[unix-history] / sys / kern / kern_physio.c

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Date: Sat, 19 Mar 1994 15:09:05 -0459
From: John Dyson <toor@jsdinc.root.com>
Message-Id: <199403192008.PAA00122@jsdinc.root.com>
To: davidg@implode.root.com
Subject: new kern_physio.c

/*
 * Copyright (c) 1989, 1990, 1991, 1992 William F. Jolitz, TeleMuse
 * All rights reserved.
 *
 * 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 software is a component of "386BSD" developed by 
	William F. Jolitz, TeleMuse.
 * 4. Neither the name of the developer nor the name "386BSD"
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS A COMPONENT OF 386BSD DEVELOPED BY WILLIAM F. JOLITZ 
 * AND IS INTENDED FOR RESEARCH AND EDUCATIONAL PURPOSES ONLY. THIS 
 * SOFTWARE SHOULD NOT BE CONSIDERED TO BE A COMMERCIAL PRODUCT. 
 * THE DEVELOPER URGES THAT USERS WHO REQUIRE A COMMERCIAL PRODUCT 
 * NOT MAKE USE THIS WORK.
 *
 * FOR USERS WHO WISH TO UNDERSTAND THE 386BSD SYSTEM DEVELOPED
 * BY WILLIAM F. JOLITZ, WE RECOMMEND THE USER STUDY WRITTEN 
 * REFERENCES SUCH AS THE  "PORTING UNIX TO THE 386" SERIES 
 * (BEGINNING JANUARY 1991 "DR. DOBBS JOURNAL", USA AND BEGINNING 
 * JUNE 1991 "UNIX MAGAZIN", GERMANY) BY WILLIAM F. JOLITZ AND 
 * LYNNE GREER JOLITZ, AS WELL AS OTHER BOOKS ON UNIX AND THE 
 * ON-LINE 386BSD USER MANUAL BEFORE USE. A BOOK DISCUSSING THE INTERNALS 
 * OF 386BSD ENTITLED "386BSD FROM THE INSIDE OUT" WILL BE AVAILABLE LATE 1992.
 *
 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPER ``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 DEVELOPER 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.
 *
 *	$Id: kern_physio.c,v 1.2 1994/03/14 21:54:16 davidg Exp $
 */

#include "param.h"
#include "systm.h"
#include "buf.h"
#include "conf.h"
#include "proc.h"
#include "malloc.h"
#include "vnode.h"
#include "vm/vm.h"
#include "vm/vm_page.h"
#include "specdev.h"

/*
 * Driver interface to do "raw" I/O in the address space of a
 * user process directly for read and write operations..
 */

int
rawread(dev, uio)
	dev_t dev; struct uio *uio;
{
	return (uioapply(physio, (caddr_t) cdevsw[major(dev)].d_strategy,
				 (caddr_t) (u_long) dev, uio));
}

int
rawwrite(dev, uio)
	dev_t dev; struct uio *uio;
{
	return (uioapply(physio, (caddr_t) cdevsw[major(dev)].d_strategy,
				(caddr_t) (u_long) dev, uio));
}


int physio(strat, dev, bp, off, rw, base, len, p)
	d_strategy_t strat; 
	dev_t dev;
	struct buf *bp;
	int rw, off;
	caddr_t base;
	int *len;
	struct proc *p;
{
	int amttodo = *len;
	int error, amtdone;
	vm_prot_t ftype;
	vm_offset_t v, lastv, pa;
	caddr_t adr;
	int oldflags;
	int s;
	
	int bp_alloc = (bp == 0);

/*
 * keep the process from being swapped
 */
	oldflags = p->p_flag;
	p->p_flag |= SPHYSIO;

	rw = rw == UIO_READ ? B_READ : 0;

