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663dbc72 BJ |
1 | /* vfs_bio.c 3.1 %H% */ |
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 | ||
14 | /* #define DISKMON 1 */ | |
15 | ||
16 | #ifdef DISKMON | |
17 | struct { | |
18 | int nbuf; | |
19 | long nread; | |
20 | long nreada; | |
21 | long ncache; | |
22 | long nwrite; | |
23 | long bufcount[NBUF]; | |
24 | } io_info; | |
25 | #endif | |
26 | ||
27 | /* | |
28 | * Swap IO headers - | |
29 | * They contain the necessary information for the swap I/O. | |
30 | * At any given time, a swap header can be in three | |
31 | * different lists. When free it is in the free list, | |
32 | * when allocated and the I/O queued, it is on the swap | |
33 | * device list, and finally, if the operation was a dirty | |
34 | * page push, when the I/O completes, it is inserted | |
35 | * in a list of cleaned pages to be processed by the pageout daemon. | |
36 | */ | |
37 | struct buf swbuf[NSWBUF]; | |
38 | short swsize[NSWBUF]; /* CAN WE JUST USE B_BCOUNT? */ | |
39 | int swpf[NSWBUF]; | |
40 | ||
41 | /* | |
42 | * The following several routines allocate and free | |
43 | * buffers with various side effects. In general the | |
44 | * arguments to an allocate routine are a device and | |
45 | * a block number, and the value is a pointer to | |
46 | * to the buffer header; the buffer is marked "busy" | |
47 | * so that no one else can touch it. If the block was | |
48 | * already in core, no I/O need be done; if it is | |
49 | * already busy, the process waits until it becomes free. | |
50 | * The following routines allocate a buffer: | |
51 | * getblk | |
52 | * bread | |
53 | * breada | |
54 | * baddr (if it is incore) | |
55 | * Eventually the buffer must be released, possibly with the | |
56 | * side effect of writing it out, by using one of | |
57 | * bwrite | |
58 | * bdwrite | |
59 | * bawrite | |
60 | * brelse | |
61 | */ | |
62 | ||
63 | #ifdef FASTVAX | |
64 | #define notavail(bp) \ | |
65 | { \ | |
66 | int s = spl6(); \ | |
67 | (bp)->av_back->av_forw = (bp)->av_forw; \ | |
68 | (bp)->av_forw->av_back = (bp)->av_back; \ | |
69 | (bp)->b_flags |= B_BUSY; \ | |
70 | splx(s); \ | |
71 | } | |
72 | #endif | |
73 | ||
74 | /* | |
75 | * Read in (if necessary) the block and return a buffer pointer. | |
76 | */ | |
77 | struct buf * | |
78 | bread(dev, blkno) | |
79 | dev_t dev; | |
80 | daddr_t blkno; | |
81 | { | |
82 | register struct buf *bp; | |
83 | ||
84 | bp = getblk(dev, blkno); | |
85 | if (bp->b_flags&B_DONE) { | |
86 | #ifdef DISKMON | |
87 | io_info.ncache++; | |
88 | #endif | |
89 | return(bp); | |
90 | } | |
91 | bp->b_flags |= B_READ; | |
92 | bp->b_bcount = BSIZE; | |
93 | (*bdevsw[major(dev)].d_strategy)(bp); | |
94 | #ifdef DISKMON | |
95 | io_info.nread++; | |
96 | #endif | |
97 | u.u_vm.vm_inblk++; /* pay for read */ | |
98 | iowait(bp); | |
99 | return(bp); | |
100 | } | |
101 | ||
102 | /* | |
103 | * Read in the block, like bread, but also start I/O on the | |
