1 /* kern_physio.c 4.30 82/05/22 */ 2 3 #include "../h/param.h" 4 #include "../h/systm.h" 5 #include "../h/dir.h" 6 #include "../h/user.h" 7 #include "../h/buf.h" 8 #include "../h/conf.h" 9 #include "../h/proc.h" 10 #include "../h/seg.h" 11 #include "../h/pte.h" 12 #include "../h/vm.h" 13 #include "../h/trace.h" 14 15 /* 16 * Swap IO headers - 17 * They contain the necessary information for the swap I/O. 18 * At any given time, a swap header can be in three 19 * different lists. When free it is in the free list, 20 * when allocated and the I/O queued, it is on the swap 21 * device list, and finally, if the operation was a dirty 22 * page push, when the I/O completes, it is inserted 23 * in a list of cleaned pages to be processed by the pageout daemon. 24 */ 25 struct buf *swbuf; 26 short *swsize; /* CAN WE JUST USE B_BCOUNT? */ 27 int *swpf; 28 29 /* 30 * swap I/O - 31 * 32 * If the flag indicates a dirty page push initiated 33 * by the pageout daemon, we map the page into the i th 34 * virtual page of process 2 (the daemon itself) where i is 35 * the index of the swap header that has been allocated. 36 * We simply initialize the header and queue the I/O but 37 * do not wait for completion. When the I/O completes, 38 * iodone() will link the header to a list of cleaned 39 * pages to be processed by the pageout daemon. 40 */ 41 swap(p, dblkno, addr, nbytes, rdflg, flag, dev, pfcent) 42 struct proc *p; 43 swblk_t dblkno; 44 caddr_t addr; 45 int flag, nbytes; 46 dev_t dev; 47 unsigned pfcent; 48 { 49 register struct buf *bp; 50 register int c; 51 int p2dp; 52 register struct pte *dpte, *vpte; 53 int s; 54 55 s = spl6(); 56 while (bswlist.av_forw == NULL) { 57 bswlist.b_flags |= B_WANTED; 58 sleep((caddr_t)&bswlist, PSWP+1); 59 } 60 bp = bswlist.av_forw; 61 bswlist.av_forw = bp->av_forw; 62 splx(s); 63 64 bp->b_flags = B_BUSY | B_PHYS | rdflg | flag; 65 if ((bp->b_flags & (B_DIRTY|B_PGIN)) == 0) 66 if (rdflg == B_READ) 67 sum.v_pswpin += btoc(nbytes); 68 else 69 sum.v_pswpout += btoc(nbytes); 70 bp->b_proc = p; 71 if (flag & B_DIRTY) { 72 p2dp = ((bp - swbuf) * CLSIZE) * KLMAX; 73 dpte = dptopte(&proc[2], p2dp); 74 vpte = vtopte(p, btop(addr)); 75 for (c = 0; c < nbytes; c += NBPG) { 76 if (vpte->pg_pfnum == 0 || vpte->pg_fod) 77 panic("swap bad pte"); 78 *dpte++ = *vpte++; 79 } 80 bp->b_un.b_addr = (caddr_t)ctob(p2dp); 81 } else 82 bp->b_un.b_addr = addr; 83 while (nbytes > 0) { 84 c = imin(ctob(120), nbytes); 85 bp->b_bcount = c; 86 bp->b_blkno = dblkno; 87 bp->b_dev = dev; 88 if (flag & B_DIRTY) { 89 swpf[bp - swbuf] = pfcent; 90 swsize[bp - swbuf] = nbytes; 91 } 92 #ifdef TRACE 93 trace(TR_SWAPIO, dev, bp->b_blkno); 94 #endif 95 (*bdevsw[major(dev)].d_strategy)(bp); 96 if (flag & B_DIRTY) { 97 if (c < nbytes) 98 panic("big push"); 99 return; 100 } 101 s = spl6(); 102 while((bp->b_flags&B_DONE)==0) 103 sleep((caddr_t)bp, PSWP); 104 splx(s); 105 bp->b_un.b_addr += c; 106 bp->b_flags &= ~B_DONE; 107 if (bp->b_flags & B_ERROR) { 108 if ((flag & (B_UAREA|B_PAGET)) || rdflg == B_WRITE) 109 panic("hard IO err