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--- old/usr/src/uts/common/syscall/poll.c
+++ new/usr/src/uts/common/syscall/poll.c
1 1 /*
2 2 * CDDL HEADER START
3 3 *
4 4 * The contents of this file are subject to the terms of the
5 5 * Common Development and Distribution License (the "License").
6 6 * You may not use this file except in compliance with the License.
7 7 *
8 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 9 * or http://www.opensolaris.org/os/licensing.
10 10 * See the License for the specific language governing permissions
11 11 * and limitations under the License.
12 12 *
13 13 * When distributing Covered Code, include this CDDL HEADER in each
14 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 15 * If applicable, add the following below this CDDL HEADER, with the
16 16 * fields enclosed by brackets "[]" replaced with your own identifying
17 17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 18 *
19 19 * CDDL HEADER END
20 20 */
21 21
22 22 /*
23 23 * Copyright 2010 Sun Microsystems, Inc. All rights reserved.
24 24 * Use is subject to license terms.
25 25 */
26 26
27 27 /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
28 28 /* All Rights Reserved */
29 29
30 30 /*
31 31 * Copyright (c) 2012 by Delphix. All rights reserved.
32 32 * Copyright 2016, Joyent, Inc.
33 33 */
34 34
35 35 /*
36 36 * Portions of this source code were derived from Berkeley 4.3 BSD
37 37 * under license from the Regents of the University of California.
38 38 */
39 39
40 40 #include <sys/param.h>
41 41 #include <sys/isa_defs.h>
42 42 #include <sys/types.h>
43 43 #include <sys/sysmacros.h>
44 44 #include <sys/user.h>
45 45 #include <sys/systm.h>
46 46 #include <sys/errno.h>
47 47 #include <sys/time.h>
48 48 #include <sys/vnode.h>
49 49 #include <sys/file.h>
50 50 #include <sys/mode.h>
51 51 #include <sys/proc.h>
52 52 #include <sys/uio.h>
53 53 #include <sys/poll_impl.h>
54 54 #include <sys/kmem.h>
55 55 #include <sys/cmn_err.h>
56 56 #include <sys/debug.h>
57 57 #include <sys/bitmap.h>
58 58 #include <sys/kstat.h>
59 59 #include <sys/rctl.h>
60 60 #include <sys/port_impl.h>
61 61 #include <sys/schedctl.h>
62 62 #include <sys/cpu.h>
63 63
64 64 #define NPHLOCKS 64 /* Number of locks; must be power of 2 */
65 65 #define PHLOCKADDR(php) &plocks[(((uintptr_t)(php)) >> 8) & (NPHLOCKS - 1)]
66 66 #define PHLOCK(php) PHLOCKADDR(php).pp_lock
67 67 #define PH_ENTER(php) mutex_enter(PHLOCK(php))
68 68 #define PH_EXIT(php) mutex_exit(PHLOCK(php))
69 69 #define VALID_POLL_EVENTS (POLLIN | POLLPRI | POLLOUT | POLLRDNORM \
70 70 | POLLRDBAND | POLLWRBAND | POLLHUP | POLLERR | POLLNVAL)
71 71
72 72 /*
73 73 * global counters to collect some stats
74 74 */
75 75 static struct {
76 76 kstat_named_t polllistmiss; /* failed to find a cached poll list */
77 77 kstat_named_t pollcachehit; /* list matched 100% w/ cached one */
78 78 kstat_named_t pollcachephit; /* list matched < 100% w/ cached one */
79 79 kstat_named_t pollcachemiss; /* every list entry is dif from cache */
80 80 kstat_named_t pollunlockfail; /* failed to perform pollunlock */
81 81 } pollstats = {
82 82 { "polllistmiss", KSTAT_DATA_UINT64 },
83 83 { "pollcachehit", KSTAT_DATA_UINT64 },
84 84 { "pollcachephit", KSTAT_DATA_UINT64 },
85 85 { "pollcachemiss", KSTAT_DATA_UINT64 },
86 86 { "pollunlockfail", KSTAT_DATA_UINT64 }
87 87 };
88 88
89 89 kstat_named_t *pollstats_ptr = (kstat_named_t *)&pollstats;
90 90 uint_t pollstats_ndata = sizeof (pollstats) / sizeof (kstat_named_t);
91 91
92 92 struct pplock {
93 93 kmutex_t pp_lock;
94 94 short pp_flag;
95 95 kcondvar_t pp_wait_cv;
96 96 int32_t pp_pad; /* to a nice round 16 bytes */
97 97 };
98 98
99 99 static struct pplock plocks[NPHLOCKS]; /* Hash array of pollhead locks */
100 100
101 101 /* Contention lock & list for preventing deadlocks in recursive /dev/poll. */
102 102 static kmutex_t pollstate_contenders_lock;
103 103 static pollstate_t *pollstate_contenders = NULL;
104 104
105 105 #ifdef DEBUG
106 106 static int pollchecksanity(pollstate_t *, nfds_t);
107 107 static int pollcheckxref(pollstate_t *, int);
108 108 static void pollcheckphlist(void);
109 109 static int pollcheckrevents(pollstate_t *, int, int, int);
110 110 static void checkpolldat(pollstate_t *);
111 111 #endif /* DEBUG */
112 112 static int plist_chkdupfd(file_t *, polldat_t *, pollstate_t *, pollfd_t *, int,
113 113 int *);
114 114
115 115 /*
116 116 * Data structure overview:
117 117 * The per-thread poll state consists of
118 118 * one pollstate_t
119 119 * one pollcache_t
120 120 * one bitmap with one event bit per fd
121 121 * a (two-dimensional) hashed array of polldat_t structures - one entry
122 122 * per fd
123 123 *
124 124 * This conglomerate of data structures interact with
125 125 * the pollhead which is used by VOP_POLL and pollwakeup
126 126 * (protected by the PHLOCK, cached array of plocks), and
127 127 * the fpollinfo list hanging off the fi_list which is used to notify
128 128 * poll when a cached fd is closed. This is protected by uf_lock.
129 129 *
130 130 * Invariants:
131 131 * pd_php (pollhead pointer) is set iff (if and only if) the polldat
132 132 * is on that pollhead. This is modified atomically under pc_lock.
133 133 *
134 134 * pd_fp (file_t pointer) is set iff the thread is on the fpollinfo
135 135 * list for that open file.
136 136 * This is modified atomically under pc_lock.
137 137 *
138 138 * pd_count is the sum (over all values of i) of pd_ref[i].xf_refcnt.
139 139 * Iff pd_ref[i].xf_refcnt >= 1 then
140 140 * ps_pcacheset[i].pcs_pollfd[pd_ref[i].xf_position].fd == pd_fd
141 141 * Iff pd_ref[i].xf_refcnt > 1 then
142 142 * In ps_pcacheset[i].pcs_pollfd between index
143 143 * pd_ref[i].xf_position] and the end of the list
144 144 * there are xf_refcnt entries with .fd == pd_fd
145 145 *
146 146 * Locking design:
147 147 * Whenever possible the design relies on the fact that the poll cache state
148 148 * is per thread thus for both poll and exit it is self-synchronizing.
149 149 * Thus the key interactions where other threads access the state are:
150 150 * pollwakeup (and polltime), and
151 151 * close cleaning up the cached references to an open file
152 152 *
153 153 * The two key locks in poll proper is ps_lock and pc_lock.
154 154 *
155 155 * The ps_lock is used for synchronization between poll, (lwp_)exit and close
156 156 * to ensure that modifications to pollcacheset structure are serialized.
157 157 * This lock is held through most of poll() except where poll sleeps
158 158 * since there is little need to handle closes concurrently with the execution
159 159 * of poll.
160 160 * The pc_lock protects most of the fields in pollcache structure and polldat
161 161 * structures (which are accessed by poll, pollwakeup, and polltime)
162 162 * with the exception of fields that are only modified when only one thread
163 163 * can access this per-thread state.
164 164 * Those exceptions occur in poll when first allocating the per-thread state,
165 165 * when poll grows the number of polldat (never shrinks), and when
166 166 * exit/pollcleanup has ensured that there are no references from either
167 167 * pollheads or fpollinfo to the threads poll state.
168 168 *
169 169 * Poll(2) system call is the only path which ps_lock and pc_lock are both
170 170 * held, in that order. It needs ps_lock to synchronize with close and
171 171 * lwp_exit; and pc_lock with pollwakeup.
172 172 *
173 173 * The locking interaction between pc_lock and PHLOCK take into account
174 174 * that poll acquires these locks in the order of pc_lock and then PHLOCK
175 175 * while pollwakeup does it in the reverse order. Thus pollwakeup implements
176 176 * deadlock avoidance by dropping the locks and reacquiring them in the
177 177 * reverse order. For this to work pollwakeup needs to prevent the thread
178 178 * from exiting and freeing all of the poll related state. Thus is done
179 179 * using
180 180 * the pc_no_exit lock
181 181 * the pc_busy counter
182 182 * the pc_busy_cv condition variable
183 183 *
184 184 * The locking interaction between pc_lock and uf_lock has similar
185 185 * issues. Poll holds ps_lock and/or pc_lock across calls to getf/releasef
186 186 * which acquire uf_lock. The poll cleanup in close needs to hold uf_lock
187 187 * to prevent poll or exit from doing a delfpollinfo after which the thread
188 188 * might exit. But the cleanup needs to acquire pc_lock when modifying
189 189 * the poll cache state. The solution is to use pc_busy and do the close
190 190 * cleanup in two phases:
191 191 * First close calls pollblockexit which increments pc_busy.
192 192 * This prevents the per-thread poll related state from being freed.
193 193 * Then close drops uf_lock and calls pollcacheclean.
194 194 * This routine can then acquire pc_lock and remove any references
195 195 * to the closing fd (as well as recording that it has been closed
196 196 * so that a POLLNVAL can be generated even if the fd is reused before
197 197 * poll has been woken up and checked getf() again).
198 198 *
199 199 * When removing a polled fd from poll cache, the fd is always removed
200 200 * from pollhead list first and then from fpollinfo list, i.e.,
201 201 * pollhead_delete() is called before delfpollinfo().
202 202 *
203 203 *
204 204 * Locking hierarchy:
205 205 * pc_no_exit is a leaf level lock.
206 206 * ps_lock is held when acquiring pc_lock (except when pollwakeup
207 207 * acquires pc_lock).
208 208 * pc_lock might be held when acquiring PHLOCK (pollhead_insert/
209 209 * pollhead_delete)
210 210 * pc_lock is always held (but this is not required)
211 211 * when acquiring PHLOCK (in polladd/pollhead_delete and pollwakeup called
212 212 * from pcache_clean_entry).
213 213 * pc_lock is held across addfpollinfo/delfpollinfo which acquire
214 214 * uf_lock.
215 215 * pc_lock is held across getf/releasef which acquire uf_lock.
216 216 * ps_lock might be held across getf/releasef which acquire uf_lock.
217 217 * pollwakeup tries to acquire pc_lock while holding PHLOCK
218 218 * but drops the locks and reacquire them in reverse order to avoid
219 219 * deadlock.
220 220 *
221 221 * Note also that there is deadlock avoidance support for VOP_POLL routines
222 222 * and pollwakeup involving a file system or driver lock.
223 223 * See below.
224 224 */
225 225
226 226 /*
227 227 * Deadlock avoidance support for VOP_POLL() routines. This is
228 228 * sometimes necessary to prevent deadlock between polling threads
229 229 * (which hold poll locks on entry to xx_poll(), then acquire foo)
230 230 * and pollwakeup() threads (which hold foo, then acquire poll locks).
231 231 *
232 232 * pollunlock(*cookie) releases whatever poll locks the current thread holds,
233 233 * setting a cookie for use by pollrelock();
234 234 *
235 235 * pollrelock(cookie) reacquires previously dropped poll locks;
236 236 *
237 237 * polllock(php, mutex) does the common case: pollunlock(),
238 238 * acquire the problematic mutex, pollrelock().
239 239 *
240 240 * If polllock() or pollunlock() return non-zero, it indicates that a recursive
241 241 * /dev/poll is in progress and pollcache locks cannot be dropped. Callers
242 242 * must handle this by indicating a POLLNVAL in the revents of the VOP_POLL.
243 243 */
244 244 int
245 245 pollunlock(int *lockstate)
246 246 {
247 247 pollstate_t *ps = curthread->t_pollstate;
248 248 pollcache_t *pcp;
249 249
250 250 ASSERT(lockstate != NULL);
251 251
252 252 /*
253 253 * There is no way to safely perform a pollunlock() while in the depths
254 254 * of a recursive /dev/poll operation.
255 255 */
256 256 if (ps != NULL && ps->ps_depth > 1) {
257 257 ps->ps_flags |= POLLSTATE_ULFAIL;
258 258 pollstats.pollunlockfail.value.ui64++;
259 259 return (-1);
260 260 }
261 261
262 262 /*
263 263 * t_pollcache is set by /dev/poll and event ports (port_fd.c).
264 264 * If the pollrelock/pollunlock is called as a result of poll(2),
265 265 * the t_pollcache should be NULL.
266 266 */
267 267 if (curthread->t_pollcache == NULL)
268 268 pcp = ps->ps_pcache;
269 269 else
270 270 pcp = curthread->t_pollcache;
271 271
272 272 if (!mutex_owned(&pcp->pc_lock)) {
273 273 *lockstate = 0;
274 274 } else {
275 275 *lockstate = 1;
276 276 mutex_exit(&pcp->pc_lock);
277 277 }
278 278 return (0);
279 279 }
280 280
281 281 void
282 282 pollrelock(int lockstate)
283 283 {
284 284 pollstate_t *ps = curthread->t_pollstate;
285 285 pollcache_t *pcp;
286 286
287 287 /* Skip this whole ordeal if the pollcache was not locked to begin */
288 288 if (lockstate == 0)
289 289 return;
290 290
291 291 /*
292 292 * t_pollcache is set by /dev/poll and event ports (port_fd.c).
293 293 * If the pollrelock/pollunlock is called as a result of poll(2),
294 294 * the t_pollcache should be NULL.
295 295 */
296 296 if (curthread->t_pollcache == NULL)
297 297 pcp = ps->ps_pcache;
298 298 else
299 299 pcp = curthread->t_pollcache;
300 300
301 301 mutex_enter(&pcp->pc_lock);
302 302 }
303 303
304 304 /* ARGSUSED */
305 305 int
306 306 polllock(pollhead_t *php, kmutex_t *lp)
307 307 {
308 308 if (mutex_tryenter(lp) == 0) {
309 309 int state;
310 310
311 311 if (pollunlock(&state) != 0) {
312 312 return (-1);
313 313 }
314 314 mutex_enter(lp);
315 315 pollrelock(state);
316 316 }
317 317 return (0);
318 318 }
319 319
320 320 int
321 321 poll_copyin(pollstate_t *ps, pollfd_t *fds, nfds_t nfds)
322 322 {
323 323 pollfd_t *pollfdp;
324 324 nfds_t old_nfds;
325 325
326 326 /*
327 327 * NOTE: for performance, buffers are saved across poll() calls.
328 328 * The theory is that if a process polls heavily, it tends to poll
329 329 * on the same set of descriptors. Therefore, we only reallocate
330 330 * buffers when nfds changes. There is no hysteresis control,
331 331 * because there is no data to suggest that this is necessary;
332 332 * the penalty of reallocating is not *that* great in any event.
333 333 */
334 334 old_nfds = ps->ps_nfds;
335 335 if (nfds != old_nfds) {
336 336 kmem_free(ps->ps_pollfd, old_nfds * sizeof (pollfd_t));
337 337 pollfdp = kmem_alloc(nfds * sizeof (pollfd_t), KM_SLEEP);
338 338 ps->ps_pollfd = pollfdp;
339 339 ps->ps_nfds = nfds;
340 340 }
341 341
342 342 pollfdp = ps->ps_pollfd;
343 343 if (copyin(fds, pollfdp, nfds * sizeof (pollfd_t))) {
344 344 return (EFAULT);
345 345 }
346 346
347 347 if (fds == NULL) {
348 348 /*
349 349 * If the process has page 0 mapped, then the copyin() above
350 350 * will succeed even if fds is NULL. However, our cached
351 351 * poll lists are keyed by the address of the passed-in fds
352 352 * structure, and we use the value NULL to indicate an unused
353 353 * poll cache list entry. As such, we elect not to support
354 354 * NULL as a valid (user) memory address and fail the poll()
355 355 * call.
