1 /* 2 * Copyright (c) 1982, 1986, 1990 Regents of the University of California. 3 * All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 * 7 * @(#)kern_physio.c 7.17 (Berkeley) 03/17/91 8 */ 9 10 #include "param.h" 11 #include "systm.h" 12 #include "user.h" 13 #include "buf.h" 14 #include "conf.h" 15 #include "proc.h" 16 #include "seg.h" 17 #include "trace.h" 18 #include "map.h" 19 #include "vnode.h" 20 #include "specdev.h" 21 22 /* 23 * Raw I/O. The arguments are 24 * The strategy routine for the device 25 * A buffer, which will either be a special buffer header owned 26 * exclusively by the device for this purpose, or NULL, 27 * indicating that we should use a swap buffer 28 * The device number 29 * Read/write flag 30 * Essentially all the work is computing physical addresses and 31 * validating them. 32 * If the user has the proper access privilidges, the process is 33 * marked 'delayed unlock' and the pages involved in the I/O are 34 * faulted and locked. After the completion of the I/O, the above pages 35 * are unlocked. 36 */ 37 physio(strat, bp, dev, rw, mincnt, uio) 38 int (*strat)(); 39 register struct buf *bp; 40 dev_t dev; 41 int rw; 42 u_int (*mincnt)(); 43 struct uio *uio; 44 { 45 register struct iovec *iov; 46 register int requested, done; 47 register struct proc *p = curproc; 48 char *a; 49 int s, allocbuf = 0, error = 0; 50 struct buf *getswbuf(); 51 52 if (bp == NULL) { 53 allocbuf = 1; 54 bp = getswbuf(PRIBIO+1); 55 } 56 for (; uio->uio_iovcnt; uio->uio_iov++, uio->uio_iovcnt--) { 57 iov = uio->uio_iov; 58 if (!useracc(iov->iov_base, (u_int)iov->iov_len, 59 rw == B_READ ? B_WRITE : B_READ)) { 60 error = EFAULT; 61 break; 62 } 63 if (!allocbuf) { /* only if sharing caller's buffer */ 64 s = splbio(); 65 while (bp->b_flags&B_BUSY) { 66 bp->b_flags |= B_WANTED; 67 sleep((caddr_t)bp, PRIBIO+1); 68 } 69 splx(s); 70 } 71 bp->b_error = 0; 72 bp->b_proc = p; 73 #ifdef HPUXCOMPAT 74 if (ISHPMMADDR(iov->iov_base)) 75 bp->b_un.b_addr = (caddr_t)HPMMBASEADDR(iov->iov_base); 76 else 77 #endif 78 bp->b_un.b_addr = iov->iov_base; 79 while (iov->iov_len > 0) { 80 bp->b_flags = B_BUSY | B_PHYS | B_RAW | rw; 81 bp->b_dev = dev; 82 bp->b_blkno = btodb(uio->uio_offset); 83 bp->b_bcount = iov->iov_len; 84 (*mincnt)(bp); 85 requested = bp->b_bcount; 86 p->p_flag |= SPHYSIO; 87 vslock(a = bp->b_un.b_addr, requested); 88 #if defined(hp300) || defined(i386) 89 vmapbuf(bp); 90 #endif 91 (*strat)(bp); 92 s = splbio(); 93 while ((bp->b_flags & B_DONE) == 0) 94 sleep((caddr_t)bp, PRIBIO); 95 #if defined(hp300) || defined(i386) 96 vunmapbuf(bp); 97 #endif 98 vsunlock(a, requested, rw); 99 p->p_flag &= ~SPHYSIO; 100 if (bp->b_flags&B_WANTED) /* rare */ 101 wakeup((caddr_t)bp); 102 splx(s); 103 done = bp->b_bcount - bp->b_resid; 104 bp->b_un.b_addr += done; 105 iov->iov_len -= done; 106 uio->uio_resid -= done; 107 uio->uio_offset += done; 108 /* temp kludge for disk drives */ 109 if (done < requested || bp->b_flags & B_ERROR) 110 break; 111 } 112 bp->b_flags &= ~(B_BUSY | B_WANTED | B_PHYS | B_RAW); 113 error = biowait(bp); 114 /* temp kludge for disk drives */ 115 if (done < requested || bp->b_flags & B_ERROR) 116 break; 117 } 118 #if defined(hp300) 119 DCIU(); 120 #endif 121 if (allocbuf) 122 freeswbuf(bp); 123 return (error); 124 } 125 126 u_int 127 minphys(bp) 128 struct buf *bp; 129 { 130 if (bp->b_bcount > MAXPHYS) 131 bp->b_bcount = MAXPHYS; 132 } 133 134 static 135 struct buf * 136 getswbuf(prio) 137 int prio; 138 { 139 int s; 140 struct buf *bp; 141 142 s = splbio(); 143 while (bswlist.av_forw == NULL) { 144 bswlist.b_flags |= B_WANTED; 145 sleep((caddr_t)&bswlist, prio); 146 } 147 bp = bswlist.av_forw; 148 bswlist.av_forw = bp->av_forw; 149 splx(s); 150 return (bp); 151 } 152 153 static 154 freeswbuf(bp) 155 struct buf *bp; 156 { 157 int s; 158 159 s = splbio(); 160 bp->av_forw = bswlist.av_forw; 161 bswlist.av_forw = bp; 162 if (bp->b_vp) 163 brelvp(bp); 164 if (bswlist.b_flags & B_WANTED) { 165 bswlist.b_flags &= ~B_WANTED; 166 wakeup((caddr_t)&bswlist); 167 wakeup((caddr_t)pageproc); 168 } 169 splx(s); 170 } 171 172 rawread(dev, uio) 173 dev_t dev; 174 struct uio *uio; 175 { 176 return (physio(cdevsw[major(dev)].d_strategy, (struct buf *)NULL, 177 dev, B_READ, minphys, uio)); 178 } 179 180 rawwrite(dev, uio) 181 dev_t dev; 182 struct uio *uio; 183 { 184 return (physio(cdevsw[major(dev)].d_strategy, (struct buf *)NULL, 185 dev, B_WRITE, minphys, uio)); 186 } 187