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 * $FreeBSD: releng/5.0/sys/kern/kern_physio.c 104908 2002-10-11 14:58:34Z mike $
20 */
21
22 #include <sys/param.h>
23 #include <sys/systm.h>
24 #include <sys/bio.h>
25 #include <sys/buf.h>
26 #include <sys/conf.h>
27 #include <sys/proc.h>
28 #include <sys/uio.h>
29
30 #include <vm/vm.h>
31 #include <vm/vm_extern.h>
32
33 static void
34 physwakeup(struct buf *bp)
35 {
36 wakeup(bp);
37 }
38
39 int
40 physio(dev_t dev, struct uio *uio, int ioflag)
41 {
42 int i;
43 int error;
44 int spl;
45 caddr_t sa;
46 u_int iolen;
47 struct buf *bp;
48
49 /* Keep the process UPAGES from being swapped. XXX: why ? */
50 PHOLD(curproc);
51
52 bp = getpbuf(NULL);
53 sa = bp->b_data;
54 error = bp->b_error = 0;
55
56 /* XXX: sanity check */
57 if(dev->si_iosize_max < PAGE_SIZE) {
58 printf("WARNING: %s si_iosize_max=%d, using DFLTPHYS.\n",
59 devtoname(dev), dev->si_iosize_max);
60 dev->si_iosize_max = DFLTPHYS;
61 }
62
63 for (i = 0; i < uio->uio_iovcnt; i++) {
64 while (uio->uio_iov[i].iov_len) {
65 bp->b_flags = B_PHYS;
66 if (uio->uio_rw == UIO_READ)
67 bp->b_iocmd = BIO_READ;
68 else
69 bp->b_iocmd = BIO_WRITE;
70 bp->b_dev = dev;
71 bp->b_iodone = physwakeup;
72 bp->b_data = uio->uio_iov[i].iov_base;
73 bp->b_bcount = uio->uio_iov[i].iov_len;
74 bp->b_offset = uio->uio_offset;
75 bp->b_saveaddr = sa;
76
77 /* Don't exceed drivers iosize limit */
78 if (bp->b_bcount > dev->si_iosize_max)
79 bp->b_bcount = dev->si_iosize_max;
80
81 /*
82 * Make sure the pbuf can map the request
83 * XXX: The pbuf has kvasize = MAXPHYS so a request
84 * XXX: larger than MAXPHYS - PAGE_SIZE must be
85 * XXX: page aligned or it will be fragmented.
86 */
87 iolen = ((vm_offset_t) bp->b_data) & PAGE_MASK;
88 if ((bp->b_bcount + iolen) > bp->b_kvasize) {
89 bp->b_bcount = bp->b_kvasize;
90 if (iolen != 0)
91 bp->b_bcount -= PAGE_SIZE;
92 }
93 bp->b_bufsize = bp->b_bcount;
94
95 bp->b_blkno = btodb(bp->b_offset);
96
97 if (uio->uio_segflg == UIO_USERSPACE) {
98 if (!useracc(bp->b_data, bp->b_bufsize,
99 bp->b_iocmd == BIO_READ ?
100 VM_PROT_WRITE : VM_PROT_READ)) {
101 error = EFAULT;
102 goto doerror;
103 }
104 vmapbuf(bp);
105 }
106
107 DEV_STRATEGY(bp, 0);
108 spl = splbio();
109 while ((bp->b_flags & B_DONE) == 0)
110 tsleep(bp, PRIBIO, "physstr", 0);
111 splx(spl);
112
113 if (uio->uio_segflg == UIO_USERSPACE)
114 vunmapbuf(bp);
115 iolen = bp->b_bcount - bp->b_resid;
116 if (iolen == 0 && !(bp->b_ioflags & BIO_ERROR))
117 goto doerror; /* EOF */
118 uio->uio_iov[i].iov_len -= iolen;
119 uio->uio_iov[i].iov_base =
120 (char *)uio->uio_iov[i].iov_base + iolen;
121 uio->uio_resid -= iolen;
122 uio->uio_offset += iolen;
123 if( bp->b_ioflags & BIO_ERROR) {
124 error = bp->b_error;
125 goto doerror;
126 }
127 }
128 }
129 doerror:
130 relpbuf(bp, NULL);
131 PRELE(curproc);
132 return (error);
133 }
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