[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>

int
physio(strategy, bp, dev, flags, minphys, uio, blocksize)
	void (*strategy)(); 
	buf_t bp;
	dev_t dev;
	int flags;
	u_int (*minphys)();
	struct uio *uio;
	int blocksize;
{
	struct proc *p = current_proc();
	int error, i, nobuf, todo, iosize;
#if LP64KERN
	int64_t done;
#else
	int done;
#endif

	error = 0;
	flags &= B_READ | B_WRITE;

	/*
	 * [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)) {
			if (!useracc(uio_iov_base_at(uio, i),
					uio_iov_len_at(uio, i),
		    		(flags == B_READ) ? B_WRITE : B_READ))
			return (EFAULT);
		}
	}
	/* Make sure we have a buffer, creating one if necessary. */
	if (nobuf = (bp == NULL)) {
			bp = buf_alloc((vnode_t)0);
		}

	/* [while the buffer is marked busy] */
	while (((error = (int)buf_acquire(bp, 0, 0, 0)) == EAGAIN));
	
	if (error) {
			if (nobuf)
				buf_free(bp);
	        return (error);
	}

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

	buf_seterror(bp, 0);
	/*
	 * [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.
	 */
	for (i = 0; i < uio->uio_iovcnt; i++) {
		while (uio_iov_len_at(uio, i) > 0) {
			/*
			 * [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 | flags);
			
			if ( (iosize = uio_iov_len_at(uio, i)) > MAXPHYSIO_WIRED)
			        iosize = MAXPHYSIO_WIRED;

			/* [set up the buffer for a maximum-sized transfer] */
 			buf_setblkno(bp, uio->uio_offset / blocksize);
			buf_setcount(bp, iosize);
			// LP64todo - fix this!
			buf_setdataptr(bp, CAST_DOWN(caddr_t, uio_iov_base_at(uio, i)));
			
			/*
			 * [call minphys to bound the tranfer size]
			 * and remember the amount of data to transfer,
			 * for later comparison.
			 */
			(*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))
				vslock(CAST_USER_ADDR_T(buf_dataptr(bp)),
				       (user_size_t)todo);
			
			/* [call strategy to start the transfer] */
			(*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_iov_len_add_at(uio, -done, i);
			uio_iov_base_add_at(uio, done, i);
			uio->uio_offset += done;
			uio_setresid(uio, (uio_resid(uio) - done));

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

done:
	/*
	 * [clean up the state of the buffer]
	 * Remember if somebody wants it, so we can wake them up below.
	 * Also, if we had to steal it, give it back.
	 */

	buf_clearflags(bp, B_PHYS | B_RAW);
	if (nobuf)
		buf_free(bp);
	else 
	        {
		        buf_drop(bp);
		}

	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(bp)
	struct buf *bp;
{

	buf_setcount(bp, min(MAXPHYS, buf_count(bp)));
        return buf_count(bp);
}

/*
 * Do a read on a device for a user process.
 */
rawread(dev, uio)
	dev_t dev;
	struct uio *uio;
{
	return (physio(cdevsw[major(dev)].d_strategy, (struct buf *)NULL,
	    dev, B_READ, minphys, uio, DEV_BSIZE));
}

