1 /* 2 * Copyright (c) 1982 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 6.9 (Berkeley) 02/21/86 7 */ 8 9 #include "../machine/pte.h" 10 11 #include "param.h" 12 #include "systm.h" 13 #include "dir.h" 14 #include "user.h" 15 #include "buf.h" 16 #include "conf.h" 17 #include "proc.h" 18 #include "seg.h" 19 #include "vm.h" 20 #include "trace.h" 21 #include "map.h" 22 #include "uio.h" 23 24 /* 25 * Swap IO headers - 26 * They contain the necessary information for the swap I/O. 27 * At any given time, a swap header can be in three 28 * different lists. When free it is in the free list, 29 * when allocated and the I/O queued, it is on the swap 30 * device list, and finally, if the operation was a dirty 31 * page push, when the I/O completes, it is inserted 32 * in a list of cleaned pages to be processed by the pageout daemon. 33 */ 34 struct buf *swbuf; 35 36 /* 37 * swap I/O - 38 * 39 * If the flag indicates a dirty page push initiated 40 * by the pageout daemon, we map the page into the i th 41 * virtual page of process 2 (the daemon itself) where i is 42 * the index of the swap header that has been allocated. 43 * We simply initialize the header and queue the I/O but 44 * do not wait for completion. When the I/O completes, 45 * iodone() will link the header to a list of cleaned 46 * pages to be processed by the pageout daemon. 47 */ 48 swap(p, dblkno, addr, nbytes, rdflg, flag, dev, pfcent) 49 struct proc *p; 50 swblk_t dblkno; 51 caddr_t addr; 52 int nbytes, rdflg, flag; 53 dev_t dev; 54 u_int pfcent; 55 { 56 register struct buf *bp; 57 register u_int c; 58 int p2dp; 59 register struct pte *dpte, *vpte; 60 int s; 61 extern swdone(); 62 int error = 0; 63 64 s = splbio(); 65 while (bswlist.av_forw == NULL) { 66 bswlist.b_flags |= B_WANTED; 67 sleep((caddr_t)&bswlist, PSWP+1); 68 } 69 bp = bswlist.av_forw; 70 bswlist.av_forw = bp->av_forw; 71 splx(s); 72 73 bp->b_flags = B_BUSY | B_PHYS | rdflg | flag; 74 if ((bp->b_flags & (B_DIRTY|B_PGIN)) == 0) 75 if (rdflg == B_READ) 76 sum.v_pswpin += btoc(nbytes); 77 else 78 sum.v_pswpout += btoc(nbytes); 79 bp->b_proc = p; 80 if (flag & B_DIRTY) { 81 p2dp = ((bp - swbuf) * CLSIZE) * KLMAX; 82 dpte = dptopte(&proc[2], p2dp); 83 vpte = vtopte(p, btop(addr)); 84 for (c = 0; c < nbytes; c += NBPG) { 85 if (vpte->pg_pfnum == 0 || vpte->pg_fod) 86 panic("swap bad pte"); 87 *dpte++ = *vpte++; 88 } 89 bp->b_un.b_addr = (caddr_t)ctob(dptov(&proc[2], p2dp)); 90 bp->b_flags |= B_CALL; 91 bp->b_iodone = swdone; 92 bp->b_pfcent = pfcent; 93 } else 94 bp->b_un.b_addr = addr; 95 while (nbytes > 0) { 96 bp->b_bcount = nbytes; 97 minphys(bp); 98 c = bp->b_bcount; 99 bp->b_blkno = dblkno; 100 bp->b_dev = dev; 101 #ifdef TRACE 102 trace(TR_SWAPIO, dev, bp->b_blkno); 103 #endif 104 physstrat(bp, bdevsw[major(dev)].d_strategy, PSWP); 105 if (flag & B_DIRTY) { 106 if (c < nbytes) 107 panic("big push"); 108 return (error); 109 } 110 bp->b_un.b_addr += c; 111 bp->b_flags &= ~B_DONE; 112 if (bp->b_flags & B_ERROR) { 113 if ((flag & (B_UAREA|B_PAGET)) || rdflg == B_WRITE) 114 panic("hard IO err in swap"); 115 swkill(p, "swap: read error from swap device"); 116 error = EIO; 117 } 118 nbytes -= c; 119 dblkno += btodb(c); 120 } 121 s = splbio(); 122 bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_PAGET|B_UAREA|B_DIRTY); 123 bp->av_forw = bswlist.av_forw; 124 bswlist.av_forw = bp; 125 if (bswlist.b_flags & B_WANTED) { 126 bswlist.b_flags &= ~B_WANTED; 127 wakeup((caddr_t)&bswlist); 128 wakeup((caddr_t)&proc[2]); 129 } 130 splx(s); 131 return (error); 132 } 133 134 /* 135 * Put a buffer on the clean list after I/O is done. 136 * Called from biodone. 