1 /* 2 * Copyright (c) 1982, 1986 Regents of the University of California. 3 * All rights reserved. The Berkeley software License Agreement 4 * specifies the terms and conditions for redistribution. 5 * 6 * @(#)kern_physio.c 7.12 (Berkeley) 01/04/90 7 */ 8 9 #include "param.h" 10 #include "systm.h" 11 #include "user.h" 12 #include "buf.h" 13 #include "conf.h" 14 #include "proc.h" 15 #include "seg.h" 16 #include "vm.h" 17 #include "trace.h" 18 #include "map.h" 19 #include "vnode.h" 20 21 #include "machine/pte.h" 22 23 /* 24 * Swap IO headers - 25 * They contain the necessary information for the swap I/O. 26 * At any given time, a swap header can be in three 27 * different lists. When free it is in the free list, 28 * when allocated and the I/O queued, it is on the swap 29 * device list, and finally, if the operation was a dirty 30 * page push, when the I/O completes, it is inserted 31 * in a list of cleaned pages to be processed by the pageout daemon. 32 */ 33 struct buf *swbuf; 34 35 /* 36 * swap I/O - 37 * 38 * If the flag indicates a dirty page push initiated 39 * by the pageout daemon, we map the page into the i th 40 * virtual page of process 2 (the daemon itself) where i is 41 * the index of the swap header that has been allocated. 42 * We simply initialize the header and queue the I/O but 43 * do not wait for completion. When the I/O completes, 44 * biodone() will link the header to a list of cleaned 45 * pages to be processed by the pageout daemon. 46 */ 47 swap(p, dblkno, addr, nbytes, rdflg, flag, vp, pfcent) 48 struct proc *p; 49 swblk_t dblkno; 50 caddr_t addr; 51 int nbytes, rdflg, flag; 52 struct vnode *vp; 53 u_int pfcent; 54 { 55 register struct buf *bp; 56 register struct pte *dpte, *vpte; 57 register u_int c; 58 int p2dp, s, error = 0; 59 struct buf *getswbuf(); 60 int swdone(); 61 62 bp = getswbuf(PSWP+1); 63 bp->b_flags = B_BUSY | B_PHYS | rdflg | flag; 64 if ((bp->b_flags & (B_DIRTY|B_PGIN)) == 0) 65 if (rdflg == B_READ) 66 sum.v_pswpin += btoc(nbytes); 67 else 68 sum.v_pswpout += btoc(nbytes); 69 bp->b_proc = p; 70 if (flag & B_DIRTY) { 71 p2dp = ((bp - swbuf) * CLSIZE) * KLMAX; 72 dpte = dptopte(&proc[2], p2dp); 73 vpte = vtopte(p, btop(addr)); 74 for (c = 0; c < nbytes; c += NBPG) { 75 if (vpte->pg_pfnum == 0 || vpte->pg_fod) 76 panic("swap bad pte"); 77 *dpte++ = *vpte++; 78 } 79 bp->b_un.b_addr = (caddr_t)ctob(dptov(&proc[2], p2dp)); 80 bp->b_flags |= B_CALL; 81 bp->b_iodone = swdone; 82 bp->b_pfcent = pfcent; 83 } else 84 bp->b_un.b_addr = addr; 85 while (nbytes > 0) { 86 bp->b_blkno = dblkno; 87 if (bp->b_vp) 88 brelvp(bp); 89 VHOLD(vp); 90 bp->b_vp = vp; 91 bp->b_dev = vp->v_rdev; 92 bp->b_bcount = nbytes; 93 if ((bp->b_flags & B_READ) == 0) 94 vp->v_numoutput++; 95 minphys(bp); 96 c = bp->b_bcount; 97 #ifdef TRACE 98 trace(TR_SWAPIO, vp, bp->b_blkno); 99 #endif 100 VOP_STRATEGY(bp); 101 /* pageout daemon doesn't wait for pushed pages */ 102 if (flag & B_DIRTY) { 103 if (c < nbytes) 104 panic("big push"); 105 return (0); 106 } else { 107 s = splbio(); 108 while ((bp->b_flags & B_DONE) == 0) 109 sleep((caddr_t)bp, PSWP); 110 splx(s); 111 } 112 bp->b_un.b_addr += c; 113 bp->b_flags &= ~B_DONE; 114 if (bp->b_flags & B_ERROR) { 115 if ((flag & (B_UAREA|B_PAGET)) || rdflg == B_WRITE) 116 panic("hard IO err in swap"); 117 swkill(p, "swap: read error from swap device"); 118 error = EIO; 119 } 120 nbytes -= c; 121 dblkno += btodb(c); 122 } 123 bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_PAGET|B_UAREA|B_DIRTY); 124 freeswbuf(bp); 125 return (error); 126 } 127 128 /* 129 * Put a buffer on the clean list after I/O is done. 130 * Called from biodone. 131 */ 132 swdone(bp) 133 register struct buf *bp; 134 { 135 register int s; 136 137 if (bp->b_flags & B_ERROR) 138 panic("IO err in push"); 139 s = splbio(); 140 bp->av_forw = bclnlist; 141 cnt.v_pgout++; 142 cnt.v_pgpgout += bp->b_bcount / NBPG; 143 bclnlist = bp; 144 if (bswlist.b_flags & B_WANTED) 145 wakeup((caddr_t)&proc[2]); 146 splx(s); 147 } 148 149 /* 150 * If rout == 0 then killed on swap error, else 151 * rout is the name of the routine where we ran out of 152 * swap space. 