, or enable the circumvention or violation of, any
	13	* terms of an Apple operating system software license agreement.
8f6c56a5	14	*
2d21ac55 A	15	* Please obtain a copy of the License at
	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
	17	*
	18	* The Original Code and all software distributed under the License are
	19	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
8f6c56a5 A	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
8f6c56a5 A	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
2d21ac55 A	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
	24	* limitations under the License.
8f6c56a5	25	*
2d21ac55	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
1c79356b A	27	*/
	28	/*-
	29	* Copyright (c) 1982, 1986, 1990, 1993
	30	* The Regents of the University of California. All rights reserved.
	31	* (c) UNIX System Laboratories, Inc.
	32	* All or some portions of this file are derived from material licensed
	33	* to the University of California by American Telephone and Telegraph
	34	* Co. or Unix System Laboratories, Inc. and are reproduced herein with
	35	* the permission of UNIX System Laboratories, Inc.
	36	*
	37	* Redistribution and use in source and binary forms, with or without
	38	* modification, are permitted provided that the following conditions
	39	* are met:
	40	* 1. Redistributions of source code must retain the above copyright
	41	* notice, this list of conditions and the following disclaimer.
	42	* 2. Redistributions in binary form must reproduce the above copyright
	43	* notice, this list of conditions and the following disclaimer in the
	44	* documentation and/or other materials provided with the distribution.
	45	* 3. All advertising materials mentioning features or use of this software
	46	* must display the following acknowledgement:
	47	* This product includes software developed by the University of
	48	* California, Berkeley and its contributors.
	49	* 4. Neither the name of the University nor the names of its contributors
	50	* may be used to endorse or promote products derived from this software
	51	* without specific prior written permission.
	52	*
	53	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	54	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	55	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	56	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	57	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	58	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	59	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	60	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	61	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	62	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	63	* SUCH DAMAGE.
	64	*
	65	* from: @(#)kern_physio.c 8.1 (Berkeley) 6/10/93
	66	*/
	67	/*
	68	* HISTORY
	69	* 27-July-97 Umesh Vaishampayan (umeshv@apple.com)
	70	* Allow physio() to kernel space.
	71	*/
	72
	73	#include <sys/param.h>
	74	#include <sys/systm.h>
91447636	75	#include <sys/buf_internal.h>
1c79356b	76	#include <sys/conf.h>
91447636 A	77	#include <sys/proc_internal.h>
91447636 A	78	#include <sys/uio_internal.h>
2d21ac55 A	79	#include <kern/assert.h>
2d21ac55 A	80
1c79356b	81	int
2d21ac55 A	82	physio( void (*f_strategy)(buf_t),
	83	buf_t bp,
	84	dev_t dev,
	85	int flags,
	86	u_int (*f_minphys)(buf_t),
	87	struct uio *uio,
	88	int blocksize)
1c79356b	89	{
1c79356b	90	struct proc *p = current_proc();
2d21ac55 A	91	int error, i, buf_allocated, todo, iosize;
2d21ac55 A	92	int orig_bflags = 0;
91447636 A	93	#if LP64KERN
	94	int64_t done;
	95	#else
	96	int done;
	97	#endif
1c79356b A	98
	99	error = 0;
	100	flags &= B_READ \| B_WRITE;
2d21ac55	101	buf_allocated = 0;
1c79356b A	102
	103	/*
	104	* [check user read/write access to the data buffer]
	105	*
	106	* Check each iov one by one. Note that we know if we're reading or
	107	* writing, so we ignore the uio's rw parameter. Also note that if
	108	* we're doing a read, that's a write to user-space.
	109	*/
	110	for (i = 0; i < uio->uio_iovcnt; i++) {
2d21ac55	111	if (UIO_SEG_IS_USER_SPACE(uio->uio_segflg)) {
b0d623f7 A	112	user_addr_t base;
	113	user_size_t len;
	114
	115	if (uio_getiov(uio, i, &base, &len) \|\|
	116	!useracc(base,
	117	len,
1c79356b A	118	(flags == B_READ) ? B_WRITE : B_READ))
	119	return (EFAULT);
	120	}
	121	}
2d21ac55 A	122	/*
	123	* Make sure we have a buffer, creating one if necessary.