104 | * read-ahead block (which is not allocated to the caller) | |
105 | */ | |
106 | struct buf * | |
107 | breada(dev, blkno, rablkno) | |
108 | dev_t dev; | |
109 | daddr_t blkno, rablkno; | |
110 | { | |
111 | register struct buf *bp, *rabp; | |
112 | ||
113 | bp = NULL; | |
114 | if (!incore(dev, blkno)) { | |
115 | bp = getblk(dev, blkno); | |
116 | if ((bp->b_flags&B_DONE) == 0) { | |
117 | bp->b_flags |= B_READ; | |
118 | bp->b_bcount = BSIZE; | |
119 | (*bdevsw[major(dev)].d_strategy)(bp); | |
120 | #ifdef DISKMON | |
121 | io_info.nread++; | |
122 | #endif | |
123 | u.u_vm.vm_inblk++; /* pay for read */ | |
124 | } | |
125 | } | |
126 | if (rablkno && !incore(dev, rablkno)) { | |
127 | rabp = getblk(dev, rablkno); | |
128 | if (rabp->b_flags & B_DONE) | |
129 | brelse(rabp); | |
130 | else { | |
131 | rabp->b_flags |= B_READ|B_ASYNC; | |
132 | rabp->b_bcount = BSIZE; | |
133 | (*bdevsw[major(dev)].d_strategy)(rabp); | |
134 | #ifdef DISKMON | |
135 | io_info.nreada++; | |
136 | #endif | |
137 | u.u_vm.vm_inblk++; /* pay in advance */ | |
138 | } | |
139 | } | |
140 | if(bp == NULL) | |
141 | return(bread(dev, blkno)); | |
142 | iowait(bp); | |
143 | return(bp); | |
144 | } | |
145 | ||
146 | /* | |
147 | * Write the buffer, waiting for completion. | |
148 | * Then release the buffer. | |
149 | */ | |
150 | bwrite(bp) | |
151 | register struct buf *bp; | |
152 | { | |
153 | register flag; | |
154 | ||
155 | flag = bp->b_flags; | |
156 | bp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI | B_AGE); | |
157 | bp->b_bcount = BSIZE; | |
158 | #ifdef DISKMON | |
159 | io_info.nwrite++; | |
160 | #endif | |
161 | if ((flag&B_DELWRI) == 0) | |
162 | u.u_vm.vm_oublk++; /* noone paid yet */ | |
163 | (*bdevsw[major(bp->b_dev)].d_strategy)(bp); | |
164 | if ((flag&B_ASYNC) == 0) { | |
165 | iowait(bp); | |
166 | brelse(bp); | |
167 | } else if (flag & B_DELWRI) | |
168 | bp->b_flags |= B_AGE; | |
169 | else | |
170 | geterror(bp); | |
171 | } | |
172 | ||
173 | /* | |
174 | * Release the buffer, marking it so that if it is grabbed | |
175 | * for another purpose it will be written out before being | |
176 | * given up (e.g. when writing a partial block where it is | |
177 | * assumed that another write for the same block will soon follow). | |
178 | * This can't be done for magtape, since writes must be done | |
179 | * in the same order as requested. | |
180 | */ | |
181 | bdwrite(bp) | |
182 | register struct buf *bp; | |
183 | { | |
184 | register struct buf *dp; | |
185 | ||
186 | if ((bp->b_flags&B_DELWRI) == 0) | |
187 | u.u_vm.vm_oublk++; /* noone paid yet */ | |
188 | dp = bdevsw[major(bp->b_dev)].d_tab; | |
189 | if(dp->b_flags & B_TAPE) | |
190 | bawrite(bp); | |
191 | else { | |
192 | bp->b_flags |= B_DELWRI | B_DONE; | |
193 | brelse(bp); | |
194 | } | |
195 | } | |
196 | ||
197 | /* | |
198 | * Release the buffer, start I/O on it, but don't wait for completion. | |