	/* create and build a buffer header for a transfer */

	if (bp_alloc) {
		bp = (struct buf *)getpbuf();
		bzero((char *)bp, sizeof(*bp));			/* 09 Sep 92*/
	} else {
		s = splbio();
		while (bp->b_flags & B_BUSY) {
			bp->b_flags |= B_WANTED;
			tsleep((caddr_t)bp, PRIBIO, "physbw", 0);
		}
		bp->b_flags |= B_BUSY;
		splx(s);
	}

	bp->b_flags = B_BUSY | B_PHYS | rw;
	bp->b_proc = p;
	bp->b_dev = dev;
	bp->b_error = 0;
	bp->b_blkno = off/DEV_BSIZE;
	amtdone = 0;

	/* iteratively do I/O on as large a chunk as possible */
	do {
		bp->b_flags &= ~B_DONE;
		bp->b_un.b_addr = base;
		/* XXX limit */
		bp->b_bcount = min (256*1024, amttodo);

		/* first, check if accessible */
		if (rw == B_READ && !useracc(base, bp->b_bcount, B_WRITE)) {
			error = EFAULT;
			goto errrtn;
		}
		if (rw == B_WRITE && !useracc(base, bp->b_bcount, B_READ)) {
			error = EFAULT;
			goto errrtn;
		}

		/* update referenced and dirty bits, handle copy objects */
		if (rw == B_READ)
			ftype = VM_PROT_READ | VM_PROT_WRITE;
		else
			ftype = VM_PROT_READ;

		lastv = 0;
		for (adr = (caddr_t)trunc_page(base); adr < base + bp->b_bcount;
			adr += NBPG) {
	
/*
 * make sure that the pde is valid and held
 */
			v = trunc_page(((vm_offset_t)vtopte(adr)));
			if (v != lastv) {
				
				*(volatile int *)v += 0;
				pa = pmap_extract(&p->p_vmspace->vm_pmap, v);
				vm_page_hold(PHYS_TO_VM_PAGE(pa));
				lastv = v;
			}

/*
 * do the vm_fault if needed, do the copy-on-write thing when
 * reading stuff off device into memory.
 */
			if (ftype & VM_PROT_WRITE) {
				/*
				 * properly handle copy-on-write
				 */
				*(volatile int *) adr += 0;
			} 
#if defined(HOLD_WORKS_FOR_SHARING)
			else {
				*(volatile int *) adr;
			}
			pa = pmap_extract(&p->p_vmspace->vm_pmap, (vm_offset_t) adr);
/*
 * hold the data page
 */
			vm_page_hold(PHYS_TO_VM_PAGE(pa));
#endif
		}

#if !defined(HOLD_WORKS_FOR_SHARING)
		vslock(base, bp->b_bcount);
#endif
		/* perform transfer */
		physstrat(bp, strat, PRIBIO);
#if !defined(HOLD_WORKS_FOR_SHARING)
		vsunlock(base, bp->b_bcount);
#endif

/*
 * unhold the pde, and data pages
 */
		lastv = 0;
		for (adr = (caddr_t)trunc_page(base); adr < base + bp->b_bcount;
			adr += NBPG) {
			v = trunc_page(((vm_offset_t)vtopte(adr)));
			if (v != lastv) {
				pa = pmap_extract(&p->p_vmspace->vm_pmap, v);
				vm_page_unhold(PHYS_TO_VM_PAGE(pa));
				lastv = v;
			}
#if defined(HOLD_WORKS_FOR_SHARING)
			pa = pmap_extract(&p->p_vmspace->vm_pmap, (vm_offset_t) adr);
			vm_page_unhold(PHYS_TO_VM_PAGE(pa));
#endif
		}
			

		amtdone = bp->b_bcount - bp->b_resid;
		amttodo -= amtdone;
		base += amtdone;
		bp->b_blkno += amtdone/DEV_BSIZE;
	} while (amttodo && (bp->b_flags & B_ERROR) == 0 && amtdone > 0);

	error = bp->b_error;
errrtn:
	if (bp_alloc) {
		relpbuf(bp);
	} else {
		bp->b_flags &= ~B_BUSY;
		wakeup((caddr_t)bp);
	}
	*len = amttodo;