/*
 * Do a write on a device for a user process.
 */
rawwrite(dev, uio)
	dev_t dev;
	struct uio *uio;
{
	return (physio(cdevsw[major(dev)].d_strategy, (struct buf *)NULL,
	    dev, B_WRITE, minphys, uio, DEV_BSIZE));
}
Commit	Line	Data
1c79356b	1	/*
5d5c5d0d A	2	* Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
5d5c5d0d A	3	*
8f6c56a5	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
1c79356b	5	*
8f6c56a5 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.
	14	*
	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
	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
8ad349bb	24	* limitations under the License.
8f6c56a5 A	25	*
8f6c56a5 A	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>
1c79356b A	79
	80	int
	81	physio(strategy, bp, dev, flags, minphys, uio, blocksize)
	82	void (*strategy)();
91447636	83	buf_t bp;
1c79356b A	84	dev_t dev;
	85	int flags;
	86	u_int (*minphys)();
	87	struct uio *uio;
	88	int blocksize;
	89	{
1c79356b	90	struct proc *p = current_proc();
91447636 A	91	int error, i, nobuf, todo, iosize;
	92	#if LP64KERN
	93	int64_t done;
	94	#else
	95	int done;
	96	#endif
1c79356b A	97
	98	error = 0;
	99	flags &= B_READ \| B_WRITE;
	100
	101	/*
	102	* [check user read/write access to the data buffer]
	103	*
	104	* Check each iov one by one. Note that we know if we're reading or
	105	* writing, so we ignore the uio's rw parameter. Also note that if
	106	* we're doing a read, that's a write to user-space.
	107	*/
	108	for (i = 0; i < uio->uio_iovcnt; i++) {
91447636 A	109	if(UIO_SEG_IS_USER_SPACE(uio->uio_segflg)) {
	110	if (!useracc(uio_iov_base_at(uio, i),
	111	uio_iov_len_at(uio, i),
1c79356b A	112	(flags == B_READ) ? B_WRITE : B_READ))
	113	return (EFAULT);
	114	}
	115	}
	116	/* Make sure we have a buffer, creating one if necessary. */
	117	if (nobuf = (bp == NULL)) {
91447636	118	bp = buf_alloc((vnode_t)0);
1c79356b A	119	}
1c79356b A	120
1c79356b	121	/* [while the buffer is marked busy] */
91447636 A	122	while (((error = (int)buf_acquire(bp, 0, 0, 0)) == EAGAIN));
	123
	124	if (error) {
	125	if (nobuf)
	126	buf_free(bp);
	127	return (error);
1c79356b A	128	}
1c79356b A	129
1c79356b A	130	/* [set up the fixed part of the buffer for a transfer] */
1c79356b A	131	bp->b_dev = dev;
1c79356b A	132	bp->b_proc = p;
1c79356b A	133
91447636	134	buf_seterror(bp, 0);
1c79356b	135	/*
91447636	136	* [while there is data to transfer and no I/O error]
1c79356b A	137	* Note that I/O errors are handled with a 'goto' at the bottom
	138	* of the 'while' loop.
	139	*/
	140	for (i = 0; i < uio->uio_iovcnt; i++) {
91447636	141	while (uio_iov_len_at(uio, i) > 0) {
1c79356b A	142	/*
	143	* [mark the buffer busy for physical I/O]
	144	* (i.e. set B_PHYS (because it's an I/O to user
	145	* memory, and B_RAW, because B_RAW is to be
	146	* "Set by physio for raw transfers.", in addition
91447636	147	* to the read/write flag.)
1c79356b	148	*/
91447636 A	149	buf_setflags(bp, B_PHYS \| B_RAW \| flags);
	150
	151	if ( (iosize = uio_iov_len_at(uio, i)) > MAXPHYSIO_WIRED)
	152	iosize = MAXPHYSIO_WIRED;
1c79356b A	153
1c79356b A	154	/* [set up the buffer for a maximum-sized transfer] */
91447636 A	155	buf_setblkno(bp, uio->uio_offset / blocksize);
	156	buf_setcount(bp, iosize);
	157	// LP64todo - fix this!
	158	buf_setdataptr(bp, CAST_DOWN(caddr_t, uio_iov_base_at(uio, i)));
1c79356b A	159
	160	/*
	161	* [call minphys to bound the tranfer size]
	162	* and remember the amount of data to transfer,
	163	* for later comparison.
	164	*/
	165	(*minphys)(bp);
91447636	166	todo = buf_count(bp);
1c79356b A	167
	168	/*
	169	* [lock the part of the user address space involved
	170	* in the transfer]
1c79356b A	171	*/
1c79356b A	172
91447636 A	173	if(UIO_SEG_IS_USER_SPACE(uio->uio_segflg))
	174	vslock(CAST_USER_ADDR_T(buf_dataptr(bp)),
	175	(user_size_t)todo);
1c79356b	176
1c79356b A	177	/* [call strategy to start the transfer] */
	178	(*strategy)(bp);
	179
1c79356b A	180
1c79356b A	181	/* [wait for the transfer to complete] */
91447636	182	error = (int)buf_biowait(bp);
1c79356b A	183
	184	/*
	185	* [unlock the part of the address space previously
	186	* locked]
	187	*/
91447636 A	188	if(UIO_SEG_IS_USER_SPACE(uio->uio_segflg))
	189	vsunlock(CAST_USER_ADDR_T(buf_dataptr(bp)),
	190	(user_size_t)todo,
	191	(flags & B_READ));
1c79356b A	192
	193	/*
	194	* [deduct the transfer size from the total number
	195	* of data to transfer]
	196	*/
91447636 A	197	done = buf_count(bp) - buf_resid(bp);
	198	uio_iov_len_add_at(uio, -done, i);
	199	uio_iov_base_add_at(uio, done, i);
	200	uio->uio_offset += done;
	201	uio_setresid(uio, (uio_resid(uio) - done));
1c79356b A	202
	203	/*
	204	* Now, check for an error.
	205	* Also, handle weird end-of-disk semantics.
	206	*/
	207	if (error \|\| done < todo)
	208	goto done;
	209	}
	210	}
	211
	212	done:
	213	/*
	214	* [clean up the state of the buffer]
	215	* Remember if somebody wants it, so we can wake them up below.
	216	* Also, if we had to steal it, give it back.
	217	*/
1c79356b	218
91447636 A	219	buf_clearflags(bp, B_PHYS \| B_RAW);
	220	if (nobuf)
	221	buf_free(bp);
1c79356b	222	else
91447636 A	223	{
91447636 A	224	buf_drop(bp);
1c79356b	225	}
1c79356b A	226
	227	return (error);
	228	}
	229
	230	/*
	231	* Leffler, et al., says on p. 231:
	232	* "The minphys() routine is called by physio() to adjust the
	233	* size of each I/O transfer before the latter is passed to
	234	* the strategy routine..."
	235	*
	236	* so, just adjust the buffer's count accounting to MAXPHYS here,
	237	* and return the new count;
	238	*/
	239	u_int
	240	minphys(bp)
	241	struct buf *bp;
	242	{
	243
91447636 A	244	buf_setcount(bp, min(MAXPHYS, buf_count(bp)));
91447636 A	245	return buf_count(bp);
1c79356b A	246	}
	247
	248	/*
	249	* Do a read on a device for a user process.
	250	*/
	251	rawread(dev, uio)
	252	dev_t dev;
	253	struct uio *uio;
	254	{
	255	return (physio(cdevsw[major(dev)].d_strategy, (struct buf *)NULL,
	256	dev, B_READ, minphys, uio, DEV_BSIZE));
	257	}
	258
	259	/*
	260	* Do a write on a device for a user process.
	261	*/
	262	rawwrite(dev, uio)
	263	dev_t dev;
	264	struct uio *uio;
	265	{
	266	return (physio(cdevsw[major(dev)].d_strategy, (struct buf *)NULL,
	267	dev, B_WRITE, minphys, uio, DEV_BSIZE));
	268	}