199 | */ | |
200 | bawrite(bp) | |
201 | register struct buf *bp; | |
202 | { | |
203 | ||
204 | bp->b_flags |= B_ASYNC; | |
205 | bwrite(bp); | |
206 | } | |
207 | ||
208 | /* | |
209 | * release the buffer, with no I/O implied. | |
210 | */ | |
211 | brelse(bp) | |
212 | register struct buf *bp; | |
213 | { | |
214 | register struct buf **backp; | |
215 | register s; | |
216 | ||
217 | if (bp->b_flags&B_WANTED) | |
218 | wakeup((caddr_t)bp); | |
219 | if (bfreelist.b_flags&B_WANTED) { | |
220 | bfreelist.b_flags &= ~B_WANTED; | |
221 | wakeup((caddr_t)&bfreelist); | |
222 | } | |
223 | if (bp->b_flags&B_ERROR) | |
224 | bp->b_dev = NODEV; /* no assoc. on error */ | |
225 | s = spl6(); | |
226 | if(bp->b_flags & (B_AGE|B_ERROR)) { | |
227 | backp = &bfreelist.av_forw; | |
228 | (*backp)->av_back = bp; | |
229 | bp->av_forw = *backp; | |
230 | *backp = bp; | |
231 | bp->av_back = &bfreelist; | |
232 | } else { | |
233 | backp = &bfreelist.av_back; | |
234 | (*backp)->av_forw = bp; | |
235 | bp->av_back = *backp; | |
236 | *backp = bp; | |
237 | bp->av_forw = &bfreelist; | |
238 | } | |
239 | bp->b_flags &= ~(B_WANTED|B_BUSY|B_ASYNC|B_AGE); | |
240 | splx(s); | |
241 | } | |
242 | ||
243 | /* | |
244 | * See if the block is associated with some buffer | |
245 | * (mainly to avoid getting hung up on a wait in breada) | |
246 | */ | |
247 | incore(dev, blkno) | |
248 | dev_t dev; | |
249 | daddr_t blkno; | |
250 | { | |
251 | register struct buf *bp; | |
252 | register struct buf *dp; | |
253 | register int dblkno = fsbtodb(blkno); | |
254 | ||
255 | dp = bdevsw[major(dev)].d_tab; | |
256 | for (bp=dp->b_forw; bp != dp; bp = bp->b_forw) | |
257 | if (bp->b_blkno==dblkno && bp->b_dev==dev) | |
258 | return(1); | |
259 | return(0); | |
260 | } | |
261 | ||
262 | struct buf * | |
263 | baddr(dev, blkno) | |
264 | dev_t dev; | |
265 | daddr_t blkno; | |
266 | { | |
267 | ||
268 | if (incore(dev, blkno)) | |
269 | return (bread(dev, blkno)); | |
270 | return (0); | |
271 | } | |
272 | ||
273 | /* | |
274 | * Assign a buffer for the given block. If the appropriate | |
275 | * block is already associated, return it; otherwise search | |
276 | * for the oldest non-busy buffer and reassign it. | |
277 | */ | |
278 | struct buf * | |
279 | getblk(dev, blkno) | |
280 | dev_t dev; | |
281 | daddr_t blkno; | |
282 | { | |
283 | register struct buf *bp; | |
284 | register struct buf *dp; | |
285 | #ifdef DISKMON | |
286 | register i; | |
287 | #endif | |
288 | register int dblkno = fsbtodb(blkno); | |
289 | ||
290 | if(major(dev) >= nblkdev) | |
291 | panic("blkdev"); | |
292 | ||
293 | loop: | |
294 | VOID spl0(); | |
295 | dp = bdevsw[major(dev)].d_tab; | |
296 | if(dp == NULL) | |
297 | panic("devtab"); | |
298 | for (bp=dp->b_forw; bp != dp; bp = bp->b_forw) { | |
299 | if (bp->b_blkno!=dblkno || bp->b_dev!=dev) | |
300 | continue; | |
301 | VOID spl6(); | |
302 | if (bp->b_flags&B_BUSY) { | |