	124	*/
	125	if (bp == NULL) {
	126	bp = buf_alloc((vnode_t)0);
	127	buf_allocated = 1;
	128	} else
	129	orig_bflags = buf_flags(bp);
	130	/*
	131	* at this point we should have a buffer
	132	* that is marked BL_BUSY... we either
	133	* acquired it via buf_alloc, or it was
	134	* passed into us... if it was passed
	135	* in, it needs to already be owned by
	136	* the caller (i.e. BL_BUSY is set)
	137	*/
	138	assert(bp->b_lflags & BL_BUSY);
1c79356b	139
2d21ac55 A	140	/*
	141	* [set up the fixed part of the buffer for a transfer]
	142	*/
1c79356b	143	bp->b_dev = dev;
1c79356b A	144	bp->b_proc = p;
1c79356b A	145
2d21ac55 A	146	/*
	147	* [mark the buffer busy for physical I/O]
	148	* (i.e. set B_PHYS (because it's an I/O to user
	149	* memory, and B_RAW, because B_RAW is to be
	150	* "Set by physio for raw transfers.", in addition
	151	* to the read/write flag.)
	152	*/
	153	buf_setflags(bp, B_PHYS \| B_RAW);
	154
1c79356b	155	/*
91447636	156	* [while there is data to transfer and no I/O error]
1c79356b A	157	* Note that I/O errors are handled with a 'goto' at the bottom
	158	* of the 'while' loop.
	159	*/
b0d623f7	160	while (uio_resid(uio) > 0) {
91447636	161
b0d623f7	162	if ( (iosize = uio_curriovlen(uio)) > MAXPHYSIO_WIRED)
91447636	163	iosize = MAXPHYSIO_WIRED;
2d21ac55 A	164	/*
	165	* make sure we're set to issue a fresh I/O
	166	* in the right direction
	167	*/
	168	buf_reset(bp, flags);
1c79356b A	169
1c79356b A	170	/* [set up the buffer for a maximum-sized transfer] */
b0d623f7	171	buf_setblkno(bp, uio_offset(uio) / blocksize);
91447636	172	buf_setcount(bp, iosize);
b0d623f7	173	buf_setdataptr(bp, (uintptr_t)CAST_DOWN(caddr_t, uio_curriovbase(uio)));
1c79356b A	174
1c79356b A	175	/*
2d21ac55	176	* [call f_minphys to bound the tranfer size]
1c79356b A	177	* and remember the amount of data to transfer,
	178	* for later comparison.
	179	*/
2d21ac55	180	(*f_minphys)(bp);
91447636	181	todo = buf_count(bp);
1c79356b A	182
	183	/*
	184	* [lock the part of the user address space involved
	185	* in the transfer]
1c79356b A	186	*/
1c79356b A	187
2d21ac55 A	188	if(UIO_SEG_IS_USER_SPACE(uio->uio_segflg)) {
	189	error = vslock(CAST_USER_ADDR_T(buf_dataptr(bp)),
	190	(user_size_t)todo);
	191	if (error)
	192	goto done;
	193	}
1c79356b	194
2d21ac55 A	195	/* [call f_strategy to start the transfer] */
2d21ac55 A	196	(*f_strategy)(bp);
1c79356b	197
1c79356b A	198
1c79356b A	199	/* [wait for the transfer to complete] */
91447636	200	error = (int)buf_biowait(bp);
1c79356b A	201
	202	/*
	203	* [unlock the part of the address space previously
	204	* locked]
	205	*/
91447636 A	206	if(UIO_SEG_IS_USER_SPACE(uio->uio_segflg))
	207	vsunlock(CAST_USER_ADDR_T(buf_dataptr(bp)),
	208	(user_size_t)todo,
	209	(flags & B_READ));
1c79356b A	210
	211	/*
	212	* [deduct the transfer size from the total number
	213	* of data to transfer]
	214	*/
91447636	215	done = buf_count(bp) - buf_resid(bp);
b0d623f7	216	uio_update(uio, done);
1c79356b A	217
	218	/*
	219	* Now, check for an error.
	220	* Also, handle weird end-of-disk semantics.
	221	*/
	222	if (error \|\| done < todo)
	223	goto done;
1c79356b A	224	}
	225
	226	done:
2d21ac55 A	227	if (buf_allocated)
	228	buf_free(bp);
	229	else
	230	buf_setflags(bp, orig_bflags);
1c79356b A	231
	232	return (error);
	233	}
	234
	235	/*
	236	* Leffler, et al., says on p. 231:
	237	* "The minphys() routine is called by physio() to adjust the
	238	* size of each I/O transfer before the latter is passed to
	239	* the strategy routine..."
	240	*
	241	* so, just adjust the buffer's count accounting to MAXPHYS here,
	242	* and return the new count;
	243	*/
	244	u_int
2d21ac55	245	minphys(struct buf *bp)
1c79356b A	246	{
1c79356b A	247
91447636 A	248	buf_setcount(bp, min(MAXPHYS, buf_count(bp)));
91447636 A	249	return buf_count(bp);
1c79356b	250	}