356 356 */
357 357 return (EFAULT);
358 358 }
359 359 return (0);
360 360 }
361 361
362 362 int
363 363 poll_common(pollstate_t *ps, pollfd_t *fds, nfds_t nfds, timespec_t *tsp,
364 364 int *fdcnt)
365 365 {
366 366 kthread_t *t = curthread;
367 367 hrtime_t deadline; /* hrtime value when we want to return */
368 368 pollfd_t *pollfdp;
369 369 pollcache_t *pcp;
370 370 int error = 0;
371 371 int cacheindex = 0; /* which cache set is used */
372 372
373 373 /*
374 374 * Determine the precise future time of the requested timeout, if any.
375 375 */
376 376 if (tsp == NULL) {
377 377 deadline = -1;
378 378 } else if (tsp->tv_sec == 0 && tsp->tv_nsec == 0) {
379 379 deadline = 0;
380 380 } else if (tsp->tv_sec >= HRTIME_MAX/NANOSEC) {
381 381 /* Use an indefinite timeout if tv_sec would cause overflow */
382 382 deadline = -1;
383 383 } else {
384 384 /*
385 385 * The above check, when combined with the protections offered
386 386 * by itimerspecfix (ensuring that neither field is negative
387 387 * and that tv_nsec represents less than a whole second), will
388 388 * prevent overflow during the conversion from timespec_t to
389 389 * uhrtime_t.
390 390 */
391 391 uhrtime_t utime = tsp->tv_sec * NANOSEC;
392 392 utime += tsp->tv_nsec;
393 393
394 394 /* They must wait at least a tick. */
395 395 utime = MAX(utime, nsec_per_tick);
396 396
397 397 /*
398 398 * Since utime has an upper bound of HRTIME_MAX, adding the
399 399 * gethrtime() result cannot incur an overflow as the unsigned
400 400 * type has an adequate bound.
401 401 */
402 402 utime += (uhrtime_t)gethrtime();
403 403 if (utime > HRTIME_MAX) {
404 404 deadline = -1;
405 405 } else {
406 406 deadline = (hrtime_t)utime;
407 407 }
408 408 }
409 409
410 410 /*
411 411 * Check to see if the caller just wants to use poll() as a timeout.
412 412 * If yes then bypass all the other stuff and make him sleep.
413 413 */
414 414 if (nfds == 0) {
415 415 *fdcnt = 0;
416 416 /*
417 417 * Sleep until we have passed the requested future
418 418 * time or until interrupted by a signal.
419 419 * Do not check for signals if we do not want to wait.
420 420 */
421 421 if (deadline != 0) {
422 422 mutex_enter(&t->t_delay_lock);
423 423 while ((error = cv_timedwait_sig_hrtime(&t->t_delay_cv,
424 424 &t->t_delay_lock, deadline)) > 0)
425 425 continue;
426 426 mutex_exit(&t->t_delay_lock);
427 427 return ((error == 0) ? EINTR : 0);
428 428 }
429 429 return (0);
430 430 }
431 431
432 432 VERIFY(ps != NULL);
433 433 pollfdp = ps->ps_pollfd;
434 434 VERIFY(pollfdp != NULL);
435 435
436 436 /*
437 437 * If this thread polls for the first time, allocate ALL poll
438 438 * cache data structures and cache the poll fd list. This
439 439 * allocation is delayed till now because lwp's polling 0 fd
440 440 * (i.e. using poll as timeout()) don't need this memory.
441 441 */
442 442 mutex_enter(&ps->ps_lock);
443 443 pcp = ps->ps_pcache;
444 444 ASSERT(pcp != NULL);
445 445 if (pcp->pc_bitmap == NULL) {
446 446 pcache_create(pcp, nfds);
447 447 /*
448 448 * poll and cache this poll fd list in ps_pcacheset[0].
449 449 */
450 450 error = pcacheset_cache_list(ps, fds, fdcnt, cacheindex);
451 451 if (error || *fdcnt) {
452 452 mutex_exit(&ps->ps_lock);
453 453 return (error);
454 454 }
455 455 } else {
456 456 pollcacheset_t *pcset = ps->ps_pcacheset;
457 457
458 458 /*
459 459 * Not first time polling. Select a cached poll list by
460 460 * matching user pollfd list buffer address.
461 461 */
462 462 for (cacheindex = 0; cacheindex < ps->ps_nsets; cacheindex++) {
463 463 if (pcset[cacheindex].pcs_usradr == (uintptr_t)fds) {
464 464 if ((++pcset[cacheindex].pcs_count) == 0) {
465 465 /*
466 466 * counter is wrapping around.
467 467 */
468 468 pcacheset_reset_count(ps, cacheindex);
469 469 }
470 470 /*
471 471 * examine and resolve possible
472 472 * difference of the current poll
473 473 * list and previously cached one.
474 474 * If there is an error during resolve(),
475 475 * the callee will guarantee the consistency
476 476 * of cached poll list and cache content.
477 477 */
478 478 error = pcacheset_resolve(ps, nfds, fdcnt,
479 479 cacheindex);
480 480 if (error) {
481 481 mutex_exit(&ps->ps_lock);
482 482 return (error);
483 483 }
484 484 break;
485 485 }
486 486
487 487 /*
488 488 * Note that pcs_usradr field of an used entry won't be
489 489 * NULL because it stores the address of passed-in fds,
490 490 * and NULL fds will not be cached (Then it is either
491 491 * the special timeout case when nfds is 0 or it returns
492 492 * failure directly).
493 493 */
494 494 if (pcset[cacheindex].pcs_usradr == NULL) {
495 495 /*
496 496 * found an unused entry. Use it to cache
497 497 * this poll list.
498 498 */
499 499 error = pcacheset_cache_list(ps, fds, fdcnt,
500 500 cacheindex);
501 501 if (error || *fdcnt) {
502 502 mutex_exit(&ps->ps_lock);
503 503 return (error);
504 504 }
505 505 break;
506 506 }
507 507 }
508 508 if (cacheindex == ps->ps_nsets) {
509 509 /*
510 510 * We failed to find a matching cached poll fd list.
511 511 * replace an old list.
512 512 */
513 513 pollstats.polllistmiss.value.ui64++;
514 514 cacheindex = pcacheset_replace(ps);
515 515 ASSERT(cacheindex < ps->ps_nsets);
516 516 pcset[cacheindex].pcs_usradr = (uintptr_t)fds;
517 517 error = pcacheset_resolve(ps, nfds, fdcnt, cacheindex);
518 518 if (error) {
519 519 mutex_exit(&ps->ps_lock);
520 520 return (error);
521 521 }
522 522 }
523 523 }
524 524
525 525 /*
526 526 * Always scan the bitmap with the lock on the pollcache held.
527 527 * This is to make sure that a wakeup does not come undetected.
528 528 * If the lock is not held, a pollwakeup could have come for an
529 529 * fd we already checked but before this thread sleeps, in which
530 530 * case the wakeup is missed. Now we hold the pcache lock and
531 531 * check the bitmap again. This will prevent wakeup from happening
532 532 * while we hold pcache lock since pollwakeup() will also lock
533 533 * the pcache before updating poll bitmap.
534 534 */
535 535 mutex_enter(&pcp->pc_lock);
536 536 for (;;) {
537 537 pcp->pc_flag = 0;
538 538 error = pcache_poll(pollfdp, ps, nfds, fdcnt, cacheindex);
539 539 if (error || *fdcnt) {
540 540 mutex_exit(&pcp->pc_lock);
541 541 mutex_exit(&ps->ps_lock);
542 542 break;
543 543 }
544 544
545 545 /*
546 546 * If PC_POLLWAKE is set, a pollwakeup() was performed on
547 547 * one of the file descriptors. This can happen only if
548 548 * one of the VOP_POLL() functions dropped pcp->pc_lock.
549 549 * The only current cases of this is in procfs (prpoll())
550 550 * and STREAMS (strpoll()).
551 551 */
552 552 if (pcp->pc_flag & PC_POLLWAKE)
553 553 continue;
554 554
555 555 /*
556 556 * If you get here, the poll of fds was unsuccessful.
557 557 * Wait until some fd becomes readable, writable, or gets
558 558 * an exception, or until a signal or a timeout occurs.
559 559 * Do not check for signals if we have a zero timeout.
560 560 */
561 561 mutex_exit(&ps->ps_lock);
562 562 if (deadline == 0) {
563 563 error = -1;
564 564 } else {
565 565 error = cv_timedwait_sig_hrtime(&pcp->pc_cv,
566 566 &pcp->pc_lock, deadline);
567 567 }
568 568 mutex_exit(&pcp->pc_lock);
569 569 /*
570 570 * If we have received a signal or timed out
571 571 * then break out and return.
572 572 */
573 573 if (error <= 0) {
574 574 error = (error == 0) ? EINTR : 0;
575 575 break;
576 576 }
577 577 /*
578 578 * We have not received a signal or timed out.
579 579 * Continue around and poll fds again.
580 580 */
581 581 mutex_enter(&ps->ps_lock);
582 582 mutex_enter(&pcp->pc_lock);
583 583 }
584 584
585 585 return (error);
586 586 }
587 587
588 588 /*
589 589 * This is the system call trap that poll(),
590 590 * select() and pselect() are built upon.
591 591 * It is a private interface between libc and the kernel.
592 592 */
593 593 int
594 594 pollsys(pollfd_t *fds, nfds_t nfds, timespec_t *timeoutp, sigset_t *setp)
595 595 {
596 596 kthread_t *t = curthread;
597 597 klwp_t *lwp = ttolwp(t);
598 598 proc_t *p = ttoproc(t);
599 599 timespec_t ts;
600 600 timespec_t *tsp;
601 601 k_sigset_t kset;
602 602 pollstate_t *ps = NULL;
603 603 pollfd_t *pollfdp = NULL;
604 604 int error = 0, fdcnt = 0;
605 605
606 606 /*
607 607 * Copy in timeout
608 608 */
609 609 if (timeoutp == NULL) {
610 610 tsp = NULL;
611 611 } else {
612 612 if (get_udatamodel() == DATAMODEL_NATIVE) {
613 613 if (copyin(timeoutp, &ts, sizeof (ts)))
614 614 return (set_errno(EFAULT));
615 615 } else {
616 616 timespec32_t ts32;
617 617
618 618 if (copyin(timeoutp, &ts32, sizeof (ts32)))
619 619 return (set_errno(EFAULT));
620 620 TIMESPEC32_TO_TIMESPEC(&ts, &ts32)
621 621 }
622 622
623 623 if (itimerspecfix(&ts))
624 624 return (set_errno(EINVAL));
625 625 tsp = &ts;
626 626 }
627 627
628 628 /*
629 629 * Copy in and reset signal mask, if requested.
630 630 */
631 631 if (setp != NULL) {
632 632 sigset_t set;
633 633
634 634 if (copyin(setp, &set, sizeof (set)))
635 635 return (set_errno(EFAULT));
636 636 sigutok(&set, &kset);
637 637
638 638 mutex_enter(&p->p_lock);
639 639 schedctl_finish_sigblock(t);
640 640 lwp->lwp_sigoldmask = t->t_hold;
641 641 t->t_hold = kset;
642 642 t->t_flag |= T_TOMASK;
643 643 /*
644 644 * Call cv_reltimedwait_sig() just to check for signals.
645 645 * We will return immediately with either 0 or -1.
646 646 */
647 647 if (!cv_reltimedwait_sig(&t->t_delay_cv, &p->p_lock, 0,
648 648 TR_CLOCK_TICK)) {
649 649 mutex_exit(&p->p_lock);
650 650 error = EINTR;
651 651 goto pollout;
652 652 }
653 653 mutex_exit(&p->p_lock);
654 654 }
655 655
656 656 /*
657 657 * Initialize pollstate and copy in pollfd data if present.
658 658 * If nfds == 0, we will skip all of the copying and check steps and
659 659 * proceed directly into poll_common to process the supplied timeout.
660 660 */
661 661 if (nfds != 0) {
662 662 if (nfds > p->p_fno_ctl) {
663 663 mutex_enter(&p->p_lock);
664 664 (void) rctl_action(rctlproc_legacy[RLIMIT_NOFILE],
665 665 p->p_rctls, p, RCA_SAFE);
666 666 mutex_exit(&p->p_lock);
667 667 error = EINVAL;
668 668 goto pollout;
669 669 }
670 670
671 671 /*
672 672 * Need to allocate memory for pollstate before anything
673 673 * because the mutex and cv are created in this space
674 674 */
675 675 ps = pollstate_create();
676 676 if (ps->ps_pcache == NULL)
677 677 ps->ps_pcache = pcache_alloc();
678 678
679 679 if ((error = poll_copyin(ps, fds, nfds)) != 0)
680 680 goto pollout;
681 681 pollfdp = ps->ps_pollfd;
682 682 }
683 683
684 684 /*
685 685 * Perform the actual poll.
686 686 */
687 687 error = poll_common(ps, fds, nfds, tsp, &fdcnt);
688 688
689 689 pollout:
690 690 /*
691 691 * If we changed the signal mask but we received no signal then restore
692 692 * the signal mask. Otherwise psig() will deal with the signal mask.
693 693 */
694 694 if (setp != NULL) {
695 695 mutex_enter(&p->p_lock);
696 696 if (lwp->lwp_cursig == 0) {
697 697 t->t_hold = lwp->lwp_sigoldmask;
698 698 t->t_flag &= ~T_TOMASK;
699 699 }
700 700 mutex_exit(&p->p_lock);
701 701 }
702 702
703 703 if (error)
704 704 return (set_errno(error));
705 705 /*
706 706 * Copy out the events and return the fdcnt to the user.
707 707 */
708 708 if (nfds != 0 && copyout(pollfdp, fds, nfds * sizeof (pollfd_t)))
709 709 return (set_errno(EFAULT));
710 710
711 711 #ifdef DEBUG
712 712 /*
713 713 * Another sanity check:
714 714 */
715 715 if (fdcnt) {
716 716 int i, reventcnt = 0;
717 717
718 718 for (i = 0; i < nfds; i++) {
719 719 if (pollfdp[i].fd < 0) {
720 720 ASSERT(pollfdp[i].revents == 0);
721 721 continue;
722 722 }
723 723 if (pollfdp[i].revents) {
724 724 reventcnt++;
725 725 }
726 726 }
727 727 ASSERT(fdcnt == reventcnt);
728 728 } else {
729 729 int i;
730 730
731 731 for (i = 0; i < nfds; i++) {
732 732 ASSERT(pollfdp[i].revents == 0);
733 733 }
734 734 }
735 735 #endif /* DEBUG */
736 736
737 737 return (fdcnt);
738 738 }
739 739
740 740 /*
741 741 * Clean up any state left around by poll(2). Called when a thread exits.
742 742 */
743 743 void
744 744 pollcleanup()
745 745 {
746 746 pollstate_t *ps = curthread->t_pollstate;
747 747 pollcache_t *pcp;
748 748
749 749 if (ps == NULL)
750 750 return;
751 751 pcp = ps->ps_pcache;
752 752 /*
753 753 * free up all cached poll fds
754 754 */
755 755 if (pcp == NULL) {
756 756 /* this pollstate is used by /dev/poll */
757 757 goto pollcleanout;
758 758 }
759 759
760 760 if (pcp->pc_bitmap != NULL) {
761 761 ASSERT(MUTEX_NOT_HELD(&ps->ps_lock));
762 762 /*
763 763 * a close lwp can race with us when cleaning up a polldat
764 764 * entry. We hold the ps_lock when cleaning hash table.
765 765 * Since this pollcache is going away anyway, there is no
766 766 * need to hold the pc_lock.
767 767 */
768 768 mutex_enter(&ps->ps_lock);
769 769 pcache_clean(pcp);
770 770 mutex_exit(&ps->ps_lock);
771 771 #ifdef DEBUG
772 772 /*
773 773 * At this point, all fds cached by this lwp should be
774 774 * cleaned up. There should be no fd in fi_list still
775 775 * reference this thread.
776 776 */
777 777 checkfpollinfo(); /* sanity check */
778 778 pollcheckphlist(); /* sanity check */
779 779 #endif /* DEBUG */
780 780 }
781 781 /*
782 782 * Be sure no one is referencing thread before exiting
783 783 */
784 784 mutex_enter(&pcp->pc_no_exit);
785 785 ASSERT(pcp->pc_busy >= 0);
786 786 while (pcp->pc_busy > 0)
787 787 cv_wait(&pcp->pc_busy_cv, &pcp->pc_no_exit);
788 788 mutex_exit(&pcp->pc_no_exit);
789 789 pollcleanout:
790 790 pollstate_destroy(ps);
791 791 curthread->t_pollstate = NULL;
792 792 }
793 793
794 794 /*
795 795 * pollwakeup() - poke threads waiting in poll() for some event
796 796 * on a particular object.
797 797 *
798 798 * The threads hanging off of the specified pollhead structure are scanned.
799 799 * If their event mask matches the specified event(s), then pollnotify() is
800 800 * called to poke the thread.
801 801 *
802 802 * Multiple events may be specified. When POLLHUP or POLLERR are specified,
803 803 * all waiting threads are poked.