303 | bp->b_flags |= B_WANTED; | |
304 | sleep((caddr_t)bp, PRIBIO+1); | |
305 | goto loop; | |
306 | } | |
307 | VOID spl0(); | |
308 | #ifdef DISKMON | |
309 | i = 0; | |
310 | dp = bp->av_forw; | |
311 | while (dp != &bfreelist) { | |
312 | i++; | |
313 | dp = dp->av_forw; | |
314 | } | |
315 | if (i<NBUF) | |
316 | io_info.bufcount[i]++; | |
317 | #endif | |
318 | notavail(bp); | |
319 | bp->b_flags |= B_CACHE; | |
320 | return(bp); | |
321 | } | |
322 | VOID spl6(); | |
323 | if (bfreelist.av_forw == &bfreelist) { | |
324 | bfreelist.b_flags |= B_WANTED; | |
325 | sleep((caddr_t)&bfreelist, PRIBIO+1); | |
326 | goto loop; | |
327 | } | |
328 | spl0(); | |
329 | bp = bfreelist.av_forw; | |
330 | notavail(bp); | |
331 | if (bp->b_flags & B_DELWRI) { | |
332 | bp->b_flags |= B_ASYNC; | |
333 | bwrite(bp); | |
334 | goto loop; | |
335 | } | |
336 | bp->b_flags = B_BUSY; | |
337 | bp->b_back->b_forw = bp->b_forw; | |
338 | bp->b_forw->b_back = bp->b_back; | |
339 | bp->b_forw = dp->b_forw; | |
340 | bp->b_back = dp; | |
341 | dp->b_forw->b_back = bp; | |
342 | dp->b_forw = bp; | |
343 | bp->b_dev = dev; | |
344 | bp->b_blkno = dblkno; | |
345 | return(bp); | |
346 | } | |
347 | ||
348 | /* | |
349 | * get an empty block, | |
350 | * not assigned to any particular device | |
351 | */ | |
352 | struct buf * | |
353 | geteblk() | |
354 | { | |
355 | register struct buf *bp; | |
356 | register struct buf *dp; | |
357 | ||
358 | loop: | |
359 | VOID spl6(); | |
360 | while (bfreelist.av_forw == &bfreelist) { | |
361 | bfreelist.b_flags |= B_WANTED; | |
362 | sleep((caddr_t)&bfreelist, PRIBIO+1); | |
363 | } | |
364 | VOID spl0(); | |
365 | dp = &bfreelist; | |
366 | bp = bfreelist.av_forw; | |
367 | notavail(bp); | |
368 | if (bp->b_flags & B_DELWRI) { | |
369 | bp->b_flags |= B_ASYNC; | |
370 | bwrite(bp); | |
371 | goto loop; | |
372 | } | |
373 | bp->b_flags = B_BUSY; | |
374 | bp->b_back->b_forw = bp->b_forw; | |
375 | bp->b_forw->b_back = bp->b_back; | |
376 | bp->b_forw = dp->b_forw; | |
377 | bp->b_back = dp; | |
378 | dp->b_forw->b_back = bp; | |
379 | dp->b_forw = bp; | |
380 | bp->b_dev = (dev_t)NODEV; | |
381 | return(bp); | |
382 | } | |
383 | ||
384 | /* | |
385 | * Wait for I/O completion on the buffer; return errors | |
386 | * to the user. | |
387 | */ | |
388 | iowait(bp) | |
389 | register struct buf *bp; | |
390 | { | |
391 | ||
392 | VOID spl6(); | |
393 | while ((bp->b_flags&B_DONE)==0) | |
394 | sleep((caddr_t)bp, PRIBIO); | |
395 | VOID spl0(); | |
396 | geterror(bp); | |
397 | } | |
398 | ||
399 | #ifndef FASTVAX | |
400 | /* | |
401 | * Unlink a buffer from the available list and mark it busy. | |
402 | * (internal interface) | |
403 | */ | |
404 | notavail(bp) | |
405 | register struct buf *bp; | |
406 | { | |
407 | register s; | |
408 | ||
409 | s = spl6(); | |
410 | bp->av_back->av_forw = bp->av_forw; | |
411 | bp->av_forw->av_back = bp->av_back; | |
412 | bp->b_flags |= B_BUSY; | |
413 | splx(s); | |
