| 1 | /* |
| 2 | * Copyright (c) 1982, 1986, 1989 Regents of the University of California. |
| 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, this list of conditions and the following disclaimer. |
| 10 | * 2. Redistributions in binary form must reproduce the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer in the |
| 12 | * documentation and/or other materials provided with the distribution. |
| 13 | * 3. All advertising materials mentioning features or use of this software |
| 14 | * must display the following acknowledgement: |
| 15 | * This product includes software developed by the University of |
| 16 | * California, Berkeley and its contributors. |
| 17 | * 4. Neither the name of the University nor the names of its contributors |
| 18 | * may be used to endorse or promote products derived from this software |
| 19 | * without specific prior written permission. |
| 20 | * |
| 21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 31 | * SUCH DAMAGE. |
| 32 | * |
| 33 | * @(#)vm_swap.c 7.18 (Berkeley) 5/6/91 |
| 34 | */ |
| 35 | |
| 36 | #include "param.h" |
| 37 | #include "systm.h" |
| 38 | #include "buf.h" |
| 39 | #include "conf.h" |
| 40 | #include "proc.h" |
| 41 | #include "namei.h" |
| 42 | #include "dmap.h" /* XXX */ |
| 43 | #include "vnode.h" |
| 44 | #include "specdev.h" |
| 45 | #include "map.h" |
| 46 | #include "file.h" |
| 47 | |
| 48 | /* |
| 49 | * Indirect driver for multi-controller paging. |
| 50 | */ |
| 51 | |
| 52 | int nswap, nswdev; |
| 53 | |
| 54 | /* |
| 55 | * Set up swap devices. |
| 56 | * Initialize linked list of free swap |
| 57 | * headers. These do not actually point |
| 58 | * to buffers, but rather to pages that |
| 59 | * are being swapped in and out. |
| 60 | */ |
| 61 | swapinit() |
| 62 | { |
| 63 | register int i; |
| 64 | register struct buf *sp = swbuf; |
| 65 | struct swdevt *swp; |
| 66 | int error; |
| 67 | |
| 68 | /* |
| 69 | * Count swap devices, and adjust total swap space available. |
| 70 | * Some of this space will not be available until a swapon() |
| 71 | * system is issued, usually when the system goes multi-user. |
| 72 | */ |
| 73 | nswdev = 0; |
| 74 | nswap = 0; |
| 75 | for (swp = swdevt; swp->sw_dev; swp++) { |
| 76 | nswdev++; |
| 77 | if (swp->sw_nblks > nswap) |
| 78 | nswap = swp->sw_nblks; |
| 79 | } |
| 80 | if (nswdev == 0) |
| 81 | panic("swapinit"); |
| 82 | if (nswdev > 1) |
| 83 | nswap = ((nswap + dmmax - 1) / dmmax) * dmmax; |
| 84 | nswap *= nswdev; |
| 85 | if (bdevvp(swdevt[0].sw_dev, &swdevt[0].sw_vp)) |
| 86 | panic("swapvp"); |
| 87 | if (error = swfree(&proc0, 0)) { |
| 88 | printf("swfree errno %d\n", error); /* XXX */ |
| 89 | panic("swapinit swfree 0"); |
| 90 | } |
| 91 | |
| 92 | /* |
| 93 | * Now set up swap buffer headers. |
| 94 | */ |
| 95 | bswlist.av_forw = sp; |
| 96 | for (i = 0; i < nswbuf - 1; i++, sp++) |
| 97 | sp->av_forw = sp + 1; |
| 98 | sp->av_forw = NULL; |
| 99 | } |
| 100 | |
| 101 | swstrategy(bp) |
| 102 | register struct buf *bp; |
| 103 | { |
| 104 | int sz, off, seg, index; |
| 105 | register struct swdevt *sp; |
| 106 | struct vnode *vp; |
| 107 | |
| 108 | #ifdef GENERIC |
| 109 | /* |
| 110 | * A mini-root gets copied into the front of the swap |
| 111 | * and we run over top of the swap area just long |
| 112 | * enough for us to do a mkfs and restor of the real |
| 113 | * root (sure beats rewriting standalone restor). |
| 114 | */ |
| 115 | #define MINIROOTSIZE 4096 |
| 116 | if (rootdev == dumpdev) |
| 117 | bp->b_blkno += MINIROOTSIZE; |
| 118 | #endif |
| 119 | sz = howmany(bp->b_bcount, DEV_BSIZE); |
| 120 | if (bp->b_blkno + sz > nswap) { |
| 121 | bp->b_flags |= B_ERROR; |
| 122 | biodone(bp); |
| 123 | return; |
| 124 | } |
| 125 | if (nswdev > 1) { |
| 126 | off = bp->b_blkno % dmmax; |
| 127 | if (off+sz > dmmax) { |
| 128 | bp->b_flags |= B_ERROR; |
| 129 | biodone(bp); |
| 130 | return; |
| 131 | } |
| 132 | seg = bp->b_blkno / dmmax; |
| 133 | index = seg % nswdev; |