804 804 *
805 805 * It is important that pollnotify() not drop the lock protecting the list
806 806 * of threads.
807 807 */
808 808 void
809 809 pollwakeup(pollhead_t *php, short events_arg)
810 810 {
811 811 polldat_t *pdp;
812 812 int events = (ushort_t)events_arg;
813 813 struct plist {
814 814 port_t *pp;
815 815 int pevents;
816 816 struct plist *next;
817 817 };
818 818 struct plist *plhead = NULL, *pltail = NULL;
819 819
820 820 retry:
821 821 PH_ENTER(php);
822 822
823 823 for (pdp = php->ph_list; pdp; pdp = pdp->pd_next) {
824 824 if ((pdp->pd_events & events) ||
825 825 (events & (POLLHUP | POLLERR))) {
826 826
827 827 pollcache_t *pcp;
828 828
829 829 if (pdp->pd_portev != NULL) {
830 830 port_kevent_t *pkevp = pdp->pd_portev;
831 831 /*
832 832 * Object (fd) is associated with an event port,
833 833 * => send event notification to the port.
834 834 */
835 835 ASSERT(pkevp->portkev_source == PORT_SOURCE_FD);
836 836 mutex_enter(&pkevp->portkev_lock);
837 837 if (pkevp->portkev_flags & PORT_KEV_VALID) {
838 838 int pevents;
839 839
840 840 pkevp->portkev_flags &= ~PORT_KEV_VALID;
841 841 pkevp->portkev_events |= events &
842 842 (pdp->pd_events | POLLHUP |
843 843 POLLERR);
844 844 /*
845 845 * portkev_lock mutex will be released
846 846 * by port_send_event().
847 847 */
848 848 port_send_event(pkevp);
849 849
850 850 /*
851 851 * If we have some thread polling the
852 852 * port's fd, add it to the list. They
853 853 * will be notified later.
854 854 * The port_pollwkup() will flag the
855 855 * port_t so that it will not disappear
856 856 * till port_pollwkdone() is called.
857 857 */
858 858 pevents =
859 859 port_pollwkup(pkevp->portkev_port);
860 860 if (pevents) {
861 861 struct plist *t;
862 862 t = kmem_zalloc(
863 863 sizeof (struct plist),
864 864 KM_SLEEP);
865 865 t->pp = pkevp->portkev_port;
866 866 t->pevents = pevents;
867 867 if (plhead == NULL) {
868 868 plhead = t;
869 869 } else {
870 870 pltail->next = t;
871 871 }
872 872 pltail = t;
873 873 }
874 874 } else {
875 875 mutex_exit(&pkevp->portkev_lock);
876 876 }
877 877 continue;
878 878 }
879 879
880 880 pcp = pdp->pd_pcache;
881 881
882 882 /*
883 883 * Try to grab the lock for this thread. If
884 884 * we don't get it then we may deadlock so
885 885 * back out and restart all over again. Note
886 886 * that the failure rate is very very low.
887 887 */
888 888 if (mutex_tryenter(&pcp->pc_lock)) {
889 889 pollnotify(pcp, pdp->pd_fd);
890 890 mutex_exit(&pcp->pc_lock);
891 891 } else {
892 892 /*
893 893 * We are here because:
894 894 * 1) This thread has been woke up
895 895 * and is trying to get out of poll().
896 896 * 2) Some other thread is also here
897 897 * but with a different pollhead lock.
898 898 *
899 899 * So, we need to drop the lock on pollhead
900 900 * because of (1) but we want to prevent
901 901 * that thread from doing lwp_exit() or
902 902 * devpoll close. We want to ensure that
903 903 * the pollcache pointer is still invalid.
904 904 *
905 905 * Solution: Grab the pcp->pc_no_exit lock,
906 906 * increment the pc_busy counter, drop every
907 907 * lock in sight. Get out of the way and wait
908 908 * for type (2) threads to finish.
909 909 */
910 910
911 911 mutex_enter(&pcp->pc_no_exit);
912 912 pcp->pc_busy++; /* prevents exit()'s */
913 913 mutex_exit(&pcp->pc_no_exit);
914 914
915 915 PH_EXIT(php);
916 916 mutex_enter(&pcp->pc_lock);
917 917 mutex_exit(&pcp->pc_lock);
918 918 mutex_enter(&pcp->pc_no_exit);
919 919 pcp->pc_busy--;
920 920 if (pcp->pc_busy == 0) {
921 921 /*
922 922 * Wakeup the thread waiting in
923 923 * thread_exit().
924 924 */
925 925 cv_signal(&pcp->pc_busy_cv);
926 926 }
927 927 mutex_exit(&pcp->pc_no_exit);
928 928 goto retry;
929 929 }
930 930 }
931 931 }
932 932
933 933
934 934 /*
935 935 * Event ports - If this php is of the port on the list,
936 936 * call port_pollwkdone() to release it. The port_pollwkdone()
937 937 * needs to be called before dropping the PH lock so that any new
938 938 * thread attempting to poll this port are blocked. There can be
939 939 * only one thread here in pollwakeup notifying this port's fd.
940 940 */
941 941 if (plhead != NULL && &plhead->pp->port_pollhd == php) {
942 942 struct plist *t;
943 943 port_pollwkdone(plhead->pp);
944 944 t = plhead;
945 945 plhead = plhead->next;
946 946 kmem_free(t, sizeof (struct plist));
947 947 }
948 948 PH_EXIT(php);
949 949
950 950 /*
951 951 * Event ports - Notify threads polling the event port's fd.
952 952 * This is normally done in port_send_event() where it calls
953 953 * pollwakeup() on the port. But, for PORT_SOURCE_FD source alone,
954 954 * we do it here in pollwakeup() to avoid a recursive call.
955 955 */
956 956 if (plhead != NULL) {
957 957 php = &plhead->pp->port_pollhd;
958 958 events = plhead->pevents;
959 959 goto retry;
960 960 }
961 961 }
962 962
963 963 /*
964 964 * This function is called to inform a thread (or threads) that an event being
965 965 * polled on has occurred. The pollstate lock on the thread should be held
966 966 * on entry.
967 967 */
968 968 void
969 969 pollnotify(pollcache_t *pcp, int fd)
970 970 {
971 971 ASSERT(fd < pcp->pc_mapsize);
972 972 ASSERT(MUTEX_HELD(&pcp->pc_lock));
973 973 BT_SET(pcp->pc_bitmap, fd);
974 974 pcp->pc_flag |= PC_POLLWAKE;
975 975 cv_broadcast(&pcp->pc_cv);
976 976 pcache_wake_parents(pcp);
977 977 }
978 978
979 979 /*
980 980 * add a polldat entry to pollhead ph_list. The polldat struct is used
981 981 * by pollwakeup to wake sleeping pollers when polled events has happened.
982 982 */
983 983 void
984 984 pollhead_insert(pollhead_t *php, polldat_t *pdp)
985 985 {
986 986 PH_ENTER(php);
987 987 ASSERT(pdp->pd_next == NULL);
988 988 #ifdef DEBUG
989 989 {
990 990 /*
991 991 * the polldat should not be already on the list
992 992 */
993 993 polldat_t *wp;
994 994 for (wp = php->ph_list; wp; wp = wp->pd_next) {
995 995 ASSERT(wp != pdp);
996 996 }
997 997 }
998 998 #endif /* DEBUG */
999 999 pdp->pd_next = php->ph_list;
1000 1000 php->ph_list = pdp;
1001 1001 PH_EXIT(php);
1002 1002 }
1003 1003
1004 1004 /*
1005 1005 * Delete the polldat entry from ph_list.
1006 1006 */
1007 1007 void
1008 1008 pollhead_delete(pollhead_t *php, polldat_t *pdp)
1009 1009 {
1010 1010 polldat_t *wp;
1011 1011 polldat_t **wpp;
1012 1012
1013 1013 PH_ENTER(php);
1014 1014 for (wpp = &php->ph_list; (wp = *wpp) != NULL; wpp = &wp->pd_next) {
1015 1015 if (wp == pdp) {
1016 1016 *wpp = pdp->pd_next;
1017 1017 pdp->pd_next = NULL;
1018 1018 break;
1019 1019 }
1020 1020 }
1021 1021 #ifdef DEBUG
1022 1022 /* assert that pdp is no longer in the list */
1023 1023 for (wp = *wpp; wp; wp = wp->pd_next) {
1024 1024 ASSERT(wp != pdp);
1025 1025 }
1026 1026 #endif /* DEBUG */
1027 1027 PH_EXIT(php);
1028 1028 }
1029 1029
1030 1030 /*
1031 1031 * walk through the poll fd lists to see if they are identical. This is an
1032 1032 * expensive operation and should not be done more than once for each poll()
1033 1033 * call.
1034 1034 *
1035 1035 * As an optimization (i.e., not having to go through the lists more than
1036 1036 * once), this routine also clear the revents field of pollfd in 'current'.
1037 1037 * Zeroing out the revents field of each entry in current poll list is
1038 1038 * required by poll man page.
1039 1039 *
1040 1040 * Since the events field of cached list has illegal poll events filtered
1041 1041 * out, the current list applies the same filtering before comparison.
1042 1042 *
1043 1043 * The routine stops when it detects a meaningful difference, or when it
1044 1044 * exhausts the lists.
1045 1045 */
1046 1046 int
1047 1047 pcacheset_cmp(pollfd_t *current, pollfd_t *cached, pollfd_t *newlist, int n)
1048 1048 {
1049 1049 int ix;
1050 1050
1051 1051 for (ix = 0; ix < n; ix++) {
1052 1052 /* Prefetch 64 bytes worth of 8-byte elements */
1053 1053 if ((ix & 0x7) == 0) {
1054 1054 prefetch_write_many((caddr_t)¤t[ix + 8]);
1055 1055 prefetch_write_many((caddr_t)&cached[ix + 8]);
1056 1056 }
1057 1057 if (current[ix].fd == cached[ix].fd) {
1058 1058 /*
1059 1059 * Filter out invalid poll events while we are in
1060 1060 * inside the loop.
1061 1061 */
1062 1062 if (current[ix].events & ~VALID_POLL_EVENTS) {
1063 1063 current[ix].events &= VALID_POLL_EVENTS;
1064 1064 if (newlist != NULL)
1065 1065 newlist[ix].events = current[ix].events;
1066 1066 }
1067 1067 if (current[ix].events == cached[ix].events) {
1068 1068 current[ix].revents = 0;
1069 1069 continue;
1070 1070 }
1071 1071 }
1072 1072 if ((current[ix].fd < 0) && (cached[ix].fd < 0)) {
1073 1073 current[ix].revents = 0;
1074 1074 continue;
1075 1075 }
1076 1076 return (ix);
1077 1077 }
1078 1078 return (ix);
1079 1079 }
1080 1080
1081 1081 /*
1082 1082 * This routine returns a pointer to a cached poll fd entry, or NULL if it
1083 1083 * does not find it in the hash table.
1084 1084 */
1085 1085 polldat_t *
1086 1086 pcache_lookup_fd(pollcache_t *pcp, int fd)
1087 1087 {
1088 1088 int hashindex;
1089 1089 polldat_t *pdp;
1090 1090
1091 1091 hashindex = POLLHASH(pcp->pc_hashsize, fd);
1092 1092 pdp = pcp->pc_hash[hashindex];
1093 1093 while (pdp != NULL) {
1094 1094 if (pdp->pd_fd == fd)
1095 1095 break;
1096 1096 pdp = pdp->pd_hashnext;
1097 1097 }
1098 1098 return (pdp);
1099 1099 }
1100 1100
1101 1101 polldat_t *
1102 1102 pcache_alloc_fd(int nsets)
1103 1103 {
1104 1104 polldat_t *pdp;
1105 1105
1106 1106 pdp = kmem_zalloc(sizeof (polldat_t), KM_SLEEP);
1107 1107 if (nsets > 0) {
1108 1108 pdp->pd_ref = kmem_zalloc(sizeof (xref_t) * nsets, KM_SLEEP);
1109 1109 pdp->pd_nsets = nsets;
1110 1110 }
1111 1111 return (pdp);
1112 1112 }
1113 1113
1114 1114 /*
1115 1115 * This routine inserts a polldat into the pollcache's hash table. It
1116 1116 * may be necessary to grow the size of the hash table.
1117 1117 */
1118 1118 void
1119 1119 pcache_insert_fd(pollcache_t *pcp, polldat_t *pdp, nfds_t nfds)
1120 1120 {
1121 1121 int hashindex;
1122 1122 int fd;
1123 1123
1124 1124 if ((pcp->pc_fdcount > pcp->pc_hashsize * POLLHASHTHRESHOLD) ||
1125 1125 (nfds > pcp->pc_hashsize * POLLHASHTHRESHOLD)) {
1126 1126 pcache_grow_hashtbl(pcp, nfds);
1127 1127 }
1128 1128 fd = pdp->pd_fd;
1129 1129 hashindex = POLLHASH(pcp->pc_hashsize, fd);
1130 1130 pdp->pd_hashnext = pcp->pc_hash[hashindex];
1131 1131 pcp->pc_hash[hashindex] = pdp;
1132 1132 pcp->pc_fdcount++;
1133 1133
1134 1134 #ifdef DEBUG
1135 1135 {
1136 1136 /*
1137 1137 * same fd should not appear on a hash list twice
1138 1138 */
1139 1139 polldat_t *pdp1;
1140 1140 for (pdp1 = pdp->pd_hashnext; pdp1; pdp1 = pdp1->pd_hashnext) {
1141 1141 ASSERT(pdp->pd_fd != pdp1->pd_fd);
1142 1142 }
1143 1143 }
1144 1144 #endif /* DEBUG */
1145 1145 }
1146 1146
1147 1147 /*
1148 1148 * Grow the hash table -- either double the table size or round it to the
1149 1149 * nearest multiples of POLLHASHCHUNKSZ, whichever is bigger. Rehash all the
1150 1150 * elements on the hash table.
1151 1151 */
1152 1152 void
1153 1153 pcache_grow_hashtbl(pollcache_t *pcp, nfds_t nfds)
1154 1154 {
1155 1155 int oldsize;
1156 1156 polldat_t **oldtbl;
1157 1157 polldat_t *pdp, *pdp1;
1158 1158 int i;
1159 1159 #ifdef DEBUG
1160 1160 int count = 0;
1161 1161 #endif
1162 1162
1163 1163 ASSERT(pcp->pc_hashsize % POLLHASHCHUNKSZ == 0);
1164 1164 oldsize = pcp->pc_hashsize;
1165 1165 oldtbl = pcp->pc_hash;
1166 1166 if (nfds > pcp->pc_hashsize * POLLHASHINC) {
1167 1167 pcp->pc_hashsize = (nfds + POLLHASHCHUNKSZ - 1) &
1168 1168 ~(POLLHASHCHUNKSZ - 1);
1169 1169 } else {
1170 1170 pcp->pc_hashsize = pcp->pc_hashsize * POLLHASHINC;
1171 1171 }
1172 1172 pcp->pc_hash = kmem_zalloc(pcp->pc_hashsize * sizeof (polldat_t *),
1173 1173 KM_SLEEP);
1174 1174 /*
1175 1175 * rehash existing elements
1176 1176 */
1177 1177 pcp->pc_fdcount = 0;
1178 1178 for (i = 0; i < oldsize; i++) {
1179 1179 pdp = oldtbl[i];
1180 1180 while (pdp != NULL) {
1181 1181 pdp1 = pdp->pd_hashnext;
1182 1182 pcache_insert_fd(pcp, pdp, nfds);
1183 1183 pdp = pdp1;
1184 1184 #ifdef DEBUG
1185 1185 count++;
1186 1186 #endif
1187 1187 }
1188 1188 }
1189 1189 kmem_free(oldtbl, oldsize * sizeof (polldat_t *));
1190 1190 ASSERT(pcp->pc_fdcount == count);
1191 1191 }
1192 1192
1193 1193 void
1194 1194 pcache_grow_map(pollcache_t *pcp, int fd)
1195 1195 {
1196 1196 int newsize;
1197 1197 ulong_t *newmap;
1198 1198
1199 1199 /*
1200 1200 * grow to nearest multiple of POLLMAPCHUNK, assuming POLLMAPCHUNK is
1201 1201 * power of 2.
1202 1202 */
1203 1203 newsize = (fd + POLLMAPCHUNK) & ~(POLLMAPCHUNK - 1);
1204 1204 newmap = kmem_zalloc((newsize / BT_NBIPUL) * sizeof (ulong_t),
1205 1205 KM_SLEEP);
1206 1206 /*
1207 1207 * don't want pollwakeup to set a bit while growing the bitmap.
