d8aed754e83f5e2cbf1e0e95a57e417508267b3e
[dragonfly.git] / sys / kern / kern_physio.c
blobd8aed754e83f5e2cbf1e0e95a57e417508267b3e
1 /*
2 * Copyright (c) 1994 John S. Dyson
3 * All rights reserved.
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.
19 * $FreeBSD: src/sys/kern/kern_physio.c,v 1.46.2.4 2003/11/14 09:51:47 simokawa Exp $
20 * $DragonFly: src/sys/kern/kern_physio.c,v 1.25 2007/08/21 17:26:45 dillon Exp $
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>
29 #include <sys/device.h>
30 #include <sys/thread2.h>
32 #include <vm/vm.h>
33 #include <vm/vm_extern.h>
35 static void
36 physwakeup(struct bio *bio)
38 bio->bio_buf->b_cmd = BUF_CMD_DONE;
39 wakeup(bio);
42 static int
43 physio(cdev_t dev, struct uio *uio, int ioflag)
45 int i;
46 int error;
47 int chk_blockno;
48 int saflags;
49 int iolen;
50 int bcount;
51 struct buf *bp;
53 bp = getpbuf(NULL);
54 saflags = bp->b_flags;
55 error = 0;
57 /* XXX: sanity check */
58 if(dev->si_iosize_max < PAGE_SIZE) {
59 kprintf("WARNING: %s si_iosize_max=%d, using DFLTPHYS.\n",
60 devtoname(dev), dev->si_iosize_max);
61 dev->si_iosize_max = DFLTPHYS;
64 /* Must be a real uio */
65 KKASSERT(uio->uio_segflg != UIO_NOCOPY);
67 /* Don't check block number overflow for D_MEM */
68 if ((dev_dflags(dev) & D_TYPEMASK) == D_MEM)
69 chk_blockno = 0;
70 else
71 chk_blockno = 1;
73 for (i = 0; i < uio->uio_iovcnt; i++) {
74 while (uio->uio_iov[i].iov_len) {
75 if (uio->uio_rw == UIO_READ)
76 bp->b_cmd = BUF_CMD_READ;
77 else
78 bp->b_cmd = BUF_CMD_WRITE;
79 bp->b_flags = saflags;
80 bcount = uio->uio_iov[i].iov_len;
82 reinitbufbio(bp); /* clear translation cache */
83 bp->b_bio1.bio_offset = uio->uio_offset;
84 bp->b_bio1.bio_done = physwakeup;
86 /* Don't exceed drivers iosize limit */
87 if (bcount > dev->si_iosize_max)
88 bcount = dev->si_iosize_max;
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.
96 iolen = ((vm_offset_t) uio->uio_iov[i].iov_base) &
97 PAGE_MASK;
98 if ((bcount + iolen) > bp->b_kvasize) {
99 bcount = bp->b_kvasize;
100 if (iolen != 0)
101 bcount -= PAGE_SIZE;
103 if (uio->uio_segflg == UIO_USERSPACE) {
104 if (vmapbuf(bp, uio->uio_iov[i].iov_base, bcount) < 0) {
105 error = EFAULT;
106 goto doerror;
108 } else {
109 bp->b_data = uio->uio_iov[i].iov_base;
110 bp->b_bcount = bcount;
112 dev_dstrategy(dev, &bp->b_bio1);
113 crit_enter();
114 while (bp->b_cmd != BUF_CMD_DONE)
115 tsleep(&bp->b_bio1, 0, "physstr", 0);
116 crit_exit();
118 if (uio->uio_segflg == UIO_USERSPACE)
119 vunmapbuf(bp);
120 iolen = bp->b_bcount - bp->b_resid;
121 if (iolen == 0 && !(bp->b_flags & B_ERROR))
122 goto doerror; /* EOF */
123 uio->uio_iov[i].iov_len -= iolen;
124 uio->uio_iov[i].iov_base += iolen;
125 uio->uio_resid -= iolen;
126 uio->uio_offset += iolen;
127 if( bp->b_flags & B_ERROR) {
128 error = bp->b_error;
129 goto doerror;
133 doerror:
134 relpbuf(bp, NULL);
135 return (error);
139 physread(struct dev_read_args *ap)
141 return(physio(ap->a_head.a_dev, ap->a_uio, ap->a_ioflag));
145 physwrite(struct dev_write_args *ap)
147 return(physio(ap->a_head.a_dev, ap->a_uio, ap->a_ioflag));