414 | } | |
415 | #endif | |
416 | ||
417 | /* | |
418 | * Mark I/O complete on a buffer. If the header | |
419 | * indicates a dirty page push completion, the | |
420 | * header is inserted into the ``cleaned'' list | |
421 | * to be processed by the pageout daemon. Otherwise | |
422 | * release it if I/O is asynchronous, and wake | |
423 | * up anyone waiting for it. | |
424 | */ | |
425 | iodone(bp) | |
426 | register struct buf *bp; | |
427 | { | |
428 | register int s; | |
429 | ||
430 | bp->b_flags |= B_DONE; | |
431 | if (bp->b_flags & B_DIRTY) { | |
432 | if (bp->b_flags & B_ERROR) | |
433 | panic("IO err in push"); | |
434 | s = spl6(); | |
435 | cnt.v_pgout++; | |
436 | bp->av_forw = bclnlist; | |
437 | bp->b_bcount = swsize[bp - swbuf]; | |
438 | bp->b_pfcent = swpf[bp - swbuf]; | |
439 | bclnlist = bp; | |
440 | if (bswlist.b_flags & B_WANTED) | |
441 | wakeup((caddr_t)&proc[2]); | |
442 | splx(s); | |
443 | } | |
444 | if (bp->b_flags&B_ASYNC) | |
445 | brelse(bp); | |
446 | else { | |
447 | bp->b_flags &= ~B_WANTED; | |
448 | wakeup((caddr_t)bp); | |
449 | } | |
450 | } | |
451 | ||
452 | /* | |
453 | * Zero the core associated with a buffer. | |
454 | */ | |
455 | clrbuf(bp) | |
456 | struct buf *bp; | |
457 | { | |
458 | register *p; | |
459 | register c; | |
460 | ||
461 | p = bp->b_un.b_words; | |
462 | c = BSIZE/sizeof(int); | |
463 | do | |
464 | *p++ = 0; | |
465 | while (--c); | |
466 | bp->b_resid = 0; | |
467 | } | |
468 | ||
469 | /* | |
470 | * swap I/O - | |
471 | * | |
472 | * If the flag indicates a dirty page push initiated | |
473 | * by the pageout daemon, we map the page into the i th | |
474 | * virtual page of process 2 (the daemon itself) where i is | |
475 | * the index of the swap header that has been allocated. | |
476 | * We simply initialize the header and queue the I/O but | |
477 | * do not wait for completion. When the I/O completes, | |
478 | * iodone() will link the header to a list of cleaned | |
479 | * pages to be processed by the pageout daemon. | |
480 | */ | |
481 | swap(p, dblkno, addr, nbytes, rdflg, flag, dev, pfcent) | |
482 | struct proc *p; | |
483 | swblk_t dblkno; | |
484 | caddr_t addr; | |
485 | int flag, nbytes; | |
486 | dev_t dev; | |
487 | unsigned pfcent; | |
488 | { | |
489 | register struct buf *bp; | |
490 | register int c; | |
491 | int p2dp; | |
492 | register struct pte *dpte, *vpte; | |
493 | ||
494 | VOID spl6(); | |
495 | while (bswlist.av_forw == NULL) { | |
496 | bswlist.b_flags |= B_WANTED; | |
497 | sleep((caddr_t)&bswlist, PSWP+1); | |
498 | } | |
499 | bp = bswlist.av_forw; | |
500 | bswlist.av_forw = bp->av_forw; | |
501 | VOID spl0(); | |
502 | ||
503 | bp->b_flags = B_BUSY | B_PHYS | rdflg | flag; | |
504 | if ((bp->b_flags & (B_DIRTY|B_PGIN)) == 0) | |
505 | if (rdflg == B_READ) | |
506 | sum.v_pswpin += btoc(nbytes); | |
507 | else | |
508 | sum.v_pswpout += btoc(nbytes); | |
509 | bp->b_proc = p; | |