1208 1208 */
1209 1209 ASSERT(mutex_owned(&pcp->pc_lock) == 0);
1210 1210 mutex_enter(&pcp->pc_lock);
1211 1211 bcopy(pcp->pc_bitmap, newmap,
1212 1212 (pcp->pc_mapsize / BT_NBIPUL) * sizeof (ulong_t));
1213 1213 kmem_free(pcp->pc_bitmap,
1214 1214 (pcp->pc_mapsize /BT_NBIPUL) * sizeof (ulong_t));
1215 1215 pcp->pc_bitmap = newmap;
1216 1216 pcp->pc_mapsize = newsize;
1217 1217 mutex_exit(&pcp->pc_lock);
1218 1218 }
1219 1219
1220 1220 /*
1221 1221 * remove all the reference from pollhead list and fpollinfo lists.
1222 1222 */
1223 1223 void
1224 1224 pcache_clean(pollcache_t *pcp)
1225 1225 {
1226 1226 int i;
1227 1227 polldat_t **hashtbl;
1228 1228 polldat_t *pdp;
1229 1229
1230 1230 ASSERT(MUTEX_HELD(&curthread->t_pollstate->ps_lock));
1231 1231 hashtbl = pcp->pc_hash;
1232 1232 for (i = 0; i < pcp->pc_hashsize; i++) {
1233 1233 for (pdp = hashtbl[i]; pdp; pdp = pdp->pd_hashnext) {
1234 1234 if (pdp->pd_php != NULL) {
1235 1235 pollhead_delete(pdp->pd_php, pdp);
1236 1236 pdp->pd_php = NULL;
1237 1237 }
1238 1238 if (pdp->pd_fp != NULL) {
1239 1239 delfpollinfo(pdp->pd_fd);
1240 1240 pdp->pd_fp = NULL;
1241 1241 }
1242 1242 }
1243 1243 }
1244 1244 }
1245 1245
1246 1246 void
1247 1247 pcacheset_invalidate(pollstate_t *ps, polldat_t *pdp)
1248 1248 {
1249 1249 int i;
1250 1250 int fd = pdp->pd_fd;
1251 1251
1252 1252 /*
1253 1253 * we come here because an earlier close() on this cached poll fd.
1254 1254 */
1255 1255 ASSERT(pdp->pd_fp == NULL);
1256 1256 ASSERT(MUTEX_HELD(&ps->ps_lock));
1257 1257 pdp->pd_events = 0;
1258 1258 for (i = 0; i < ps->ps_nsets; i++) {
1259 1259 xref_t *refp;
1260 1260 pollcacheset_t *pcsp;
1261 1261
1262 1262 ASSERT(pdp->pd_ref != NULL);
1263 1263 refp = &pdp->pd_ref[i];
1264 1264 if (refp->xf_refcnt) {
1265 1265 ASSERT(refp->xf_position >= 0);
1266 1266 pcsp = &ps->ps_pcacheset[i];
1267 1267 if (refp->xf_refcnt == 1) {
1268 1268 pcsp->pcs_pollfd[refp->xf_position].fd = -1;
1269 1269 refp->xf_refcnt = 0;
1270 1270 pdp->pd_count--;
1271 1271 } else if (refp->xf_refcnt > 1) {
1272 1272 int j;
1273 1273
1274 1274 /*
1275 1275 * turn off every appearance in pcs_pollfd list
1276 1276 */
1277 1277 for (j = refp->xf_position;
1278 1278 j < pcsp->pcs_nfds; j++) {
1279 1279 if (pcsp->pcs_pollfd[j].fd == fd) {
1280 1280 pcsp->pcs_pollfd[j].fd = -1;
1281 1281 refp->xf_refcnt--;
1282 1282 pdp->pd_count--;
1283 1283 }
1284 1284 }
1285 1285 }
1286 1286 ASSERT(refp->xf_refcnt == 0);
1287 1287 refp->xf_position = POLLPOSINVAL;
1288 1288 }
1289 1289 }
1290 1290 ASSERT(pdp->pd_count == 0);
1291 1291 }
1292 1292
1293 1293 /*
1294 1294 * Insert poll fd into the pollcache, and add poll registration.
1295 1295 * This routine is called after getf() and before releasef(). So the vnode
1296 1296 * can not disappear even if we block here.
1297 1297 * If there is an error, the polled fd is not cached.
1298 1298 */
1299 1299 int
1300 1300 pcache_insert(pollstate_t *ps, file_t *fp, pollfd_t *pollfdp, int *fdcntp,
1301 1301 ssize_t pos, int which)
1302 1302 {
1303 1303 pollcache_t *pcp = ps->ps_pcache;
1304 1304 polldat_t *pdp;
1305 1305 int error;
1306 1306 int fd;
1307 1307 pollhead_t *memphp = NULL;
1308 1308 xref_t *refp;
1309 1309 int newpollfd = 0;
1310 1310
1311 1311 ASSERT(MUTEX_HELD(&ps->ps_lock));
1312 1312 /*
1313 1313 * The poll caching uses the existing VOP_POLL interface. If there
1314 1314 * is no polled events, we want the polled device to set its "some
1315 1315 * one is sleeping in poll" flag. When the polled events happen
1316 1316 * later, the driver will call pollwakeup(). We achieve this by
1317 1317 * always passing 0 in the third parameter ("anyyet") when calling
1318 1318 * VOP_POLL. This parameter is not looked at by drivers when the
1319 1319 * polled events exist. If a driver chooses to ignore this parameter
1320 1320 * and call pollwakeup whenever the polled events happen, that will
1321 1321 * be OK too.
1322 1322 */
1323 1323 ASSERT(curthread->t_pollcache == NULL);
1324 1324 error = VOP_POLL(fp->f_vnode, pollfdp->events, 0, &pollfdp->revents,
1325 1325 &memphp, NULL);
1326 1326 if (error) {
1327 1327 return (error);
1328 1328 }
1329 1329 if (pollfdp->revents) {
1330 1330 (*fdcntp)++;
1331 1331 }
1332 1332 /*
1333 1333 * polling the underlying device succeeded. Now we can cache it.
1334 1334 * A close can't come in here because we have not done a releasef()
1335 1335 * yet.
1336 1336 */
1337 1337 fd = pollfdp->fd;
1338 1338 pdp = pcache_lookup_fd(pcp, fd);
1339 1339 if (pdp == NULL) {
1340 1340 ASSERT(ps->ps_nsets > 0);
1341 1341 pdp = pcache_alloc_fd(ps->ps_nsets);
1342 1342 newpollfd = 1;
1343 1343 }
1344 1344 /*
1345 1345 * If this entry was used to cache a poll fd which was closed, and
1346 1346 * this entry has not been cleaned, do it now.
1347 1347 */
1348 1348 if ((pdp->pd_count > 0) && (pdp->pd_fp == NULL)) {
1349 1349 pcacheset_invalidate(ps, pdp);
1350 1350 ASSERT(pdp->pd_next == NULL);
1351 1351 }
1352 1352 if (pdp->pd_count == 0) {
1353 1353 pdp->pd_fd = fd;
1354 1354 pdp->pd_fp = fp;
1355 1355 addfpollinfo(fd);
1356 1356 pdp->pd_thread = curthread;
1357 1357 pdp->pd_pcache = pcp;
1358 1358 /*
1359 1359 * the entry is never used or cleared by removing a cached
1360 1360 * pollfd (pcache_delete_fd). So all the fields should be clear.
1361 1361 */
1362 1362 ASSERT(pdp->pd_next == NULL);
1363 1363 }
1364 1364
1365 1365 /*
1366 1366 * A polled fd is considered cached. So there should be a fpollinfo
1367 1367 * entry on uf_fpollinfo list.
1368 1368 */
1369 1369 ASSERT(infpollinfo(fd));
1370 1370 /*
1371 1371 * If there is an inconsistency, we want to know it here.
1372 1372 */
1373 1373 ASSERT(pdp->pd_fp == fp);
1374 1374
1375 1375 /*
1376 1376 * XXX pd_events is a union of all polled events on this fd, possibly
1377 1377 * by different threads. Unless this is a new first poll(), pd_events
1378 1378 * never shrinks. If an event is no longer polled by a process, there
1379 1379 * is no way to cancel that event. In that case, poll degrade to its
1380 1380 * old form -- polling on this fd every time poll() is called. The
1381 1381 * assumption is an app always polls the same type of events.
1382 1382 */
1383 1383 pdp->pd_events |= pollfdp->events;
1384 1384
1385 1385 pdp->pd_count++;
1386 1386 /*
1387 1387 * There is not much special handling for multiple appearances of
1388 1388 * same fd other than xf_position always recording the first
1389 1389 * appearance in poll list. If this is called from pcacheset_cache_list,
1390 1390 * a VOP_POLL is called on every pollfd entry; therefore each
1391 1391 * revents and fdcnt should be set correctly. If this is called from
1392 1392 * pcacheset_resolve, we don't care about fdcnt here. Pollreadmap will
1393 1393 * pick up the right count and handle revents field of each pollfd
1394 1394 * entry.
1395 1395 */
1396 1396 ASSERT(pdp->pd_ref != NULL);
1397 1397 refp = &pdp->pd_ref[which];
1398 1398 if (refp->xf_refcnt == 0) {
1399 1399 refp->xf_position = pos;
1400 1400 } else {
1401 1401 /*
1402 1402 * xf_position records the fd's first appearance in poll list
1403 1403 */
1404 1404 if (pos < refp->xf_position) {
1405 1405 refp->xf_position = pos;
1406 1406 }
1407 1407 }
1408 1408 ASSERT(pollfdp->fd == ps->ps_pollfd[refp->xf_position].fd);
1409 1409 refp->xf_refcnt++;
1410 1410 if (fd >= pcp->pc_mapsize) {
1411 1411 pcache_grow_map(pcp, fd);
1412 1412 }
1413 1413 if (fd > pcp->pc_mapend) {
1414 1414 pcp->pc_mapend = fd;
1415 1415 }
1416 1416 if (newpollfd != 0) {
1417 1417 pcache_insert_fd(ps->ps_pcache, pdp, ps->ps_nfds);
1418 1418 }
1419 1419 if (memphp) {
1420 1420 if (pdp->pd_php == NULL) {
1421 1421 pollhead_insert(memphp, pdp);
1422 1422 pdp->pd_php = memphp;
1423 1423 } else {
1424 1424 if (memphp != pdp->pd_php) {
1425 1425 /*
1426 1426 * layered devices (e.g. console driver)
1427 1427 * may change the vnode and thus the pollhead
1428 1428 * pointer out from underneath us.
1429 1429 */
1430 1430 pollhead_delete(pdp->pd_php, pdp);
1431 1431 pollhead_insert(memphp, pdp);
1432 1432 pdp->pd_php = memphp;
1433 1433 }
1434 1434 }
1435 1435 }
1436 1436 /*
1437 1437 * Since there is a considerable window between VOP_POLL and when
1438 1438 * we actually put the polldat struct on the pollhead list, we could
1439 1439 * miss a pollwakeup. In the case of polling additional events, we
1440 1440 * don't update the events until after VOP_POLL. So we could miss
1441 1441 * pollwakeup there too. So we always set the bit here just to be
1442 1442 * safe. The real performance gain is in subsequent pcache_poll.
1443 1443 */
1444 1444 mutex_enter(&pcp->pc_lock);
1445 1445 BT_SET(pcp->pc_bitmap, fd);
1446 1446 mutex_exit(&pcp->pc_lock);
1447 1447 return (0);
1448 1448 }
1449 1449
1450 1450 /*
1451 1451 * The entry is not really deleted. The fields are cleared so that the
1452 1452 * entry is no longer useful, but it will remain in the hash table for reuse
1453 1453 * later. It will be freed when the polling lwp exits.
1454 1454 */
1455 1455 int
1456 1456 pcache_delete_fd(pollstate_t *ps, int fd, size_t pos, int which, uint_t cevent)
1457 1457 {
1458 1458 pollcache_t *pcp = ps->ps_pcache;
1459 1459 polldat_t *pdp;
1460 1460 xref_t *refp;
1461 1461
1462 1462 ASSERT(fd < pcp->pc_mapsize);
1463 1463 ASSERT(MUTEX_HELD(&ps->ps_lock));
1464 1464
1465 1465 pdp = pcache_lookup_fd(pcp, fd);
1466 1466 ASSERT(pdp != NULL);
1467 1467 ASSERT(pdp->pd_count > 0);
1468 1468 ASSERT(pdp->pd_ref != NULL);
1469 1469 refp = &pdp->pd_ref[which];
1470 1470 if (pdp->pd_count == 1) {
1471 1471 pdp->pd_events = 0;
1472 1472 refp->xf_position = POLLPOSINVAL;
1473 1473 ASSERT(refp->xf_refcnt == 1);
1474 1474 refp->xf_refcnt = 0;
1475 1475 if (pdp->pd_php) {
1476 1476 /*
1477 1477 * It is possible for a wakeup thread to get ahead
1478 1478 * of the following pollhead_delete and set the bit in
1479 1479 * bitmap. It is OK because the bit will be cleared
1480 1480 * here anyway.
1481 1481 */
1482 1482 pollhead_delete(pdp->pd_php, pdp);
1483 1483 pdp->pd_php = NULL;
1484 1484 }
1485 1485 pdp->pd_count = 0;
1486 1486 if (pdp->pd_fp != NULL) {
1487 1487 pdp->pd_fp = NULL;
1488 1488 delfpollinfo(fd);
1489 1489 }
1490 1490 mutex_enter(&pcp->pc_lock);
1491 1491 BT_CLEAR(pcp->pc_bitmap, fd);
1492 1492 mutex_exit(&pcp->pc_lock);
1493 1493 return (0);
1494 1494 }
1495 1495 if ((cevent & POLLCLOSED) == POLLCLOSED) {
1496 1496 /*
1497 1497 * fd cached here has been closed. This is the first
1498 1498 * pcache_delete_fd called after the close. Clean up the
1499 1499 * entire entry.
1500 1500 */
1501 1501 pcacheset_invalidate(ps, pdp);
1502 1502 ASSERT(pdp->pd_php == NULL);
1503 1503 mutex_enter(&pcp->pc_lock);
1504 1504 BT_CLEAR(pcp->pc_bitmap, fd);
1505 1505 mutex_exit(&pcp->pc_lock);
1506 1506 return (0);
1507 1507 }
1508 1508 #ifdef DEBUG
1509 1509 if (getf(fd) != NULL) {
1510 1510 ASSERT(infpollinfo(fd));
1511 1511 releasef(fd);
1512 1512 }
1513 1513 #endif /* DEBUG */
1514 1514 pdp->pd_count--;
1515 1515 ASSERT(refp->xf_refcnt > 0);
1516 1516 if (--refp->xf_refcnt == 0) {
1517 1517 refp->xf_position = POLLPOSINVAL;
1518 1518 } else {
1519 1519 ASSERT(pos >= refp->xf_position);
1520 1520 if (pos == refp->xf_position) {
1521 1521 /*
1522 1522 * The xref position is no longer valid.
1523 1523 * Reset it to a special value and let
1524 1524 * caller know it needs to updatexref()
1525 1525 * with a new xf_position value.
1526 1526 */
1527 1527 refp->xf_position = POLLPOSTRANS;
1528 1528 return (1);
1529 1529 }
1530 1530 }
1531 1531 return (0);
1532 1532 }
1533 1533
1534 1534 void
1535 1535 pcache_update_xref(pollcache_t *pcp, int fd, ssize_t pos, int which)
1536 1536 {
1537 1537 polldat_t *pdp;
1538 1538
1539 1539 pdp = pcache_lookup_fd(pcp, fd);
1540 1540 ASSERT(pdp != NULL);
1541 1541 ASSERT(pdp->pd_ref != NULL);
1542 1542 pdp->pd_ref[which].xf_position = pos;
1543 1543 }
1544 1544
1545 1545 #ifdef DEBUG
1546 1546 /*
1547 1547 * For each polled fd, it's either in the bitmap or cached in
1548 1548 * pcache hash table. If this routine returns 0, something is wrong.
