131 lines
3.4 KiB
C
131 lines
3.4 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/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/bio.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 <sys/uio.h>
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#include <vm/vm.h>
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#include <vm/vm_extern.h>
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int
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physio(struct cdev *dev, struct uio *uio, int ioflag)
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{
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int i;
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int error;
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int spl;
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caddr_t sa;
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u_int iolen;
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struct buf *bp;
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/* We cannot trust the device driver to hold Giant for us */
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mtx_lock(&Giant);
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/* Keep the process UPAGES from being swapped. XXX: why ? */
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PHOLD(curproc);
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bp = getpbuf(NULL);
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sa = bp->b_data;
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error = 0;
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/* XXX: sanity check */
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if(dev->si_iosize_max < PAGE_SIZE) {
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printf("WARNING: %s si_iosize_max=%d, using DFLTPHYS.\n",
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devtoname(dev), dev->si_iosize_max);
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dev->si_iosize_max = DFLTPHYS;
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}
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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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bp->b_flags = 0;
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if (uio->uio_rw == UIO_READ)
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bp->b_iocmd = BIO_READ;
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else
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bp->b_iocmd = BIO_WRITE;
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bp->b_dev = dev;
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bp->b_iodone = bdone;
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bp->b_data = uio->uio_iov[i].iov_base;
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bp->b_bcount = uio->uio_iov[i].iov_len;
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bp->b_offset = uio->uio_offset;
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bp->b_iooffset = uio->uio_offset;
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bp->b_saveaddr = sa;
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/* Don't exceed drivers iosize limit */
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if (bp->b_bcount > dev->si_iosize_max)
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bp->b_bcount = dev->si_iosize_max;
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/*
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* Make sure the pbuf can map the request
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* XXX: The pbuf has kvasize = MAXPHYS so a request
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* XXX: larger than MAXPHYS - PAGE_SIZE must be
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* XXX: page aligned or it will be fragmented.
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*/
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iolen = ((vm_offset_t) bp->b_data) & PAGE_MASK;
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if ((bp->b_bcount + iolen) > bp->b_kvasize) {
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bp->b_bcount = bp->b_kvasize;
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if (iolen != 0)
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bp->b_bcount -= PAGE_SIZE;
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}
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bp->b_bufsize = bp->b_bcount;
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bp->b_blkno = btodb(bp->b_offset);
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if (uio->uio_segflg == UIO_USERSPACE)
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if (vmapbuf(bp) < 0) {
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error = EFAULT;
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goto doerror;
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}
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DEV_STRATEGY(bp);
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spl = splbio();
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if (uio->uio_rw == UIO_READ)
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bwait(bp, PRIBIO, "physrd");
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else
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bwait(bp, PRIBIO, "physwr");
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splx(spl);
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if (uio->uio_segflg == UIO_USERSPACE)
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vunmapbuf(bp);
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iolen = bp->b_bcount - bp->b_resid;
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if (iolen == 0 && !(bp->b_ioflags & BIO_ERROR))
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goto doerror; /* EOF */
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uio->uio_iov[i].iov_len -= iolen;
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uio->uio_iov[i].iov_base =
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(char *)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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if( bp->b_ioflags & BIO_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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relpbuf(bp, NULL);
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PRELE(curproc);
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mtx_unlock(&Giant);
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return (error);
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}
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