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Annotation of Net2/kern/kern__physio.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1989, 1990, 1991, 1992 William F. Jolitz, TeleMuse
        !             3:  * All rights reserved.
        !             4:  *
        !             5:  * Redistribution and use in source and binary forms, with or without
        !             6:  * modification, are permitted provided that the following conditions
        !             7:  * are met:
        !             8:  * 1. Redistributions of source code must retain the above copyright
        !             9:  *    notice, this list of conditions and the following disclaimer.
        !            10:  * 2. Redistributions in binary form must reproduce the above copyright
        !            11:  *    notice, this list of conditions and the following disclaimer in the
        !            12:  *    documentation and/or other materials provided with the distribution.
        !            13:  * 3. All advertising materials mentioning features or use of this software
        !            14:  *    must display the following acknowledgement:
        !            15:  *     This software is a component of "386BSD" developed by 
        !            16:        William F. Jolitz, TeleMuse.
        !            17:  * 4. Neither the name of the developer nor the name "386BSD"
        !            18:  *    may be used to endorse or promote products derived from this software
        !            19:  *    without specific prior written permission.
        !            20:  *
        !            21:  * THIS SOFTWARE IS A COMPONENT OF 386BSD DEVELOPED BY WILLIAM F. JOLITZ 
        !            22:  * AND IS INTENDED FOR RESEARCH AND EDUCATIONAL PURPOSES ONLY. THIS 
        !            23:  * SOFTWARE SHOULD NOT BE CONSIDERED TO BE A COMMERCIAL PRODUCT. 
        !            24:  * THE DEVELOPER URGES THAT USERS WHO REQUIRE A COMMERCIAL PRODUCT 
        !            25:  * NOT MAKE USE THIS WORK.
        !            26:  *
        !            27:  * FOR USERS WHO WISH TO UNDERSTAND THE 386BSD SYSTEM DEVELOPED
        !            28:  * BY WILLIAM F. JOLITZ, WE RECOMMEND THE USER STUDY WRITTEN 
        !            29:  * REFERENCES SUCH AS THE  "PORTING UNIX TO THE 386" SERIES 
        !            30:  * (BEGINNING JANUARY 1991 "DR. DOBBS JOURNAL", USA AND BEGINNING 
        !            31:  * JUNE 1991 "UNIX MAGAZIN", GERMANY) BY WILLIAM F. JOLITZ AND 
        !            32:  * LYNNE GREER JOLITZ, AS WELL AS OTHER BOOKS ON UNIX AND THE 
        !            33:  * ON-LINE 386BSD USER MANUAL BEFORE USE. A BOOK DISCUSSING THE INTERNALS 
        !            34:  * OF 386BSD ENTITLED "386BSD FROM THE INSIDE OUT" WILL BE AVAILABLE LATE 1992.
        !            35:  *
        !            36:  * THIS SOFTWARE IS PROVIDED BY THE DEVELOPER ``AS IS'' AND
        !            37:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            38:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            39:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE DEVELOPER BE LIABLE
        !            40:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            41:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            42:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            43:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            44:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            45:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            46:  * SUCH DAMAGE.
        !            47:  *
        !            48:  */
        !            49: static char rcsid[] = "$Header: /usr/bill/working/sys/kern/RCS/kern__physio.c,v 1.3 92/01/21 21:29:06 william Exp $";
        !            50: 
        !            51: #include "param.h"
        !            52: #include "systm.h"
        !            53: #include "buf.h"
        !            54: #include "conf.h"
        !            55: #include "proc.h"
        !            56: #include "malloc.h"
        !            57: #include "vnode.h"
        !            58: #include "specdev.h"
        !            59: 
        !            60: static physio(int (*)(), int, int, int, caddr_t, int *, struct proc *);
        !            61: 
        !            62: /*
        !            63:  * Driver interface to do "raw" I/O in the address space of a
        !            64:  * user process directly for read and write operations..
        !            65:  */
        !            66: 
        !            67: rawread(dev, uio)
        !            68:        dev_t dev; struct uio *uio;
        !            69: {
        !            70:        return (uioapply(physio, cdevsw[major(dev)].d_strategy, dev, uio));
        !            71: }
        !            72: 
        !            73: rawwrite(dev, uio)
        !            74:        dev_t dev; struct uio *uio;
        !            75: {
        !            76:        return (uioapply(physio, cdevsw[major(dev)].d_strategy, dev, uio));
        !            77: }
        !            78: 
        !            79: static physio(strat, dev, off, rw, base, len, p)
        !            80:        int (*strat)(); 
        !            81:        dev_t dev;
        !            82:        int rw, off;
        !            83:        caddr_t base;
        !            84:        int *len;
        !            85:        struct proc *p;
        !            86: {
        !            87:        register struct buf *bp;
        !            88:        int resid = *len, error;
        !            89: 
        !            90:        rw = rw == UIO_READ ? B_READ : 0;
        !            91: 
        !            92:        /* create and build a buffer header for a transfer */
        !            93:        bp = (struct buf *)malloc(sizeof(*bp), M_TEMP, M_NOWAIT);
        !            94:        bp->b_flags = B_BUSY | B_PHYS | rw;
        !            95:        bp->b_proc = p;
        !            96:        bp->b_dev = dev;
        !            97:        bp->b_error = 0;
        !            98:        bp->b_blkno = off/DEV_BSIZE;
        !            99: 
        !           100:        /* iteratively do I/O on as large a chunk as possible */
        !           101:        do {
        !           102:                bp->b_flags &= ~B_DONE;
        !           103:                bp->b_un.b_addr = base;
        !           104:                /* DMA controller limit */
        !           105:                bp->b_bcount = min (64*1024, resid);
        !           106:                resid -= bp->b_bcount;
        !           107:                off += bp->b_bcount;
        !           108: 
        !           109:                /* first, check if accessible */
        !           110:                if (rw == B_READ && !useracc(base, bp->b_bcount, B_WRITE))
        !           111:                        return (EFAULT);
        !           112:                if (rw == B_WRITE && !useracc(base, bp->b_bcount, B_READ))
        !           113:                        return (EFAULT);
        !           114: 
        !           115:                /* lock in core */
        !           116:                vslock (base, bp->b_bcount);
        !           117: 
        !           118:                /* perform transfer */
        !           119:                physstrat(bp, strat, PRIBIO);
        !           120: 
        !           121:                /* unlock */
        !           122:                vsunlock (base, bp->b_bcount, 0);
        !           123:                resid += bp->b_resid;
        !           124:                bp->b_blkno = off/DEV_BSIZE;
        !           125:        } while (resid && (bp->b_flags & B_ERROR) == 0 && bp->b_resid == 0);
        !           126: 
        !           127:        error = bp->b_error;
        !           128:        free(bp, M_TEMP);
        !           129:        *len = resid;
        !           130:        return (error);
        !           131: }

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