1549 1549 */
1550 1550 static int
1551 1551 pollchecksanity(pollstate_t *ps, nfds_t nfds)
1552 1552 {
1553 1553 int i;
1554 1554 int fd;
1555 1555 pollcache_t *pcp = ps->ps_pcache;
1556 1556 polldat_t *pdp;
1557 1557 pollfd_t *pollfdp = ps->ps_pollfd;
1558 1558 file_t *fp;
1559 1559
1560 1560 ASSERT(MUTEX_HELD(&ps->ps_lock));
1561 1561 for (i = 0; i < nfds; i++) {
1562 1562 fd = pollfdp[i].fd;
1563 1563 if (fd < 0) {
1564 1564 ASSERT(pollfdp[i].revents == 0);
1565 1565 continue;
1566 1566 }
1567 1567 if (pollfdp[i].revents == POLLNVAL)
1568 1568 continue;
1569 1569 if ((fp = getf(fd)) == NULL)
1570 1570 continue;
1571 1571 pdp = pcache_lookup_fd(pcp, fd);
1572 1572 ASSERT(pdp != NULL);
1573 1573 ASSERT(infpollinfo(fd));
1574 1574 ASSERT(pdp->pd_fp == fp);
1575 1575 releasef(fd);
1576 1576 if (BT_TEST(pcp->pc_bitmap, fd))
1577 1577 continue;
1578 1578 if (pdp->pd_php == NULL)
1579 1579 return (0);
1580 1580 }
1581 1581 return (1);
1582 1582 }
1583 1583 #endif /* DEBUG */
1584 1584
1585 1585 /*
1586 1586 * resolve the difference between the current poll list and a cached one.
1587 1587 */
1588 1588 int
1589 1589 pcacheset_resolve(pollstate_t *ps, nfds_t nfds, int *fdcntp, int which)
1590 1590 {
1591 1591 int i;
1592 1592 pollcache_t *pcp = ps->ps_pcache;
1593 1593 pollfd_t *newlist = NULL;
1594 1594 pollfd_t *current = ps->ps_pollfd;
1595 1595 pollfd_t *cached;
1596 1596 pollcacheset_t *pcsp;
1597 1597 int common;
1598 1598 int count = 0;
1599 1599 int offset;
1600 1600 int remain;
1601 1601 int fd;
1602 1602 file_t *fp;
1603 1603 int fdcnt = 0;
1604 1604 int cnt = 0;
1605 1605 nfds_t old_nfds;
1606 1606 int error = 0;
1607 1607 int mismatch = 0;
1608 1608
1609 1609 ASSERT(MUTEX_HELD(&ps->ps_lock));
1610 1610 #ifdef DEBUG
1611 1611 checkpolldat(ps);
1612 1612 #endif
1613 1613 pcsp = &ps->ps_pcacheset[which];
1614 1614 old_nfds = pcsp->pcs_nfds;
1615 1615 common = (nfds > old_nfds) ? old_nfds : nfds;
1616 1616 if (nfds != old_nfds) {
1617 1617 /*
1618 1618 * the length of poll list has changed. allocate a new
1619 1619 * pollfd list.
1620 1620 */
1621 1621 newlist = kmem_alloc(nfds * sizeof (pollfd_t), KM_SLEEP);
1622 1622 bcopy(current, newlist, sizeof (pollfd_t) * nfds);
1623 1623 }
1624 1624 /*
1625 1625 * Compare the overlapping part of the current fd list with the
1626 1626 * cached one. Whenever a difference is found, resolve it.
1627 1627 * The comparison is done on the current poll list and the
1628 1628 * cached list. But we may be setting up the newlist to be the
1629 1629 * cached list for next poll.
1630 1630 */
1631 1631 cached = pcsp->pcs_pollfd;
1632 1632 remain = common;
1633 1633
1634 1634 while (count < common) {
1635 1635 int tmpfd;
1636 1636 pollfd_t *np;
1637 1637
1638 1638 np = (newlist != NULL) ? &newlist[count] : NULL;
1639 1639 offset = pcacheset_cmp(¤t[count], &cached[count], np,
1640 1640 remain);
1641 1641 /*
1642 1642 * Collect stats. If lists are completed the first time,
1643 1643 * it's a hit. Otherwise, it's a partial hit or miss.
1644 1644 */
1645 1645 if ((count == 0) && (offset == common)) {
1646 1646 pollstats.pollcachehit.value.ui64++;
1647 1647 } else {
1648 1648 mismatch++;
1649 1649 }
1650 1650 count += offset;
1651 1651 if (offset < remain) {
1652 1652 ASSERT(count < common);
1653 1653 ASSERT((current[count].fd != cached[count].fd) ||
1654 1654 (current[count].events != cached[count].events));
1655 1655 /*
1656 1656 * Filter out invalid events.
1657 1657 */
1658 1658 if (current[count].events & ~VALID_POLL_EVENTS) {
1659 1659 if (newlist != NULL) {
1660 1660 newlist[count].events =
1661 1661 current[count].events &=
1662 1662 VALID_POLL_EVENTS;
1663 1663 } else {
1664 1664 current[count].events &=
1665 1665 VALID_POLL_EVENTS;
1666 1666 }
1667 1667 }
1668 1668 /*
1669 1669 * when resolving a difference, we always remove the
1670 1670 * fd from cache before inserting one into cache.
1671 1671 */
1672 1672 if (cached[count].fd >= 0) {
1673 1673 tmpfd = cached[count].fd;
1674 1674 if (pcache_delete_fd(ps, tmpfd, count, which,
1675 1675 (uint_t)cached[count].events)) {
1676 1676 /*
1677 1677 * This should be rare but needed for
1678 1678 * correctness.
1679 1679 *
1680 1680 * The first appearance in cached list
1681 1681 * is being "turned off". The same fd
1682 1682 * appear more than once in the cached
1683 1683 * poll list. Find the next one on the
1684 1684 * list and update the cached
1685 1685 * xf_position field.
1686 1686 */
1687 1687 for (i = count + 1; i < old_nfds; i++) {
1688 1688 if (cached[i].fd == tmpfd) {
1689 1689 pcache_update_xref(pcp,
1690 1690 tmpfd, (ssize_t)i,
1691 1691 which);
1692 1692 break;
1693 1693 }
1694 1694 }
1695 1695 ASSERT(i <= old_nfds);
1696 1696 }
1697 1697 /*
1698 1698 * In case a new cache list is allocated,
1699 1699 * need to keep both cache lists in sync
1700 1700 * b/c the new one can be freed if we have
1701 1701 * an error later.
1702 1702 */
1703 1703 cached[count].fd = -1;
1704 1704 if (newlist != NULL) {
1705 1705 newlist[count].fd = -1;
1706 1706 }
1707 1707 }
1708 1708 if ((tmpfd = current[count].fd) >= 0) {
1709 1709 /*
1710 1710 * add to the cached fd tbl and bitmap.
1711 1711 */
1712 1712 if ((fp = getf(tmpfd)) == NULL) {
1713 1713 current[count].revents = POLLNVAL;
1714 1714 if (newlist != NULL) {
1715 1715 newlist[count].fd = -1;
1716 1716 }
1717 1717 cached[count].fd = -1;
1718 1718 fdcnt++;
1719 1719 } else {
1720 1720 /*
1721 1721 * Here we don't care about the
1722 1722 * fdcnt. We will examine the bitmap
1723 1723 * later and pick up the correct
1724 1724 * fdcnt there. So we never bother
1725 1725 * to check value of 'cnt'.
1726 1726 */
1727 1727 error = pcache_insert(ps, fp,
1728 1728 ¤t[count], &cnt,
1729 1729 (ssize_t)count, which);
1730 1730 /*
1731 1731 * if no error, we want to do releasef
1732 1732 * after we updated cache poll list
1733 1733 * entry so that close() won't race
1734 1734 * us.
1735 1735 */
1736 1736 if (error) {
1737 1737 /*
1738 1738 * If we encountered an error,
1739 1739 * we have invalidated an
1740 1740 * entry in cached poll list
1741 1741 * (in pcache_delete_fd() above)
1742 1742 * but failed to add one here.
1743 1743 * This is OK b/c what's in the
1744 1744 * cached list is consistent
1745 1745 * with content of cache.
1746 1746 * It will not have any ill
1747 1747 * effect on next poll().
1748 1748 */
1749 1749 releasef(tmpfd);
1750 1750 if (newlist != NULL) {
1751 1751 kmem_free(newlist,
1752 1752 nfds *
1753 1753 sizeof (pollfd_t));
1754 1754 }
1755 1755 return (error);
1756 1756 }
1757 1757 /*
1758 1758 * If we have allocated a new(temp)
1759 1759 * cache list, we need to keep both
1760 1760 * in sync b/c the new one can be freed
1761 1761 * if we have an error later.
1762 1762 */
1763 1763 if (newlist != NULL) {
1764 1764 newlist[count].fd =
1765 1765 current[count].fd;
1766 1766 newlist[count].events =
1767 1767 current[count].events;
1768 1768 }
1769 1769 cached[count].fd = current[count].fd;
1770 1770 cached[count].events =
1771 1771 current[count].events;
1772 1772 releasef(tmpfd);
1773 1773 }
1774 1774 } else {
1775 1775 current[count].revents = 0;
1776 1776 }
1777 1777 count++;
1778 1778 remain = common - count;
1779 1779 }
1780 1780 }
1781 1781 if (mismatch != 0) {
1782 1782 if (mismatch == common) {
1783 1783 pollstats.pollcachemiss.value.ui64++;
1784 1784 } else {
1785 1785 pollstats.pollcachephit.value.ui64++;
1786 1786 }
1787 1787 }
1788 1788 /*
1789 1789 * take care of the non overlapping part of a list
1790 1790 */
1791 1791 if (nfds > old_nfds) {
1792 1792 ASSERT(newlist != NULL);
1793 1793 for (i = old_nfds; i < nfds; i++) {
1794 1794 /* filter out invalid events */
1795 1795 if (current[i].events & ~VALID_POLL_EVENTS) {
1796 1796 newlist[i].events = current[i].events =
1797 1797 current[i].events & VALID_POLL_EVENTS;
1798 1798 }
1799 1799 if ((fd = current[i].fd) < 0) {
1800 1800 current[i].revents = 0;
1801 1801 continue;
1802 1802 }
1803 1803 /*
1804 1804 * add to the cached fd tbl and bitmap.
1805 1805 */
1806 1806 if ((fp = getf(fd)) == NULL) {
1807 1807 current[i].revents = POLLNVAL;
1808 1808 newlist[i].fd = -1;
1809 1809 fdcnt++;
1810 1810 continue;
1811 1811 }
1812 1812 /*
1813 1813 * Here we don't care about the
1814 1814 * fdcnt. We will examine the bitmap
1815 1815 * later and pick up the correct
1816 1816 * fdcnt there. So we never bother to
1817 1817 * check 'cnt'.
1818 1818 */
1819 1819 error = pcache_insert(ps, fp, ¤t[i], &cnt,
1820 1820 (ssize_t)i, which);
1821 1821 releasef(fd);
1822 1822 if (error) {
1823 1823 /*
1824 1824 * Here we are half way through adding newly
1825 1825 * polled fd. Undo enough to keep the cache
1826 1826 * list consistent with the cache content.
1827 1827 */
1828 1828 pcacheset_remove_list(ps, current, old_nfds,
1829 1829 i, which, 0);
1830 1830 kmem_free(newlist, nfds * sizeof (pollfd_t));
1831 1831 return (error);
1832 1832 }
1833 1833 }
1834 1834 }
1835 1835 if (old_nfds > nfds) {
1836 1836 /*
1837 1837 * remove the fd's which are no longer polled.
1838 1838 */
1839 1839 pcacheset_remove_list(ps, pcsp->pcs_pollfd, nfds, old_nfds,
1840 1840 which, 1);
1841 1841 }
1842 1842 /*
1843 1843 * set difference resolved. update nfds and cachedlist
1844 1844 * in pollstate struct.
1845 1845 */
1846 1846 if (newlist != NULL) {
1847 1847 kmem_free(pcsp->pcs_pollfd, old_nfds * sizeof (pollfd_t));
1848 1848 /*
1849 1849 * By now, the pollfd.revents field should
1850 1850 * all be zeroed.
1851 1851 */
1852 1852 pcsp->pcs_pollfd = newlist;
1853 1853 pcsp->pcs_nfds = nfds;
1854 1854 }
1855 1855 ASSERT(*fdcntp == 0);
1856 1856 *fdcntp = fdcnt;
1857 1857 /*
1858 1858 * By now for every fd in pollfdp, one of the following should be
1859 1859 * true. Otherwise we will miss a polled event.
1860 1860 *
1861 1861 * 1. the bit corresponding to the fd in bitmap is set. So VOP_POLL
1862 1862 * will be called on this fd in next poll.
1863 1863 * 2. the fd is cached in the pcache (i.e. pd_php is set). So
1864 1864 * pollnotify will happen.
1865 1865 */
1866 1866 ASSERT(pollchecksanity(ps, nfds));
1867 1867 /*
1868 1868 * make sure cross reference between cached poll lists and cached
1869 1869 * poll fds are correct.
1870 1870 */
1871 1871 ASSERT(pollcheckxref(ps, which));
1872 1872 /*
1873 1873 * ensure each polldat in pollcache reference a polled fd in
1874 1874 * pollcacheset.
1875 1875 */
1876 1876 #ifdef DEBUG
1877 1877 checkpolldat(ps);
1878 1878 #endif
1879 1879 return (0);
1880 1880 }
1881 1881
1882 1882 #ifdef DEBUG
1883 1883 static int
1884 1884 pollscanrevents(pollcache_t *pcp, pollfd_t *pollfdp, nfds_t nfds)
1885 1885 {
1886 1886 int i;
1887 1887 int reventcnt = 0;
1888 1888
1889 1889 for (i = 0; i < nfds; i++) {
1890 1890 if (pollfdp[i].fd < 0) {
1891 1891 ASSERT(pollfdp[i].revents == 0);
1892 1892 continue;
1893 1893 }
1894 1894 if (pollfdp[i].revents) {
1895 1895 reventcnt++;
1896 1896 }
1897 1897 if (pollfdp[i].revents && (pollfdp[i].revents != POLLNVAL)) {
1898 1898 ASSERT(BT_TEST(pcp->pc_bitmap, pollfdp[i].fd));
1899 1899 }
1900 1900 }
1901 1901 return (reventcnt);
1902 1902 }
1903 1903 #endif /* DEBUG */
1904 1904
1905 1905 /*
1906 1906 * read the bitmap and poll on fds corresponding to the '1' bits. The ps_lock
1907 1907 * is held upon entry.
1908 1908 */
1909 1909 int
1910 1910 pcache_poll(pollfd_t *pollfdp, pollstate_t *ps, nfds_t nfds, int *fdcntp,
1911 1911 int which)
1912 1912 {
1913 1913 int i;
1914 1914 pollcache_t *pcp;
1915 1915 int fd;
1916 1916 int begin, end, done;
1917 1917 pollhead_t *php;
1918 1918 int fdcnt;
1919 1919 int error = 0;
1920 1920 file_t *fp;
1921 1921 polldat_t *pdp;
1922 1922 xref_t *refp;
1923 1923 int entry;
1924 1924
1925 1925 pcp = ps->ps_pcache;
1926 1926 ASSERT(MUTEX_HELD(&ps->ps_lock));
1927 1927 ASSERT(MUTEX_HELD(&pcp->pc_lock));
1928 1928 retry:
1929 1929 done = 0;
1930 1930 begin = 0;
1931 1931 fdcnt = 0;
1932 1932 end = pcp->pc_mapend;
1933 1933 while ((fdcnt < nfds) && !done) {
1934 1934 php = NULL;
1935 1935 /*
1936 1936 * only poll fds which may have events
1937 1937 */
1938 1938 fd = bt_getlowbit(pcp->pc_bitmap, begin, end);
1939 1939 ASSERT(fd <= end);
1940 1940 if (fd >= 0) {
1941 1941 ASSERT(pollcheckrevents(ps, begin, fd, which));
1942 1942 /*
1943 1943 * adjust map pointers for next round
1944 1944 */
1945 1945 if (fd == end) {
1946 1946 done = 1;
1947 1947 } else {
1948 1948 begin = fd + 1;
1949 1949 }
1950 1950 /*
1951 1951 * A bitmap caches poll state information of
1952 1952 * multiple poll lists. Call VOP_POLL only if
1953 1953 * the bit corresponds to an fd in this poll
1954 1954 * list.
1955 1955 */
1956 1956 pdp = pcache_lookup_fd(pcp, fd);
1957 1957 ASSERT(pdp != NULL);
1958 1958 ASSERT(pdp->pd_ref != NULL);
1959 1959 refp = &pdp->pd_ref[which];
1960 1960 if (refp->xf_refcnt == 0)
1961 1961 continue;
1962 1962 entry = refp->xf_position;
1963 1963 ASSERT((entry >= 0) && (entry < nfds));
1964 1964 ASSERT(pollfdp[entry].fd == fd);
1965 1965 /*
1966 1966 * we are in this routine implies that we have
1967 1967 * successfully polled this fd in the past.
1968 1968 * Check to see this fd is closed while we are
1969 1969 * blocked in poll. This ensures that we don't
1970 1970 * miss a close on the fd in the case this fd is
1971 1971 * reused.