153 */ 154 swkill(p, rout) 155 struct proc *p; 156 char *rout; 157 { 158 159 printf("pid %d: %s\n", p->p_pid, rout); 160 uprintf("sorry, pid %d was killed in %s\n", p->p_pid, rout); 161 /* 162 * To be sure no looping (e.g. in vmsched trying to 163 * swap out) mark process locked in core (as though 164 * done by user) after killing it so noone will try 165 * to swap it out. 166 */ 167 psignal(p, SIGKILL); 168 p->p_flag |= SULOCK; 169 } 170 171 /* 172 * Raw I/O. The arguments are 173 * The strategy routine for the device 174 * A buffer, which will either be a special buffer header owned 175 * exclusively by the device for this purpose, or NULL, 176 * indicating that we should use a swap buffer 177 * The device number 178 * Read/write flag 179 * Essentially all the work is computing physical addresses and 180 * validating them. 181 * If the user has the proper access privilidges, the process is 182 * marked 'delayed unlock' and the pages involved in the I/O are 183 * faulted and locked. After the completion of the I/O, the above pages 184 * are unlocked. 185 */ 186 physio(strat, bp, dev, rw, mincnt, uio) 187 int (*strat)(); 188 register struct buf *bp; 189 dev_t dev; 190 int rw; 191 u_int (*mincnt)(); 192 struct uio *uio; 193 { 194 register struct iovec *iov; 195 register int requested, done; 196 char *a; 197 int s, allocbuf = 0, error = 0; 198 struct buf *getswbuf(); 199 200 if (bp == NULL) { 201 allocbuf = 1; 202 bp = getswbuf(PRIBIO+1); 203 } 204 for (; uio->uio_iovcnt; uio->uio_iov++, uio->uio_iovcnt--) { 205 iov = uio->uio_iov; 206 if (!useracc(iov->iov_base, (u_int)iov->iov_len, 207 rw == B_READ ? B_WRITE : B_READ)) { 208 error = EFAULT; 209 break; 210 } 211 if (!allocbuf) { /* only if sharing caller's buffer */ 212 s = splbio(); 213 while (bp->b_flags&B_BUSY) { 214 bp->b_flags |= B_WANTED; 215 sleep((caddr_t)bp, PRIBIO+1); 216 } 217 splx(s); 218 } 219 bp->b_error = 0; 220 bp->b_proc = u.u_procp; 221 bp->b_un.b_addr = iov->iov_base; 222 while (iov->iov_len > 0) { 223 bp->b_flags = B_BUSY | B_PHYS | B_RAW | rw; 224 bp->b_dev = dev; 225 bp->b_blkno = btodb(uio->uio_offset); 226 bp->b_bcount = iov->iov_len; 227 (*mincnt)(bp); 228 requested = bp->b_bcount; 229 u.u_procp->p_flag |= SPHYSIO; 230 vslock(a = bp->b_un.b_addr, requested); 231 (*strat)(bp); 232 s = splbio(); 233 while ((bp->b_flags & B_DONE) == 0) 234 sleep((caddr_t)bp, PRIBIO); 235 vsunlock(a, requested, rw); 236 u.u_procp->p_flag &= ~SPHYSIO; 237 if (bp->b_flags&B_WANTED) /* rare */ 238 wakeup((caddr_t)bp); 239 splx(s); 240 done = bp->b_bcount - bp->b_resid; 241 bp->b_un.b_addr += done; 242 iov->iov_len -= done; 243 uio->uio_resid -= done; 244 uio->uio_offset += done; 245 /* temp kludge for disk drives */ 246 if (done < requested || bp->b_flags & B_ERROR) 247 break; 248 } 249 bp->b_flags &= ~(B_BUSY | B_WANTED | B_PHYS | B_RAW); 250 error = biowait(bp); 251 /* temp kludge for disk drives */ 252 if (done < requested || bp->b_flags & B_ERROR) 253 break; 254 } 255 if (allocbuf) 256 freeswbuf(bp); 257 return (error); 258 } 259 260 u_int 261 minphys(bp) 262 struct buf *bp; 263 { 264 if (bp->b_bcount > MAXPHYS) 265 bp->b_bcount = MAXPHYS; 266 } 267 268 static 269 struct buf * 270 getswbuf(prio) 271 int prio; 272 { 273 int s; 274 struct buf *bp; 275 276 s = splbio(); 277 while (bswlist.av_forw == NULL) { 278 bswlist.b_flags |= B_WANTED; 279 sleep((caddr_t)&bswlist, prio); 280 } 281 bp = bswlist.av_forw; 282 bswlist.av_forw = bp->av_forw; 283 splx(s); 284 return (bp); 285 } 286 287 static 288 freeswbuf(bp) 289 struct buf *bp; 290 { 291 int s; 292 293 s = splbio(); 294 bp->av_forw = bswlist.av_forw; 295 bswlist.av_forw = bp; 296 if (bp->b_vp) 297 brelvp(bp); 298 if (bswlist.b_flags & B_WANTED) { 299 bswlist.b_flags &= ~B_WANTED; 300 wakeup((caddr_t)&bswlist); 301 wakeup((caddr_t)&proc[2]); 302 } 303 splx(s); 304 } 305 306 rawread(dev, uio) 307 dev_t dev; 308 struct uio *uio; 309 { 310 return (physio(cdevsw[major(dev)].d_strategy, (struct buf *)NULL, 311 dev, B_READ, minphys, uio)); 312 } 313 314 rawwrite(dev, uio) 315 dev_t dev; 316 struct uio *uio; 317 { 318 return (physio(cdevsw[major(dev)].d_strategy, (struct buf *)NULL, 319 dev, B_WRITE, minphys, uio)); 320 } 321