/*
 * allow the process to be swapped
 */
	p->p_flag &= ~SPHYSIO;
	p->p_flag |= (oldflags & SPHYSIO);

	return (error);
}
Commit	Line	Data
6232f830 DG	1	Received: from jsdinc.root.com (uucp@localhost) by Root.COM (8.6.5/8.6.5) with UUCP id MAA09093 for implode.root.com!davidg; Sat, 19 Mar 1994 12:12:17 -0800
	2	Received: from localhost (root@localhost) by jsdinc.root.com (8.6.5/8.6.5) id PAA00122 for implode!davidg; Sat, 19 Mar 1994 15:09:05 -0459
	3	Date: Sat, 19 Mar 1994 15:09:05 -0459
	4	From: John Dyson <toor@jsdinc.root.com>
	5	Message-Id: <199403192008.PAA00122@jsdinc.root.com>
	6	To: davidg@implode.root.com
	7	Subject: new kern_physio.c
	8
dd403947 DG	9	/*
	10	* Copyright (c) 1989, 1990, 1991, 1992 William F. Jolitz, TeleMuse
	11	* All rights reserved.
	12	*
	13	* Redistribution and use in source and binary forms, with or without
	14	* modification, are permitted provided that the following conditions
	15	* are met:
	16	* 1. Redistributions of source code must retain the above copyright
	17	* notice, this list of conditions and the following disclaimer.
	18	* 2. Redistributions in binary form must reproduce the above copyright
	19	* notice, this list of conditions and the following disclaimer in the
	20	* documentation and/or other materials provided with the distribution.
	21	* 3. All advertising materials mentioning features or use of this software
	22	* must display the following acknowledgement:
	23	* This software is a component of "386BSD" developed by
	24	William F. Jolitz, TeleMuse.
	25	* 4. Neither the name of the developer nor the name "386BSD"
	26	* may be used to endorse or promote products derived from this software
	27	* without specific prior written permission.
	28	*
	29	* THIS SOFTWARE IS A COMPONENT OF 386BSD DEVELOPED BY WILLIAM F. JOLITZ
	30	* AND IS INTENDED FOR RESEARCH AND EDUCATIONAL PURPOSES ONLY. THIS
	31	* SOFTWARE SHOULD NOT BE CONSIDERED TO BE A COMMERCIAL PRODUCT.
	32	* THE DEVELOPER URGES THAT USERS WHO REQUIRE A COMMERCIAL PRODUCT
	33	* NOT MAKE USE THIS WORK.
	34	*
	35	* FOR USERS WHO WISH TO UNDERSTAND THE 386BSD SYSTEM DEVELOPED
	36	* BY WILLIAM F. JOLITZ, WE RECOMMEND THE USER STUDY WRITTEN
	37	* REFERENCES SUCH AS THE "PORTING UNIX TO THE 386" SERIES
	38	* (BEGINNING JANUARY 1991 "DR. DOBBS JOURNAL", USA AND BEGINNING
	39	* JUNE 1991 "UNIX MAGAZIN", GERMANY) BY WILLIAM F. JOLITZ AND
	40	* LYNNE GREER JOLITZ, AS WELL AS OTHER BOOKS ON UNIX AND THE
	41	* ON-LINE 386BSD USER MANUAL BEFORE USE. A BOOK DISCUSSING THE INTERNALS
	42	* OF 386BSD ENTITLED "386BSD FROM THE INSIDE OUT" WILL BE AVAILABLE LATE 1992.
	43	*
	44	* THIS SOFTWARE IS PROVIDED BY THE DEVELOPER ``AS IS'' AND
	45	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	46	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	47	* ARE DISCLAIMED. IN NO EVENT SHALL THE DEVELOPER BE LIABLE
