1 /*-
2 * Copyright (c) 1994 John S. Dyson
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 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
15 * John S. Dyson.
16 * 4. Modifications may be freely made to this file if the above conditions
17 * are met.
18 */
19
20 #include <sys/cdefs.h>
21 __FBSDID("$FreeBSD$");
22
23 #include <sys/param.h>
24 #include <sys/systm.h>
25 #include <sys/bio.h>
26 #include <sys/buf.h>
27 #include <sys/conf.h>
28 #include <sys/proc.h>
29 #include <sys/uio.h>
30
31 #include <vm/vm.h>
32 #include <vm/vm_extern.h>
33
34 int
35 physio(struct cdev *dev, struct uio *uio, int ioflag)
36 {
37 struct buf *bp;
38 struct cdevsw *csw;
39 caddr_t sa;
40 u_int iolen;
41 int error, i, mapped;
42
43 /* Keep the process UPAGES from being swapped. XXX: why ? */
44 PHOLD(curproc);
45
46 bp = getpbuf(NULL);
47 sa = bp->b_data;
48 error = 0;
49
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;
55 }
56
57 for (i = 0; i < uio->uio_iovcnt; i++) {
58 while (uio->uio_iov[i].iov_len) {
59 bp->b_flags = 0;
60 if (uio->uio_rw == UIO_READ) {
61 bp->b_iocmd = BIO_READ;
62 curthread->td_ru.ru_inblock++;
63 } else {
64 bp->b_iocmd = BIO_WRITE;
65 curthread->td_ru.ru_oublock++;
66 }
67 bp->b_iodone = bdone;
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;
72 bp->b_saveaddr = sa;
73
74 /* Don't exceed drivers iosize limit */
75 if (bp->b_bcount > dev->si_iosize_max)
76 bp->b_bcount = dev->si_iosize_max;
77
78 /*
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.
83 */
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;
87 if (iolen != 0)
88 bp->b_bcount -= PAGE_SIZE;
89 }
90 bp->b_bufsize = bp->b_bcount;
91
92 bp->b_blkno = btodb(bp->b_offset);
93
94 csw = dev->si_devsw;
95 if (uio->uio_segflg == UIO_USERSPACE) {
96 if (dev->si_flags & SI_UNMAPPED)
97 mapped = 0;
98 else
99 mapped = 1;
100 if (vmapbuf(bp, mapped) < 0) {
101 error = EFAULT;
102 goto doerror;
103 }
104 }
105
106 dev_strategy_csw(dev, csw, bp);
107 if (uio->uio_rw == UIO_READ)
108 bwait(bp, PRIBIO, "physrd");
109 else
110 bwait(bp, PRIBIO, "physwr");
111
112 if (uio->uio_segflg == UIO_USERSPACE)
113 vunmapbuf(bp);
114 iolen = bp->b_bcount - bp->b_resid;
115 if (iolen == 0 && !(bp->b_ioflags & BIO_ERROR))
116 goto doerror; /* EOF */
117 uio->uio_iov[i].iov_len -= iolen;
118 uio->uio_iov[i].iov_base =
119 (char *)uio->uio_iov[i].iov_base + iolen;
120 uio->uio_resid -= iolen;
121 uio->uio_offset += iolen;
122 if( bp->b_ioflags & BIO_ERROR) {
123 error = bp->b_error;
124 goto doerror;
125 }
126 }
127 }
128 doerror:
129 relpbuf(bp, NULL);
130 PRELE(curproc);
131 return (error);
132 }
Cache object: f6158b8970d2d2fdaac6c1ec5e556be6
|