2 * Copyright (c) 1994 John S. Dyson
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice immediately at the beginning of the file, without modification,
10 * this list of conditions, and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Absolutely no warranty of function or purpose is made by the author
16 * 4. Modifications may be freely made to this file if the above conditions
20 #include <sys/cdefs.h>
21 __FBSDID("$FreeBSD$");
23 #include <sys/param.h>
24 #include <sys/systm.h>
32 #include <vm/vm_extern.h>
35 physio(struct cdev *dev, struct uio *uio, int ioflag)
43 /* Keep the process UPAGES from being swapped. XXX: why ? */
50 /* XXX: sanity check */
51 if(dev->si_iosize_max < PAGE_SIZE) {
52 printf("WARNING: %s si_iosize_max=%d, using DFLTPHYS.\n",
53 devtoname(dev), dev->si_iosize_max);
54 dev->si_iosize_max = DFLTPHYS;
57 for (i = 0; i < uio->uio_iovcnt; i++) {
58 while (uio->uio_iov[i].iov_len) {
60 if (uio->uio_rw == UIO_READ) {
61 bp->b_iocmd = BIO_READ;
62 curthread->td_ru.ru_inblock++;
64 bp->b_iocmd = BIO_WRITE;
65 curthread->td_ru.ru_oublock++;
68 bp->b_data = uio->uio_iov[i].iov_base;
69 bp->b_bcount = uio->uio_iov[i].iov_len;
70 bp->b_offset = uio->uio_offset;
71 bp->b_iooffset = uio->uio_offset;
74 /* Don't exceed drivers iosize limit */
75 if (bp->b_bcount > dev->si_iosize_max)
76 bp->b_bcount = dev->si_iosize_max;
79 * Make sure the pbuf can map the request
80 * XXX: The pbuf has kvasize = MAXPHYS so a request
81 * XXX: larger than MAXPHYS - PAGE_SIZE must be
82 * XXX: page aligned or it will be fragmented.
84 iolen = ((vm_offset_t) bp->b_data) & PAGE_MASK;
85 if ((bp->b_bcount + iolen) > bp->b_kvasize) {
86 bp->b_bcount = bp->b_kvasize;
88 bp->b_bcount -= PAGE_SIZE;
90 bp->b_bufsize = bp->b_bcount;
92 bp->b_blkno = btodb(bp->b_offset);
94 if (uio->uio_segflg == UIO_USERSPACE)
95 if (vmapbuf(bp) < 0) {
100 dev_strategy(dev, bp);
101 if (uio->uio_rw == UIO_READ)
102 bwait(bp, PRIBIO, "physrd");
104 bwait(bp, PRIBIO, "physwr");
106 if (uio->uio_segflg == UIO_USERSPACE)
108 iolen = bp->b_bcount - bp->b_resid;
109 if (iolen == 0 && !(bp->b_ioflags & BIO_ERROR))
110 goto doerror; /* EOF */
111 uio->uio_iov[i].iov_len -= iolen;
112 uio->uio_iov[i].iov_base =
113 (char *)uio->uio_iov[i].iov_base + iolen;
114 uio->uio_resid -= iolen;
115 uio->uio_offset += iolen;
116 if( bp->b_ioflags & BIO_ERROR) {