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: releng/10.0/sys/kern/kern_physio.c 255032 2013-08-29 16:41:40Z ken $");
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 /*
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.
60 */
61 if (dev->si_flags & SI_NOSPLIT &&
62 (uio->uio_resid > dev->si_iosize_max || uio->uio_resid > MAXPHYS ||
63 uio->uio_iovcnt > 1)) {
64 /*
65 * Tell the user why his I/O was rejected.
66 */
67 if (uio->uio_resid > dev->si_iosize_max)
68 uprintf("%s: request size=%zd > si_iosize_max=%d; "
69 "cannot split request\n", devtoname(dev),
70 uio->uio_resid, dev->si_iosize_max);
71 if (uio->uio_resid > MAXPHYS)
72 uprintf("%s: request size=%zd > MAXPHYS=%d; "
73 "cannot split request\n", devtoname(dev),
74 uio->uio_resid, MAXPHYS);
75 if (uio->uio_iovcnt > 1)
76 uprintf("%s: request vectors=%d > 1; "
77 "cannot split request\n", devtoname(dev),
78 uio->uio_iovcnt);
79
80 error = EFBIG;
81 goto doerror;
82 }
83
84 for (i = 0; i < uio->uio_iovcnt; i++) {
85 while (uio->uio_iov[i].iov_len) {
86 bp->b_flags = 0;
87 if (uio->uio_rw == UIO_READ) {
88 bp->b_iocmd = BIO_READ;
89 curthread->td_ru.ru_inblock++;
90 } else {
91 bp->b_iocmd = BIO_WRITE;
92 curthread->td_ru.ru_oublock++;
93 }
94 bp->b_iodone = bdone;
95 bp->b_data = uio->uio_iov[i].iov_base;
96 bp->b_bcount = uio->uio_iov[i].iov_len;
97 bp->b_offset = uio->uio_offset;
98 bp->b_iooffset = uio->uio_offset;
99 bp->b_saveaddr = sa;
100
101 /* Don't exceed drivers iosize limit */
102 if (bp->b_bcount > dev->si_iosize_max)
103 bp->b_bcount = dev->si_iosize_max;
104
105 /*
106 * Make sure the pbuf can map the request
107 * XXX: The pbuf has kvasize = MAXPHYS so a request
108 * XXX: larger than MAXPHYS - PAGE_SIZE must be
109 * XXX: page aligned or it will be fragmented.
110 */
111 iolen = ((vm_offset_t) bp->b_data) & PAGE_MASK;
112 if ((bp->b_bcount + iolen) > bp->b_kvasize) {
113 /*
114 * This device does not want I/O to be split.
115 */
116 if (dev->si_flags & SI_NOSPLIT) {
117 uprintf("%s: request ptr %p is not "
118 "on a page boundary; cannot split "
119 "request\n", devtoname(dev),
120 bp->b_data);
121 error = EFBIG;
122 goto doerror;
123 }
124 bp->b_bcount = bp->b_kvasize;
125 if (iolen != 0)
126 bp->b_bcount -= PAGE_SIZE;
127 }
128 bp->b_bufsize = bp->b_bcount;
129
130 bp->b_blkno = btodb(bp->b_offset);
131
132 csw = dev->si_devsw;
133 if (uio->uio_segflg == UIO_USERSPACE) {
134 if (dev->si_flags & SI_UNMAPPED)
135 mapped = 0;
136 else
137 mapped = 1;
138 if (vmapbuf(bp, mapped) < 0) {
139 error = EFAULT;
140 goto doerror;
141 }
142 }
143
144 dev_strategy_csw(dev, csw, bp);
145 if (uio->uio_rw == UIO_READ)
146 bwait(bp, PRIBIO, "physrd");
147 else
148 bwait(bp, PRIBIO, "physwr");
149
150 if (uio->uio_segflg == UIO_USERSPACE)
151 vunmapbuf(bp);
152 iolen = bp->b_bcount - bp->b_resid;
153 if (iolen == 0 && !(bp->b_ioflags & BIO_ERROR))
154 goto doerror; /* EOF */
155 uio->uio_iov[i].iov_len -= iolen;
156 uio->uio_iov[i].iov_base =
157 (char *)uio->uio_iov[i].iov_base + iolen;
158 uio->uio_resid -= iolen;
159 uio->uio_offset += iolen;
160 if( bp->b_ioflags & BIO_ERROR) {
161 error = bp->b_error;
162 goto doerror;
163 }
164 }
165 }
166 doerror:
167 relpbuf(bp, NULL);
168 PRELE(curproc);
169 return (error);
170 }
Cache object: 75c9b116a773e2756dcf4272897ac6f1
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