The pbuf subsystem now initializes b_kvabase and b_kvasize at startup and
[dragonfly.git] / sys / kern / kern_physio.c
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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 *
f366cb61 19 * $FreeBSD: src/sys/kern/kern_physio.c,v 1.46.2.4 2003/11/14 09:51:47 simokawa Exp $
10f3fee5 20 * $DragonFly: src/sys/kern/kern_physio.c,v 1.18 2006/04/30 17:22:17 dillon Exp $
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21 */
22
23#include <sys/param.h>
24#include <sys/systm.h>
25#include <sys/buf.h>
26#include <sys/conf.h>
27#include <sys/proc.h>
28#include <sys/uio.h>
335dda38 29#include <sys/device.h>
54048233 30#include <sys/thread2.h>
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31
32#include <vm/vm.h>
33#include <vm/vm_extern.h>
34
35static void
81b5c339 36physwakeup(struct bio *bio)
984263bc 37{
10f3fee5 38 bio->bio_buf->b_cmd = BUF_CMD_DONE;
81b5c339 39 wakeup(bio);
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40}
41
42int
43physio(dev_t dev, struct uio *uio, int ioflag)
44{
45 int i;
46 int error;
f366cb61 47 int chk_blockno;
a8f169e2 48 int saflags;
984263bc 49 caddr_t sa;
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50 u_int iolen;
51 struct buf *bp;
52
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53 bp = getpbuf(NULL);
54 sa = bp->b_data;
a8f169e2 55 saflags = bp->b_flags;
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56 error = 0;
57
58 /* XXX: sanity check */
59 if(dev->si_iosize_max < PAGE_SIZE) {
60 printf("WARNING: %s si_iosize_max=%d, using DFLTPHYS.\n",
61 devtoname(dev), dev->si_iosize_max);
62 dev->si_iosize_max = DFLTPHYS;
63 }
64
f366cb61 65 /* Don't check block number overflow for D_MEM */
978d73e7 66 if ((dev_dflags(dev) & D_TYPEMASK) == D_MEM)
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67 chk_blockno = 0;
68 else
69 chk_blockno = 1;
70
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71 for (i = 0; i < uio->uio_iovcnt; i++) {
72 while (uio->uio_iov[i].iov_len) {
73 if (uio->uio_rw == UIO_READ)
10f3fee5 74 bp->b_cmd = BUF_CMD_READ;
984263bc 75 else
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76 bp->b_cmd = BUF_CMD_WRITE;
77 bp->b_flags = saflags;
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78 bp->b_data = uio->uio_iov[i].iov_base;
79 bp->b_bcount = uio->uio_iov[i].iov_len;
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80 bp->b_saveaddr = sa;
81
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82 reinitbufbio(bp); /* clear translation cache */
83 bp->b_bio1.bio_offset = uio->uio_offset;
84 bp->b_bio1.bio_done = physwakeup;
85
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86 /* Don't exceed drivers iosize limit */
87 if (bp->b_bcount > dev->si_iosize_max)
88 bp->b_bcount = dev->si_iosize_max;
89
90 /*
91 * Make sure the pbuf can map the request
92 * XXX: The pbuf has kvasize = MAXPHYS so a request
93 * XXX: larger than MAXPHYS - PAGE_SIZE must be
94 * XXX: page aligned or it will be fragmented.
95 */
96 iolen = ((vm_offset_t) bp->b_data) & PAGE_MASK;
97 if ((bp->b_bcount + iolen) > bp->b_kvasize) {
98 bp->b_bcount = bp->b_kvasize;
99 if (iolen != 0)
100 bp->b_bcount -= PAGE_SIZE;
101 }
102 bp->b_bufsize = bp->b_bcount;
103
81b5c339 104 if (uio->uio_segflg == UIO_USERSPACE) {
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105 if (vmapbuf(bp) < 0) {
106 error = EFAULT;
107 goto doerror;
108 }
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109 }
110 dev_dstrategy(dev, &bp->b_bio1);
e43a034f 111 crit_enter();
10f3fee5 112 while (bp->b_cmd != BUF_CMD_DONE)
81b5c339 113 tsleep(&bp->b_bio1, 0, "physstr", 0);
e43a034f 114 crit_exit();
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115
116 if (uio->uio_segflg == UIO_USERSPACE)
117 vunmapbuf(bp);
118 iolen = bp->b_bcount - bp->b_resid;
119 if (iolen == 0 && !(bp->b_flags & B_ERROR))
120 goto doerror; /* EOF */
121 uio->uio_iov[i].iov_len -= iolen;
122 uio->uio_iov[i].iov_base += iolen;
123 uio->uio_resid -= iolen;
124 uio->uio_offset += iolen;
125 if( bp->b_flags & B_ERROR) {
126 error = bp->b_error;
127 goto doerror;
128 }
129 }
130 }
131doerror:
d094eee8 132 bp->b_data = sa;
984263bc 133 relpbuf(bp, NULL);
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134 return (error);
135}