510 | if (flag & B_DIRTY) { | |
511 | p2dp = ((bp - swbuf) * CLSIZE) * KLMAX; | |
512 | dpte = dptopte(&proc[2], p2dp); | |
513 | vpte = vtopte(p, btop(addr)); | |
514 | for (c = 0; c < nbytes; c += NBPG) { | |
515 | if (vpte->pg_pfnum == 0 || vpte->pg_fod) | |
516 | panic("swap bad pte"); | |
517 | *dpte++ = *vpte++; | |
518 | } | |
519 | bp->b_un.b_addr = (caddr_t)ctob(p2dp); | |
520 | } else | |
521 | bp->b_un.b_addr = addr; | |
522 | while (nbytes > 0) { | |
523 | c = imin(ctob(120), nbytes); | |
524 | bp->b_bcount = c; | |
525 | bp->b_blkno = dblkno; | |
526 | bp->b_dev = dev; | |
527 | if (dev == swapdev) | |
528 | bp->b_blkno += swplo; | |
529 | (*bdevsw[major(dev)].d_strategy)(bp); | |
530 | if (flag & B_DIRTY) { | |
531 | if (c < nbytes) | |
532 | panic("big push"); | |
533 | swsize[bp - swbuf] = nbytes; | |
534 | swpf[bp - swbuf] = pfcent; | |
535 | return; | |
536 | } | |
537 | VOID spl6(); | |
538 | while((bp->b_flags&B_DONE)==0) | |
539 | sleep((caddr_t)bp, PSWP); | |
540 | VOID spl0(); | |
541 | bp->b_un.b_addr += c; | |
542 | bp->b_flags &= ~B_DONE; | |
543 | if (bp->b_flags & B_ERROR) { | |
544 | if ((flag & (B_UAREA|B_PAGET)) || rdflg == B_WRITE) | |
545 | panic("hard IO err in swap"); | |
546 | swkill(p, (char *)0); | |
547 | } | |
548 | nbytes -= c; | |
549 | dblkno += btoc(c); | |
550 | } | |
551 | VOID spl6(); | |
552 | bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_PAGET|B_UAREA|B_DIRTY); | |
553 | bp->av_forw = bswlist.av_forw; | |
554 | bswlist.av_forw = bp; | |
555 | if (bswlist.b_flags & B_WANTED) { | |
556 | bswlist.b_flags &= ~B_WANTED; | |
557 | wakeup((caddr_t)&bswlist); | |
558 | wakeup((caddr_t)&proc[2]); | |
559 | } | |
560 | VOID spl0(); | |
561 | } | |
562 | ||
563 | /* | |
564 | * If rout == 0 then killed on swap error, else | |
565 | * rout is the name of the routine where we ran out of | |
566 | * swap space. | |
567 | */ | |
568 | swkill(p, rout) | |
569 | struct proc *p; | |
570 | char *rout; | |
571 | { | |
572 | ||
573 | printf("%d: ", p->p_pid); | |
574 | if (rout) | |
575 | printf("out of swap space in %s\n", rout); | |
576 | else | |
577 | printf("killed on swap error\n"); | |
578 | /* | |
579 | * To be sure no looping (e.g. in vmsched trying to | |
580 | * swap out) mark process locked in core (as though | |
581 | * done by user) after killing it so noone will try | |
582 | * to swap it out. | |
583 | */ | |
584 | psignal(p, SIGKIL); | |
585 | p->p_flag |= SULOCK; | |
586 | } | |
587 | ||
588 | /* | |
589 | * make sure all write-behind blocks | |
590 | * on dev (or NODEV for all) | |
591 | * are flushed out. | |
592 | * (from umount and update) | |
593 | */ | |
594 | bflush(dev) | |
595 | dev_t dev; | |
596 | { | |
597 | register struct buf *bp; | |
598 | ||
599 | loop: | |
600 | VOID spl6(); | |
601 | for (bp = bfreelist.av_forw; bp != &bfreelist; bp = bp->av_forw) { | |
602 | if (bp->b_flags&B_DELWRI && (dev == NODEV||dev==bp->b_dev)) { | |
603 | bp->b_flags |= B_ASYNC; | |
