Initial import from FreeBSD RELENG_4:
[dragonfly.git] / sys / kern / kern_physio.c
CommitLineData
984263bc
MD
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: src/sys/kern/kern_physio.c,v 1.46.2.3 2003/05/29 06:15:35 alc Exp $
20 */
21
22#include <sys/param.h>
23#include <sys/systm.h>
24#include <sys/buf.h>
25#include <sys/conf.h>
26#include <sys/proc.h>
27#include <sys/uio.h>
28
29#include <vm/vm.h>
30#include <vm/vm_extern.h>
31
32static void
33physwakeup(struct buf *bp)
34{
35 wakeup((caddr_t) bp);
36}
37
38int
39physio(dev_t dev, struct uio *uio, int ioflag)
40{
41 int i;
42 int error;
43 int spl;
44 caddr_t sa;
45 off_t blockno;
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 = 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 if (uio->uio_rw == UIO_READ)
66 bp->b_flags = B_PHYS | B_CALL | B_READ;
67 else
68 bp->b_flags = B_PHYS | B_CALL | B_WRITE;
69 bp->b_dev = dev;
70 bp->b_iodone = physwakeup;
71 bp->b_data = uio->uio_iov[i].iov_base;
72 bp->b_bcount = uio->uio_iov[i].iov_len;
73 bp->b_offset = uio->uio_offset;
74 bp->b_saveaddr = sa;
75
76 /* Don't exceed drivers iosize limit */
77 if (bp->b_bcount > dev->si_iosize_max)
78 bp->b_bcount = dev->si_iosize_max;
79
80 /*
81 * Make sure the pbuf can map the request
82 * XXX: The pbuf has kvasize = MAXPHYS so a request
83 * XXX: larger than MAXPHYS - PAGE_SIZE must be
84 * XXX: page aligned or it will be fragmented.
85 */
86 iolen = ((vm_offset_t) bp->b_data) & PAGE_MASK;
87 if ((bp->b_bcount + iolen) > bp->b_kvasize) {
88 bp->b_bcount = bp->b_kvasize;
89 if (iolen != 0)
90 bp->b_bcount -= PAGE_SIZE;
91 }
92 bp->b_bufsize = bp->b_bcount;
93
94 blockno = bp->b_offset >> DEV_BSHIFT;
95 if ((daddr_t)blockno != blockno) {
96 error = EINVAL; /* blockno overflow */
97 goto doerror;
98 }
99 bp->b_blkno = blockno;
100
101 if (uio->uio_segflg == UIO_USERSPACE)
102 if (vmapbuf(bp) < 0) {
103 error = EFAULT;
104 goto doerror;
105 }
106
107 BUF_STRATEGY(bp, 0);
108 spl = splbio();
109 while ((bp->b_flags & B_DONE) == 0)
110 tsleep((caddr_t)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_flags & B_ERROR))
117 goto doerror; /* EOF */
118 uio->uio_iov[i].iov_len -= iolen;
119 uio->uio_iov[i].iov_base += iolen;
120 uio->uio_resid -= iolen;
121 uio->uio_offset += iolen;
122 if( bp->b_flags & B_ERROR) {
123 error = bp->b_error;
124 goto doerror;
125 }
126 }
127 }
128doerror:
129 relpbuf(bp, NULL);
130 PRELE(curproc);
131 return (error);
132}