1972 1972 */
1973 1973 if (pdp->pd_fp == NULL) {
1974 1974 ASSERT(pdp->pd_count > 0);
1975 1975 pollfdp[entry].revents = POLLNVAL;
1976 1976 fdcnt++;
1977 1977 if (refp->xf_refcnt > 1) {
1978 1978 /*
1979 1979 * this fd appeared multiple time
1980 1980 * in the poll list. Find all of them.
1981 1981 */
1982 1982 for (i = entry + 1; i < nfds; i++) {
1983 1983 if (pollfdp[i].fd == fd) {
1984 1984 pollfdp[i].revents =
1985 1985 POLLNVAL;
1986 1986 fdcnt++;
1987 1987 }
1988 1988 }
1989 1989 }
1990 1990 pcacheset_invalidate(ps, pdp);
1991 1991 continue;
1992 1992 }
1993 1993 /*
1994 1994 * We can be here polling a device that is being
1995 1995 * closed (i.e. the file pointer is set to NULL,
1996 1996 * but pollcacheclean has not happened yet).
1997 1997 */
1998 1998 if ((fp = getf(fd)) == NULL) {
1999 1999 pollfdp[entry].revents = POLLNVAL;
2000 2000 fdcnt++;
2001 2001 if (refp->xf_refcnt > 1) {
2002 2002 /*
2003 2003 * this fd appeared multiple time
2004 2004 * in the poll list. Find all of them.
2005 2005 */
2006 2006 for (i = entry + 1; i < nfds; i++) {
2007 2007 if (pollfdp[i].fd == fd) {
2008 2008 pollfdp[i].revents =
2009 2009 POLLNVAL;
2010 2010 fdcnt++;
2011 2011 }
2012 2012 }
2013 2013 }
2014 2014 continue;
2015 2015 }
2016 2016 ASSERT(pdp->pd_fp == fp);
2017 2017 ASSERT(infpollinfo(fd));
2018 2018 /*
2019 2019 * Since we no longer hold poll head lock across
2020 2020 * VOP_POLL, pollunlock logic can be simplifed.
2021 2021 */
2022 2022 ASSERT(pdp->pd_php == NULL ||
2023 2023 MUTEX_NOT_HELD(PHLOCK(pdp->pd_php)));
2024 2024 /*
2025 2025 * underlying file systems may set a "pollpending"
2026 2026 * flag when it sees the poll may block. Pollwakeup()
2027 2027 * is called by wakeup thread if pollpending is set.
2028 2028 * Pass a 0 fdcnt so that the underlying file system
2029 2029 * will set the "pollpending" flag set when there is
2030 2030 * no polled events.
2031 2031 *
2032 2032 * Use pollfdp[].events for actual polling because
2033 2033 * the pd_events is union of all cached poll events
2034 2034 * on this fd. The events parameter also affects
2035 2035 * how the polled device sets the "poll pending"
2036 2036 * flag.
2037 2037 */
2038 2038 ASSERT(curthread->t_pollcache == NULL);
2039 2039 error = VOP_POLL(fp->f_vnode, pollfdp[entry].events, 0,
2040 2040 &pollfdp[entry].revents, &php, NULL);
2041 2041 /*
2042 2042 * releasef after completely done with this cached
2043 2043 * poll entry. To prevent close() coming in to clear
2044 2044 * this entry.
2045 2045 */
2046 2046 if (error) {
2047 2047 releasef(fd);
2048 2048 break;
2049 2049 }
2050 2050 /*
2051 2051 * layered devices (e.g. console driver)
2052 2052 * may change the vnode and thus the pollhead
2053 2053 * pointer out from underneath us.
2054 2054 */
2055 2055 if (php != NULL && pdp->pd_php != NULL &&
2056 2056 php != pdp->pd_php) {
2057 2057 releasef(fd);
2058 2058 pollhead_delete(pdp->pd_php, pdp);
2059 2059 pdp->pd_php = php;
2060 2060 pollhead_insert(php, pdp);
2061 2061 /*
2062 2062 * We could have missed a wakeup on the new
2063 2063 * target device. Make sure the new target
2064 2064 * gets polled once.
2065 2065 */
2066 2066 BT_SET(pcp->pc_bitmap, fd);
2067 2067 goto retry;
2068 2068 }
2069 2069
2070 2070 if (pollfdp[entry].revents) {
2071 2071 ASSERT(refp->xf_refcnt >= 1);
2072 2072 fdcnt++;
2073 2073 if (refp->xf_refcnt > 1) {
2074 2074 /*
2075 2075 * this fd appeared multiple time
2076 2076 * in the poll list. This is rare but
2077 2077 * we have to look at all of them for
2078 2078 * correctness.
2079 2079 */
2080 2080 error = plist_chkdupfd(fp, pdp, ps,
2081 2081 pollfdp, entry, &fdcnt);
2082 2082 if (error > 0) {
2083 2083 releasef(fd);
2084 2084 break;
2085 2085 }
2086 2086 if (error < 0) {
2087 2087 goto retry;
2088 2088 }
2089 2089 }
2090 2090 releasef(fd);
2091 2091 } else {
2092 2092 /*
2093 2093 * VOP_POLL didn't return any revents. We can
2094 2094 * clear the bit in bitmap only if we have the
2095 2095 * pollhead ptr cached and no other cached
2096 2096 * entry is polling different events on this fd.
2097 2097 * VOP_POLL may have dropped the ps_lock. Make
2098 2098 * sure pollwakeup has not happened before clear
2099 2099 * the bit.
2100 2100 */
2101 2101 if ((pdp->pd_php != NULL) &&
2102 2102 (pollfdp[entry].events == pdp->pd_events) &&
2103 2103 ((pcp->pc_flag & PC_POLLWAKE) == 0)) {
2104 2104 BT_CLEAR(pcp->pc_bitmap, fd);
2105 2105 }
2106 2106 /*
2107 2107 * if the fd can be cached now but not before,
2108 2108 * do it now.
2109 2109 */
2110 2110 if ((pdp->pd_php == NULL) && (php != NULL)) {
2111 2111 pdp->pd_php = php;
2112 2112 pollhead_insert(php, pdp);
2113 2113 /*
2114 2114 * We are inserting a polldat struct for
2115 2115 * the first time. We may have missed a
2116 2116 * wakeup on this device. Re-poll once.
2117 2117 * This should be a rare event.
2118 2118 */
2119 2119 releasef(fd);
2120 2120 goto retry;
2121 2121 }
2122 2122 if (refp->xf_refcnt > 1) {
2123 2123 /*
2124 2124 * this fd appeared multiple time
2125 2125 * in the poll list. This is rare but
2126 2126 * we have to look at all of them for
2127 2127 * correctness.
2128 2128 */
2129 2129 error = plist_chkdupfd(fp, pdp, ps,
2130 2130 pollfdp, entry, &fdcnt);
2131 2131 if (error > 0) {
2132 2132 releasef(fd);
2133 2133 break;
2134 2134 }
2135 2135 if (error < 0) {
2136 2136 goto retry;
2137 2137 }
2138 2138 }
2139 2139 releasef(fd);
2140 2140 }
2141 2141 } else {
2142 2142 done = 1;
2143 2143 ASSERT(pollcheckrevents(ps, begin, end + 1, which));
2144 2144 }
2145 2145 }
2146 2146 if (!error) {
2147 2147 ASSERT(*fdcntp + fdcnt == pollscanrevents(pcp, pollfdp, nfds));
2148 2148 *fdcntp += fdcnt;
2149 2149 }
2150 2150 return (error);
2151 2151 }
2152 2152
2153 2153 /*
2154 2154 * Going through the poll list without much locking. Poll all fds and
2155 2155 * cache all valid fds in the pollcache.
2156 2156 */
2157 2157 int
2158 2158 pcacheset_cache_list(pollstate_t *ps, pollfd_t *fds, int *fdcntp, int which)
2159 2159 {
2160 2160 pollfd_t *pollfdp = ps->ps_pollfd;
2161 2161 pollcacheset_t *pcacheset = ps->ps_pcacheset;
2162 2162 pollfd_t *newfdlist;
2163 2163 int i;
2164 2164 int fd;
2165 2165 file_t *fp;
2166 2166 int error = 0;
2167 2167
2168 2168 ASSERT(MUTEX_HELD(&ps->ps_lock));
2169 2169 ASSERT(which < ps->ps_nsets);
2170 2170 ASSERT(pcacheset != NULL);
2171 2171 ASSERT(pcacheset[which].pcs_pollfd == NULL);
2172 2172 newfdlist = kmem_alloc(ps->ps_nfds * sizeof (pollfd_t), KM_SLEEP);
2173 2173 /*
2174 2174 * cache the new poll list in pollcachset.
2175 2175 */
2176 2176 bcopy(pollfdp, newfdlist, sizeof (pollfd_t) * ps->ps_nfds);
2177 2177
2178 2178 pcacheset[which].pcs_pollfd = newfdlist;
2179 2179 pcacheset[which].pcs_nfds = ps->ps_nfds;
2180 2180 pcacheset[which].pcs_usradr = (uintptr_t)fds;
2181 2181
2182 2182 /*
2183 2183 * We have saved a copy of current poll fd list in one pollcacheset.
2184 2184 * The 'revents' field of the new list is not yet set to 0. Loop
2185 2185 * through the new list just to do that is expensive. We do that
2186 2186 * while polling the list.
2187 2187 */
2188 2188 for (i = 0; i < ps->ps_nfds; i++) {
2189 2189 fd = pollfdp[i].fd;
2190 2190 /*
2191 2191 * We also filter out the illegal poll events in the event
2192 2192 * field for the cached poll list/set.
2193 2193 */
2194 2194 if (pollfdp[i].events & ~VALID_POLL_EVENTS) {
2195 2195 newfdlist[i].events = pollfdp[i].events =
2196 2196 pollfdp[i].events & VALID_POLL_EVENTS;
2197 2197 }
2198 2198 if (fd < 0) {
2199 2199 pollfdp[i].revents = 0;
2200 2200 continue;
2201 2201 }
2202 2202 if ((fp = getf(fd)) == NULL) {
2203 2203 pollfdp[i].revents = POLLNVAL;
2204 2204 /*
2205 2205 * invalidate this cache entry in the cached poll list
2206 2206 */
2207 2207 newfdlist[i].fd = -1;
2208 2208 (*fdcntp)++;
2209 2209 continue;
2210 2210 }
2211 2211 /*
2212 2212 * cache this fd.
2213 2213 */
2214 2214 error = pcache_insert(ps, fp, &pollfdp[i], fdcntp, (ssize_t)i,
2215 2215 which);
2216 2216 releasef(fd);
2217 2217 if (error) {
2218 2218 /*
2219 2219 * Here we are half way through caching a new
2220 2220 * poll list. Undo every thing.
2221 2221 */
2222 2222 pcacheset_remove_list(ps, pollfdp, 0, i, which, 0);
2223 2223 kmem_free(newfdlist, ps->ps_nfds * sizeof (pollfd_t));
2224 2224 pcacheset[which].pcs_pollfd = NULL;
2225 2225 pcacheset[which].pcs_usradr = NULL;
2226 2226 break;
2227 2227 }
2228 2228 }
2229 2229 return (error);
2230 2230 }
2231 2231
2232 2232 /*
2233 2233 * called by pollcacheclean() to set the fp NULL. It also sets polled events
2234 2234 * in pcacheset entries to a special events 'POLLCLOSED'. Do a pollwakeup to
2235 2235 * wake any sleeping poller, then remove the polldat from the driver.
2236 2236 * The routine is called with ps_pcachelock held.
2237 2237 */
2238 2238 void
2239 2239 pcache_clean_entry(pollstate_t *ps, int fd)
2240 2240 {
2241 2241 pollcache_t *pcp;
2242 2242 polldat_t *pdp;
2243 2243 int i;
2244 2244
2245 2245 ASSERT(ps != NULL);
2246 2246 ASSERT(MUTEX_HELD(&ps->ps_lock));
2247 2247 pcp = ps->ps_pcache;
2248 2248 ASSERT(pcp);
2249 2249 pdp = pcache_lookup_fd(pcp, fd);
2250 2250 ASSERT(pdp != NULL);
2251 2251 /*
2252 2252 * the corresponding fpollinfo in fi_list has been removed by
2253 2253 * a close on this fd. Reset the cached fp ptr here.
2254 2254 */
2255 2255 pdp->pd_fp = NULL;
2256 2256 /*
2257 2257 * XXX - This routine also touches data in pcacheset struct.
2258 2258 *
2259 2259 * set the event in cached poll lists to POLLCLOSED. This invalidate
2260 2260 * the cached poll fd entry in that poll list, which will force a
2261 2261 * removal of this cached entry in next poll(). The cleanup is done
2262 2262 * at the removal time.
2263 2263 */
2264 2264 ASSERT(pdp->pd_ref != NULL);
2265 2265 for (i = 0; i < ps->ps_nsets; i++) {
2266 2266 xref_t *refp;
2267 2267 pollcacheset_t *pcsp;
2268 2268
2269 2269 refp = &pdp->pd_ref[i];
2270 2270 if (refp->xf_refcnt) {
2271 2271 ASSERT(refp->xf_position >= 0);
2272 2272 pcsp = &ps->ps_pcacheset[i];
2273 2273 if (refp->xf_refcnt == 1) {
2274 2274 pcsp->pcs_pollfd[refp->xf_position].events =
2275 2275 (short)POLLCLOSED;
2276 2276 }
2277 2277 if (refp->xf_refcnt > 1) {
2278 2278 int j;
2279 2279 /*
2280 2280 * mark every matching entry in pcs_pollfd
2281 2281 */
2282 2282 for (j = refp->xf_position;
2283 2283 j < pcsp->pcs_nfds; j++) {
2284 2284 if (pcsp->pcs_pollfd[j].fd == fd) {
2285 2285 pcsp->pcs_pollfd[j].events =
2286 2286 (short)POLLCLOSED;
2287 2287 }
2288 2288 }
2289 2289 }
2290 2290 }
2291 2291 }
2292 2292 if (pdp->pd_php) {
2293 2293 pollwakeup(pdp->pd_php, POLLHUP);
2294 2294 pollhead_delete(pdp->pd_php, pdp);
2295 2295 pdp->pd_php = NULL;
2296 2296 }
2297 2297 }
2298 2298
2299 2299 void
2300 2300 pcache_wake_parents(pollcache_t *pcp)
2301 2301 {
2302 2302 pcachelink_t *pl, *pln;
2303 2303
2304 2304 ASSERT(MUTEX_HELD(&pcp->pc_lock));
2305 2305
2306 2306 for (pl = pcp->pc_parents; pl != NULL; pl = pln) {
2307 2307 mutex_enter(&pl->pcl_lock);
2308 2308 if (pl->pcl_state == PCL_VALID) {
2309 2309 ASSERT(pl->pcl_parent_pc != NULL);
2310 2310 cv_broadcast(&pl->pcl_parent_pc->pc_cv);
2311 2311 }
2312 2312 pln = pl->pcl_parent_next;
2313 2313 mutex_exit(&pl->pcl_lock);
2314 2314 }
2315 2315 }
2316 2316
2317 2317 /*
2318 2318 * Initialize thread pollstate structure.
2319 2319 * It will persist for the life of the thread, until it calls pollcleanup().
2320 2320 */
2321 2321 pollstate_t *
2322 2322 pollstate_create()
2323 2323 {
2324 2324 pollstate_t *ps = curthread->t_pollstate;
2325 2325
2326 2326 if (ps == NULL) {
2327 2327 /*
2328 2328 * This is the first time this thread has ever polled, so we
2329 2329 * have to create its pollstate structure.
2330 2330 */
2331 2331 ps = kmem_zalloc(sizeof (pollstate_t), KM_SLEEP);
2332 2332 ps->ps_nsets = POLLFDSETS;
2333 2333 ps->ps_pcacheset = pcacheset_create(ps->ps_nsets);
2334 2334 curthread->t_pollstate = ps;
2335 2335 } else {
2336 2336 ASSERT(ps->ps_depth == 0);
2337 2337 ASSERT(ps->ps_flags == 0);
2338 2338 ASSERT(ps->ps_pc_stack[0] == 0);
2339 2339 }
2340 2340 return (ps);
2341 2341 }
2342 2342
2343 2343 void
2344 2344 pollstate_destroy(pollstate_t *ps)
2345 2345 {
2346 2346 if (ps->ps_pollfd != NULL) {
2347 2347 kmem_free(ps->ps_pollfd, ps->ps_nfds * sizeof (pollfd_t));
2348 2348 ps->ps_pollfd = NULL;
2349 2349 }
2350 2350 if (ps->ps_pcache != NULL) {
2351 2351 pcache_destroy(ps->ps_pcache);
2352 2352 ps->ps_pcache = NULL;
2353 2353 }
2354 2354 pcacheset_destroy(ps->ps_pcacheset, ps->ps_nsets);
2355 2355 ps->ps_pcacheset = NULL;
2356 2356 if (ps->ps_dpbuf != NULL) {
2357 2357 kmem_free(ps->ps_dpbuf, ps->ps_dpbufsize);
2358 2358 ps->ps_dpbuf = NULL;
2359 2359 }
2360 2360 mutex_destroy(&ps->ps_lock);
2361 2361 kmem_free(ps, sizeof (pollstate_t));
2362 2362 }
2363 2363
2364 2364 static int
2365 2365 pollstate_contend(pollstate_t *ps, pollcache_t *pcp)
2366 2366 {
2367 2367 pollstate_t *rem, *next;
2368 2368 pollcache_t *desired_pc;
2369 2369 int result = 0, depth_total;
2370 2370
2371 2371 mutex_enter(&pollstate_contenders_lock);
2372 2372 /*
2373 2373 * There is a small chance that the pollcache of interest became
2374 2374 * available while we were waiting on the contenders lock.