| 134 | seg /= nswdev; |
| 135 | bp->b_blkno = seg*dmmax + off; |
| 136 | } else |
| 137 | index = 0; |
| 138 | sp = &swdevt[index]; |
| 139 | if ((bp->b_dev = sp->sw_dev) == 0) |
| 140 | panic("swstrategy"); |
| 141 | if (sp->sw_vp == NULL) { |
| 142 | bp->b_error |= B_ERROR; |
| 143 | biodone(bp); |
| 144 | return; |
| 145 | } |
| 146 | VHOLD(sp->sw_vp); |
| 147 | if ((bp->b_flags & B_READ) == 0) { |
| 148 | if (vp = bp->b_vp) { |
| 149 | vp->v_numoutput--; |
| 150 | if ((vp->v_flag & VBWAIT) && vp->v_numoutput <= 0) { |
| 151 | vp->v_flag &= ~VBWAIT; |
| 152 | wakeup((caddr_t)&vp->v_numoutput); |
| 153 | } |
| 154 | } |
| 155 | sp->sw_vp->v_numoutput++; |
| 156 | } |
| 157 | if (bp->b_vp != NULL) |
| 158 | brelvp(bp); |
| 159 | bp->b_vp = sp->sw_vp; |
| 160 | VOP_STRATEGY(bp); |
| 161 | } |
| 162 | |
| 163 | /* |
| 164 | * System call swapon(name) enables swapping on device name, |
| 165 | * which must be in the swdevsw. Return EBUSY |
| 166 | * if already swapping on this device. |
| 167 | */ |
| 168 | /* ARGSUSED */ |
| 169 | swapon(p, uap, retval) |
| 170 | struct proc *p; |
| 171 | struct args { |
| 172 | char *name; |
| 173 | } *uap; |
| 174 | int *retval; |
| 175 | { |
| 176 | register struct vnode *vp; |
| 177 | register struct swdevt *sp; |
| 178 | register struct nameidata *ndp; |
| 179 | dev_t dev; |
| 180 | int error; |
| 181 | struct nameidata nd; |
| 182 | |
| 183 | if (error = suser(p->p_ucred, &p->p_acflag)) |
| 184 | return (error); |
| 185 | ndp = &nd; |
| 186 | ndp->ni_nameiop = LOOKUP | FOLLOW; |
| 187 | ndp->ni_segflg = UIO_USERSPACE; |
| 188 | ndp->ni_dirp = uap->name; |
| 189 | if (error = namei(ndp, p)) |
| 190 | return (error); |
| 191 | vp = ndp->ni_vp; |
| 192 | if (vp->v_type != VBLK) { |
| 193 | vrele(vp); |
| 194 | return (ENOTBLK); |
| 195 | } |
| 196 | dev = (dev_t)vp->v_rdev; |
| 197 | if (major(dev) >= nblkdev) { |
| 198 | vrele(vp); |
| 199 | return (ENXIO); |
| 200 | } |
| 201 | for (sp = &swdevt[0]; sp->sw_dev; sp++) |
| 202 | if (sp->sw_dev == dev) { |
| 203 | if (sp->sw_freed) { |
| 204 | vrele(vp); |
| 205 | return (EBUSY); |
| 206 | } |
| 207 | sp->sw_vp = vp; |
| 208 | if (error = swfree(p, sp - swdevt)) { |
| 209 | vrele(vp); |
| 210 | return (error); |
| 211 | } |
| 212 | return (0); |
| 213 | } |
| 214 | vrele(vp); |
| 215 | return (EINVAL); |
| 216 | } |
| 217 | |
| 218 | /* |
| 219 | * Swfree(index) frees the index'th portion of the swap map. |
| 220 | * Each of the nswdev devices provides 1/nswdev'th of the swap |
| 221 | * space, which is laid out with blocks of dmmax pages circularly |
| 222 | * among the devices. |
| 223 | */ |
| 224 | swfree(p, index) |
| 225 | struct proc *p; |
| 226 | int index; |
| 227 | { |
| 228 | register struct swdevt *sp; |
| 229 | register swblk_t vsbase; |
| 230 | register long blk; |
| 231 | struct vnode *vp; |
| 232 | register swblk_t dvbase; |
| 233 | register int nblks; |
| 234 | int error; |
| 235 | |
| 236 | sp = &swdevt[index]; |
| 237 | vp = sp->sw_vp; |
| 238 | if (error = VOP_OPEN(vp, FREAD|FWRITE, p->p_ucred, p)) |
| 239 | return (error); |
| 240 | sp->sw_freed = 1; |
| 241 | nblks = sp->sw_nblks; |
| 242 | for (dvbase = 0; dvbase < nblks; dvbase += dmmax) { |
| 243 | blk = nblks - dvbase; |
| 244 | if ((vsbase = index*dmmax + dvbase*nswdev) >= nswap) |
| 245 | panic("swfree"); |
| 246 | if (blk > dmmax) |
| 247 | blk = dmmax; |
| 248 | if (vsbase == 0) { |
| 249 | /* |
| 250 | * First of all chunks... initialize the swapmap |
| 251 | * the second half of the hunk. |
| 252 | */ |
| 253 | rminit(swapmap, (long)(blk/2), (long)(blk/2), |
| 254 | "swap", nswapmap); |
| 255 | } else if (dvbase == 0) { |
| 256 | /* |
| 257 | * Don't use the first cluster of the device |
| 258 | * in case it starts with a label or boot block. |
| 259 | */ |
| 260 | rmfree(swapmap, blk - ctod(CLSIZE), |
| 261 | vsbase + ctod(CLSIZE)); |
| 262 | } else |
| 263 | rmfree(swapmap, blk, vsbase); |
| 264 | } |
| 265 | return (0); |
| 266 | } |