137 */ 138 swdone(bp) 139 register struct buf *bp; 140 { 141 register int s; 142 143 if (bp->b_flags & B_ERROR) 144 panic("IO err in push"); 145 s = splbio(); 146 bp->av_forw = bclnlist; 147 cnt.v_pgout++; 148 cnt.v_pgpgout += bp->b_bcount / NBPG; 149 bclnlist = bp; 150 if (bswlist.b_flags & B_WANTED) 151 wakeup((caddr_t)&proc[2]); 152 splx(s); 153 } 154 155 /* 156 * If rout == 0 then killed on swap error, else 157 * rout is the name of the routine where we ran out of 158 * swap space. 159 */ 160 swkill(p, rout) 161 struct proc *p; 162 char *rout; 163 { 164 165 printf("pid %d: %s\n", p->p_pid, rout); 166 uprintf("sorry, pid %d was killed in %s\n", p->p_pid, rout); 167 /* 168 * To be sure no looping (e.g. in vmsched trying to 169 * swap out) mark process locked in core (as though 170 * done by user) after killing it so noone will try 171 * to swap it out. 172 */ 173 psignal(p, SIGKILL); 174 p->p_flag |= SULOCK; 175 } 176 177 /* 178 * Raw I/O. The arguments are 179 * The strategy routine for the device 180 * A buffer, which will always be a special buffer 181 * header owned exclusively by the device for this purpose 182 * The device number 183 * Read/write flag 184 * Essentially all the work is computing physical addresses and 185 * validating them. 186 * If the user has the proper access privilidges, the process is 187 * marked 'delayed unlock' and the pages involved in the I/O are 188 * faulted and locked. After the completion of the I/O, the above pages 189 * are unlocked. 190 */ 191 physio(strat, bp, dev, rw, mincnt, uio) 192 int (*strat)(); 193 register struct buf *bp; 194 dev_t dev; 195 int rw; 196 unsigned (*mincnt)(); 197 struct uio *uio; 198 { 199 register struct iovec *iov; 200 register int c; 201 char *a; 202 int s, error = 0; 203 204 nextiov: 205 if (uio->uio_iovcnt == 0) 206 return (0); 207 iov = uio->uio_iov; 208 if (useracc(iov->iov_base,(u_int)iov->iov_len,rw==B_READ?B_WRITE:B_READ) == NULL) 209 return (EFAULT); 210 s = splbio(); 211 while (bp->b_flags&B_BUSY) { 212 bp->b_flags |= B_WANTED; 213 sleep((caddr_t)bp, PRIBIO+1); 214 } 215 splx(s); 216 bp->b_error = 0; 217 bp->b_proc = u.u_procp; 218 bp->b_un.b_addr = iov->iov_base; 219 while (iov->iov_len > 0) { 220 bp->b_flags = B_BUSY | B_PHYS | rw; 221 bp->b_dev = dev; 222 bp->b_blkno = btodb(uio->uio_offset); 223 bp->b_bcount = iov->iov_len; 224 (*mincnt)(bp); 225 c = bp->b_bcount; 226 u.u_procp->p_flag |= SPHYSIO; 227 vslock(a = bp->b_un.b_addr, c); 228 physstrat(bp, strat, PRIBIO); 229 (void) splbio(); 230 vsunlock(a, c, rw); 231 u.u_procp->p_flag &= ~SPHYSIO; 232 if (bp->b_flags&B_WANTED) 233 wakeup((caddr_t)bp); 234 splx(s); 235 c -= bp->b_resid; 236 bp->b_un.b_addr += c; 237 iov->iov_len -= c; 238 uio->uio_resid -= c; 239 uio->uio_offset += c; 240 /* temp kludge for tape drives */ 241 if (bp->b_resid || (bp->b_flags&B_ERROR)) 242 break; 243 } 244 bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS); 245 error = geterror(bp); 246 /* temp kludge for tape drives */ 247 if (bp->b_resid || error) 248 return (error); 249 uio->uio_iov++; 250 uio->uio_iovcnt--; 251 goto nextiov; 252 } 253 254 #define MAXPHYS (63 * 1024) 255 256 unsigned 257 minphys(bp) 258 struct buf *bp; 259 { 260 261 if (bp->b_bcount > MAXPHYS) 262 bp->b_bcount = MAXPHYS; 263 } 264