	48	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	49	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	50	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	51	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	52	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	53	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	54	* SUCH DAMAGE.
	55	*
6232f830	56	* $Id: kern_physio.c,v 1.2 1994/03/14 21:54:16 davidg Exp $
dd403947 DG	57	*/
	58
	59	#include "param.h"
	60	#include "systm.h"
	61	#include "buf.h"
	62	#include "conf.h"
	63	#include "proc.h"
	64	#include "malloc.h"
	65	#include "vnode.h"
	66	#include "vm/vm.h"
41aefbec	67	#include "vm/vm_page.h"
dd403947 DG	68	#include "specdev.h"
	69
	70	/*
	71	* Driver interface to do "raw" I/O in the address space of a
	72	* user process directly for read and write operations..
	73	*/
	74
	75	int
	76	rawread(dev, uio)
	77	dev_t dev; struct uio *uio;
	78	{
	79	return (uioapply(physio, (caddr_t) cdevsw[major(dev)].d_strategy,
	80	(caddr_t) (u_long) dev, uio));
	81	}
	82
	83	int
	84	rawwrite(dev, uio)
	85	dev_t dev; struct uio *uio;
	86	{
	87	return (uioapply(physio, (caddr_t) cdevsw[major(dev)].d_strategy,
	88	(caddr_t) (u_long) dev, uio));
	89	}
	90
	91
	92	int physio(strat, dev, bp, off, rw, base, len, p)
	93	d_strategy_t strat;
	94	dev_t dev;
	95	struct buf *bp;
	96	int rw, off;
	97	caddr_t base;
	98	int *len;
	99	struct proc *p;
	100	{
	101	int amttodo = *len;
	102	int error, amtdone;
	103	vm_prot_t ftype;
41aefbec	104	vm_offset_t v, lastv, pa;
dd403947 DG	105	caddr_t adr;
	106	int oldflags;
	107	int s;
	108
	109	int bp_alloc = (bp == 0);
	110
	111	/*
	112	* keep the process from being swapped
	113	*/
	114	oldflags = p->p_flag;
	115	p->p_flag \|= SPHYSIO;
	116
	117	rw = rw == UIO_READ ? B_READ : 0;
	118
	119	/* create and build a buffer header for a transfer */
	120
	121	if (bp_alloc) {
	122	bp = (struct buf *)getpbuf();
	123	bzero((char )bp, sizeof(bp)); /* 09 Sep 92*/
	124	} else {
	125	s = splbio();
	126	while (bp->b_flags & B_BUSY) {
	127	bp->b_flags \|= B_WANTED;
	128	tsleep((caddr_t)bp, PRIBIO, "physbw", 0);
	129	}
	130	bp->b_flags \|= B_BUSY;
	131	splx(s);
	132	}
	133
	134	bp->b_flags = B_BUSY \| B_PHYS \| rw;
	135	bp->b_proc = p;
	136	bp->b_dev = dev;
	137	bp->b_error = 0;
	138	bp->b_blkno = off/DEV_BSIZE;
	139	amtdone = 0;
	140
	141	/* iteratively do I/O on as large a chunk as possible */
	142	do {
	143	bp->b_flags &= ~B_DONE;
	144	bp->b_un.b_addr = base;
	145	/* XXX limit */
	146	bp->b_bcount = min (256*1024, amttodo);
	147
	148	/* first, check if accessible */
	149	if (rw == B_READ && !useracc(base, bp->b_bcount, B_WRITE)) {
	150	error = EFAULT;
	151	goto errrtn;
	152	}
	153	if (rw == B_WRITE && !useracc(base, bp->b_bcount, B_READ)) {