in swap"); 110 swkill(p, (char *)0); 111 } 112 nbytes -= c; 113 dblkno += btoc(c); 114 } 115 s = spl6(); 116 bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_PAGET|B_UAREA|B_DIRTY); 117 bp->av_forw = bswlist.av_forw; 118 bswlist.av_forw = bp; 119 if (bswlist.b_flags & B_WANTED) { 120 bswlist.b_flags &= ~B_WANTED; 121 wakeup((caddr_t)&bswlist); 122 wakeup((caddr_t)&proc[2]); 123 } 124 splx(s); 125 } 126 127 /* 128 * If rout == 0 then killed on swap error, else 129 * rout is the name of the routine where we ran out of 130 * swap space. 131 */ 132 swkill(p, rout) 133 struct proc *p; 134 char *rout; 135 { 136 char *mesg; 137 138 printf("pid %d: ", p->p_pid); 139 if (rout) 140 printf(mesg = "killed due to no swap space\n"); 141 else 142 printf(mesg = "killed on swap error\n"); 143 uprintf("sorry, pid %d was %s", p->p_pid, mesg); 144 /* 145 * To be sure no looping (e.g. in vmsched trying to 146 * swap out) mark process locked in core (as though 147 * done by user) after killing it so noone will try 148 * to swap it out. 149 */ 150 psignal(p, SIGKILL); 151 p->p_flag |= SULOCK; 152 } 153 154 /* 155 * Raw I/O. The arguments are 156 * The strategy routine for the device 157 * A buffer, which will always be a special buffer 158 * header owned exclusively by the device for this purpose 159 * The device number 160 * Read/write flag 161 * Essentially all the work is computing physical addresses and 162 * validating them. 163 * If the user has the proper access privilidges, the process is 164 * marked 'delayed unlock' and the pages involved in the I/O are 165 * faulted and locked. After the completion of the I/O, the above pages 166 * are unlocked. 167 */ 168 physio(strat, bp, dev, rw, mincnt) 169 int (*strat)(); 170 register struct buf *bp; 171 unsigned (*mincnt)(); 172 { 173 register int c; 174 char *a; 175 int s; 176 177 if (useracc(u.u_base,u.u_count,rw==B_READ?B_WRITE:B_READ) == NULL) { 178 u.u_error = EFAULT; 179 return; 180 } 181 s = spl6(); 182 while (bp->b_flags&B_BUSY) { 183 bp->b_flags |= B_WANTED; 184 sleep((caddr_t)bp, PRIBIO+1); 185 } 186 splx(s); 187 bp->b_error = 0; 188 bp->b_proc = u.u_procp; 189 bp->b_un.b_addr = u.u_base; 190 while (u.u_count != 0) { 191 bp->b_flags = B_BUSY | B_PHYS | rw; 192 bp->b_dev = dev; 193 bp->b_blkno = u.u_offset >> PGSHIFT; 194 bp->b_bcount = u.u_count; 195 (*mincnt)(bp); 196 c = bp->b_bcount; 197 u.u_procp->p_flag |= SPHYSIO; 198 vslock(a = bp->b_un.b_addr, c); 199 (*strat)(bp); 200 (void) spl6(); 201 while ((bp->b_flags&B_DONE) == 0) 202 sleep((caddr_t)bp, PRIBIO); 203 vsunlock(a, c, rw); 204 u.u_procp->p_flag &= ~SPHYSIO; 205 if (bp->b_flags&B_WANTED) 206 wakeup((caddr_t)bp); 207 splx(s); 208 bp->b_un.b_addr += c; 209 u.u_count -= c; 210 u.u_offset += c; 211 if (bp->b_flags&B_ERROR) 212 break; 213 } 214 bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS); 215 u.u_count = bp->b_resid; 216 geterror(bp); 217 } 218 219 /*ARGSUSED*/ 220 unsigned 221 minphys(bp) 222 struct buf *bp; 223 { 224 225 if (bp->b_bcount > 63 * 1024) 226 bp->b_bcount = 63 * 1024; 227 } 228 229