604 | notavail(bp); | |
605 | bwrite(bp); | |
606 | goto loop; | |
607 | } | |
608 | } | |
609 | VOID spl0(); | |
610 | } | |
611 | ||
612 | /* | |
613 | * Raw I/O. The arguments are | |
614 | * The strategy routine for the device | |
615 | * A buffer, which will always be a special buffer | |
616 | * header owned exclusively by the device for this purpose | |
617 | * The device number | |
618 | * Read/write flag | |
619 | * Essentially all the work is computing physical addresses and | |
620 | * validating them. | |
621 | * If the user has the proper access privilidges, the process is | |
622 | * marked 'delayed unlock' and the pages involved in the I/O are | |
623 | * faulted and locked. After the completion of the I/O, the above pages | |
624 | * are unlocked. | |
625 | */ | |
626 | physio(strat, bp, dev, rw, mincnt) | |
627 | int (*strat)(); | |
628 | register struct buf *bp; | |
629 | unsigned (*mincnt)(); | |
630 | { | |
631 | register int c; | |
632 | char *a; | |
633 | ||
634 | if (useracc(u.u_base,u.u_count,rw==B_READ?B_WRITE:B_READ) == NULL) { | |
635 | u.u_error = EFAULT; | |
636 | return; | |
637 | } | |
638 | VOID spl6(); | |
639 | while (bp->b_flags&B_BUSY) { | |
640 | bp->b_flags |= B_WANTED; | |
641 | sleep((caddr_t)bp, PRIBIO+1); | |
642 | } | |
643 | bp->b_error = 0; | |
644 | bp->b_proc = u.u_procp; | |
645 | bp->b_un.b_addr = u.u_base; | |
646 | while (u.u_count != 0 && bp->b_error==0) { | |
647 | bp->b_flags = B_BUSY | B_PHYS | rw; | |
648 | bp->b_dev = dev; | |
649 | bp->b_blkno = u.u_offset >> PGSHIFT; | |
650 | bp->b_bcount = u.u_count; | |
651 | (*mincnt)(bp); | |
652 | c = bp->b_bcount; | |
653 | u.u_procp->p_flag |= SPHYSIO; | |
654 | vslock(a = bp->b_un.b_addr, c); | |
655 | (*strat)(bp); | |
656 | VOID spl6(); | |
657 | while ((bp->b_flags&B_DONE) == 0) | |
658 | sleep((caddr_t)bp, PRIBIO); | |
659 | vsunlock(a, c, rw); | |
660 | u.u_procp->p_flag &= ~SPHYSIO; | |
661 | if (bp->b_flags&B_WANTED) | |
662 | wakeup((caddr_t)bp); | |
663 | VOID spl0(); | |
664 | bp->b_un.b_addr += c; | |
665 | u.u_count -= c; | |
666 | u.u_offset += c; | |
667 | } | |
668 | bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS); | |
669 | u.u_count = bp->b_resid; | |
670 | geterror(bp); | |
671 | } | |
672 | ||
673 | /*ARGSUSED*/ | |
674 | unsigned | |
675 | minphys(bp) | |
676 | struct buf *bp; | |
677 | { | |
678 | ||
679 | if (bp->b_bcount > 60 * 1024) | |
680 | bp->b_bcount = 60 * 1024; | |
681 | } | |
682 | ||
683 | /* | |
684 | * Pick up the device's error number and pass it to the user; | |
685 | * if there is an error but the number is 0 set a generalized | |
686 | * code. Actually the latter is always true because devices | |
687 | * don't yet return specific errors. | |
688 | */ | |
689 | geterror(bp) | |
690 | register struct buf *bp; | |
691 | { | |
692 | ||
693 | if (bp->b_flags&B_ERROR) | |
694 | if ((u.u_error = bp->b_error)==0) | |
695 | u.u_error = EIO; | |
696 | } |