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;
58 * If the driver does not want I/O to be split, that means that we
59 * need to reject any requests that will not fit into one buffer.
61 if ((dev->si_flags & SI_NOSPLIT) &&
62 ((uio->uio_resid > dev->si_iosize_max) ||
63 (uio->uio_resid > MAXPHYS) ||
64 (uio->uio_iovcnt > 1))) {
66 * Tell the user why his I/O was rejected.
68 if (uio->uio_resid > dev->si_iosize_max)
69 printf("%s: request size %zd > si_iosize_max=%d, "
70 "cannot split request\n", devtoname(dev),
71 uio->uio_resid, dev->si_iosize_max);
73 if (uio->uio_resid > MAXPHYS)
74 printf("%s: request size %zd > MAXPHYS=%d, "
75 "cannot split request\n", devtoname(dev),
76 uio->uio_resid, MAXPHYS);
78 if (uio->uio_iovcnt > 1)
79 printf("%s: request vectors=%d > 1, "
80 "cannot split request\n", devtoname(dev),
87 for (i = 0; i < uio->uio_iovcnt; i++) {
88 while (uio->uio_iov[i].iov_len) {
90 if (uio->uio_rw == UIO_READ) {
91 bp->b_iocmd = BIO_READ;
92 curthread->td_ru.ru_inblock++;
94 bp->b_iocmd = BIO_WRITE;
95 curthread->td_ru.ru_oublock++;
98 bp->b_data = uio->uio_iov[i].iov_base;
99 bp->b_bcount = uio->uio_iov[i].iov_len;
100 bp->b_offset = uio->uio_offset;
101 bp->b_iooffset = uio->uio_offset;
104 /* Don't exceed drivers iosize limit */
105 if (bp->b_bcount > dev->si_iosize_max)
106 bp->b_bcount = dev->si_iosize_max;
109 * Make sure the pbuf can map the request
110 * XXX: The pbuf has kvasize = MAXPHYS so a request
111 * XXX: larger than MAXPHYS - PAGE_SIZE must be
112 * XXX: page aligned or it will be fragmented.
114 iolen = ((vm_offset_t) bp->b_data) & PAGE_MASK;
115 if ((bp->b_bcount + iolen) > bp->b_kvasize) {
117 * This device does not want I/O to be split.
119 if (dev->si_flags & SI_NOSPLIT) {
120 printf("%s: request ptr %p is not "
121 "on a page boundary, cannot split "
122 "request\n", devtoname(dev),
127 bp->b_bcount = bp->b_kvasize;
129 bp->b_bcount -= PAGE_SIZE;
131 bp->b_bufsize = bp->b_bcount;
133 bp->b_blkno = btodb(bp->b_offset);
136 if (uio->uio_segflg == UIO_USERSPACE) {
137 if (dev->si_flags & SI_UNMAPPED)
141 if (vmapbuf(bp, mapped) < 0) {
147 dev_strategy_csw(dev, csw, bp);
148 if (uio->uio_rw == UIO_READ)
149 bwait(bp, PRIBIO, "physrd");
151 bwait(bp, PRIBIO, "physwr");
153 if (uio->uio_segflg == UIO_USERSPACE)
155 iolen = bp->b_bcount - bp->b_resid;
156 if (iolen == 0 && !(bp->b_ioflags & BIO_ERROR))
157 goto doerror; /* EOF */
158 uio->uio_iov[i].iov_len -= iolen;
159 uio->uio_iov[i].iov_base =
160 (char *)uio->uio_iov[i].iov_base + iolen;
161 uio->uio_resid -= iolen;
162 uio->uio_offset += iolen;
163 if( bp->b_ioflags & BIO_ERROR) {