2 * Copyright (c) 1994 John S. Dyson
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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
16 * 4. Modifications may be freely made to this file if the above conditions
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 1.12 2005/08/04 21:08:35 hmp Exp $
23 #include <sys/param.h>
24 #include <sys/systm.h>
29 #include <sys/device.h>
30 #include <sys/thread2.h>
33 #include <vm/vm_extern.h>
36 physwakeup(struct buf *bp)
42 physio(dev_t dev, struct uio *uio, int ioflag)
53 * NOTE: we no longer have to PHOLD() the process, because the
54 * kernel stack / uarea cannot be swapped, and when it can be in
55 * the future it will only happen if the process is sleeping on
56 * a particular address.
62 /* XXX: sanity check */
63 if(dev->si_iosize_max < PAGE_SIZE) {
64 printf("WARNING: %s si_iosize_max=%d, using DFLTPHYS.\n",
65 devtoname(dev), dev->si_iosize_max);
66 dev->si_iosize_max = DFLTPHYS;
69 /* Don't check block number overflow for D_MEM */
70 if ((dev_dflags(dev) & D_TYPEMASK) == D_MEM)
75 for (i = 0; i < uio->uio_iovcnt; i++) {
76 while (uio->uio_iov[i].iov_len) {
77 if (uio->uio_rw == UIO_READ)
78 bp->b_flags = B_PHYS | B_READ;
80 bp->b_flags = B_PHYS | B_WRITE;
82 bp->b_iodone = physwakeup;
83 bp->b_data = uio->uio_iov[i].iov_base;
84 bp->b_bcount = uio->uio_iov[i].iov_len;
85 bp->b_offset = uio->uio_offset;
88 /* Don't exceed drivers iosize limit */
89 if (bp->b_bcount > dev->si_iosize_max)
90 bp->b_bcount = dev->si_iosize_max;
93 * Make sure the pbuf can map the request
94 * XXX: The pbuf has kvasize = MAXPHYS so a request
95 * XXX: larger than MAXPHYS - PAGE_SIZE must be
96 * XXX: page aligned or it will be fragmented.
98 iolen = ((vm_offset_t) bp->b_data) & PAGE_MASK;
99 if ((bp->b_bcount + iolen) > bp->b_kvasize) {
100 bp->b_bcount = bp->b_kvasize;
102 bp->b_bcount -= PAGE_SIZE;
104 bp->b_bufsize = bp->b_bcount;
106 blockno = bp->b_offset >> DEV_BSHIFT;
107 if (chk_blockno && (daddr_t)blockno != blockno) {
108 error = EINVAL; /* blockno overflow */
111 bp->b_blkno = blockno;
113 if (uio->uio_segflg == UIO_USERSPACE)
114 if (vmapbuf(bp) < 0) {
121 while ((bp->b_flags & B_DONE) == 0)
122 tsleep((caddr_t)bp, 0, "physstr", 0);
125 if (uio->uio_segflg == UIO_USERSPACE)
127 iolen = bp->b_bcount - bp->b_resid;
128 if (iolen == 0 && !(bp->b_flags & B_ERROR))
129 goto doerror; /* EOF */
130 uio->uio_iov[i].iov_len -= iolen;
131 uio->uio_iov[i].iov_base += iolen;
132 uio->uio_resid -= iolen;
133 uio->uio_offset += iolen;
134 if( bp->b_flags & B_ERROR) {