Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]
FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_physio.c
Version:
- FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
SearchContext: - none - 3 - 10
SearchContext: - none - 3 - 10
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 * $FreeBSD$ 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 32 static void physwakeup __P((struct buf *bp)); 33 static struct buf * phygetvpbuf(dev_t dev, int resid); 34 35 int 36 physio(strategy, bp, dev, rw, minp, uio) 37 d_strategy_t *strategy; 38 struct buf *bp; 39 dev_t dev; 40 int rw; 41 u_int (*minp) __P((struct buf *bp)); 42 struct uio *uio; 43 { 44 int i; 45 int bufflags = rw?B_READ:0; 46 int error; 47 int spl; 48 caddr_t sa; 49 int bp_alloc = (bp == 0); 50 struct buf *bpa; 51 52 /* 53 * keep the process from being swapped 54 */ 55 curproc->p_flag |= P_PHYSIO; 56 57 /* create and build a buffer header for a transfer */ 58 bpa = (struct buf *)phygetvpbuf(dev, uio->uio_resid); 59 if (!bp_alloc) { 60 spl = splbio(); 61 while (bp->b_flags & B_BUSY) { 62 bp->b_flags |= B_WANTED; 63 tsleep((caddr_t)bp, PRIBIO, "physbw", 0); 64 } 65 bp->b_flags |= B_BUSY; 66 splx(spl); 67 } else { 68 bp = bpa; 69 } 70 71 /* 72 * get a copy of the kva from the physical buffer 73 */ 74 sa = bpa->b_data; 75 bp->b_proc = curproc; 76 error = bp->b_error = 0; 77 78 for(i=0;i<uio->uio_iovcnt;i++) { 79 while( uio->uio_iov[i].iov_len) { 80 81 bp->b_dev = dev; 82 bp->b_bcount = uio->uio_iov[i].iov_len; 83 bp->b_flags = B_BUSY | B_PHYS | B_CALL | bufflags; 84 bp->b_iodone = physwakeup; 85 bp->b_data = uio->uio_iov[i].iov_base; 86 bp->b_bcount = minp( bp); 87 if( minp != minphys) 88 bp->b_bcount = minphys( bp); 89 bp->b_bufsize = bp->b_bcount; 90 /* 91 * pass in the kva from the physical buffer 92 * for the temporary kernel mapping. 93 */ 94 bp->b_saveaddr = sa; 95 bp->b_blkno = btodb(uio->uio_offset); 96 bp->b_offset = uio->uio_offset; 97 98 if (uio->uio_segflg == UIO_USERSPACE) { 99 if (rw && !useracc(bp->b_data, bp->b_bufsize, B_WRITE)) { 100 error = EFAULT; 101 goto doerror; 102 } 103 if (!rw && !useracc(bp->b_data, bp->b_bufsize, B_READ)) { 104 error = EFAULT; 105 goto doerror; 106 } 107 108 /* bring buffer into kernel space */ 109 vmapbuf(bp); 110 } 111 112 /* perform transfer */ 113 (*strategy)(bp); 114 115 spl = splbio(); 116 while ((bp->b_flags & B_DONE) == 0) 117 tsleep((caddr_t)bp, PRIBIO, "physstr", 0); 118 splx(spl); 119 120 /* release mapping into kernel space */ 121 if (uio->uio_segflg == UIO_USERSPACE) 122 vunmapbuf(bp); 123 124 /* 125 * update the uio data 126 */ 127 { 128 int iolen = bp->b_bcount - bp->b_resid; 129 130 if (iolen == 0 && !(bp->b_flags & B_ERROR)) 131 goto doerror; /* EOF */ 132 uio->uio_iov[i].iov_len -= iolen; 133 uio->uio_iov[i].iov_base += iolen; 134 uio->uio_resid -= iolen; 135 uio->uio_offset += iolen; 136 } 137 138 /* 139 * check for an error 140 */ 141 if( bp->b_flags & B_ERROR) { 142 error = bp->b_error; 143 goto doerror; 144 } 145 } 146 } 147 148 149 doerror: 150 relpbuf(bpa); 151 if (!bp_alloc) { 152 bp->b_flags &= ~(B_BUSY|B_PHYS); 153 if( bp->b_flags & B_WANTED) { 154 bp->b_flags &= ~B_WANTED; 155 wakeup((caddr_t)bp); 156 } 157 } 158 /* 159 * allow the process to be swapped 160 */ 161 curproc->p_flag &= ~P_PHYSIO; 162 163 return (error); 164 } 165 166 u_int 167 minphys(bp) 168 struct buf *bp; 169 { 170 u_int maxphys = DFLTPHYS; 171 struct cdevsw *bdsw; 172 173 bdsw = cdevsw[major(bp->b_dev)]; 174 175 if (bdsw && bdsw->d_maxio) { 176 maxphys = bdsw->d_maxio; 177 } 178 if (bp->b_kvasize && (bp->b_kvasize < maxphys)) 179 maxphys = bp->b_kvasize; 180 181 if(((vm_offset_t) bp->b_data) & PAGE_MASK) { 182 maxphys -= PAGE_SIZE; 183 } 184 185 if( bp->b_bcount > maxphys) { 186 bp->b_bcount = maxphys; 187 } 188 189 return bp->b_bcount; 190 } 191 192 struct buf * 193 phygetvpbuf(dev_t dev, int resid) 194 { 195 struct cdevsw *bdsw; 196 int maxio; 197 198 bdsw = cdevsw[major(dev)]; 199 if ((bdsw == NULL) || (bdsw->d_bmaj == -1)) 200 return getpbuf(); 201 202 maxio = bdsw->d_maxio; 203 if (resid > maxio) 204 resid = maxio; 205 206 return getpbuf(); 207 } 208 209 static void 210 physwakeup(bp) 211 struct buf *bp; 212 { 213 wakeup((caddr_t) bp); 214 bp->b_flags &= ~B_CALL; 215 }
Cache object: 95a45a639aa56b4ddfa9723e126523f4
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]