2375 2375 */
2376 2376 if (mutex_tryenter(&pcp->pc_lock) != 0) {
2377 2377 goto out;
2378 2378 }
2379 2379
2380 2380 /*
2381 2381 * Walk the list of contended pollstates, searching for evidence of a
2382 2382 * deadlock condition.
2383 2383 */
2384 2384 depth_total = ps->ps_depth;
2385 2385 desired_pc = pcp;
2386 2386 for (rem = pollstate_contenders; rem != NULL; rem = next) {
2387 2387 int i, j;
2388 2388 next = rem->ps_contend_nextp;
2389 2389
2390 2390 /* Is this pollstate holding the pollcache of interest? */
2391 2391 for (i = 0; i < rem->ps_depth; i++) {
2392 2392 if (rem->ps_pc_stack[i] != desired_pc) {
2393 2393 continue;
2394 2394 }
2395 2395
2396 2396 /*
2397 2397 * The remote pollstate holds the pollcache lock we
2398 2398 * desire. If it is waiting on a pollcache we hold,
2399 2399 * then we can report the obvious deadlock.
2400 2400 */
2401 2401 ASSERT(rem->ps_contend_pc != NULL);
2402 2402 for (j = 0; j < ps->ps_depth; j++) {
2403 2403 if (rem->ps_contend_pc == ps->ps_pc_stack[j]) {
2404 2404 rem->ps_flags |= POLLSTATE_STALEMATE;
2405 2405 result = -1;
2406 2406 goto out;
2407 2407 }
2408 2408 }
2409 2409
2410 2410 /*
2411 2411 * The remote pollstate is not blocking on a pollcache
2412 2412 * which would deadlock against us. That pollcache
2413 2413 * may, however, be held by a pollstate which would
2414 2414 * result in a deadlock.
2415 2415 *
2416 2416 * To detect such a condition, we continue walking
2417 2417 * through the list using the pollcache blocking the
2418 2418 * remote thread as our new search target.
2419 2419 *
2420 2420 * Return to the front of pollstate_contenders since it
2421 2421 * is not ordered to guarantee complete dependency
2422 2422 * traversal. The below depth tracking places an upper
2423 2423 * bound on iterations.
2424 2424 */
2425 2425 desired_pc = rem->ps_contend_pc;
2426 2426 next = pollstate_contenders;
2427 2427
2428 2428 /*
2429 2429 * The recursion depth of the remote pollstate is used
2430 2430 * to calculate a final depth for the local /dev/poll
2431 2431 * recursion, since those locks will be acquired
2432 2432 * eventually. If that value exceeds the defined
2433 2433 * limit, we can report the failure now instead of
2434 2434 * recursing to that failure depth.
2435 2435 */
2436 2436 depth_total += (rem->ps_depth - i);
2437 2437 if (depth_total >= POLLMAXDEPTH) {
2438 2438 result = -1;
2439 2439 goto out;
2440 2440 }
2441 2441 }
2442 2442 }
2443 2443
2444 2444 /*
2445 2445 * No deadlock partner was found. The only course of action is to
2446 2446 * record ourself as a contended pollstate and wait for the pollcache
2447 2447 * mutex to become available.
2448 2448 */
2449 2449 ps->ps_contend_pc = pcp;
2450 2450 ps->ps_contend_nextp = pollstate_contenders;
2451 2451 ps->ps_contend_pnextp = &pollstate_contenders;
2452 2452 if (pollstate_contenders != NULL) {
2453 2453 pollstate_contenders->ps_contend_pnextp =
2454 2454 &ps->ps_contend_nextp;
2455 2455 }
2456 2456 pollstate_contenders = ps;
2457 2457
2458 2458 mutex_exit(&pollstate_contenders_lock);
2459 2459 mutex_enter(&pcp->pc_lock);
2460 2460 mutex_enter(&pollstate_contenders_lock);
2461 2461
2462 2462 /*
2463 2463 * Our acquisition of the pollcache mutex may be due to another thread
2464 2464 * giving up in the face of deadlock with us. If that is the case,
2465 2465 * we too should report the failure.
2466 2466 */
2467 2467 if ((ps->ps_flags & POLLSTATE_STALEMATE) != 0) {
2468 2468 result = -1;
2469 2469 ps->ps_flags &= ~POLLSTATE_STALEMATE;
2470 2470 mutex_exit(&pcp->pc_lock);
2471 2471 }
2472 2472
2473 2473 /* Remove ourself from the contenders list. */
2474 2474 if (ps->ps_contend_nextp != NULL) {
2475 2475 ps->ps_contend_nextp->ps_contend_pnextp =
2476 2476 ps->ps_contend_pnextp;
2477 2477 }
2478 2478 *ps->ps_contend_pnextp = ps->ps_contend_nextp;
2479 2479 ps->ps_contend_pc = NULL;
2480 2480 ps->ps_contend_nextp = NULL;
2481 2481 ps->ps_contend_pnextp = NULL;
2482 2482
2483 2483 out:
2484 2484 mutex_exit(&pollstate_contenders_lock);
2485 2485 return (result);
2486 2486 }
2487 2487
2488 2488 int
2489 2489 pollstate_enter(pollcache_t *pcp)
2490 2490 {
2491 2491 pollstate_t *ps = curthread->t_pollstate;
2492 2492 int i;
2493 2493
2494 2494 if (ps == NULL) {
2495 2495 /*
2496 2496 * The thread pollstate may not be initialized if VOP_POLL is
2497 2497 * called on a recursion-enabled /dev/poll handle from outside
2498 2498 * the poll() or /dev/poll codepaths.
2499 2499 */
2500 2500 return (PSE_FAIL_POLLSTATE);
2501 2501 }
2502 2502 if (ps->ps_depth >= POLLMAXDEPTH) {
2503 2503 return (PSE_FAIL_DEPTH);
2504 2504 }
2505 2505 /*
2506 2506 * Check the desired pollcache against pollcaches we already have
2507 2507 * locked. Such a loop is the most simple deadlock scenario.
2508 2508 */
2509 2509 for (i = 0; i < ps->ps_depth; i++) {
2510 2510 if (ps->ps_pc_stack[i] == pcp) {
2511 2511 return (PSE_FAIL_LOOP);
2512 2512 }
2513 2513 }
2514 2514 ASSERT(ps->ps_pc_stack[i] == NULL);
2515 2515
2516 2516 if (ps->ps_depth == 0) {
2517 2517 /* Locking initial the pollcache requires no caution */
2518 2518 mutex_enter(&pcp->pc_lock);
2519 2519 } else if (mutex_tryenter(&pcp->pc_lock) == 0) {
2520 2520 if (pollstate_contend(ps, pcp) != 0) {
2521 2521 /* This pollcache cannot safely be locked. */
2522 2522 return (PSE_FAIL_DEADLOCK);
2523 2523 }
2524 2524 }
2525 2525
2526 2526 ps->ps_pc_stack[ps->ps_depth++] = pcp;
2527 2527 return (PSE_SUCCESS);
2528 2528 }
2529 2529
2530 2530 void
2531 2531 pollstate_exit(pollcache_t *pcp)
2532 2532 {
2533 2533 pollstate_t *ps = curthread->t_pollstate;
2534 2534
2535 2535 VERIFY(ps != NULL);
2536 2536 VERIFY(ps->ps_pc_stack[ps->ps_depth - 1] == pcp);
2537 2537
2538 2538 mutex_exit(&pcp->pc_lock);
2539 2539 ps->ps_pc_stack[--ps->ps_depth] = NULL;
2540 2540 VERIFY(ps->ps_depth >= 0);
2541 2541 }
2542 2542
2543 2543
2544 2544 /*
2545 2545 * We are holding the appropriate uf_lock entering this routine.
2546 2546 * Bump up the ps_busy count to prevent the thread from exiting.
2547 2547 */
2548 2548 void
2549 2549 pollblockexit(fpollinfo_t *fpip)
2550 2550 {
2551 2551 for (; fpip; fpip = fpip->fp_next) {
2552 2552 pollcache_t *pcp = fpip->fp_thread->t_pollstate->ps_pcache;
2553 2553
2554 2554 mutex_enter(&pcp->pc_no_exit);
2555 2555 pcp->pc_busy++; /* prevents exit()'s */
2556 2556 mutex_exit(&pcp->pc_no_exit);
2557 2557 }
2558 2558 }
2559 2559
2560 2560 /*
2561 2561 * Complete phase 2 of cached poll fd cleanup. Call pcache_clean_entry to mark
2562 2562 * the pcacheset events field POLLCLOSED to force the next poll() to remove
2563 2563 * this cache entry. We can't clean the polldat entry clean up here because
2564 2564 * lwp block in poll() needs the info to return. Wakeup anyone blocked in
2565 2565 * poll and let exiting lwp go. No lock is help upon entry. So it's OK for
2566 2566 * pcache_clean_entry to call pollwakeup().
2567 2567 */
2568 2568 void
2569 2569 pollcacheclean(fpollinfo_t *fip, int fd)
2570 2570 {
2571 2571 struct fpollinfo *fpip, *fpip2;
2572 2572
2573 2573 fpip = fip;
2574 2574 while (fpip) {
2575 2575 pollstate_t *ps = fpip->fp_thread->t_pollstate;
2576 2576 pollcache_t *pcp = ps->ps_pcache;
2577 2577
2578 2578 mutex_enter(&ps->ps_lock);
2579 2579 pcache_clean_entry(ps, fd);
2580 2580 mutex_exit(&ps->ps_lock);
2581 2581 mutex_enter(&pcp->pc_no_exit);
2582 2582 pcp->pc_busy--;
2583 2583 if (pcp->pc_busy == 0) {
2584 2584 /*
2585 2585 * Wakeup the thread waiting in
2586 2586 * thread_exit().
2587 2587 */
2588 2588 cv_signal(&pcp->pc_busy_cv);
2589 2589 }
2590 2590 mutex_exit(&pcp->pc_no_exit);
2591 2591
2592 2592 fpip2 = fpip;
2593 2593 fpip = fpip->fp_next;
2594 2594 kmem_free(fpip2, sizeof (fpollinfo_t));
2595 2595 }
2596 2596 }
2597 2597
2598 2598 /*
2599 2599 * one of the cache line's counter is wrapping around. Reset all cache line
2600 2600 * counters to zero except one. This is simplistic, but probably works
2601 2601 * effectively.
2602 2602 */
2603 2603 void
2604 2604 pcacheset_reset_count(pollstate_t *ps, int index)
2605 2605 {
2606 2606 int i;
2607 2607
2608 2608 ASSERT(MUTEX_HELD(&ps->ps_lock));
2609 2609 for (i = 0; i < ps->ps_nsets; i++) {
2610 2610 if (ps->ps_pcacheset[i].pcs_pollfd != NULL) {
2611 2611 ps->ps_pcacheset[i].pcs_count = 0;
2612 2612 }
2613 2613 }
2614 2614 ps->ps_pcacheset[index].pcs_count = 1;
2615 2615 }
2616 2616
2617 2617 /*
2618 2618 * this routine implements poll cache list replacement policy.
2619 2619 * It is currently choose the "least used".
2620 2620 */
2621 2621 int
2622 2622 pcacheset_replace(pollstate_t *ps)
2623 2623 {
2624 2624 int i;
2625 2625 int index = 0;
2626 2626
2627 2627 ASSERT(MUTEX_HELD(&ps->ps_lock));
2628 2628 for (i = 1; i < ps->ps_nsets; i++) {
2629 2629 if (ps->ps_pcacheset[index].pcs_count >
2630 2630 ps->ps_pcacheset[i].pcs_count) {
2631 2631 index = i;
2632 2632 }
2633 2633 }
2634 2634 ps->ps_pcacheset[index].pcs_count = 0;
2635 2635 return (index);
2636 2636 }
2637 2637
2638 2638 /*
2639 2639 * this routine is called by strclose to remove remaining polldat struct on
2640 2640 * the pollhead list of the device being closed. There are two reasons as why
2641 2641 * the polldat structures still remain on the pollhead list:
2642 2642 *
2643 2643 * (1) The layered device(e.g.the console driver).
2644 2644 * In this case, the existence of a polldat implies that the thread putting
2645 2645 * the polldat on this list has not exited yet. Before the thread exits, it
2646 2646 * will have to hold this pollhead lock to remove the polldat. So holding the
2647 2647 * pollhead lock here effectively prevents the thread which put the polldat
2648 2648 * on this list from exiting.
2649 2649 *
2650 2650 * (2) /dev/poll.
2651 2651 * When a polled fd is cached in /dev/poll, its polldat will remain on the
2652 2652 * pollhead list if the process has not done a POLLREMOVE before closing the
2653 2653 * polled fd. We just unlink it here.
2654 2654 */
2655 2655 void
2656 2656 pollhead_clean(pollhead_t *php)
2657 2657 {
2658 2658 polldat_t *pdp;
2659 2659
2660 2660 /*
2661 2661 * In case(1), while we must prevent the thread in question from
2662 2662 * exiting, we must also obey the proper locking order, i.e.
2663 2663 * (ps_lock -> phlock).
2664 2664 */
2665 2665 PH_ENTER(php);
2666 2666 while (php->ph_list != NULL) {
2667 2667 pollstate_t *ps;
2668 2668 pollcache_t *pcp;
2669 2669
2670 2670 pdp = php->ph_list;
2671 2671 ASSERT(pdp->pd_php == php);
2672 2672 if (pdp->pd_thread == NULL) {
2673 2673 /*
2674 2674 * This is case(2). Since the ph_lock is sufficient
2675 2675 * to synchronize this lwp with any other /dev/poll
2676 2676 * lwp, just unlink the polldat.
2677 2677 */
2678 2678 php->ph_list = pdp->pd_next;
2679 2679 pdp->pd_php = NULL;
2680 2680 pdp->pd_next = NULL;
2681 2681 continue;
2682 2682 }
2683 2683 ps = pdp->pd_thread->t_pollstate;
2684 2684 ASSERT(ps != NULL);
2685 2685 pcp = pdp->pd_pcache;
2686 2686 ASSERT(pcp != NULL);
2687 2687 mutex_enter(&pcp->pc_no_exit);
2688 2688 pcp->pc_busy++; /* prevents exit()'s */
2689 2689 mutex_exit(&pcp->pc_no_exit);
2690 2690 /*
2691 2691 * Now get the locks in proper order to avoid deadlock.
2692 2692 */
2693 2693 PH_EXIT(php);
2694 2694 mutex_enter(&ps->ps_lock);
2695 2695 /*
2696 2696 * while we dropped the pollhead lock, the element could be
2697 2697 * taken off the list already.
2698 2698 */
2699 2699 PH_ENTER(php);
2700 2700 if (pdp->pd_php == php) {
2701 2701 ASSERT(pdp == php->ph_list);
2702 2702 php->ph_list = pdp->pd_next;
2703 2703 pdp->pd_php = NULL;
2704 2704 pdp->pd_next = NULL;
2705 2705 }
2706 2706 PH_EXIT(php);
2707 2707 mutex_exit(&ps->ps_lock);
2708 2708 mutex_enter(&pcp->pc_no_exit);
2709 2709 pcp->pc_busy--;
2710 2710 if (pcp->pc_busy == 0) {
2711 2711 /*
2712 2712 * Wakeup the thread waiting in
2713 2713 * thread_exit().
2714 2714 */
2715 2715 cv_signal(&pcp->pc_busy_cv);
2716 2716 }
2717 2717 mutex_exit(&pcp->pc_no_exit);
2718 2718 PH_ENTER(php);
2719 2719 }
2720 2720 PH_EXIT(php);
2721 2721 }
2722 2722
2723 2723 /*
2724 2724 * The remove_list is called to cleanup a partially cached 'current' list or
2725 2725 * to remove a partial list which is no longer cached. The flag value of 1
2726 2726 * indicates the second case.
