172 lines
3.5 KiB
C
172 lines
3.5 KiB
C
/*
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* Copyright (c) 1994 John S. Dyson
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* All rights reserved.
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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 immediately at the beginning of the file, without modification,
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* 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. Absolutely no warranty of function or purpose is made by the author
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* John S. Dyson.
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* 4. Modifications may be freely made to this file if the above conditions
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* are met.
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/buf.h>
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#include <sys/conf.h>
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#include <sys/proc.h>
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#include <vm/vm.h>
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static void physwakeup();
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int
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physio(strategy, bp, dev, rw, minp, uio)
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int (*strategy)();
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struct buf *bp;
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dev_t dev;
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int rw;
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u_int (*minp)();
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struct uio *uio;
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{
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int i;
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int bp_alloc = (bp == 0);
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int bufflags = rw?B_READ:0;
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int error;
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int spl;
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/*
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* keep the process from being swapped
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*/
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curproc->p_flag |= P_PHYSIO;
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/* create and build a buffer header for a transfer */
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if (bp_alloc) {
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bp = (struct buf *)getpbuf();
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} else {
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spl = splbio();
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while (bp->b_flags & B_BUSY) {
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bp->b_flags |= B_WANTED;
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tsleep((caddr_t)bp, PRIBIO, "physbw", 0);
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}
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bp->b_flags |= B_BUSY;
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splx(spl);
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}
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bp->b_proc = curproc;
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bp->b_dev = dev;
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error = bp->b_error = 0;
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for(i=0;i<uio->uio_iovcnt;i++) {
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while( uio->uio_iov[i].iov_len) {
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vm_offset_t v, lastv, pa;
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caddr_t adr;
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bp->b_bcount = uio->uio_iov[i].iov_len;
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bp->b_bufsize = bp->b_bcount;
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bp->b_flags = B_BUSY | B_PHYS | B_CALL | bufflags;
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bp->b_iodone = physwakeup;
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bp->b_data = uio->uio_iov[i].iov_base;
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bp->b_blkno = btodb(uio->uio_offset);
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if (rw && !useracc(bp->b_data, bp->b_bufsize, B_WRITE)) {
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error = EFAULT;
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goto doerror;
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}
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if (!rw && !useracc(bp->b_data, bp->b_bufsize, B_READ)) {
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error = EFAULT;
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goto doerror;
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}
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vmapbuf(bp);
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/* perform transfer */
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(*strategy)(bp);
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spl = splbio();
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while ((bp->b_flags & B_DONE) == 0)
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tsleep((caddr_t)bp, PRIBIO, "physstr", 0);
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splx(spl);
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vunmapbuf(bp);
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/*
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* update the uio data
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*/
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{
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int iolen = bp->b_bcount - bp->b_resid;
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uio->uio_iov[i].iov_len -= iolen;
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uio->uio_iov[i].iov_base += iolen;
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uio->uio_resid -= iolen;
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uio->uio_offset += iolen;
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}
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/*
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* check for an error
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*/
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if( bp->b_flags & B_ERROR) {
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error = bp->b_error;
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goto doerror;
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}
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}
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}
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doerror:
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if (bp_alloc) {
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relpbuf(bp);
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} else {
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bp->b_flags &= ~(B_BUSY|B_PHYS);
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if( bp->b_flags & B_WANTED) {
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bp->b_flags &= ~B_WANTED;
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wakeup((caddr_t)bp);
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}
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}
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/*
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* allow the process to be swapped
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*/
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curproc->p_flag &= ~P_PHYSIO;
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return (error);
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}
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u_int
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minphys(struct buf *bp)
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{
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if( bp->b_bcount > MAXBSIZE) {
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bp->b_bcount = MAXBSIZE;
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}
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return bp->b_bcount;
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}
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int
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rawread(dev_t dev, struct uio *uio)
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{
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return (physio(cdevsw[major(dev)].d_strategy, (struct buf *)NULL,
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dev, 1, minphys, uio));
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}
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int
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rawwrite(dev_t dev, struct uio *uio)
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{
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return (physio(cdevsw[major(dev)].d_strategy, (struct buf *)NULL,
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dev, 0, minphys, uio));
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}
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static void
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physwakeup(bp)
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struct buf *bp;
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{
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wakeup((caddr_t) bp);
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bp->b_flags &= ~B_CALL;
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}
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