	154	error = EFAULT;
	155	goto errrtn;
	156	}
	157
	158	/* update referenced and dirty bits, handle copy objects */
	159	if (rw == B_READ)
	160	ftype = VM_PROT_READ \| VM_PROT_WRITE;
	161	else
	162	ftype = VM_PROT_READ;
	163
	164	lastv = 0;
	165	for (adr = (caddr_t)trunc_page(base); adr < base + bp->b_bcount;
	166	adr += NBPG) {
	167
	168	/*
41aefbec	169	* make sure that the pde is valid and held
dd403947 DG	170	*/
	171	v = trunc_page(((vm_offset_t)vtopte(adr)));
	172	if (v != lastv) {
41aefbec DG	173
	174	(volatile int )v += 0;
	175	pa = pmap_extract(&p->p_vmspace->vm_pmap, v);
	176	vm_page_hold(PHYS_TO_VM_PAGE(pa));
dd403947 DG	177	lastv = v;
	178	}
	179
	180	/*
	181	* do the vm_fault if needed, do the copy-on-write thing when
	182	* reading stuff off device into memory.
	183	*/
	184	if (ftype & VM_PROT_WRITE) {
	185	/*
	186	* properly handle copy-on-write
	187	*/
	188	(volatile int ) adr += 0;
6232f830 DG	189	}
	190	#if defined(HOLD_WORKS_FOR_SHARING)
	191	else {
dd403947 DG	192	(volatile int ) adr;
dd403947 DG	193	}
41aefbec	194	pa = pmap_extract(&p->p_vmspace->vm_pmap, (vm_offset_t) adr);
dd403947	195	/*
41aefbec	196	* hold the data page
dd403947	197	*/
41aefbec	198	vm_page_hold(PHYS_TO_VM_PAGE(pa));
6232f830	199	#endif
41aefbec	200	}
dd403947	201
6232f830 DG	202	#if !defined(HOLD_WORKS_FOR_SHARING)
	203	vslock(base, bp->b_bcount);
	204	#endif
dd403947 DG	205	/* perform transfer */
dd403947 DG	206	physstrat(bp, strat, PRIBIO);
6232f830 DG	207	#if !defined(HOLD_WORKS_FOR_SHARING)
	208	vsunlock(base, bp->b_bcount);
	209	#endif
dd403947	210
dd403947	211	/*
41aefbec	212	* unhold the pde, and data pages
dd403947	213	*/
41aefbec	214	lastv = 0;
dd403947 DG	215	for (adr = (caddr_t)trunc_page(base); adr < base + bp->b_bcount;
	216	adr += NBPG) {
	217	v = trunc_page(((vm_offset_t)vtopte(adr)));
	218	if (v != lastv) {
41aefbec DG	219	pa = pmap_extract(&p->p_vmspace->vm_pmap, v);
41aefbec DG	220	vm_page_unhold(PHYS_TO_VM_PAGE(pa));
dd403947 DG	221	lastv = v;
dd403947 DG	222	}
6232f830	223	#if defined(HOLD_WORKS_FOR_SHARING)
41aefbec DG	224	pa = pmap_extract(&p->p_vmspace->vm_pmap, (vm_offset_t) adr);
41aefbec DG	225	vm_page_unhold(PHYS_TO_VM_PAGE(pa));
6232f830	226	#endif
dd403947 DG	227	}
	228
	229
	230	amtdone = bp->b_bcount - bp->b_resid;
	231	amttodo -= amtdone;
	232	base += amtdone;
	233	bp->b_blkno += amtdone/DEV_BSIZE;
	234	} while (amttodo && (bp->b_flags & B_ERROR) == 0 && amtdone > 0);
	235
	236	error = bp->b_error;
	237	errrtn:
	238	if (bp_alloc) {
	239	relpbuf(bp);
	240	} else {
	241	bp->b_flags &= ~B_BUSY;
	242	wakeup((caddr_t)bp);
	243	}
	244	*len = amttodo;
	245
	246	/*
	247	* allow the process to be swapped
	248	*/
	249	p->p_flag &= ~SPHYSIO;
	250	p->p_flag \|= (oldflags & SPHYSIO);
	251
	252	return (error);
	253	}