2727 2727 */
2728 2728 void
2729 2729 pcacheset_remove_list(pollstate_t *ps, pollfd_t *pollfdp, int start, int end,
2730 2730 int cacheindex, int flag)
2731 2731 {
2732 2732 int i;
2733 2733
2734 2734 ASSERT(MUTEX_HELD(&ps->ps_lock));
2735 2735 for (i = start; i < end; i++) {
2736 2736 if ((pollfdp[i].fd >= 0) &&
2737 2737 (flag || !(pollfdp[i].revents & POLLNVAL))) {
2738 2738 if (pcache_delete_fd(ps, pollfdp[i].fd, i, cacheindex,
2739 2739 (uint_t)pollfdp[i].events)) {
2740 2740 int j;
2741 2741 int fd = pollfdp[i].fd;
2742 2742
2743 2743 for (j = i + 1; j < end; j++) {
2744 2744 if (pollfdp[j].fd == fd) {
2745 2745 pcache_update_xref(
2746 2746 ps->ps_pcache, fd,
2747 2747 (ssize_t)j, cacheindex);
2748 2748 break;
2749 2749 }
2750 2750 }
2751 2751 ASSERT(j <= end);
2752 2752 }
2753 2753 }
2754 2754 }
2755 2755 }
2756 2756
2757 2757 #ifdef DEBUG
2758 2758
2759 2759 #include<sys/strsubr.h>
2760 2760 /*
2761 2761 * make sure curthread is not on anyone's pollhead list any more.
2762 2762 */
2763 2763 static void
2764 2764 pollcheckphlist()
2765 2765 {
2766 2766 int i;
2767 2767 file_t *fp;
2768 2768 uf_entry_t *ufp;
2769 2769 uf_info_t *fip = P_FINFO(curproc);
2770 2770 struct stdata *stp;
2771 2771 polldat_t *pdp;
2772 2772
2773 2773 mutex_enter(&fip->fi_lock);
2774 2774 for (i = 0; i < fip->fi_nfiles; i++) {
2775 2775 UF_ENTER(ufp, fip, i);
2776 2776 if ((fp = ufp->uf_file) != NULL) {
2777 2777 if ((stp = fp->f_vnode->v_stream) != NULL) {
2778 2778 PH_ENTER(&stp->sd_pollist);
2779 2779 pdp = stp->sd_pollist.ph_list;
2780 2780 while (pdp) {
2781 2781 ASSERT(pdp->pd_thread != curthread);
2782 2782 pdp = pdp->pd_next;
2783 2783 }
2784 2784 PH_EXIT(&stp->sd_pollist);
2785 2785 }
2786 2786 }
2787 2787 UF_EXIT(ufp);
2788 2788 }
2789 2789 mutex_exit(&fip->fi_lock);
2790 2790 }
2791 2791
2792 2792 /*
2793 2793 * for resolved set poll list, the xref info in the pcache should be
2794 2794 * consistent with this poll list.
2795 2795 */
2796 2796 static int
2797 2797 pollcheckxref(pollstate_t *ps, int cacheindex)
2798 2798 {
2799 2799 pollfd_t *pollfdp = ps->ps_pcacheset[cacheindex].pcs_pollfd;
2800 2800 pollcache_t *pcp = ps->ps_pcache;
2801 2801 polldat_t *pdp;
2802 2802 int i;
2803 2803 xref_t *refp;
2804 2804
2805 2805 for (i = 0; i < ps->ps_pcacheset[cacheindex].pcs_nfds; i++) {
2806 2806 if (pollfdp[i].fd < 0) {
2807 2807 continue;
2808 2808 }
2809 2809 pdp = pcache_lookup_fd(pcp, pollfdp[i].fd);
2810 2810 ASSERT(pdp != NULL);
2811 2811 ASSERT(pdp->pd_ref != NULL);
2812 2812 refp = &pdp->pd_ref[cacheindex];
2813 2813 if (refp->xf_position >= 0) {
2814 2814 ASSERT(refp->xf_refcnt >= 1);
2815 2815 ASSERT(pollfdp[refp->xf_position].fd == pdp->pd_fd);
2816 2816 if (refp->xf_refcnt > 1) {
2817 2817 int j;
2818 2818 int count = 0;
2819 2819
2820 2820 for (j = refp->xf_position;
2821 2821 j < ps->ps_pcacheset[cacheindex].pcs_nfds;
2822 2822 j++) {
2823 2823 if (pollfdp[j].fd == pdp->pd_fd) {
2824 2824 count++;
2825 2825 }
2826 2826 }
2827 2827 ASSERT(count == refp->xf_refcnt);
2828 2828 }
2829 2829 }
2830 2830 }
2831 2831 return (1);
2832 2832 }
2833 2833
2834 2834 /*
2835 2835 * For every cached pollfd, its polldat struct should be consistent with
2836 2836 * what is in the pcacheset lists.
2837 2837 */
2838 2838 static void
2839 2839 checkpolldat(pollstate_t *ps)
2840 2840 {
2841 2841 pollcache_t *pcp = ps->ps_pcache;
2842 2842 polldat_t **hashtbl;
2843 2843 int i;
2844 2844
2845 2845 hashtbl = pcp->pc_hash;
2846 2846 for (i = 0; i < pcp->pc_hashsize; i++) {
2847 2847 polldat_t *pdp;
2848 2848
2849 2849 for (pdp = hashtbl[i]; pdp; pdp = pdp->pd_hashnext) {
2850 2850 ASSERT(pdp->pd_ref != NULL);
2851 2851 if (pdp->pd_count > 0) {
2852 2852 xref_t *refp;
2853 2853 int j;
2854 2854 pollcacheset_t *pcsp;
2855 2855 pollfd_t *pollfd;
2856 2856
2857 2857 for (j = 0; j < ps->ps_nsets; j++) {
2858 2858 refp = &pdp->pd_ref[j];
2859 2859 if (refp->xf_refcnt > 0) {
2860 2860 pcsp = &ps->ps_pcacheset[j];
2861 2861 ASSERT(refp->xf_position < pcsp->pcs_nfds);
2862 2862 pollfd = pcsp->pcs_pollfd;
2863 2863 ASSERT(pdp->pd_fd == pollfd[refp->xf_position].fd);
2864 2864 }
2865 2865 }
2866 2866 }
2867 2867 }
2868 2868 }
2869 2869 }
2870 2870
2871 2871 /*
2872 2872 * every wfd element on ph_list must have a corresponding fpollinfo on the
2873 2873 * uf_fpollinfo list. This is a variation of infpollinfo() w/o holding locks.
2874 2874 */
2875 2875 void
2876 2876 checkwfdlist(vnode_t *vp, fpollinfo_t *fpip)
2877 2877 {
2878 2878 stdata_t *stp;
2879 2879 polldat_t *pdp;
2880 2880 fpollinfo_t *fpip2;
2881 2881
2882 2882 if ((stp = vp->v_stream) == NULL) {
2883 2883 return;
2884 2884 }
2885 2885 PH_ENTER(&stp->sd_pollist);
2886 2886 for (pdp = stp->sd_pollist.ph_list; pdp; pdp = pdp->pd_next) {
2887 2887 if (pdp->pd_thread != NULL &&
2888 2888 pdp->pd_thread->t_procp == curthread->t_procp) {
2889 2889 for (fpip2 = fpip; fpip2; fpip2 = fpip2->fp_next) {
2890 2890 if (pdp->pd_thread == fpip2->fp_thread) {
2891 2891 break;
2892 2892 }
2893 2893 }
2894 2894 ASSERT(fpip2 != NULL);
2895 2895 }
2896 2896 }
2897 2897 PH_EXIT(&stp->sd_pollist);
2898 2898 }
2899 2899
2900 2900 /*
2901 2901 * For each cached fd whose bit is not set in bitmap, its revents field in
2902 2902 * current poll list should be 0.
2903 2903 */
2904 2904 static int
2905 2905 pollcheckrevents(pollstate_t *ps, int begin, int end, int cacheindex)
2906 2906 {
2907 2907 pollcache_t *pcp = ps->ps_pcache;
2908 2908 pollfd_t *pollfdp = ps->ps_pollfd;
2909 2909 int i;
2910 2910
2911 2911 for (i = begin; i < end; i++) {
2912 2912 polldat_t *pdp;
2913 2913
2914 2914 ASSERT(!BT_TEST(pcp->pc_bitmap, i));
2915 2915 pdp = pcache_lookup_fd(pcp, i);
2916 2916 if (pdp && pdp->pd_fp != NULL) {
2917 2917 xref_t *refp;
2918 2918 int entry;
2919 2919
2920 2920 ASSERT(pdp->pd_ref != NULL);
2921 2921 refp = &pdp->pd_ref[cacheindex];
2922 2922 if (refp->xf_refcnt == 0) {
2923 2923 continue;
2924 2924 }
2925 2925 entry = refp->xf_position;
2926 2926 ASSERT(entry >= 0);
2927 2927 ASSERT(pollfdp[entry].revents == 0);
2928 2928 if (refp->xf_refcnt > 1) {
2929 2929 int j;
2930 2930
2931 2931 for (j = entry + 1; j < ps->ps_nfds; j++) {
2932 2932 if (pollfdp[j].fd == i) {
2933 2933 ASSERT(pollfdp[j].revents == 0);
2934 2934 }
2935 2935 }
2936 2936 }
2937 2937 }
2938 2938 }
2939 2939 return (1);
2940 2940 }
2941 2941
2942 2942 #endif /* DEBUG */
2943 2943
2944 2944 pollcache_t *
2945 2945 pcache_alloc()
2946 2946 {
2947 2947 return (kmem_zalloc(sizeof (pollcache_t), KM_SLEEP));
2948 2948 }
2949 2949
2950 2950 void
2951 2951 pcache_create(pollcache_t *pcp, nfds_t nfds)
2952 2952 {
2953 2953 size_t mapsize;
2954 2954
2955 2955 /*
2956 2956 * allocate enough bits for the poll fd list
2957 2957 */
2958 2958 if ((mapsize = POLLMAPCHUNK) <= nfds) {
2959 2959 mapsize = (nfds + POLLMAPCHUNK - 1) & ~(POLLMAPCHUNK - 1);
2960 2960 }
2961 2961 pcp->pc_bitmap = kmem_zalloc((mapsize / BT_NBIPUL) * sizeof (ulong_t),
2962 2962 KM_SLEEP);
2963 2963 pcp->pc_mapsize = mapsize;
2964 2964 /*
2965 2965 * The hash size is at least POLLHASHCHUNKSZ. If user polls a large
2966 2966 * number of fd to start with, allocate a bigger hash table (to the
2967 2967 * nearest multiple of POLLHASHCHUNKSZ) because dynamically growing a
2968 2968 * hash table is expensive.
2969 2969 */
2970 2970 if (nfds < POLLHASHCHUNKSZ) {
2971 2971 pcp->pc_hashsize = POLLHASHCHUNKSZ;
2972 2972 } else {
2973 2973 pcp->pc_hashsize = (nfds + POLLHASHCHUNKSZ - 1) &
2974 2974 ~(POLLHASHCHUNKSZ - 1);
2975 2975 }
2976 2976 pcp->pc_hash = kmem_zalloc(pcp->pc_hashsize * sizeof (polldat_t *),
2977 2977 KM_SLEEP);
2978 2978 }
2979 2979
2980 2980 void
2981 2981 pcache_destroy(pollcache_t *pcp)
2982 2982 {
2983 2983 polldat_t **hashtbl;
2984 2984 int i;
2985 2985
2986 2986 hashtbl = pcp->pc_hash;
2987 2987 for (i = 0; i < pcp->pc_hashsize; i++) {
2988 2988 if (hashtbl[i] != NULL) {
2989 2989 polldat_t *pdp, *pdp2;
2990 2990
2991 2991 pdp = hashtbl[i];
2992 2992 while (pdp != NULL) {
2993 2993 pdp2 = pdp->pd_hashnext;
2994 2994 if (pdp->pd_ref != NULL) {
2995 2995 kmem_free(pdp->pd_ref, sizeof (xref_t) *
2996 2996 pdp->pd_nsets);
2997 2997 }
2998 2998 kmem_free(pdp, sizeof (polldat_t));
2999 2999 pdp = pdp2;
3000 3000 pcp->pc_fdcount--;
3001 3001 }
3002 3002 }
3003 3003 }
3004 3004 ASSERT(pcp->pc_fdcount == 0);
3005 3005 kmem_free(pcp->pc_hash, sizeof (polldat_t *) * pcp->pc_hashsize);
3006 3006 kmem_free(pcp->pc_bitmap,
3007 3007 sizeof (ulong_t) * (pcp->pc_mapsize/BT_NBIPUL));
3008 3008 mutex_destroy(&pcp->pc_no_exit);
3009 3009 mutex_destroy(&pcp->pc_lock);
3010 3010 cv_destroy(&pcp->pc_cv);
3011 3011 cv_destroy(&pcp->pc_busy_cv);
3012 3012 kmem_free(pcp, sizeof (pollcache_t));
3013 3013 }
3014 3014
3015 3015 pollcacheset_t *
3016 3016 pcacheset_create(int nsets)
3017 3017 {
3018 3018 return (kmem_zalloc(sizeof (pollcacheset_t) * nsets, KM_SLEEP));
3019 3019 }
3020 3020
3021 3021 void
3022 3022 pcacheset_destroy(pollcacheset_t *pcsp, int nsets)
3023 3023 {
3024 3024 int i;
3025 3025
3026 3026 for (i = 0; i < nsets; i++) {
3027 3027 if (pcsp[i].pcs_pollfd != NULL) {
3028 3028 kmem_free(pcsp[i].pcs_pollfd, pcsp[i].pcs_nfds *
3029 3029 sizeof (pollfd_t));
3030 3030 }
3031 3031 }
3032 3032 kmem_free(pcsp, sizeof (pollcacheset_t) * nsets);
3033 3033 }
3034 3034
3035 3035 /*
3036 3036 * Check each duplicated poll fd in the poll list. It may be necessary to
3037 3037 * VOP_POLL the same fd again using different poll events. getf() has been
3038 3038 * done by caller. This routine returns 0 if it can sucessfully process the
3039 3039 * entire poll fd list. It returns -1 if underlying vnode has changed during
3040 3040 * a VOP_POLL, in which case the caller has to repoll. It returns a positive
3041 3041 * value if VOP_POLL failed.
3042 3042 */
3043 3043 static int
3044 3044 plist_chkdupfd(file_t *fp, polldat_t *pdp, pollstate_t *psp, pollfd_t *pollfdp,
3045 3045 int entry, int *fdcntp)
3046 3046 {
3047 3047 int i;
3048 3048 int fd;
3049 3049 nfds_t nfds = psp->ps_nfds;
3050 3050
3051 3051 fd = pollfdp[entry].fd;
3052 3052 for (i = entry + 1; i < nfds; i++) {
3053 3053 if (pollfdp[i].fd == fd) {
3054 3054 if (pollfdp[i].events == pollfdp[entry].events) {
3055 3055 if ((pollfdp[i].revents =
3056 3056 pollfdp[entry].revents) != 0) {
3057 3057 (*fdcntp)++;
3058 3058 }
3059 3059 } else {
3060 3060
3061 3061 int error;
3062 3062 pollhead_t *php;
3063 3063 pollcache_t *pcp = psp->ps_pcache;
3064 3064
3065 3065 /*
3066 3066 * the events are different. VOP_POLL on this
3067 3067 * fd so that we don't miss any revents.
3068 3068 */
3069 3069 php = NULL;
3070 3070 ASSERT(curthread->t_pollcache == NULL);
3071 3071 error = VOP_POLL(fp->f_vnode,
3072 3072 pollfdp[i].events, 0,
3073 3073 &pollfdp[i].revents, &php, NULL);
3074 3074 if (error) {
3075 3075 return (error);
3076 3076 }
3077 3077 /*
3078 3078 * layered devices(e.g. console driver)
3079 3079 * may change the vnode and thus the pollhead
3080 3080 * pointer out from underneath us.
3081 3081 */
3082 3082 if (php != NULL && pdp->pd_php != NULL &&
3083 3083 php != pdp->pd_php) {
3084 3084 pollhead_delete(pdp->pd_php, pdp);
3085 3085 pdp->pd_php = php;
3086 3086 pollhead_insert(php, pdp);
3087 3087 /*
3088 3088 * We could have missed a wakeup on the
3089 3089 * new target device. Make sure the new
3090 3090 * target gets polled once.
3091 3091 */
3092 3092 BT_SET(pcp->pc_bitmap, fd);
3093 3093 return (-1);
3094 3094 }
3095 3095 if (pollfdp[i].revents) {
3096 3096 (*fdcntp)++;
3097 3097 }
3098 3098 }
3099 3099 }
3100 3100 }
3101 3101 return (0);
3102 3102 }
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