Commit | Line | Data |
---|---|---|
01395141 C |
1 | /* sw.c 4.4 81/03/08 */ |
2 | ||
3 | #include "../h/param.h" | |
4 | #include "../h/systm.h" | |
5 | #include "../h/buf.h" | |
6 | #include "../h/conf.h" | |
7 | #include "../h/dir.h" | |
8 | #include "../h/user.h" | |
9 | #include "../h/inode.h" | |
10 | #include "../h/map.h" | |
11 | ||
12 | struct buf rswbuf; | |
13 | /* | |
14 | * Indirect driver for multi-controller paging. | |
15 | */ | |
16 | swstrategy(bp) | |
17 | register struct buf *bp; | |
18 | { | |
19 | int sz, off, seg; | |
20 | dev_t dev; | |
21 | ||
22 | sz = (bp->b_bcount+511)/512; | |
23 | off = bp->b_blkno % DMMAX; | |
24 | if (bp->b_blkno+sz > nswap || off+sz > DMMAX) { | |
25 | bp->b_flags |= B_ERROR; | |
26 | iodone(bp); | |
27 | return; | |
28 | } | |
29 | seg = bp->b_blkno / DMMAX; | |
30 | dev = swdevt[seg % nswdev].sw_dev; | |
31 | seg /= nswdev; | |
32 | bp->b_blkno = seg*DMMAX + off; | |
33 | bp->b_dev = dev; | |
34 | if (dev == 0) | |
35 | panic("swstrategy"); | |
36 | (*bdevsw[major(dev)].d_strategy)(bp); | |
37 | } | |
38 | ||
39 | swread(dev) | |
40 | { | |
41 | ||
42 | physio(swstrategy, &rswbuf, dev, B_READ, minphys); | |
43 | } | |
44 | ||
45 | swwrite(dev) | |
46 | { | |
47 | ||
48 | physio(swstrategy, &rswbuf, dev, B_WRITE, minphys); | |
49 | } | |
50 | ||
51 | /* | |
52 | * System call swapon(name) enables swapping on device name, | |
53 | * which must be in the swdevsw. Return EBUSY | |
54 | * if already swapping on this device. | |
55 | */ | |
56 | vswapon() | |
57 | { | |
58 | register struct inode *ip; | |
59 | dev_t dev; | |
60 | register struct swdevt *sp; | |
61 | ||
62 | ip = namei(uchar, 0); | |
63 | if (ip == NULL) | |
64 | return; | |
65 | if ((ip->i_mode&IFMT) != IFBLK) { | |
66 | u.u_error = ENOTBLK; | |
67 | iput(ip); | |
68 | return; | |
69 | } | |
70 | dev = (dev_t)ip->i_un.i_rdev; | |
71 | iput(ip); | |
72 | if (major(dev) >= nblkdev) { | |
73 | u.u_error = ENXIO; | |
74 | return; | |
75 | } | |
76 | /* | |
77 | * Search starting at second table entry, | |
78 | * since first (primary swap area) is freed at boot. | |
79 | */ | |
80 | for (sp = &swdevt[1]; sp->sw_dev; sp++) | |
81 | if (sp->sw_dev == dev) { | |
82 | if (sp->sw_freed) { | |
83 | u.u_error = EBUSY; | |
84 | return; | |
85 | } | |
86 | swfree(sp - swdevt); | |
87 | return; | |
88 | } | |
89 | u.u_error = ENODEV; | |
90 | } | |
91 | ||
92 | /* | |
93 | * Swfree(index) frees the index'th portion of the swap map. | |
94 | * Each of the nswdev devices provides 1/nswdev'th of the swap | |
95 | * space, which is laid out with blocks of DMMAX pages circularly | |
96 | * among the devices. | |
97 | */ | |
98 | swfree(index) | |
99 | int index; | |
100 | { | |
101 | register swblk_t vsbase; | |
102 | register int blk; | |
103 | ||
104 | swdevt[index].sw_freed = 1; | |
105 | for (vsbase = index*DMMAX; vsbase < nswap; vsbase += nswdev*DMMAX) { | |
106 | blk = nswap - vsbase; | |
107 | if (blk > DMMAX) | |
108 | blk = DMMAX; | |
109 | if (vsbase == 0) { | |
110 | /* | |
111 | * Can't free a block starting at 0 in the swapmap | |
112 | * but need some space for argmap so use 1/2 this | |
113 | * hunk which needs special treatment anyways. | |
114 | */ | |
115 | argdev = swdevt[0].sw_dev; | |
116 | rminit(argmap, blk/2-CLSIZE, CLSIZE, | |
117 | "argmap", ARGMAPSIZE); | |
118 | /* | |
119 | * First of all chunks... initialize the swapmap | |
120 | * the second half of the hunk. | |
121 | */ | |
122 | rminit(swapmap, blk/2, blk/2, "swap", nswapmap); | |
123 | } else | |
124 | rmfree(swapmap, blk, vsbase); | |
125 | } | |
126 | } |